explain xkcd - User contributions [en]

2604: Frankenstein Captcha

2022-04-08T17:17:00Z

172.70.34.165: /* Transcript */

{{comic
| number = 2604
| date = April 8, 2022
| title = Frankenstein Captcha
| image = frankenstein_captcha.png
| titletext = The distinction between a ship and a boat is a line drawn in water.
}}

==Explanation==
{{incomplete|Created by Rated Argh -Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic strip is a play on the meanings (and misunderstanding) of the name "Frankenstein". ''{{w|Frankenstein}}; or, the Modern Prometheus'' is a 1818 novel by Mary Shelley about a medical student called Victor Frankenstein who creates an artificial life-form. The man he creates is unnamed in the book, and strictly speaking is properly known as "Frankenstein's ''monster''" (or perhaps "creation" or "son"), but is often erroneously called "Frankenstein" himself.

The Captcha shown in the comic instructs the user to select all tiles containing Frankenstein. The tiles include both a reanimated corpse (frequently called Frankenstein but actually called Frankenstein's monster) and a scientist yelling "it's alive" who is clearly intended to be Victor Frankenstein. The problem arises from the contrast between the generally accepted and technically accurate definitions of the term: Frankenstein. The correct answer to the Captcha is just the left square of the third row, unless you follow comic [[1589]].

If the images in the squares are from the famous {{w|Frankenstein (1931 film)|1931 film}} starring {{w|Boris Karloff}} as The Monster, then perhaps they could be correctly said to be "containing ''Frankenstein''", that is, the work.

This comic strip could also reference [[1897]], which would imply that someone had actually created a Frankenstein's monster.

Many of the other tiles appear to be pictures of entities that inspire similar <s>pedanticism</s> pedantry. For example, there is a picture of a turtle (or possibly a tortoise), a ship (or possibly a boat), Link (the protagonist of the {{w|Legend of Zelda}} video games, who may be erroneously referred to as Zelda), a pond (or possibly a lake), a tomato (often subject to the ''fruit or vegetable'' debate), an erupting volcano (with lava, or is it magma?), and a planet (or is it a dwarf planet?).

Other tiles seem to be inspired by images commonly occuring in actual captchas, like the STOP sign or the traffic light.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

Pictured (Starting from top left)

Row 1
* Tortoise (or turtle)
* Ship (or boat)
* Frankenstein's monster waking up (often mistaken as Frankenstein)
* Link from Legend of Zelda series (often mistaken as Zelda, aka Toon Link in SSB)
Row 2
* Fata morgana (or mirage)
* Megan
* Lava (or magma)
* Tomato (fruit vs vegetable)
Row 3
* Victor Frankenstein saying "It's alive"
* Sandwich
* Stop sign
* Girl running away from Frankenstein's monster
Row 4
* Rocket (spaceship) flying by Pluto (dwarf planet)
* Cueball and Ponytail standing next to each other
* Traffic light (also called a stoplight, possibly mistaken as stop sign?)
* Frankenstein's monster

{{comic discussion}}

2604: Frankenstein Captcha

2022-04-08T17:15:59Z

172.70.34.165: /* Transcript */

{{comic
| number = 2604
| date = April 8, 2022
| title = Frankenstein Captcha
| image = frankenstein_captcha.png
| titletext = The distinction between a ship and a boat is a line drawn in water.
}}

==Explanation==
{{incomplete|Created by Rated Argh -Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic strip is a play on the meanings (and misunderstanding) of the name "Frankenstein". ''{{w|Frankenstein}}; or, the Modern Prometheus'' is a 1818 novel by Mary Shelley about a medical student called Victor Frankenstein who creates an artificial life-form. The man he creates is unnamed in the book, and strictly speaking is properly known as "Frankenstein's ''monster''" (or perhaps "creation" or "son"), but is often erroneously called "Frankenstein" himself.

The Captcha shown in the comic instructs the user to select all tiles containing Frankenstein. The tiles include both a reanimated corpse (frequently called Frankenstein but actually called Frankenstein's monster) and a scientist yelling "it's alive" who is clearly intended to be Victor Frankenstein. The problem arises from the contrast between the generally accepted and technically accurate definitions of the term: Frankenstein. The correct answer to the Captcha is just the left square of the third row, unless you follow comic [[1589]].

If the images in the squares are from the famous {{w|Frankenstein (1931 film)|1931 film}} starring {{w|Boris Karloff}} as The Monster, then perhaps they could be correctly said to be "containing ''Frankenstein''", that is, the work.

This comic strip could also reference [[1897]], which would imply that someone had actually created a Frankenstein's monster.

Many of the other tiles appear to be pictures of entities that inspire similar <s>pedanticism</s> pedantry. For example, there is a picture of a turtle (or possibly a tortoise), a ship (or possibly a boat), Link (the protagonist of the {{w|Legend of Zelda}} video games, who may be erroneously referred to as Zelda), a pond (or possibly a lake), a tomato (often subject to the ''fruit or vegetable'' debate), an erupting volcano (with lava, or is it magma?), and a planet (or is it a dwarf planet?).

Other tiles seem to be inspired by images commonly occuring in actual captchas, like the STOP sign or the traffic light.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

Pictured (Starting from top left)

Row 1
* Tortoise (or turtle)
* Ship (or boat)
* Frankenstein's monster waking up (often mistaken as Frankenstein)
* Link from Legend of Zelda series (often mistaken as Zelda, aka Toon Link in SSB)
Row 2
* Mirage of a lake (or pond)
* Megan
* Lava (or magma)
* Tomato (fruit vs vegetable)
Row 3
* Victor Frankenstein saying "It's alive"
* Sandwich
* Stop sign
* Girl running away from Frankenstein's monster
Row 4
* Rocket (spaceship) flying by Pluto (dwarf planet)
* Cueball and Ponytail standing next to each other
* Traffic light (also called a stoplight, possibly mistaken as stop sign?)
* Frankenstein's monster

{{comic discussion}}

1491: Stories of the Past and Future

2022-02-14T23:02:22Z

172.70.34.165: /* Explanation */

{{comic
| number = 1491
| date = February 25, 2015
| title = Stories of the Past and Future
| image = stories_of_the_past_and_future.png
| titletext = Little-known fact: The 'Dawn of Man' opening sequence in 2001 cuts away seconds before the Flintstones theme becomes recognizable.
}}
*A [http://xkcd.com/1491/large/ larger version] of this image can be found by clicking the image at xkcd.com which can as always be accessed by clicking on the comic number above.
{{TOC}}

== Explanation ==

It's long been common for narrative works to be set in the past, and this tendency goes back to ancient mythology. The opposite approach, setting a work in a speculative future, has been less common prior to modern times. The oldest example Randall presents is from 1733, but it didn't really become a trend until well into the 19th century, and didn't become really common until the 20th century.

For works set in the future, particularly in the near future, there's a real possibility that audiences will still read or watch it past the date in which is was set, allowing them to compare the real world of this era to the one the author projected. This doesn't make the work less valuable, necessarily, but it does make the limits of such speculation painfully obvious, and tends to make the [https://tvtropes.org/pmwiki/pmwiki.php/Main/Zeerust future presented there look dated and quaint]. Randall labels these futuristic works as "obsolete".

For works set in the past, there's an opposite and somewhat more subtle effect. Once the work itself is old enough, audiences tend to forget that they were intended as historical fiction in the first place. If an old work is set in the past, it's often assumed that they were set in their own time, not in the still more distant past. That impacts how we experience the work, because we tend to assume that it's a faithful representation of its own time, not a later interpretation that was intended to be old (and possibly nostalgic) even in its own time.

To demonstrate those impacts, this chart sorts various works by the year they were created, graphed against how far in the past or future they were originally set. Lines on the chart are added to separate when each work ceases to work as either a prediction or as a [https://tvtropes.org/pmwiki/pmwiki.php/Main/PeriodPiece period piece]. For future works, the cut-off is obvious: if it was set in a year prior to the current year, we know that the predictions are obsolete (and can easily determine how accurate or inaccurate that future is). Hence, at the time the chart was written (in 2015), works like ''1984'' and ''2001: A Space Odyssey'' are obsolete, while works like ''Star Trek'', which take place in a more distant future, are still theoretically possible. (''Back to the Future Part II'' is deliberately right on the line, as it was set in 2015).

For the past works, Randall sets the cut-off as when the work itself is older than the events in question were when it was first written/made. Hence, modern audiences are unlikely to realize that the Epic of Gilgamesh was intended to sound ancient, even when it was new, or that novels like ''Les Miserables'' were intended as historical fiction, or even that films like ''Chinatown'' or shows like ''Happy Days'' were intended as period pieces when they were made. To modern audiences, we just see an old work set in an old time, and tend to assume that the two periods were the same.

The setup of the chart points to the reality that, in process of time, more and more works will cross those lines. Future audiences will likely assume that films like ''Apollo 13'' and ''Schindler's List'' were made around the time of the events in question. And modern science fiction works, if they're still remembered in the future, will become just as obsolete as past works. And Randall even indicates "this chart" on the chart, apparently acknowledging that it will become dated as time goes by.

How to read the graph:
* X-axis: Date of publication.
* Y-axis, "Years in the future": Number of years the story's events take place, after the story's publication.
* Y-axis, "Years in the past": Number of years the story's events take place, before the story's publication.
: For example, "Water Margin" was published in the 14th century (x ~= 1300) and relates events from the 12th century, about 200 years before its publication (y ~= 200 in the past).
: Another example: The film ''{{w|The Bridge on the River Kwai}}'' was released in 1957 and it was set around 14 years before (~1942-43).
* Grey area in the "Years in the future" part: Stories set in the future (relative to their publication date), for which the date of the events in the story is already in the past (relative to the publication date of the comic). The white and gray areas in this part of the graph are defined as "still possible" and "obsolete", respectively. The gray area (obsolete) will expand over time, assuming more works aren't added in the future: predictions from science fiction or futuristic work that are not confirmed by reality are doomed to be obsolete.
* Grey area in the "Years in the past" part: Stories set in the past (relative to their publication date) but published closer to their setting than to today. The warning "Modern audiences may not recognize which part were supposed to sound old" is a recurrent theme in the author's work, being already formulated in [[771: Period Speech|Period Speech]] comic. The white area seems to be the region where modern readers will be able to distinguish the past setting of a work from the age of the work itself. This gray area will grow over time (again assuming new works set in the past are not added) with more and more works being indistinguishable as works set in the past.

Taking the "years in the past" on the y-axis to be read as negatives like in most graphs one can write
* Dates on the lower line satisfy the equation y = x-2015. Corresponding works were published in the year x = 2015+y and are set in the year x+y = 2015+2y.
* Dates on the upper line satisfy the equation y = 2015-x. Corresponding works were published in the year x = 2015-y and are set in the year x+y = 2015.
Thus it's clear that the definitions of the lines are consistent with each other as they follow similar but inverted functions.
The graph uses variable {{w|logarithmic scale}}s, adjusting the scale in various regions to the temporal density of works being plotted. If the scale were linear, the graph would in fact represent a (bidimensional) {{w|Minkowski diagram}}, which depicts the moving cones of past and future in spacetime as one's present advances in time.

The title text jokes that ''2001'' cuts from prehistoria to the future before ''The Flintstones'' theme can become recognizable. This references the fact that, despite being primarily set in what was then the future, the film opens in the ancient past, thus appearing in both parts of the graph, with one part being very close to ''The Flintstones''. This plays on the fact that one of these was a very serious work and the other a playful animated show that was intended as family comedy.

=== Works listed ===
Differences listed in bright red are "former period pieces." Differences listed in dark red are other works set in the past. Differences listed in bright green are "obsolete" works set in the future. Differences listed in dark green are other works set in the future.

Asterisks (*) after a year of publication denote that it applies to the first installment in a series that spanned more than one year.

You can sort by a specific column in this table by clicking on its header.

{| class="wikitable sortable"
! align="center" style="background:#f0f0f0;"|'''Publication'''
! align="center" style="background:#f0f0f0;"|'''Description'''
! align="center" style="background:#f0f0f0;" data-sort-type="number"|'''Year written'''
! align="center" style="background:#f0f0f0;" data-sort-type="number"|'''Year difference'''
! align="center" style="background:#f0f0f0;" data-sort-type="number"|'''Year set in'''
! align="center" style="background:#f0f0f0;"|'''Notes'''
|-
| ''{{w|Epic of Gilgamesh}}''|| ancient Mesopotamian epic poem || data-sort-value="-2100"|~2100 BCE||style="color:#FF0000;" data-sort-value="500" | ~500|| data-sort-value="-2600"|~2600 BCE|| {{w|Enmebaragesi}}, a historically attested ''Epic of Gilgamesh'' character, is thought to have lived around 2600 BCE
|-
| ''{{w|Iliad|The Iliad}}''||epic written by Greek poet Homer || data-sort-value="-750"|700s BCE ||style="color:#FF0000;" data-sort-value="500" | ~500 || data-sort-value="-1260"| 1260–1240 BCE ||
|-
| ''{{w|Book of Genesis}}''||first book of the Bible, describing the creation of the world || data-sort-value="-500"|500s–400s BCE ||style="color:#8B0000;" data-sort-value="3200" | ~3200 || data-sort-value="-3761"| 3761 BCE || The ''{{w|Anno Mundi}}'' epoch, the product of scriptural calculations by {{w|Maimonides}}, places the Genesis date of the creation of the world at October 7, 3761 BCE in the {{w|proleptic Julian calendar}}
|-
| ''{{w|History of the Peloponnesian War}}''||history written by Thucydides|| data-sort-value="-400"|~400 BCE||style="color:#FF0000;" data-sort-value="10" | ~10|| data-sort-value="-431"|431–411 BCE||
|-
| ''{{w|Gospels}}''|| collection of literary works detailing the life of Jesus of Nazareth || data-sort-value="65"|~65–110 CE ||style="color:#FF0000;" | 25–75 || data-sort-value="-7"|7–2 BCE – 30–33 CE || Setting dates are those of Jesus' estimated lifetime. Writing dates are as follows: Mark 65–73 CE; Matthew 70–100 CE; Luke 80–100 CE; John 90–110 CE. Randall's difference calculation seems to be based on the date of Jesus' death, as the majority of the Gospels' events takes place during the three years prior to Jesus's death.
|-
| ''{{w|Ashokavadana}}''||narrative of the life of Ashoka the Great||100s CE||style="color:#FF0000;" data-sort-value="400" | ~400|| data-sort-value="-304"|304–232 BCE||
|-
| ''{{w|The Pillow Book}}''||book written by Sei Shōnagon||1002||style="color:#FF0000;" | 6||996||
|-
| ''{{w|Water Margin}}''||novel by Shi Nai'an|| data-sort-value="1375"|late 1300s||style="color:#FF0000;" data-sort-value="150" | ~150|| data-sort-value="1100"|early 1100s
|-
| ''{{w|Richard III (play)|Richard III}}''||play by William Shakespeare||1597||style="color:#FF0000;" | 112–119||1478–1485||
|-
| ''{{w|Henry IV (play)|Henry IV}}''||plays by William Shakespeare||1598*||style="color:#FF0000;" | 185–196||1402–1413||
|-
| ''{{w|King Lear}}''||play by William Shakespeare||1608||style="color:#8B0000;" | 2400|| data-sort-value="-700"|700s BCE||
|-
| ''{{w|King John (play)|King John}}''||play by William Shakespeare||1623||style="color:#8B0000;" data-sort-value="400" | ~400|| data-sort-value="1200"|~1200–1216||
|-
| ''{{w|Henry VIII (play)|Henry VIII}}''||play by William Shakespeare||1623||style="color:#FF0000;" | 90–102||1521–1533||
|-
| ''{{w|Julius Caesar (play)|Julius Caesar}}''||play by William Shakespeare||1623||style="color:#8B0000;" | 1667–1670|| data-sort-value="-45"|45–42 BCE||
|-
| ''{{w|Memoirs of the Twentieth Century}}''|| book written by Samuel Madden||1733||style="color:#32cd32;" | 264||1997||
|-
| ''{{w|Rip Van Winkle|Rip Van Winkel}}'' [sic]||short story by Washington Irving||1819||style="color:#FF0000;" | 32–52||1767–1787||It's not clear why Randall has chosen 1787 as the year that Rip Van Winkle awakes.
|-
| ''{{w|The Last of the Mohicans}}''||novel by James Cooper||1826||style="color:#FF0000;" | 69||1757||
|-
| ''{{w|Moby-Dick}}''||novel by Herman Melville||1851||style="color:#FF0000;" | 5+|| data-sort-value="1845"|before 1846 || Inspired by events occurring in 1820, the late 1830s, and the early 1840s
|-
| ''{{w|A Tale of Two Cities}}''|| book by Charles Dickens ||1859||style="color:#FF0000;" | 84||1775
|-
| ''{{w|Les Misérables|Les Miserábles}}'' [sic]||novel by Victor Hugo||1862||style="color:#FF0000;" | 47||1815–1832||
|-
| ''{{w|Treasure Island}}''||novel by Robert Louis Stevenson||1883||style="color:#FF0000;" data-sort-value="120" | ~120|| data-sort-value="1760"|~1760||
|-
| ''{{w|Looking Backward}}''|| novel written by Edward Bellamy||1888||style="color:#32cd32;" | 112||2000||
|-
| ''{{w|A Connecticut Yankee in King Arthur's Court}}''||novel by Mark Twain||1889||style="color:#8B0000;" | 1361||528||
|-
| ''{{w|Golf in the Year 2000}}''|| novel written by J. McCullough||1892||style="color:#32cd32;" | 108||2000||
|-
| ''{{w|The Time Machine}}''|| novel written by H.G. Wells||1895||style="color:#006400;" | 800,000– 1 billion||802,701– 1 billion|| Note that Randall has included only part of the book; which includes scenes all the way from the time of writing to the death of the last life on Earth. The novel itself identifies the latest part as being "more than thirty million years" in the future, based on the theories of the Sun's lifespan at the time.
|-
| ''{{w|Enoch Soames}}''|| short story by Max Beerbohm||1916||style="color:#32cd32;" | 81||1997||Soames was transported from 1897 to 1997 and back.
|-
| ''{{w|Gone With The Wind}}''|| novel by Margaret Mitchel ||1936||style="color:#FF0000;" | 75||1861
|-
| ''{{w|Lest Darkness Fall}}''||alternate history SF novel by L. Sprague de Camp||1939||style="color:#8B0000;" | 1404||535||
|-
| ''{{w|Casablanca (film)|Casablanca}}''||film directed by Michael Curtiz||1942||style="color:#FF0000;" data-sort-value="0.9" | <1||1941||The film was released 26 November 1942 and is set in early December 1941.
|-
| ''{{w|Oklahoma!}}''||Broadway musical||1943||style="color:#FF0000;" | 37||1906||
|-
| ''{{w|Nineteen Eighty-Four|1984}}''||novel written by George Orwell||1949||style="color:#32cd32;" | 35||1984||
|-
| ''{{w|The Bridge on the River Kwai}}''||film by David Lean||1952||style="color:#FF0000;" data-sort-value="10" | ~10||1942–1943||
|-
| ''{{w|Gunsmoke}}''||American radio and television series||1952*||style="color:#8B0000;" data-sort-value="75" | ~75||1870s||1952 is when the radio series started. The TV series didn't start until 1955.
|-
| ''{{w|The Ten Commandments (1956 film)|The Ten Commandments}}''||film by Cecil B. DeMille||1956||style="color:#8B0000;" data-sort-value="3000" | ~3000|| data-sort-value="-1446"|{{w|The Exodus#Date|~1446 BCE}}||The full timespan is supposedly 80 years (40 before Moses is exiled, then 40 in exile).
|-
| ''{{w|The Music Man}}''||Broadway musical||1957||style="color:#FF0000;" | 45||1912||
|-
| ''{{w|Wythnos yng Nghymru Fydd|A Week in the Wales of the Future}}''||novel written by Islwyn Ffowc Elis||1957||style="color:#006400;" | 76||2033||
|-
|''{{w|Asterix}}''||French comic by Goscinny and Uderzo||1959*||style="color:#8B0000;" | 2009|| data-sort-value="-50"|50 BCE||
|-
| ''{{w|The Flintstones}}''||TV series produced by Hanna-Barbera||1960*||style="color:#8B0000;" data-sort-value="2,500,000" | ~2.5 million|| data-sort-value="-2,500,000"|{{w|Stone Age|Stone Age}}||
|-
| ''{{w|Catch-22}}'' (Book)||novel by Joseph Heller||1961||style="color:#FF0000;" data-sort-value="17" | ~17||1942–44||
|-
| ''{{w|The Jetsons}}''||TV series produced by Hanna-Barbera||1962*||style="color:#006400;" | 100||data-sort-value="2062"|~2062||
|-
| ''{{w|Lawrence of Arabia}}''||film by David Lean||1962||style="color:#FF0000;" data-sort-value="44" | ~44||1916–1918||
|-
| ''{{w|The Great Escape (film)|The Great Escape}}''||film by John Sturges||1963||style="color:#FF0000;" | 20||1943–1944||
|-
| ''{{w|Star Trek: The Original Series|Star Trek}}'' (TOS)||TV series created by Gene Roddenberry||1966*||style="color:#006400;" | 298||2264||
|-
| ''{{w|Bonnie and Clyde (film)|Bonnie and Clyde}}''||film by Arthur Penn||1967||style="color:#FF0000;" data-sort-value="33" | ~33||1932–1934||
|-
| ''{{w|2001: A Space Odyssey (film)|2001: A Space Odyssey}}''||novel written by Arthur C. Clarke||1968||style="color:#32cd32;" | 33||2001||
|-
| ''{{w|2001: A Space Odyssey|2001: A Space Odyssey}}'' (prologue)||prologue to novel written by Arthur C. Clarke||1968||style="color:#8B0000;" data-sort-value="3,000,000" | 3 million|| data-sort-value="-3,000,000"|3 million BCE||4 million years BCE in the movie
|-
| ''{{w|Catch-22 (film)|Catch-22}}'' (Movie)||film by Mike Nichols||1970||style="color:#FF0000;" data-sort-value="26" | ~26||1942–1944||
|-
| ''{{w|MASH (film)|M*A*S*H}}''||film by Robert Altman||1970||style="color:#FF0000;" | 19||1951||
|-
| ''{{w|Patton (film)|Patton}}''||film by Franklin J. Schaffner||1970||style="color:#FF0000;" data-sort-value="25" | ~25||1943–1945||
|-
| ''{{w|American Graffiti}}''||film by George Lucas||1973||style="color:#FF0000;" | 11||1962||
|-
| ''{{w|Blazing Saddles}}''||film by Mel Brooks||1974||style="color:#8B0000;" | 100||1874||
|-
| ''{{w|Chinatown (1974 film)|Chinatown}}''||film by Roman Polanski||1974||style="color:#FF0000;" | 37||1937||
|-
| ''{{w|Happy Days}}''||TV series||1974*||style="color:#FF0000;" | 19–29||1955–1965||
|-
| ''{{w|Space: 1999}}''||TV series created by Gerry and Sylvia Anderson||1975*||style="color:#32cd32;" | 24||1999||
|-
| ''{{w|Annie (musical)|Annie}}'' (play)||Broadway musical||1977||style="color:#8B0000;" | 44||1933||
|-
| ''{{w|Roots (miniseries)|Roots}}''||TV series, adapted from eponymous novel||1977||style="color:#8B0000;" | 90–227||1750–1882||
|-
| ''{{w|Star Wars#Original trilogy|Star Wars}}'' (IV – VI)||original film trilogy ||1977*|| style="color:#8B0000;" data-sort-value="1,000,000,000" | 1 billion || data-sort-value="-1,000,000,000"|"A long time ago"|| It's not clear why Randall has chosen 1 billion years here. Wookieepedia puts the age of the ''Star Wars'' galaxy at [http://starwars.wikia.com/wiki/13,000,000,000_BBY ~13 billion years], and our Universe is only 13.8 billion years old, and the oldest known galaxy took 380 million years to form... So it would seem ''Star Wars'' should be no farther than 400 million years in the past, give or take.
|-
| ''{{w|Grease (film)|Grease}}''||film by Randall Kleiser||1978||style="color:#FF0000;" | 20||1958||
|-
| ''{{w|Apocalypse Now}}''||film by Francis Ford Coppola||1979||style="color:#FF0000;" | 10||1969||
|-
| ''{{w|Chariots of Fire}}''||film by Hugh Hudson||1981||style="color:#8B0000;" | 57||1924||
|-
| ''{{w|2010: Odyssey Two}}''||novel written by Arthur C. Clarke||1982||style="color:#32cd32;" | 28||2010||
|-
| ''{{w|Annie (1982 film)|Annie}}'' (movie)||film adaptation of the above by John Huston||1982||style="color:#8B0000;" | 49||1933||
|-
| ''{{w|Gandhi (film)|Gandhi}}''||film by Richard Attenborough||1982||style="color:#8B0000;" data-sort-value="34" | ~34||1893–1948||
|-
| ''{{w|The Right Stuff (film)|The Right Stuff}}''||film by Philip Kaufman||1983||style="color:#FF0000;" data-sort-value="20" | ~20||1947–63||
|-
| ''{{w|The Transformers (TV series)|Transformers}}'' (TV Series)||TV series||1984*||style="color:#32cd32;" data-sort-value="20" | ~20||data-sort-value="2004"|~2004||Only seasons 3 and 4 are set in the year 2005 onwards. Seasons 1 and 2 were set in 1984-85.
|-
| ''{{w|Back to the Future}}''||film by Robert Zemeckis||1985||style="color:#FF0000;" | 30||1955||
|-
| ''{{w|Platoon (film)|Platoon}}''||film by Oliver Stone||1986||style="color:#FF0000;" | 21||1967||
|-
| ''{{w|Dirty Dancing}}''||film by Emile Ardolino||1987||style="color:#FF0000;" | 24||1963||
|-
| ''{{w|Star Trek: The Next Generation|Star Trek: The Next Generation}}''||TV series created by Gene Roddenberry||1987*||style="color:#006400;" | 377||2364||
|-
| ''{{w|2061: Odyssey Three}}''||novel written by Arthur C. Clarke||1987||style="color:#006400;" | 74||2061||
|-
| ''{{w|The Wonder Years}}''||TV series||1988*||style="color:#FF0000;" | 20–25||1968–1973||
|-
| ''{{w|Back to the Future Part II|Back to the Future Part II}}''||film directed by Robert Zemeckis||1989||style="color:#32cd32;" | 26||2015||Only the first part of the movie is set in 2015; later the setting moves to an alternate 1985 and a revisit of 1955.
|-
| ''{{w|Zero Wing}}''||arcade/computer game||1989||style="color:#006400;" | 112||2101||Previously referenced in [[887: Future Timeline]]
|-
| ''{{w|Back to the Future Part III}}''||film by Robert Zemeckis||1990||style="color:#8B0000;" | 105||1885||
|-
| ''{{w|JFK (film)|JFK}}''||film by Oliver Stone||1991||style="color:#8B0000;" data-sort-value="22" | ~22||1963–1969||
|-
| ''{{w|Terminator 2: Judgment Day|Terminator 2}}'' (1995 Portion)||film directed by James Cameron||1991||style="color:#32cd32;" | 4||1995||
|-
| ''{{w|The Sandlot}}''||film by David Mickey Evans||1993||style="color:#8B0000;" | 31||1962||
|-
| ''{{w|Schindler's List}}''||film by Steven Spielberg||1993||style="color:#8B0000;" data-sort-value="50" | ~50||1939–1945||
|-
| ''{{w|Apollo 13 (film)|Apollo 13}}''||film by Ron Howard||1995||style="color:#8B0000;" | 25||1970||
|-
| ''{{w|Raptor Red}}''||novel by Robert Bakker||1995||style="color:#8B0000;" data-sort-value="65,000,000" | ~65 million|| data-sort-value="-65,000,000"|{{w|Cretaceous Period}}||
|-
| ''{{w|Evita (1996 film)|Evita}}''||film by Alan Parker||1996||style="color:#8B0000;" | 44||1952||
|-
| ''{{w|3001: The Final Odyssey}}''||novel written by Arthur C. Clarke||1997||style="color:#006400;" | 1004||3001||
|-
| ''{{w|The Big Lebowski}}''||film by the Coen Brothers||1998||style="color:#FF0000;" | 7||1991||
|-
| ''{{w|The Prince of Egypt}}''||animated film by DreamWorks||1998||style="color:#8B0000;" | 3400||data-sort-value="-1446"|{{w|The Exodus#Date|~1446 BCE}}||Despite the same plot of ''The Ten Commandments'', it covers only about 30 years given its Moses is much younger.
|-
| ''{{w|Saving Private Ryan}}''||film by Steven Spielberg||1998||style="color:#8B0000;" | 54||1944||
|-
| ''{{w|That '70s Show}}''||TV series||1998*||style="color:#8B0000;" data-sort-value="22" | ~22|||1976–1979||
|-
| ''{{w|Freaks and Geeks}}''||TV series||1999*||style="color:#8B0000;" | 19||1980–1981||
|-
| ''{{w|Star Wars#Prequel trilogy|Star Wars}}'' (I – III)||prequel film trilogy||1999*||style="color:#8B0000;" data-sort-value="1,000,000,000" | 1 billion || data-sort-value="-1,000,000,000"|"A long time ago"|| See note at episodes IV–VI
|-
| ''{{w|Pearl Harbor (film)|Pearl Harbor}}''||film by Michael Bay||2001||style="color:#8B0000;" | 60||1941||
|-
| ''{{w|Star Trek: Enterprise|Enterprise}}''||TV series||2001*||style="color:#006400;" | 150||2151||
|-
| ''{{w|I Love the '80s (U.S. TV series)|I Love the '80s}}''||TV miniseries by VH1||2002||style="color:#8B0000;" | 13–22||1980–1989||
|-
| ''{{w|Ice Age (film series)|Ice Age}}''||animated films by Blue Sky Studios||2002*||style="color:#8B0000;" data-sort-value="12,000" | ~12,000|| data-sort-value="-12,000"|{{w|Last glacial period|Paleolithic-Mesolithic}}||
|-
| ''{{w|Hotel Rwanda}}''|| film directed by Terry George||2004||style="color:#FF0000;" | 10||1994||
|-
| ''{{w|I Love the '90s (U.S. TV series)|I Love the '90s}}''|| TV miniseries on VH1||2004||style="color:#FF0000;" | 5–14||1990–1999||
|-
| ''{{w|United 93 (film)|United 93}}''|| film directed by Paul Greengrass||2006||style="color:#FF0000;" | 5||2001||
|-
| ''{{w|300 (film)|300}}''||film by Zack Snyder||2007||style="color:#8B0000;" | 2487|| data-sort-value="-480"|{{w|Battle of Thermopylae|480 BCE}}||
|-
| ''{{w|Mad Men}}''||TV series||2007*||style="color:#8B0000;" data-sort-value="47" | ~47||1960–1970||
|-
|''{{w|10,000 BC (film)|10,000 BC}}''||film by Roland Emmerich||2008||style="color:#8B0000;" data-sort-value="12007" | 12,007|| data-sort-value="-10,000"|10,000 BCE||
|-
| ''{{w|Year One (film)|Year One}}''||film by Harold Ramis||2009||style="color:#8B0000;" | 2008||data-sort-value="1"|1 CE|| The movie title is inaccurate; it is difficult to determine the film's actual year as it depicts Cain and Abel (c. 4000 BCE) existing simultaneously with Abraham, Sodom and Gomorrah (c. 2000 BCE).
|-
| ''{{w|Downton Abbey}}''||TV series||2010*||style="color:#8B0000;" data-sort-value="90" | ~90||1912–1923||
|-
| ''{{w|The Wolf of Wall Street}}''||film by Martin Scorsese||2013||style="color:#8B0000;" data-sort-value="18" | ~18||1987–1995||
|-
| ''{{w|I Love the 2000s|I Love the 2000s}}''|| TV miniseries on VH1||2014||style="color:#8B0000;" | 14||2000||
|-
| ''{{w|Star Wars sequel trilogy|Star Wars}}'' (VII – IX)||sequel film trilogy||2015*||style="color:#8B0000;" data-sort-value="1,000,000,000" | 1 billion || data-sort-value="-1,000,000,000"|"A long time ago"|| See note at episodes IV–VI
|-
|}

==Errors==

===Dates===
*''{{w|Star Trek: The Next Generation}}'' is vertically positioned at about 500 years in the future, slightly too high for its actual date. This may be to allow room for other nearby labels.
*The {{w|Gospels}} are horizontally positioned at about the year 250 CE, when they should be positioned slightly further to the left, near the 100 CE line. (While there is debate on their date of authorship, the range of "years in the past" indicated on the graph would require authorship between roughly 50 and 100 CE.)
*''{{w|Lest Darkness Fall}}'' takes place about 1400 years in the past, in the year 535. Its placement on the graph indicates it takes place about ''535'' years in the past, in the year ''1400''.

===Spelling===
*Author Washington Irving titled his work ''{{w|Rip Van Winkle}}'', not ''Rip van Winkel'' as [[Randall]] spells it. That said, ''van {{w|nl:Winkel|Winkel}}'' may be a more historically authentic spelling.
*''{{w|Les Misérables}}'' has been misspelled ''Les Miserábles'' (note that French doesn't use the character "á").

==Transcript==
{{incomplete transcript}}
:'''Date of publication'''
:[A logarithmic scale running horizontally, from 3000 BCE to past 2015 CE.]
:'''Years in the future'''
:[A logarithmic scale running vertically, from 1 billion down to 0.]
:'''Stories set in the future''' (science fiction, prediction)
::Stories set in 2015
::[A line divides this region into two. The upper side is labelled "still possible"; the lower side is labelled "obsolete".]
:[From left to right.]
::Memoirs of the Twentieth Century [1700, 265 years in the future]
::Looking Backward [1888, 112 years in the future]
::Golf in the Year 2000 [1892, 108 years in the future]
::The Time Machine [1895, 800 thousand to 30 million years in the future]
::Enoch Soames [1916, ''circa'' 60 years in the future]
::1984 [1949, 35 years in the future]
::A Week in the Wales of the Future [1957, 76 years in the future]
::The Jetsons [1962-63, 100 years in the future]
::Star Trek [1966-69, 300 years in the future]
::2001: A Space Odyssey [1968, 33 years in the future]
::Space: 1999 [1975-77, 24 years in the future]
::2010: Odyssey Two [1982, 28 years in the future]
::Transformers (TV series) [1984-87, 20 years in the future]
::2061: Odyssey Three [1987, 74 years in the future]
::Star Trek: The Next Generation [1987-94, ''circa'' 500 years in the future]
::Back to the Future Part II [1989, 26 years in the future]
::Zero Wing [1989, 112 years in the future]
::Terminator 2 (1995 portion) [1991, 4 years in the future]
::3001: The Final Odyssey [1997, 1004 years in the future]
::Enterprise [2001-2005, 150 years in the future]
::This chart [2015, 0 years in the future]
:'''Years in the past'''
:[A logarithmic scale running vertically, from 0 down past 1 billion to "Big Bang"]
:'''Stories set in the past''' (History, Period Fiction)
::Stories written X years ago and set 2X years ago
::[A line divides this region into two. The upper side is labelled as follows.]
::'''Former period pieces'''
::Stories set in the past, but created long enough ago that they were published closer to their setting than to today.
::Modern audiences may not recognize which parts were ''supposed'' to sound old.
:[From left to right.]
::The Epic of Gilgamesh [''circa'' 2100 BCE, 600 years in the past]
::The Iliad [''circa'' 800 BCE, 450 years in the past]
::History of the Peloponnesian War [''circa'' 390 BCE, 10 years in the past]
::Book of Genesis [''circa'' 500 BCE, 4000 years in the past]
::Ashokavadana [''circa'' 100 BCE, 300 years in the past]
::Gospels (various estimates) [''circa'' 250 CE, 24 to 75 years in the past]
::The Pillow Book [1000 CE, 5 years in the past]
::Water Margin [''circa'' 1300, 195 years in the past]
::Richard III [''circa'' 1590, 115 years in the past]
::Julius Caesar [1599, 1650 years in the past]
::King John [''circa'' 1600, 500 years in the past]
::Henry IV [''circa'' 1600, 190 years in the past]
::King Lear [''circa'' 1606, 3000 years in the past]
::Henry VIII [''circa'' 1612, 105 years in the past]
::The Last of the Mohicans [1826, 69 years in the past]
::Rip Van Winkel [1819, 31-51 years in the past]
::A Tale of Two Cities [1859, 60 years in the past]
::Moby-Dick [1851, anywhere from 4 to 14 years ago]
:::"Some years ago--never mind how long precisely..."
::Les Miserábles [1862, 30 years in the past]
::Treasure Island [1883, 130 years in the past]
::A Connecticut Yankee in King Arthur's Court [1889, 2000 years in the past]
::Gone with the Wind [1936, 70 years in the past]
::Lest Darkness Fall [1939, 550 years in the past]
::Casablanca [1942, 1 year in the past]
::Oklahoma! [1943, 37 years in the past]
::The Ten Commandments [1956, 1400 years in the past]
::The Bridge on the River Kwai [1957, 13 years in the past]
::Gunsmoke [1952-61, 80 years in the past]
::The Flintstones [1960-66, 100,000 years in the past]
::Catch-22 (book) [1961, 18 years in the past]
::The Great Escape [1963, 20 years in the past]
::Asterix
::Lawrence of Arabia
::The Music Man
::Bonnie and Clyde
::2001: A Space Odyssey (prologue)
::American Graffiti
::Patton
::Catch-22 (movie) [1970, 27 years in the past]
::Chinatown
::Blazing Saddles
::Apocalypse Now
::Happy Days
::Grease
::M*A*S*H
::Annie (play)
::Roots
::Chariots of Fire
::Star Wars (IV-VI)
::Annie (movie)
::The Right Stuff
::Back to the Future
::Gandhi
::Platoon
::Dirty Dancing
::Back to the Future Part III
::The Wonder Years
::JFK
::The Sandlot
::Schindler's List
::Raptor Red
::Apollo 13
::Star Wars (I-III)
::The Big Lebowski
::Evita
::Saving Private Ryan
::The Prince of Egypt
::Freaks and Geeks
::Hotel Rwanda
::I Love the '80s
::That '70s Show
::Pearl Harbor
::Ice Age
::I Love the '90s
::United 93
::300
::10,000 BC
::Year One
::The Wolf of Wall Street
::I Love the 2000s
::Mad Men
::Downton Abbey
::Star Wars (VII-IX)

==Trivia==
*Later after the initial release of this comic Randall added a link to this page. It's viewable in the HTML-source or here: [https://xkcd.com/1491/info.0.json https://xkcd.com/1491/info.0.json]. The text is: ''"this is a massive fucking graph beyond the limits of normal transcription. you can find a full listing of data points at http:\n\nwww.explainxkcd.com\nwiki\nindex.php\n1491"''.

{{comic discussion}}

[[Category:Large drawings]]
[[Category:Charts]]
[[Category:Timelines]]
[[Category:Time]]
[[Category:Star Trek]]
[[Category:Terminator]]
[[Category:Back to the Future]]

1491: Stories of the Past and Future

2022-02-14T23:00:19Z

172.70.34.165: /* Explanation */

{{comic
| number = 1491
| date = February 25, 2015
| title = Stories of the Past and Future
| image = stories_of_the_past_and_future.png
| titletext = Little-known fact: The 'Dawn of Man' opening sequence in 2001 cuts away seconds before the Flintstones theme becomes recognizable.
}}
*A [http://xkcd.com/1491/large/ larger version] of this image can be found by clicking the image at xkcd.com which can as always be accessed by clicking on the comic number above.
{{TOC}}

== Explanation ==

It's long been common for narrative works to be set in the past, and this tendency goes back to ancient mythology. The opposite approach, setting a work in a speculative future, has been less common prior to modern times. The oldest example Randall presents is from 1733, but it didn't really become a trend until well into the 19th century, and didn't become really common until the 20th century.

For works set in the future, particularly in the near future, there's a real possibility that audiences will still read or watch it past the date in which is was set, allowing them to compare the real world of this era to the one the author projected. This doesn't make the work less valuable, necessarily, but it does make the limits of such speculation painfully obvious, and tends to make the [https://tvtropes.org/pmwiki/pmwiki.php/Main/Zeerust future presented there look dated and quaint]. Randall labels these futuristic works as "obsolete".

For works set in the past, there's an opposite and somewhat more subtle effect. Once the work itself is old enough, audiences tend to forget that they were intended as historical fiction in the first place. If an old work is set in the past, it's often assumed that they were set in their own time, not in the still more distant past. That impacts how we experience the work, because we tend to assume that it's a faithful representation of its own time, not a later interpretation that was intended to be old (and possibly nostalgic) even in its own time.

To demonstrate those impacts, this chart sorts various works by the year they were created, graphed against how far in the past or future they were originally set. Lines on the chart are added to separate when each work ceases to work as either a prediction or as a [https://tvtropes.org/pmwiki/pmwiki.php/Main/PeriodPiece period piece]. For future works, the cut-off is obvious: if it was set in a year prior to the current year, we know that the predictions are obsolete (and can easily determine how accurate or inaccurate that future is). Hence, at the time the chart was written (in 2015), works like ''1984'' ''2001: A Space Odyssey'' are obsolete, while works like ''Star Trek'', which take place in a more distant future, are still theoretically possible. (''Back to the Future Part II'' is deliberately right on the line, as it was set in 2015).

For the past works, Randall sets the cut-off as when the work itself is older than the events in question were when it was first written/made. Hence, modern audiences are unlikely to realize that the Epic of Gilgamesh was intended to sound ancient, even when it was new, or that novels like ''Les Miserables'' were intended as historical fiction, or even that films like ''Chinatown'' or shows like ''Happy Days'' were intended as period pieces when they were made. To modern audiences, we just see an old work set in an old time, and tend to assume that the two periods were the same.

The setup of the chart points to the reality that, in process of time, more and more works will cross those lines. Future audiences will likely assume that films like ''Apollo 13'' and ''Schindler's List'' were made around the time of the events in question. And modern science fiction works, if they're still remembered in the future, will become just as obsolete as past works ever work. And Randall even indicates "this chart" on the chart, apparently acknowledging that it will become dated as time goes by.

How to read the graph:
* X-axis: Date of publication.
* Y-axis, "Years in the future": Number of years the story's events take place, after the story's publication.
* Y-axis, "Years in the past": Number of years the story's events take place, before the story's publication.
: For example, "Water Margin" was published in the 14th century (x ~= 1300) and relates events from the 12th century, about 200 years before its publication (y ~= 200 in the past).
: Another example: The film ''{{w|The Bridge on the River Kwai}}'' was released in 1957 and it was set around 14 years before (~1942-43).
* Grey area in the "Years in the future" part: Stories set in the future (relative to their publication date), for which the date of the events in the story is already in the past (relative to the publication date of the comic). The white and gray areas in this part of the graph are defined as "still possible" and "obsolete", respectively. The gray area (obsolete) will expand over time, assuming more works aren't added in the future: predictions from science fiction or futuristic work that are not confirmed by reality are doomed to be obsolete.
* Grey area in the "Years in the past" part: Stories set in the past (relative to their publication date) but published closer to their setting than to today. The warning "Modern audiences may not recognize which part were supposed to sound old" is a recurrent theme in the author's work, being already formulated in [[771: Period Speech|Period Speech]] comic. The white area seems to be the region where modern readers will be able to distinguish the past setting of a work from the age of the work itself. This gray area will grow over time (again assuming new works set in the past are not added) with more and more works being indistinguishable as works set in the past.

Taking the "years in the past" on the y-axis to be read as negatives like in most graphs one can write
* Dates on the lower line satisfy the equation y = x-2015. Corresponding works were published in the year x = 2015+y and are set in the year x+y = 2015+2y.
* Dates on the upper line satisfy the equation y = 2015-x. Corresponding works were published in the year x = 2015-y and are set in the year x+y = 2015.
Thus it's clear that the definitions of the lines are consistent with each other as they follow similar but inverted functions.
The graph uses variable {{w|logarithmic scale}}s, adjusting the scale in various regions to the temporal density of works being plotted. If the scale were linear, the graph would in fact represent a (bidimensional) {{w|Minkowski diagram}}, which depicts the moving cones of past and future in spacetime as one's present advances in time.

The title text jokes that ''2001'' cuts from prehistoria to the future before ''The Flintstones'' theme can become recognizable. This references the fact that, despite being primarily set in what was then the future, the film opens in the ancient past, thus appearing in both parts of the graph, with one part being very close to ''The Flintstones''. This plays on the fact that one of these was a very serious work and the other a playful animated show that was intended as family comedy.

=== Works listed ===
Differences listed in bright red are "former period pieces." Differences listed in dark red are other works set in the past. Differences listed in bright green are "obsolete" works set in the future. Differences listed in dark green are other works set in the future.

Asterisks (*) after a year of publication denote that it applies to the first installment in a series that spanned more than one year.

You can sort by a specific column in this table by clicking on its header.

{| class="wikitable sortable"
! align="center" style="background:#f0f0f0;"|'''Publication'''
! align="center" style="background:#f0f0f0;"|'''Description'''
! align="center" style="background:#f0f0f0;" data-sort-type="number"|'''Year written'''
! align="center" style="background:#f0f0f0;" data-sort-type="number"|'''Year difference'''
! align="center" style="background:#f0f0f0;" data-sort-type="number"|'''Year set in'''
! align="center" style="background:#f0f0f0;"|'''Notes'''
|-
| ''{{w|Epic of Gilgamesh}}''|| ancient Mesopotamian epic poem || data-sort-value="-2100"|~2100 BCE||style="color:#FF0000;" data-sort-value="500" | ~500|| data-sort-value="-2600"|~2600 BCE|| {{w|Enmebaragesi}}, a historically attested ''Epic of Gilgamesh'' character, is thought to have lived around 2600 BCE
|-
| ''{{w|Iliad|The Iliad}}''||epic written by Greek poet Homer || data-sort-value="-750"|700s BCE ||style="color:#FF0000;" data-sort-value="500" | ~500 || data-sort-value="-1260"| 1260–1240 BCE ||
|-
| ''{{w|Book of Genesis}}''||first book of the Bible, describing the creation of the world || data-sort-value="-500"|500s–400s BCE ||style="color:#8B0000;" data-sort-value="3200" | ~3200 || data-sort-value="-3761"| 3761 BCE || The ''{{w|Anno Mundi}}'' epoch, the product of scriptural calculations by {{w|Maimonides}}, places the Genesis date of the creation of the world at October 7, 3761 BCE in the {{w|proleptic Julian calendar}}
|-
| ''{{w|History of the Peloponnesian War}}''||history written by Thucydides|| data-sort-value="-400"|~400 BCE||style="color:#FF0000;" data-sort-value="10" | ~10|| data-sort-value="-431"|431–411 BCE||
|-
| ''{{w|Gospels}}''|| collection of literary works detailing the life of Jesus of Nazareth || data-sort-value="65"|~65–110 CE ||style="color:#FF0000;" | 25–75 || data-sort-value="-7"|7–2 BCE – 30–33 CE || Setting dates are those of Jesus' estimated lifetime. Writing dates are as follows: Mark 65–73 CE; Matthew 70–100 CE; Luke 80–100 CE; John 90–110 CE. Randall's difference calculation seems to be based on the date of Jesus' death, as the majority of the Gospels' events takes place during the three years prior to Jesus's death.
|-
| ''{{w|Ashokavadana}}''||narrative of the life of Ashoka the Great||100s CE||style="color:#FF0000;" data-sort-value="400" | ~400|| data-sort-value="-304"|304–232 BCE||
|-
| ''{{w|The Pillow Book}}''||book written by Sei Shōnagon||1002||style="color:#FF0000;" | 6||996||
|-
| ''{{w|Water Margin}}''||novel by Shi Nai'an|| data-sort-value="1375"|late 1300s||style="color:#FF0000;" data-sort-value="150" | ~150|| data-sort-value="1100"|early 1100s
|-
| ''{{w|Richard III (play)|Richard III}}''||play by William Shakespeare||1597||style="color:#FF0000;" | 112–119||1478–1485||
|-
| ''{{w|Henry IV (play)|Henry IV}}''||plays by William Shakespeare||1598*||style="color:#FF0000;" | 185–196||1402–1413||
|-
| ''{{w|King Lear}}''||play by William Shakespeare||1608||style="color:#8B0000;" | 2400|| data-sort-value="-700"|700s BCE||
|-
| ''{{w|King John (play)|King John}}''||play by William Shakespeare||1623||style="color:#8B0000;" data-sort-value="400" | ~400|| data-sort-value="1200"|~1200–1216||
|-
| ''{{w|Henry VIII (play)|Henry VIII}}''||play by William Shakespeare||1623||style="color:#FF0000;" | 90–102||1521–1533||
|-
| ''{{w|Julius Caesar (play)|Julius Caesar}}''||play by William Shakespeare||1623||style="color:#8B0000;" | 1667–1670|| data-sort-value="-45"|45–42 BCE||
|-
| ''{{w|Memoirs of the Twentieth Century}}''|| book written by Samuel Madden||1733||style="color:#32cd32;" | 264||1997||
|-
| ''{{w|Rip Van Winkle|Rip Van Winkel}}'' [sic]||short story by Washington Irving||1819||style="color:#FF0000;" | 32–52||1767–1787||It's not clear why Randall has chosen 1787 as the year that Rip Van Winkle awakes.
|-
| ''{{w|The Last of the Mohicans}}''||novel by James Cooper||1826||style="color:#FF0000;" | 69||1757||
|-
| ''{{w|Moby-Dick}}''||novel by Herman Melville||1851||style="color:#FF0000;" | 5+|| data-sort-value="1845"|before 1846 || Inspired by events occurring in 1820, the late 1830s, and the early 1840s
|-
| ''{{w|A Tale of Two Cities}}''|| book by Charles Dickens ||1859||style="color:#FF0000;" | 84||1775
|-
| ''{{w|Les Misérables|Les Miserábles}}'' [sic]||novel by Victor Hugo||1862||style="color:#FF0000;" | 47||1815–1832||
|-
| ''{{w|Treasure Island}}''||novel by Robert Louis Stevenson||1883||style="color:#FF0000;" data-sort-value="120" | ~120|| data-sort-value="1760"|~1760||
|-
| ''{{w|Looking Backward}}''|| novel written by Edward Bellamy||1888||style="color:#32cd32;" | 112||2000||
|-
| ''{{w|A Connecticut Yankee in King Arthur's Court}}''||novel by Mark Twain||1889||style="color:#8B0000;" | 1361||528||
|-
| ''{{w|Golf in the Year 2000}}''|| novel written by J. McCullough||1892||style="color:#32cd32;" | 108||2000||
|-
| ''{{w|The Time Machine}}''|| novel written by H.G. Wells||1895||style="color:#006400;" | 800,000– 1 billion||802,701– 1 billion|| Note that Randall has included only part of the book; which includes scenes all the way from the time of writing to the death of the last life on Earth. The novel itself identifies the latest part as being "more than thirty million years" in the future, based on the theories of the Sun's lifespan at the time.
|-
| ''{{w|Enoch Soames}}''|| short story by Max Beerbohm||1916||style="color:#32cd32;" | 81||1997||Soames was transported from 1897 to 1997 and back.
|-
| ''{{w|Gone With The Wind}}''|| novel by Margaret Mitchel ||1936||style="color:#FF0000;" | 75||1861
|-
| ''{{w|Lest Darkness Fall}}''||alternate history SF novel by L. Sprague de Camp||1939||style="color:#8B0000;" | 1404||535||
|-
| ''{{w|Casablanca (film)|Casablanca}}''||film directed by Michael Curtiz||1942||style="color:#FF0000;" data-sort-value="0.9" | <1||1941||The film was released 26 November 1942 and is set in early December 1941.
|-
| ''{{w|Oklahoma!}}''||Broadway musical||1943||style="color:#FF0000;" | 37||1906||
|-
| ''{{w|Nineteen Eighty-Four|1984}}''||novel written by George Orwell||1949||style="color:#32cd32;" | 35||1984||
|-
| ''{{w|The Bridge on the River Kwai}}''||film by David Lean||1952||style="color:#FF0000;" data-sort-value="10" | ~10||1942–1943||
|-
| ''{{w|Gunsmoke}}''||American radio and television series||1952*||style="color:#8B0000;" data-sort-value="75" | ~75||1870s||1952 is when the radio series started. The TV series didn't start until 1955.
|-
| ''{{w|The Ten Commandments (1956 film)|The Ten Commandments}}''||film by Cecil B. DeMille||1956||style="color:#8B0000;" data-sort-value="3000" | ~3000|| data-sort-value="-1446"|{{w|The Exodus#Date|~1446 BCE}}||The full timespan is supposedly 80 years (40 before Moses is exiled, then 40 in exile).
|-
| ''{{w|The Music Man}}''||Broadway musical||1957||style="color:#FF0000;" | 45||1912||
|-
| ''{{w|Wythnos yng Nghymru Fydd|A Week in the Wales of the Future}}''||novel written by Islwyn Ffowc Elis||1957||style="color:#006400;" | 76||2033||
|-
|''{{w|Asterix}}''||French comic by Goscinny and Uderzo||1959*||style="color:#8B0000;" | 2009|| data-sort-value="-50"|50 BCE||
|-
| ''{{w|The Flintstones}}''||TV series produced by Hanna-Barbera||1960*||style="color:#8B0000;" data-sort-value="2,500,000" | ~2.5 million|| data-sort-value="-2,500,000"|{{w|Stone Age|Stone Age}}||
|-
| ''{{w|Catch-22}}'' (Book)||novel by Joseph Heller||1961||style="color:#FF0000;" data-sort-value="17" | ~17||1942–44||
|-
| ''{{w|The Jetsons}}''||TV series produced by Hanna-Barbera||1962*||style="color:#006400;" | 100||data-sort-value="2062"|~2062||
|-
| ''{{w|Lawrence of Arabia}}''||film by David Lean||1962||style="color:#FF0000;" data-sort-value="44" | ~44||1916–1918||
|-
| ''{{w|The Great Escape (film)|The Great Escape}}''||film by John Sturges||1963||style="color:#FF0000;" | 20||1943–1944||
|-
| ''{{w|Star Trek: The Original Series|Star Trek}}'' (TOS)||TV series created by Gene Roddenberry||1966*||style="color:#006400;" | 298||2264||
|-
| ''{{w|Bonnie and Clyde (film)|Bonnie and Clyde}}''||film by Arthur Penn||1967||style="color:#FF0000;" data-sort-value="33" | ~33||1932–1934||
|-
| ''{{w|2001: A Space Odyssey (film)|2001: A Space Odyssey}}''||novel written by Arthur C. Clarke||1968||style="color:#32cd32;" | 33||2001||
|-
| ''{{w|2001: A Space Odyssey|2001: A Space Odyssey}}'' (prologue)||prologue to novel written by Arthur C. Clarke||1968||style="color:#8B0000;" data-sort-value="3,000,000" | 3 million|| data-sort-value="-3,000,000"|3 million BCE||4 million years BCE in the movie
|-
| ''{{w|Catch-22 (film)|Catch-22}}'' (Movie)||film by Mike Nichols||1970||style="color:#FF0000;" data-sort-value="26" | ~26||1942–1944||
|-
| ''{{w|MASH (film)|M*A*S*H}}''||film by Robert Altman||1970||style="color:#FF0000;" | 19||1951||
|-
| ''{{w|Patton (film)|Patton}}''||film by Franklin J. Schaffner||1970||style="color:#FF0000;" data-sort-value="25" | ~25||1943–1945||
|-
| ''{{w|American Graffiti}}''||film by George Lucas||1973||style="color:#FF0000;" | 11||1962||
|-
| ''{{w|Blazing Saddles}}''||film by Mel Brooks||1974||style="color:#8B0000;" | 100||1874||
|-
| ''{{w|Chinatown (1974 film)|Chinatown}}''||film by Roman Polanski||1974||style="color:#FF0000;" | 37||1937||
|-
| ''{{w|Happy Days}}''||TV series||1974*||style="color:#FF0000;" | 19–29||1955–1965||
|-
| ''{{w|Space: 1999}}''||TV series created by Gerry and Sylvia Anderson||1975*||style="color:#32cd32;" | 24||1999||
|-
| ''{{w|Annie (musical)|Annie}}'' (play)||Broadway musical||1977||style="color:#8B0000;" | 44||1933||
|-
| ''{{w|Roots (miniseries)|Roots}}''||TV series, adapted from eponymous novel||1977||style="color:#8B0000;" | 90–227||1750–1882||
|-
| ''{{w|Star Wars#Original trilogy|Star Wars}}'' (IV – VI)||original film trilogy ||1977*|| style="color:#8B0000;" data-sort-value="1,000,000,000" | 1 billion || data-sort-value="-1,000,000,000"|"A long time ago"|| It's not clear why Randall has chosen 1 billion years here. Wookieepedia puts the age of the ''Star Wars'' galaxy at [http://starwars.wikia.com/wiki/13,000,000,000_BBY ~13 billion years], and our Universe is only 13.8 billion years old, and the oldest known galaxy took 380 million years to form... So it would seem ''Star Wars'' should be no farther than 400 million years in the past, give or take.
|-
| ''{{w|Grease (film)|Grease}}''||film by Randall Kleiser||1978||style="color:#FF0000;" | 20||1958||
|-
| ''{{w|Apocalypse Now}}''||film by Francis Ford Coppola||1979||style="color:#FF0000;" | 10||1969||
|-
| ''{{w|Chariots of Fire}}''||film by Hugh Hudson||1981||style="color:#8B0000;" | 57||1924||
|-
| ''{{w|2010: Odyssey Two}}''||novel written by Arthur C. Clarke||1982||style="color:#32cd32;" | 28||2010||
|-
| ''{{w|Annie (1982 film)|Annie}}'' (movie)||film adaptation of the above by John Huston||1982||style="color:#8B0000;" | 49||1933||
|-
| ''{{w|Gandhi (film)|Gandhi}}''||film by Richard Attenborough||1982||style="color:#8B0000;" data-sort-value="34" | ~34||1893–1948||
|-
| ''{{w|The Right Stuff (film)|The Right Stuff}}''||film by Philip Kaufman||1983||style="color:#FF0000;" data-sort-value="20" | ~20||1947–63||
|-
| ''{{w|The Transformers (TV series)|Transformers}}'' (TV Series)||TV series||1984*||style="color:#32cd32;" data-sort-value="20" | ~20||data-sort-value="2004"|~2004||Only seasons 3 and 4 are set in the year 2005 onwards. Seasons 1 and 2 were set in 1984-85.
|-
| ''{{w|Back to the Future}}''||film by Robert Zemeckis||1985||style="color:#FF0000;" | 30||1955||
|-
| ''{{w|Platoon (film)|Platoon}}''||film by Oliver Stone||1986||style="color:#FF0000;" | 21||1967||
|-
| ''{{w|Dirty Dancing}}''||film by Emile Ardolino||1987||style="color:#FF0000;" | 24||1963||
|-
| ''{{w|Star Trek: The Next Generation|Star Trek: The Next Generation}}''||TV series created by Gene Roddenberry||1987*||style="color:#006400;" | 377||2364||
|-
| ''{{w|2061: Odyssey Three}}''||novel written by Arthur C. Clarke||1987||style="color:#006400;" | 74||2061||
|-
| ''{{w|The Wonder Years}}''||TV series||1988*||style="color:#FF0000;" | 20–25||1968–1973||
|-
| ''{{w|Back to the Future Part II|Back to the Future Part II}}''||film directed by Robert Zemeckis||1989||style="color:#32cd32;" | 26||2015||Only the first part of the movie is set in 2015; later the setting moves to an alternate 1985 and a revisit of 1955.
|-
| ''{{w|Zero Wing}}''||arcade/computer game||1989||style="color:#006400;" | 112||2101||Previously referenced in [[887: Future Timeline]]
|-
| ''{{w|Back to the Future Part III}}''||film by Robert Zemeckis||1990||style="color:#8B0000;" | 105||1885||
|-
| ''{{w|JFK (film)|JFK}}''||film by Oliver Stone||1991||style="color:#8B0000;" data-sort-value="22" | ~22||1963–1969||
|-
| ''{{w|Terminator 2: Judgment Day|Terminator 2}}'' (1995 Portion)||film directed by James Cameron||1991||style="color:#32cd32;" | 4||1995||
|-
| ''{{w|The Sandlot}}''||film by David Mickey Evans||1993||style="color:#8B0000;" | 31||1962||
|-
| ''{{w|Schindler's List}}''||film by Steven Spielberg||1993||style="color:#8B0000;" data-sort-value="50" | ~50||1939–1945||
|-
| ''{{w|Apollo 13 (film)|Apollo 13}}''||film by Ron Howard||1995||style="color:#8B0000;" | 25||1970||
|-
| ''{{w|Raptor Red}}''||novel by Robert Bakker||1995||style="color:#8B0000;" data-sort-value="65,000,000" | ~65 million|| data-sort-value="-65,000,000"|{{w|Cretaceous Period}}||
|-
| ''{{w|Evita (1996 film)|Evita}}''||film by Alan Parker||1996||style="color:#8B0000;" | 44||1952||
|-
| ''{{w|3001: The Final Odyssey}}''||novel written by Arthur C. Clarke||1997||style="color:#006400;" | 1004||3001||
|-
| ''{{w|The Big Lebowski}}''||film by the Coen Brothers||1998||style="color:#FF0000;" | 7||1991||
|-
| ''{{w|The Prince of Egypt}}''||animated film by DreamWorks||1998||style="color:#8B0000;" | 3400||data-sort-value="-1446"|{{w|The Exodus#Date|~1446 BCE}}||Despite the same plot of ''The Ten Commandments'', it covers only about 30 years given its Moses is much younger.
|-
| ''{{w|Saving Private Ryan}}''||film by Steven Spielberg||1998||style="color:#8B0000;" | 54||1944||
|-
| ''{{w|That '70s Show}}''||TV series||1998*||style="color:#8B0000;" data-sort-value="22" | ~22|||1976–1979||
|-
| ''{{w|Freaks and Geeks}}''||TV series||1999*||style="color:#8B0000;" | 19||1980–1981||
|-
| ''{{w|Star Wars#Prequel trilogy|Star Wars}}'' (I – III)||prequel film trilogy||1999*||style="color:#8B0000;" data-sort-value="1,000,000,000" | 1 billion || data-sort-value="-1,000,000,000"|"A long time ago"|| See note at episodes IV–VI
|-
| ''{{w|Pearl Harbor (film)|Pearl Harbor}}''||film by Michael Bay||2001||style="color:#8B0000;" | 60||1941||
|-
| ''{{w|Star Trek: Enterprise|Enterprise}}''||TV series||2001*||style="color:#006400;" | 150||2151||
|-
| ''{{w|I Love the '80s (U.S. TV series)|I Love the '80s}}''||TV miniseries by VH1||2002||style="color:#8B0000;" | 13–22||1980–1989||
|-
| ''{{w|Ice Age (film series)|Ice Age}}''||animated films by Blue Sky Studios||2002*||style="color:#8B0000;" data-sort-value="12,000" | ~12,000|| data-sort-value="-12,000"|{{w|Last glacial period|Paleolithic-Mesolithic}}||
|-
| ''{{w|Hotel Rwanda}}''|| film directed by Terry George||2004||style="color:#FF0000;" | 10||1994||
|-
| ''{{w|I Love the '90s (U.S. TV series)|I Love the '90s}}''|| TV miniseries on VH1||2004||style="color:#FF0000;" | 5–14||1990–1999||
|-
| ''{{w|United 93 (film)|United 93}}''|| film directed by Paul Greengrass||2006||style="color:#FF0000;" | 5||2001||
|-
| ''{{w|300 (film)|300}}''||film by Zack Snyder||2007||style="color:#8B0000;" | 2487|| data-sort-value="-480"|{{w|Battle of Thermopylae|480 BCE}}||
|-
| ''{{w|Mad Men}}''||TV series||2007*||style="color:#8B0000;" data-sort-value="47" | ~47||1960–1970||
|-
|''{{w|10,000 BC (film)|10,000 BC}}''||film by Roland Emmerich||2008||style="color:#8B0000;" data-sort-value="12007" | 12,007|| data-sort-value="-10,000"|10,000 BCE||
|-
| ''{{w|Year One (film)|Year One}}''||film by Harold Ramis||2009||style="color:#8B0000;" | 2008||data-sort-value="1"|1 CE|| The movie title is inaccurate; it is difficult to determine the film's actual year as it depicts Cain and Abel (c. 4000 BCE) existing simultaneously with Abraham, Sodom and Gomorrah (c. 2000 BCE).
|-
| ''{{w|Downton Abbey}}''||TV series||2010*||style="color:#8B0000;" data-sort-value="90" | ~90||1912–1923||
|-
| ''{{w|The Wolf of Wall Street}}''||film by Martin Scorsese||2013||style="color:#8B0000;" data-sort-value="18" | ~18||1987–1995||
|-
| ''{{w|I Love the 2000s|I Love the 2000s}}''|| TV miniseries on VH1||2014||style="color:#8B0000;" | 14||2000||
|-
| ''{{w|Star Wars sequel trilogy|Star Wars}}'' (VII – IX)||sequel film trilogy||2015*||style="color:#8B0000;" data-sort-value="1,000,000,000" | 1 billion || data-sort-value="-1,000,000,000"|"A long time ago"|| See note at episodes IV–VI
|-
|}

==Errors==

===Dates===
*''{{w|Star Trek: The Next Generation}}'' is vertically positioned at about 500 years in the future, slightly too high for its actual date. This may be to allow room for other nearby labels.
*The {{w|Gospels}} are horizontally positioned at about the year 250 CE, when they should be positioned slightly further to the left, near the 100 CE line. (While there is debate on their date of authorship, the range of "years in the past" indicated on the graph would require authorship between roughly 50 and 100 CE.)
*''{{w|Lest Darkness Fall}}'' takes place about 1400 years in the past, in the year 535. Its placement on the graph indicates it takes place about ''535'' years in the past, in the year ''1400''.

===Spelling===
*Author Washington Irving titled his work ''{{w|Rip Van Winkle}}'', not ''Rip van Winkel'' as [[Randall]] spells it. That said, ''van {{w|nl:Winkel|Winkel}}'' may be a more historically authentic spelling.
*''{{w|Les Misérables}}'' has been misspelled ''Les Miserábles'' (note that French doesn't use the character "á").

==Transcript==
{{incomplete transcript}}
:'''Date of publication'''
:[A logarithmic scale running horizontally, from 3000 BCE to past 2015 CE.]
:'''Years in the future'''
:[A logarithmic scale running vertically, from 1 billion down to 0.]
:'''Stories set in the future''' (science fiction, prediction)
::Stories set in 2015
::[A line divides this region into two. The upper side is labelled "still possible"; the lower side is labelled "obsolete".]
:[From left to right.]
::Memoirs of the Twentieth Century [1700, 265 years in the future]
::Looking Backward [1888, 112 years in the future]
::Golf in the Year 2000 [1892, 108 years in the future]
::The Time Machine [1895, 800 thousand to 30 million years in the future]
::Enoch Soames [1916, ''circa'' 60 years in the future]
::1984 [1949, 35 years in the future]
::A Week in the Wales of the Future [1957, 76 years in the future]
::The Jetsons [1962-63, 100 years in the future]
::Star Trek [1966-69, 300 years in the future]
::2001: A Space Odyssey [1968, 33 years in the future]
::Space: 1999 [1975-77, 24 years in the future]
::2010: Odyssey Two [1982, 28 years in the future]
::Transformers (TV series) [1984-87, 20 years in the future]
::2061: Odyssey Three [1987, 74 years in the future]
::Star Trek: The Next Generation [1987-94, ''circa'' 500 years in the future]
::Back to the Future Part II [1989, 26 years in the future]
::Zero Wing [1989, 112 years in the future]
::Terminator 2 (1995 portion) [1991, 4 years in the future]
::3001: The Final Odyssey [1997, 1004 years in the future]
::Enterprise [2001-2005, 150 years in the future]
::This chart [2015, 0 years in the future]
:'''Years in the past'''
:[A logarithmic scale running vertically, from 0 down past 1 billion to "Big Bang"]
:'''Stories set in the past''' (History, Period Fiction)
::Stories written X years ago and set 2X years ago
::[A line divides this region into two. The upper side is labelled as follows.]
::'''Former period pieces'''
::Stories set in the past, but created long enough ago that they were published closer to their setting than to today.
::Modern audiences may not recognize which parts were ''supposed'' to sound old.
:[From left to right.]
::The Epic of Gilgamesh [''circa'' 2100 BCE, 600 years in the past]
::The Iliad [''circa'' 800 BCE, 450 years in the past]
::History of the Peloponnesian War [''circa'' 390 BCE, 10 years in the past]
::Book of Genesis [''circa'' 500 BCE, 4000 years in the past]
::Ashokavadana [''circa'' 100 BCE, 300 years in the past]
::Gospels (various estimates) [''circa'' 250 CE, 24 to 75 years in the past]
::The Pillow Book [1000 CE, 5 years in the past]
::Water Margin [''circa'' 1300, 195 years in the past]
::Richard III [''circa'' 1590, 115 years in the past]
::Julius Caesar [1599, 1650 years in the past]
::King John [''circa'' 1600, 500 years in the past]
::Henry IV [''circa'' 1600, 190 years in the past]
::King Lear [''circa'' 1606, 3000 years in the past]
::Henry VIII [''circa'' 1612, 105 years in the past]
::The Last of the Mohicans [1826, 69 years in the past]
::Rip Van Winkel [1819, 31-51 years in the past]
::A Tale of Two Cities [1859, 60 years in the past]
::Moby-Dick [1851, anywhere from 4 to 14 years ago]
:::"Some years ago--never mind how long precisely..."
::Les Miserábles [1862, 30 years in the past]
::Treasure Island [1883, 130 years in the past]
::A Connecticut Yankee in King Arthur's Court [1889, 2000 years in the past]
::Gone with the Wind [1936, 70 years in the past]
::Lest Darkness Fall [1939, 550 years in the past]
::Casablanca [1942, 1 year in the past]
::Oklahoma! [1943, 37 years in the past]
::The Ten Commandments [1956, 1400 years in the past]
::The Bridge on the River Kwai [1957, 13 years in the past]
::Gunsmoke [1952-61, 80 years in the past]
::The Flintstones [1960-66, 100,000 years in the past]
::Catch-22 (book) [1961, 18 years in the past]
::The Great Escape [1963, 20 years in the past]
::Asterix
::Lawrence of Arabia
::The Music Man
::Bonnie and Clyde
::2001: A Space Odyssey (prologue)
::American Graffiti
::Patton
::Catch-22 (movie) [1970, 27 years in the past]
::Chinatown
::Blazing Saddles
::Apocalypse Now
::Happy Days
::Grease
::M*A*S*H
::Annie (play)
::Roots
::Chariots of Fire
::Star Wars (IV-VI)
::Annie (movie)
::The Right Stuff
::Back to the Future
::Gandhi
::Platoon
::Dirty Dancing
::Back to the Future Part III
::The Wonder Years
::JFK
::The Sandlot
::Schindler's List
::Raptor Red
::Apollo 13
::Star Wars (I-III)
::The Big Lebowski
::Evita
::Saving Private Ryan
::The Prince of Egypt
::Freaks and Geeks
::Hotel Rwanda
::I Love the '80s
::That '70s Show
::Pearl Harbor
::Ice Age
::I Love the '90s
::United 93
::300
::10,000 BC
::Year One
::The Wolf of Wall Street
::I Love the 2000s
::Mad Men
::Downton Abbey
::Star Wars (VII-IX)

==Trivia==
*Later after the initial release of this comic Randall added a link to this page. It's viewable in the HTML-source or here: [https://xkcd.com/1491/info.0.json https://xkcd.com/1491/info.0.json]. The text is: ''"this is a massive fucking graph beyond the limits of normal transcription. you can find a full listing of data points at http:\n\nwww.explainxkcd.com\nwiki\nindex.php\n1491"''.

{{comic discussion}}

[[Category:Large drawings]]
[[Category:Charts]]
[[Category:Timelines]]
[[Category:Time]]
[[Category:Star Trek]]
[[Category:Terminator]]
[[Category:Back to the Future]]

1991: Research Areas by Size and Countedness

2022-02-08T22:54:31Z

172.70.34.165: /* Explanation */

{{comic
| number = 1991
| date = May 9, 2018
| title = Research Areas by Size and Countedness
| image = research_areas_by_size_and_countedness.png
| titletext = Mathematicians give a third answer on the vertical axis, "That question is poorly defined, but we have a sub-field devoted to every plausible version of it."
}}

==Explanation==

This comic is a [[:Category:Scatter plots|scatter plot]] that ranks different research fields according to the precision of the knowledge of the number of the studied object (vertical axis) vs. how large (the size of) the studied object is on the horizontal axis.

For instance, the facts pertaining to the number of United States presidents are well known (although the exact number is disputed in that Grover Cleveland is usually counted twice, because he served non-consecutive terms, so the official count exceeds the number of unique Presidents), so the study of their history is at the top of the Y-axis. This study is placed close to the Y-axis as the size of a president is about midway in size between the two extremes of the X-axis, elementary particles to the left (small) and the entire cosmos (cosmology) to the right (big).

On the X-axis, Presidents are close to the middle. Both presidents and other larger life forms (as a research area) including extinct animals (paleontology) and exobiology are all close to the same central position just right of the Y-axis, with smaller animals like birds and insects just to the left of the Y-axis. But where the number of presidents is well known (aside from the dispute about Cleveland), then the number of exoplanet life forms (exobiology) is completely unknown (and would likely be affected by other disputes, such as whether something the size of Pluto counts as a planet) and thus it will be found at the very bottom of the Y-axis, since we have no idea if there are life elsewhere and if so how many places will it be and how varied.

The 19 research areas are listed and explained in the [[#Tables of research areas|tables]] below.

In the title text, mathematicians may give a third answer that the concept of counting the things being studied is not reasonable, because the things are abstract or otherwise not discrete. There are many different types of math that blend into each other, and many have turned into separate sub-disciplines based on different interpretations of fundamental rules. As a specific example in geometry, different interpretations of how many lines you may draw parallel to another line through a given point has lead to {{w|hyperbolic geometry|hyperbolic}} (infinite parallel lines) and {{w|spherical geometry|spherical}} (0 parallel lines) geometric systems that are just as valid (and valuable, in some contexts) as the more commonly known {{w|Euclidean geometry|Euclidean}} (1 parallel line) geometry. As a specific example of the blending, {{w|number theory}}, {{w|set theory}}, and {{w|topology}} all interrelate and it is difficult to concretely say whether many theorems belong to one branch of math or another.

==Tables of research areas==
For a table with the coordinates given in percentage for each research field, see the table in the [[#Trivia|trivia]] section

===Upper left quadrant===
This is the section with the small items with count known.

{| class = "wikitable"
! Research field
! Size of the thing
! Knowledge of #
! Explanation
|-
|{{w|Elementary particle physics}}
| The smallest subjects that we have actually detected are the {{w|elementary particles}}. In the {{w|Standard Model}} of particle physics, they are considered point masses (i.e. to have zero width). They may be made of smaller {{w|String theory|strings}} but if so these have still not been detected.
| We think we have a fairly good estimate of how many elementary particles that are known. There could be some uncertainty though, so it is not at the very top.
|Elementary particle physics is concerned with the study of subatomic particles (the smallest things that we know of), of which there are 17, not including antimatter. Most notably, until recently it was uncertain whether the {{w|Higgs boson}} was one of the elementary particles, but scientists have a "pretty good estimate" because the mathematical models don't predict the existence of many other particles
|-
|{{w|Dentistry}}
|Several mm to several centimeters
|Most teeth are visible to the naked eye, and dentists have x-ray technology to see what's not visible, so counting them is pretty straightforward.
|Dentistry is the study of teeth (pretty small, both in size as well as in quantity). Humans adults grow 32 teeth, which is a "pretty good estimate" since it is very rare for {{w|Hyperdontia|more than 32 teeth to grow}} and it is rather common for {{w|wisdom teeth}} to be surgically extracted or in some cases never to develop. Children may only have 20 teeth before they start falling out, but each tooth that falls out is because another tooth is growing underneath, so a child might have as many as 52 teeth, counting the child teeth that haven't fallen out yet plus the adult teeth that are starting to form. So while a dentist will usually have a good idea how many teeth will be in a patient's mouth, they won't know for sure until they look or consult dental records.
|-
|{{w|Shakespeare}} studies
|Most are the size of typical book. In printed form, they would be in the range of tens of centimeters in height and width and ~1 centimeter in depth. Although, if stored in digial form, they could be much smaller than a tooth, so it seems to refer to print or handwritten originals.
|Generally, 36 plays are attributed to him, but between 1 and 3 additional plays are considered "lost" (i.e. at some point between being first published or performed and scholars seriously studying Shakespeare, all known copies, references, and fragments were destroyed, making it impossible to determine whether Shakespeare actually wrote them or whether they actually existed as separate plays), and {{w|Shakespeare apocrypha|some 20 more}} are believed to have been written by him, but not signed. To make matters worse, some plays that ''were'' published or performed under Shakespeare's name are believed to have been written as collaborations (not fully by him) or mis-attributed (we don't know who wrote them but everyone says it was him).
|Shakespeare studies is concerned with the works of William Shakespeare.
|-
|{{w|Ornithology}}
|Birds tend to be small, with most species able to be held comfortably in hand; even the largest known flying bird, the {{w|Condor}}, stands smaller than the average human, with a handful of non-flying avians such as the {{w|ostrich}} being larger, but still weighing less than 2-3 humans.
|The number of known bird species is [https://en.wikipedia.org/wiki/Bird#Diversification_of_modern_birds estimated at about 10,000], though [https://www.amnh.org/about-the-museum/press-center/new-study-doubles-the-estimate-of-bird-species-in-the-world a 2016 research result] suggested a near-doubling of this figure. As for the number of individual birds, a paper aptly titled [https://link.springer.com/article/10.1023/A:1018341530497 "How many birds are there?"] examines a number of ways of counting them; the results are "surprisingly consistent", with counts of approximately 200-400 billion individual birds.
|We do have a "pretty good estimate", to within perhaps a factor of two.
|-
|Ancient {{w|literature}}
|As above, with Shakespeare plays, original or print reproductions would be the size of a book, typically. Although ancient {{w|scrolls}} may have different dimensions with similar total volume.
|Because of the high number of {{w|lost works}}, it is hard to have a solid estimate of the number, although rough lists have been made (e.g. {{w|Ancient literature#List of ancient texts}}).
|While it is fairly straightforward to look up how many books [http://www.proquest.com/products-services/Books-in-Print.html are currently in print], or how many books [https://mashable.com/2010/08/05/number-of-books-in-the-world/ all currently printed information would fit into if bound into equal-length volumes], and then limiting those estimates to those that date before a specific year, counting how many books from the period of interest haven't survived to the present day (books that were "{{w|lost work|lost}}" either by deliberate discontinuation, or accidental destruction such as in the {{w|Destruction of the Library of Alexandria|Library of Alexandria}}) is a bit more difficult. However, because we know the work existed (it is mentioned by name in some other text), we have "pretty good estimate" that the number of lost works is "only" in the tens of thousands, as is the number of surviving works.
|}

===Upper right quadrant===
This is the section with the big items with count known.

{| class = "wikitable"
! Research field
! Size
! Knowledge of #
! Explanation
|-
|{{w|Marine mammal|Marine}} {{w|Mammalogy|Mammology}}''[sic]''
|They range in size from the {{w|Marine Otter}} (about 1m) to the {{w|Blue Whale}} (up to 30m).
|About 125 non-extinct species.
|Marine mammals are the largest extant animals. The US Government [http://www.nmfs.noaa.gov/pr/species/mammals/ recognizes] 119 marine mammals. However, what constitutes each species is [https://www.marinemammalscience.org/species-information/list-marine-mammal-species-subspecies/ constantly being revised], with new studies indicating either that what used to be considered a subspecies is actually a separate species, or that what used to be considered a separate species is actually a subspecies. As the depths of the ocean are further explored, species that were outright unknown are spotted and need to be classified. However, since marine mammals breathe air and thus must surface, it's likely that all species have been observed by scientists.
|-
|{{w|List_of_Presidents_of_the_United_States|Presidential History}}
|All presidents are {{w|Heights of presidents and presidential candidates of the United States|human-sized}}, with the tallest being {{w|Abraham Lincoln}} at 6 ft 4 in and the shortest being {{w|James Madison}} at 5 ft 4 in.
|As of 2021, 46 people (only 45 are unique; Grover Cleveland is counted twice because his terms were not consecutive) have served or are serving as President of the United States.
|Presidents are generally considered "big" men in history. Therefore, each one is fairly well known and documented. There is, however, some discussion on how many presidents there have been in the history of the United States, since prior to the {{w|Twenty-fifth Amendment to the United States Constitution|25th amendment}}, it was unspecified whether vice presidents counted as presidents during the President's absence. Most notably, this ambiguity is the reason {{w|David Rice Atchison}}'s tombstone is inscribed with the words "President of the United States for one day" (he was not eligible and did not accept the duties even if he was).
|-
|{{w|Railway engineering}}
|Railways can span across countries, and therefore are fairly large
|As railroads are built by humans, we know pretty well how many there are. However small systems(parks, mines) may make this number uncertain.
|A railway can span anywhere from a few hundred feet, to thousands of miles, so they're pretty big. The type of a railway is generally given by its {{w|track gauge}}, which is defined as "standard" (the usual gauge for a region or country), "narrow" (rails closer together than that standard) and "broad" (rails farther apart than that standard). Since what is standard varies from country to country, and indeed from line to line, how many kinds of "narrow" gauge and "broad" gauge exist depend on who you ask. However, whereas every region has ''a'' standard gauge, "{{w|standard-gauge railway}}" has a specific meaning used by rail technicians and enthusiasts worldwide, of a track with rails 1435 mm (4 ft 8.5 in) apart. Anything narrower than that is often described as a narrow-gauge line, even if it is the standard gauge for a particular rail network.
|-
|{{w|Geology}}
|The {{w|Earth}} is larger, by far, than everything else on the chart except the universe (Cosmology), Black Holes, and God (at least under some conceptions, see "Theology" below).
|There is only one Earth (at least if you set aside the possibility of multiverses, see below in Cosmology).
|Geology is generally considered the study of rocks (small rocks being considered fragments of mountain layers, so what counts as a "rock" for a geologist can be pretty big). There is no universally agreed upon number to how many {{w|List of rock types|types of rock}} there are, but all geologists agree they can be grouped into igneous, metamorphic, and sedimentary rock. Alternatively, geology can be construed as the study of the planet Earth's composition ( *geo*- meaning "Earth" ), and geologists are confident that the planet Earth is big and there is only one of it.
|-
|{{w|Cosmology}}
| As this encompasses (at least) all of the visible parts of the {{w|universe}} we live in, there can be no other "items" to study that would be larger.
| There is only one visible universe, but there could be multiverses/parallel universes, and also an infinite universe beyond the borders of our own part of this universe's event horizon. So it depends on who you ask if they say there is one of and infinite number of universes to study, thus it is placed close to the middle of the two extremes.
|Cosmology is the study of the universe. There is an asterisk with the note "Depends on who you ask", relating to the estimate of how many universes there are. While it might seem obvious that there is only one universe, some branches of physics believe that our universe is part of a {{w|multiverse}}, and this remains an open and contested subject in the field.
|}

===Lower left quadrant===
This is the section with the small items with count unknown.

{| class = "wikitable"
! Research field
! Size
! Knowledge of #
! Explanation
|-
|{{w|Mycology}}
|microscopic to a few miles
|Estimated at 2.2 million to 3.8 million species.(Though of these only about 120,000 have been described.)
|Mycology is the study of fungi (since fungi tend to grow flat -- excepting for mushrooms, which are their sexual organs, and do not exceed a foot in height (see [http://www.isciencetimes.com/articles/5740/20130729/giant-fungus-china-mushroom-world-s-largest-size.htm World's Largest mushrooms] -- mushrooms are generally considered small). Many fungi are microscopic, but some get to be a few miles in diameter.[http://www.nationalgeographic.com.au/nature/the-worlds-largest-living-organism.aspx The World's largest living organism.] It is a lot harder to discern which species a fungus is, and therefore classify it, so we "have no idea" how many kinds of fungi there are. Studies [https://www.ncbi.nlm.nih.gov/pubmed/21613136 vary wildly] between about 70,000 to over 5,000,000. There is a comic named after this study: [[1664: Mycology]].
|-
|[[1012: Wrong Superhero|Entymology]]
| For insects, from a fraction of a mm to several 100.
| Estimated from 1,000,000 to 3,000,000
|It is unclear whether [[Randall]] means {{w|entomology}} or {{w|etymology}} (probably neither; it's likely that this wasn't a mistake and it is possibly a direct reference to [[1012: Wrong Superhero]]). In either case, [https://www.ncbi.nlm.nih.gov/pubmed/28938083 estimates for insects] (entomology) vary from less than 1,000,000 to 30,000,000; and [https://www.quora.com/How-many-root-words-are-there-in-the-English-language estimates for root words] (etymology) reaching hundreds of thousands. Entomology was mentioned in the title text of [[1610: Fire Ants]].
|-
|-
|{{w|Microbiology}}
|The {{w|Smallest organisms|smallest viruses}} are around 30nm long. The largest bacterium may reach almost 1mm.[https://curiosity.com/topics/the-worlds-largest-bacterium-is-visible-to-the-naked-eye-curiosity/].
|120,000 to 10,000,000+.
|Microbiology studies microscopic (too small to see) organisms, of which some 1,400 are known and "estimates for the total number of microbial species vary wildly, from as low as 120,000 to tens of millions and higher", according to [https://www.quora.com/How-many-root-words-are-there-in-the-English-language Nature magazine].
|-
|{{w|Pharmacology}}
|{{w|Drugs}}, including {{w|medications}} and {{w|recreational drug use|illegal and recreational drugs}} are molecules which are sub-microscopic (in the range of nanometers).
|Although it is possible to tally all the known drugs, this is at the extreme low end of the pile because the number of possible organic compounds is nearly infinite and the fraction of those are bioactive is completely unknown.
|The number of drugs (pharmaceuticals) discovered and synthesized is not tallied, according to [https://www.raps.org/regulatory-focus%E2%84%A2/news-articles/2014/10/how-many-drugs-has-fda-approved-in-its-entire-history-new-paper-explains recent studies], but an estimate can be obtained by seeing how many have passed through the {{w|Food and Drug Administration|U.S. FDA}} (1,453). Many home remedies, which might technically qualify as drugs, have not been approved because {{w|Novelty (patent)|"everybody knows that"}}, as well as many solely recreational drugs since regulation might result in outlawing. Because of this, "we have no idea" how many drugs truly exist. Since drugs are extremely powerful molecules that are only administered in choice amounts, they are generally perceived as small.
|}

===Lower right quadrant===
This is the section with the big items with count unknown.

{| class = "wikitable"
! Research field
! Size
! Knowledge of #
! Explanation
|-
|{{w|Botany}}
|Plants tend to range from few centimeters to hundreds of meters. Therefore, on average plants are about the same size as human beings.
|Plants estimated from 295,000 to 305,000 in total.
|Botany studies plants, which can reach {{w|List of superlative trees|hundreds of feet by any measure}}. Some {{w|Pando (tree)|clonal colonies of trees}} spread for miles. However, plant tend to clump together in forests and jungles, which makes it hard to get to them and document them. Every year, thousands of new plants are discovered, with the best estimate being that there are [https://news.mongabay.com/2016/05/many-plants-world-scientists-may-now-answer/ nearly 400,000 vascular plants] and an additional [https://www.britannica.com/topic-browse/Plants/Nonvascular-Plants 12,000 non-vascular plants]. However, the rate of discovery doesn't appear to be slowing down significantly, so we truly "have no idea."
|-
|{{w|Paleontology}}
|Paleontologists study fossils, which range in size from very small to very large. When most people think of paleontologists though, they tend to think of them as studying large animals such as dinosaurs.
|Estimated at around 5 billion species.
|Paleontology studies fossils, particularly those of extinct animals, which can reach {{w|Largest prehistoric animals|huge sizes}}. However, since fossils form under very special circumstances, if the animal did not die under those special circumstances, there will be no record of their existence. Therefore, the number of extinct animals can never truly be known, but we've found [http://scienceblogs.com/authority/2010/01/12/how-do-we-know-that-most-of-th/ around 250,000]
|-
|{{w|Black Hole}} {{w|Astronomy}}
|Compared to most astronomical objects, black holes are fairly small. However, most of them (that we are able to detect) are still larger than the Earth, so they would still fall on the "big" end of this chart. Alternatively, Randall may be referring to their mass, which is on the scale of stars.
|It has been estimated that the number of black holes in the {{w|Milky Way}} is around 100 million ([http://hubblesite.org/explore_astronomy/black_holes/encyc_mod3_q7.html]), although there is uncertainty in that estimate and the total number in the universe depends on the size of the universe (see "cosmology", above).
|"Most stellar black holes [...] are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone." ([https://science.nasa.gov/astrophysics/focus-areas/black-holes NASA Black Hole information page])
|-
|{{w|Exobiology}}
|The comic puts this in the size range of paleontology, which can include many sizes (see above), and also marine mammalogy, which tends to have individuals that are in the range of tens of centimeters to several tens of meters. However, {{w|life|life as we know it}} is dominated in numbers by {{w|microbes}}, and {{w|Evolutionary history of life|life on Earth}} began {{w|Abiogenesis|microscopic}}, leading most {{w|Astrobiology|Astrobiologists}} to hypothesize that life on other planets would necessarily include microbes and [https://en.wikipedia.org/wiki/Fermi_paradox#No_other_intelligent_species_have_arisen only possibly include macroscopic life].
|The estimate of {{w|List of potentially habitable exoplanets|how many planets with life there are}} varies from 16 to 40,000,000,000; additionally, [https://en.wikipedia.org/wiki/Habitability_of_natural_satellites#In_the_Solar_System multiple moons] are believed to be potentially habitable for some forms of life in our own solar system. However, the number of bodies apart from Earth confirmed to have life is currently zero. Even more uncertain than the number of potentially habitable exoplanets is the {{w|Rare Earth Hypothesis|huge uncertainty}} in the likelihood of life arising on a habitable planet.
|Exobiology refers to the study of life outside Earth, which requires {{w|SETI|scanning the entire universe for life}}. Currently, exobiology seeks to find a planet or similar body with life (and, {{w|definition of planet|to qualify as a planet}}, bodies capable of sustaining life are big). The uncertainty about how many planets have life in the Milky Way relates to the {{w|Fermi Paradox}}. For life, of the type we know, to exist outside of the Solar system there need to be planets around other stars. Such planets are called Exoplanets, and they have been a [[:Category:Exoplanets|recurrent subject]] on xkcd.
|-
|{{w|Theology}}
|Presumably, any god transcends the bounds of spacetime, making this the largest.
|Depends on who you ask.
|Theology is not a strict science, but as presented here it is the field concerned with the study of one or more {{w|deity|deities}} which is a sacred supernatural being. In particular, theologians study the question of whether {{w|theism|one or more gods exist}} {{w|atheism|or not}}, and, in the former case, whether there are {{w|polytheism|multiple gods}} or {{w|monotheism|just one}} or indeed whether there is literally only {{w|pantheism|one god}}. Although the existence of any supernatural being(s) is unfalsifiable by any natural means, the entire human race has very strong opinions on the subject, so this field probably deserves the “depends on who you ask” disclaimer as well. quantitative uncertainty is also mentioned in [[900: Religions]].
|}

==Transcript==
:[An X-Y scatter plot of research areas, written in gray font, where both axes have arrows in both ends. At the end of each arrow is a label. Above the left part of the X-axis there is a line which goes to a text about the meaning of the X-axis. Similarly there is a line to from the top of the Y-axis to a questions “asked” to those that study the given subject, their answers being somewhere between the two labels on the Y axis.]

:[The X-axis from left to right, text first and then labels:]
:Size of the thing you study
:Small
:Big

:[The Y-axis from top to bottom, question first and then labels:]
:"That thing you study - how many of them are there?"
:"We have a pretty good estimate."
:"We have no idea"

:[The research areas names are listed here below by sorting them into the four quadrants from top left to bottom right. In each quadrant the areas are listed after most left first, and then top to bottom for those at the same x position.]

:[Upper left quadrant (Small & count known):]
:Elementary particle physics
:Dentistry
:Shakespeare studies
:Ornithology
:Ancient Literature

:[Upper right quadrant (Big & count known):]
:Presidential History
:Marine Mammology
:Railway Engineering
:Geology
:Cosmology*
:(*Depends who you ask)

:[Lower left quadrant (Small & count unknown):]
:Pharmacology
:Microbiology
:Entymology
:Mycology

:[Upper right quadrant (Big & count unknown):]
:Botany
:Paleontology
:Exobiology
:Black Hole Astronomy
:Theology

==Trivia==
Sortable table with the coordinates in percent:
{|class="wikitable sortable"
! Research area
! Size (%)
! Estimate (%)
|-
|Elementary Particle Physics ||7 ||72
|-
|Pharmacology ||12 ||6
|-
|Microbiology ||15 ||13
|-
|Dentistry ||21 ||84
|-
|Entymology ||24 ||25
|-
|Mycology ||29 ||38
|-
|Ornithology ||34 ||62
|-
|Shakespeare Studies ||37 ||88
|-
|Ancient Literature ||38 ||53
|-
|Botany ||60 ||40
|-
|Presidential History ||62 ||89
|-
|Marine Mammology ||66 ||68
|-
|Paleontology ||68 ||31
|-
|Exobiology ||68 ||5
|-
|Railway Engineering ||79 ||81
|-
|Geology ||90 ||90
|-
|Theology ||91 ||5
|-
|Black Hole Astronomy ||92 ||26
|-
|Cosmology ||94 ||62
|}

{{comic discussion}}

[[Category:Scatter plots]]
[[Category:Rankings]]
[[Category:Science]]
[[Category:Physics]]
[[Category:Astronomy]]
[[Category:Math]] 
[[Category:Fiction]] 
[[Category:Religion]] 
[[Category:Animals]] 
[[Category:Exoplanets]] 
[[Category:Politics]] 
[[Category:Geology]]
[[Category: Research Papers]]

2559: December 25th Launch

2021-12-27T15:40:21Z

172.70.34.165: /* Explanation */

{{comic
| number = 2559
| date = December 24, 2021
| title = December 25th Launch
| image = december_25th_launch.png
| titletext = Update: Santa has been destroyed by the range safety officer.
}}

==Explanation==
{{incomplete|Created by JWST: JUST WATCHED SANTA TERMINATED BY A RANGE SAFETY OFFICER NAMED GRINCH . - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The {{w|James Webb Space Telescope}} is a space telescope jointly developed by NASA, the European Space Agency, and the Canadian Space Agency. It has suffered many, many delays over its development period (as previously referenced in [[2014: JWST Delays]]), but it finally launched on Christmas day, December 25, 2021, within hours of this comic appearing.

In this comic, the James Webb Space Telescope is finally ready to take off. However, an unfortunate circumstance occurs: Santa Claus himself, presumably on his way to or from delivering presents to children, crosses into the path of the launch rocket. The joke is the implication that, right on the brink of success, this extraordinarily unlucky incident will either destroy the telescope, harm Santa, or cause yet another delay, much to Cueball's horror.

Real launch aborts have {{w|STS-68|occurred}} with fewer than 2 seconds left in the countdown, causing delays of over a month.

According to the title text, the {{w|range safety officer}} has made the decision to shoot down Santa Claus's sleigh, in order to clear the sky above, protecting the launch window. This seems to demonstrate that they are determined not to let anything delay the launch any further (or that given a choice between destroying the telescope or destroying Santa, the range safety officer chooses the latter).

Airspace is normally [https://simpleflying.com/rocket-launches-airline-traffic/ closed to air traffic] to avoid collisions between aircraft and rocket launches. While Santa might not know about such restrictions, he already knows about this particular launch because thousands of astronomy geeks have asked for a new space telescope as a Christmas present in their letters to Santa, and the easiest way for Santa to deliver such a present is just keeping a safe distance from the launch pad. Moreover {{w|NORAD}} [https://www.noradsanta.org/en/ tracks Santa]'s flying around the world and would be able to give sufficient warning to both Santa and Ground Control to prevent such a close encounter of a festive kind; as well as to prevent accidental global thermonuclear war by {{w|1983 Soviet nuclear false alarm incident|confusing a pack of flying reindeer}} with a first-strike attack by a foreign power. Finally, Santa Claus performs deliveries overnight, while the launch is scheduled for [https://www.nytimes.com/2021/12/24/science/webb-telescope-launch-date-livestream.html morning local time], so the timing of such a collision would not occur.

The JWST has been referenced previously in [[1730: Starshade]], [[2014: JWST Delays]], [[2447: Hammer Incident]] and [[2550: Webb]], as well as indirectly in [[975: Occulting Telescope]] and [[1461: Payloads]]. Santa is known to [[838|maintain a list of humans]] responsible for technological incidents and to have suitable punishment for offenders.

==Transcript==
:[Close-up of the top of the James Webb Space Telescope launch rocket. A "Webb" logo can be seen alongside other indistinct logos. Some clouds and birds are visible in the background.]
:Caption: T-minus 10...9...8...

:[Zoom-out to show the complete rocket and the ground below. The rocket takes up the bottom-left corner. At the top-right, Santa Claus and a line of reindeer are flying in towards the left.]
:Santa: Ho ho ho! Merry Christmas!

:[Ponytail and Cueball sitting at mission control consoles.]
:Cueball: ''Oh no.''

{{comic discussion}}
[[Category: Christmas]]
[[Category: Telescopes]]
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring Ponytail]]

Talk:2549: Edge Cake

2021-12-06T14:40:18Z

172.70.34.165:

The cake being all edges is a reference to everything about her birth being an edge case.
[[Special:Contributions/172.70.110.227|172.70.110.227]] 03:41, 2 December 2021 (UTC)
: It seems likely that the title of the comic is a related pun: her birthday is an edge case, and so she has an edge cake.[[Special:Contributions/162.158.106.221|162.158.106.221]] 04:22, 2 December 2021 (UTC)
So is Hairbun officially named Emily now, sort of like how all instances of Megan are Megan even though she's only called that once? I know all the names here are just placeholders of convenience, but even then I've never know what the rules for naming are. [[User:Captain Video|Captain Video]] ([[User talk:Captain Video|talk]]) 06:11, 2 December 2021 (UTC)
: Well, Megan is referred to multiple times in the xkcds as "Megan", while the one time Hairbun was called Emily, it referred to the real{{citation needed}} Emily Dickinson. So, probably not. [[User:Bubblegum|bubblegum]]-[[User_talk:Bubblegum|talk]]|[[Special:Contributions/Bubblegum|contribs]] 02:44, 3 December 2021 (UTC)

Edge pieces on cake are often sought after because they hold more frosting, for cakes which are frosted while out of the pan. [[Special:Contributions/172.70.134.23|172.70.134.23]] 06:37, 2 December 2021 (UTC)
: I have an impression that Cueball is delighted by having only edge pieces, however some cakes edge pieces may be either sought for or avoided, depending on one's tastes. E.g. tarts have more crispy base cake content and less filling at the edges. One person may go for the filling, another for the crispy base. -- [[Special:Contributions/162.158.102.11|162.158.102.11]] 09:50, 2 December 2021 (UTC)

So it seems the events in the comic happened on Apr 1., as the "last month" birthday could be either Feb 28. or 29. -- [[Special:Contributions/162.158.102.11|162.158.102.11]] 09:50, 2 December 2021 (UTC)
:Not necessarily. Remember, Emily can have her birthday ''whenever she wants'', so the date this comic is set as is entirely arbitrary. [[Special:Contributions/172.70.178.51|172.70.178.51]] 12:26, 2 December 2021 (UTC)

Are there any particular existing arctic international flights that could have been the one Emily was born on? -- [[Special:Contributions/256.256.256.256|256.256.256.256]] 15:51, 2 December 2021 (UTC)
:There are a few possibities (at least pre-COVID, and obviously we'd be looking historically in this case anyway) as [https://interestingengineering.com/polar-routes-flights-that-go-over-earths-poles might be shown here]. There's two possible (but neither definite) International Datelines on the comic diagram, in case they help orient which from/to directions might have been diverted further in or out of their own kinks in the flightpath to coincide with 90°N. [[Special:Contributions/172.70.162.77|172.70.162.77]] 16:21, 2 December 2021 (UTC)

Expanded copies of this comic have been appearing on other comics, so large that it fills the whole screen for me. Is anyone else having this problem? [[User:Sarah the Pie(yes, the food)|Sarah the Pie(yes, the food)]] ([[User talk:Sarah the Pie(yes, the food)|talk]]) 22:24, 2 December 2021 (UTC)
:Someone (check the [[Special:RecentChanges|Recent Changes]] page, if you want) has been vandalising a lot of things. Currently I see a picture of an amphibious avian creature on this article's top (if I still need to revert it myself, I will do, but I've seen others have already been reverting other recent vandalism, so I may not need to by the time I've checked again). This very clever individual is obiviously mentally superior to us all(!) the way they can edit wiki pages seemingly at will... Impressive, eh? At some point I'm sure we'll get back to normlal, however boring that may be. [[Special:Contributions/172.70.90.67|172.70.90.67]] 23:33, 2 December 2021 (UTC)

Not to be too pedantic but isn't rotation a FREQUENCY, not a SPEED? [[User:Skulker|Skulker]] ([[User talk:Skulker|talk]]) 03:19, 3 December 2021 (UTC)
:Depends on the context (and scale). The convention is usually speed for rotation (surface(distance/time) when it's relevant, angular(revolutions/time) otherwise) to avoid conflicts with wave frequency (which is independent of speed). Also they can be freely converted, though converting to and from surface speed requires an additional radius term. The exception is, if comparing periodicity, sometimes frequency is used when it has special relevance (Ex: resonance) -- [[Special:Contributions/172.69.68.200|172.69.68.200]] 02:59, 4 December 2021 (UTC)

Tempted to add a link in the Trivia section to the [https://en.wikipedia.org/wiki/SS_Warrimoo Wikipedia] or [https://www.snopes.com/fact-check/ss-warrimoo/ Snopes] pages on the SS Warrimoo, a ship that (reportedly) was on the intersection of the Equator and the International Date Line at the stroke of midnight on January 1, 1900, with a number of interesting implications that follow. There's no way to prove that it actually happened, but it's fun to imagine and is somewhat similar to the premise of the comic. --mezimm [[Special:Contributions/108.162.221.15|108.162.221.15]] 14:33, 3 December 2021 (UTC)

Many airplanes actually have limitations written into their operating manuals that prohibit flying north of 89 deg. N or south of 89 deg. S, mostly just so that the navigation software doesn't have to deal with the singularity. [[Special:Contributions/172.69.71.187|172.69.71.187]] 23:48, 3 December 2021 (UTC)
:bloody lazy engineers! [[Special:Contributions/108.162.219.107|108.162.219.107]] 12:19, 5 December 2021 (UTC)

Is it not possible that Emily's birth happened to occur at the same moment that the contract specified transfer of ownership? Additionally, is it not possible that the airplane took off from within UTC+13:00 or UTC+14:00 and that the moment of Emily's birth happened to occur in the brief one-or-two hour period in which it was March 1st at that airport, but February 28th in UTC-12:00? UTC-11:00 is inhabited, so it would be possible that ownership of an airplane that took off from within UTC+14:00 was transferred to a company based out of UTC-11:00 during the one-hour period that it was February 28th in UTC-11:00 and March 1st in UTC+14:00 and that, at that exact moment, it was passing over the North Pole. [[User:DL Draco Rex|DL Draco Rex]] ([[User talk:DL Draco Rex|talk]])

Am I alone in thinking that babies don't get born instantaneously? I've never given birth myself but i'd always got the impression that it's a process and any attempt to pick a precise 'instant' is going to be somewhat arbitrary. This means that the plane will very probably have travelled through a variety of time zones any of which could be the 'real' time of birth. [[Special:Contributions/172.70.85.155|172.70.85.155]] 05:29, 4 December 2021 (UTC)
:Time of birth is an arbitrary decision made by the midwives filling out forms in a hospital. The more unlikely point about that is that she'd be able to correlate the precise position of the plane at the exact time listed. [[Special:Contributions/108.162.219.187|108.162.219.187]] 12:37, 5 December 2021 (UTC)

Dickenson looks like a typo. Dickinson? [[Special:Contributions/172.70.162.77|172.70.162.77]] 08:44, 4 December 2021 (UTC)

Isn't an "all edge pieces cake" just a plate of cupcakes lol? [[User:Zman350x|Zman350x]] ([[User talk:Zman350x|talk]]) 06:46, 5 December 2021 (UTC)
:Only if you frosted all sides of it.[[Special:Contributions/172.70.114.3|172.70.114.3]] 12:25, 5 December 2021 (UTC)
:Alton Brown made a similar argument, but after experimenting, I strongly disagree. As with brownies, the cooking pattern is slightly different between having more edges and having a cupcake shape. In an edge piece, the edges and the corners are crisp while the center is gooey. Meanwhile, if cooked in a cupcake tin, while there might be more crispness, there is significantly less gooeyness. [[User:Cwallenpoole|Cwallenpoole]] ([[User talk:Cwallenpoole|talk]]) 14:23, 6 December 2021 (UTC)
:If you cut the sheet into quarters or if the whole was round and cut with radial slices there won't be any center piece(s). And there are more, unusual cuts that could result in all edge pieces...[[Special:Contributions/172.70.34.165|172.70.34.165]] 14:40, 6 December 2021 (UTC)

Talk:2550: Webb

2021-12-06T14:24:57Z

172.70.34.165:

Ah, without edit-conflict being indicated (probably because subsequent new paragraphs could be considered as not 'treading on the toes' of the first one posted), I seem to have added repetitious information. Also I can see that I misbalanced the paragraph sizes as I went into increasingly more detail as I got into the edit. Was going to go back to wikilink/fix/etc, but I should probably leave it to a new eye to better re-edit the whole think 'nicer', taking how much or little inspiration the current mess of text might provide. Have fun! [[Special:Contributions/172.70.85.41|172.70.85.41]] 04:49, 4 December 2021 (UTC)
: I tried to restructure it a bit (grouping related info, rebalancing paragraph sizes) and resolve the duplication without losing any important information. Hope it looks okay? [[Special:Contributions/172.68.133.99|172.68.133.99]] 05:46, 4 December 2021 (UTC)
:: wtg guys for clearly describing these abstract issues and addressing them [[Special:Contributions/172.70.110.227|172.70.110.227]] 16:38, 5 December 2021 (UTC)

Could someone explain why the numbers are arranged the way they are?
: It looks like the mirror on the telescope. --[[Special:Contributions/172.70.110.171|172.70.110.171]] 14:04, 4 December 2021 (UTC)
: If a magic hexagon was possible, he would have done it. However, the numbers add up to 243, and with 5 rows, this makes it impossible for each row to add up to the same number. [[Special:Contributions/172.70.110.173|172.70.110.173]] 16:29, 4 December 2021 (UTC)
: I know some advent calendars go in exact order, but a lot of them are actually ordered randomly. I've got one in my living room where the top row is "2, 17, 8, 10" [[Special:Contributions/172.70.210.237|172.70.210.237]] 23:42, 4 December 2021 (UTC)

Alternate explanation: all the astronomers are Moldovian Orthodox Catholics, and they timed the telescope to launch on Christmas Eve in their slightly out-of-sync calendar in which Christmas replaced days 2 & 3 of their week long Winter Solstice Party.[[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 17:28, 4 December 2021 (UTC)

Why does it have the small hexagons oriented "pointy side up"? I know this is generally considered a good thing, as far as rocket launches are concerned, but in this case? [[Special:Contributions/162.158.88.91|162.158.88.91]] 20:28, 4 December 2021 (UTC)
:That's the way the hexagonal mirrors are oriented in the JWST [[User:256 256.256.256|256.256.256.256]] ([[User talk:256 256.256.256|talk]]) 12:09, 6 December 2021 (UTC)

The cells on the calendar go from 5 to 22, which I assumed was a reference that astronomers have been waiting since 2005 (when the current mission was replanned) until 2022 (the year the telescope will become active). Rather than counting down 25 days until Christmas, astronomers are counting down 18 years (inclusive) until they get their new toys to play with. [[Special:Contributions/172.70.134.23|172.70.134.23]] 00:29, 5 December 2021 (UTC)
: It's also just the number of mirrors the telescope has, and the day it launches. [[Special:Contributions/172.70.110.227|172.70.110.227]] 16:38, 5 December 2021 (UTC)

JWST is as fixable as Hubble, if you have Starships. Which NASA is already counting on (and funding) for Artemis.[[Special:Contributions/172.70.134.191|172.70.134.191]] 21:37, 5 December 2021 (UTC)
:Not yet available... Current tech is woefully unable (or unwilling to be put to use) to help with HST, never mind JWST. Retired tech could do Hubble, as proven, but would have been stretched to deal with the Webb. And the Webb isn't even designed ''to'' be fixed (though I'm sure they'll still have people working on it if they discover a washer's-worth of mirror misalignment, or whatever...).
:That sweet smell of Musk isn't yet right for the job. Even if the business plan says that it will be flying within the next few months, it'd be wishful thinking to rely on it at this point.
:(More so than with the sample-driller/collect/return chain of missions currently only a fraction of the way through realisation upon Mars. There's the Return stage to implement almost from scratch (setting up remote launch-site, fully fueled, etc) but the whole rover-with-manipulator thing isn't really an engineering challenge, more a matter of design nuances and the usual amount of (apparently increasing, but surely not infallible) skill and luck in executing the required landings.) [[Special:Contributions/172.70.162.155|172.70.162.155]] 00:13, 6 December 2021 (UTC)
::Off topic now, but the point about manned missions to Mars is that you _don't_ come back, you colonise. good luck.[[Special:Contributions/172.70.162.77|172.70.162.77]] 13:19, 6 December 2021 (UTC)

Could it also have to do with the fact that so called "Advent Calendars" tend to have 25 days, even though the Advent Season (Starting 4 Sundays before Christmas) is dependant on what day of the week Dec 25th falls on, and at a minimum 28 days long? Or am I the only one bothered by the fact that the companies making these calendars ignore the meaning of "advent" in the Christmas context, and just arbitrarily start them in December?[[Special:Contributions/172.70.34.165|172.70.34.165]] 14:24, 6 December 2021 (UTC)

2545: Bayes' Theorem

2021-11-22T23:30:00Z

172.70.34.165:

{{comic
| number = 2545
| date = November 22, 2021
| title = Bayes' Theorem
| image = bayes_theorem.png
| titletext = <nowiki>P((B|A)|(A|B)) represents the probability that you'll mix up the order of the terms when using Bayesian notation.</nowiki>
}}

==Explanation==
{{incomplete|Created by <nowiki> P(d/dx x^x | d/dx x^(1/x)) </nowiki> - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

{{w|Bayes' theorem}} describes the probability of an event, based on prior knowledge of conditions that might be related to the event.

In this comic, the off-panel student knows that they are studying Bayes' theorem, so they use that prior knowledge to guess that the test result is a false positive. The punch line is the caption - if you know Bayes' theorem well enough, you don't need to actually calculate the probabilities.

The title text refers to the mathematical definition of Bayes' theorem: P(A | B) = P(B|A) * P(A) / P(B). Here, P(A|B) represents the probability of some event A occurring, given that B has occurred. This is often referred to as "the probability of A given B". It can be hard to remember if P(A|B) means probability of A given B, or if it's B given A, and Randall's joke is based on this difficulty. Specifically, P((B|A)|(A|B)) would be the probability of (A|B) given (B|A), which makes it the probability that you got the order of the notation mixed up.

==Trivia==
When this comic came out, the title text was only "P((B" and the "Black Lives Matter" image in the header replaced by "(A", but this was quickly corrected.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Miss Lenhart using a pointer and pointing to a white-board with statistical formulae]
:Miss Lenhart: Given these prevalences, is it likely that the test result is a false positive?
:(off-panel voice): Well, this chapter is on Bayes' Theorem, so yes.

:[Caption below the panel]:
:Sometimes, if you understand Bayes' Theorem well enough, you don't need it.

{{comic discussion}}

[[Category:Comics featuring Miss Lenhart]]
[[Category:Statistics]]

2545: Bayes' Theorem

2021-11-22T23:29:02Z

172.70.34.165:

{{comic
| number = 2545
| date = November 22, 2021
| title = Bayes' Theorem
| image = bayes_theorem.png
| titletext = <nowiki>P((B|A)|(A|B)) represents the probability that you'll mix up the order of the terms when using Bayesian notation.</nowiki>
}}

==Explanation==
{{incomplete|Created by P(d/dx x^x|d/dx x^(1/x)) - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

{{w|Bayes' theorem}} describes the probability of an event, based on prior knowledge of conditions that might be related to the event.

In this comic, the off-panel student knows that they are studying Bayes' theorem, so they use that prior knowledge to guess that the test result is a false positive. The punch line is the caption - if you know Bayes' theorem well enough, you don't need to actually calculate the probabilities.

The title text refers to the mathematical definition of Bayes' theorem: P(A | B) = P(B|A) * P(A) / P(B). Here, P(A|B) represents the probability of some event A occurring, given that B has occurred. This is often referred to as "the probability of A given B". It can be hard to remember if P(A|B) means probability of A given B, or if it's B given A, and Randall's joke is based on this difficulty. Specifically, P((B|A)|(A|B)) would be the probability of (A|B) given (B|A), which makes it the probability that you got the order of the notation mixed up.

==Trivia==
When this comic came out, the title text was only "P((B" and the "Black Lives Matter" image in the header replaced by "(A", but this was quickly corrected.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Miss Lenhart using a pointer and pointing to a white-board with statistical formulae]
:Miss Lenhart: Given these prevalences, is it likely that the test result is a false positive?
:(off-panel voice): Well, this chapter is on Bayes' Theorem, so yes.

:[Caption below the panel]:
:Sometimes, if you understand Bayes' Theorem well enough, you don't need it.

{{comic discussion}}

[[Category:Comics featuring Miss Lenhart]]
[[Category:Statistics]]

2545: Bayes' Theorem

2021-11-22T21:24:31Z

172.70.34.165:

{{comic
| number = 2545
| date = November 22, 2021
| title = Bayes' Theorem
| image = bayes_theorem.png
| titletext = P((B
}}

==Explanation==
{{incomplete|Created by a FALSE POSITIVE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
Presenter: Given These Prevealences, Is it likely that the test result is a false positive?
Off-panel: Well, This chapter is on Baye's Theorem, so yes.
{{comic discussion}}

[[Category:Comics featuring Miss Lenhart]]
[[Category:Statistics]]

2540: TTSLTSWBD

2021-11-12T15:25:54Z

172.70.34.165: /* Explanation */ Changed link to standard wikipedia link

{{comic
| number = 2540
| date = November 10, 2021
| title = TTSLTSWBD
| image = ttsltswbd.png
| titletext = Tomorrow's sessions will be entirely devoted to sewing machine rotary hooks.
}}

==Explanation==
{{incomplete|Created by an EXCESSIVELY LONG ACRONYM THAT SEEMS LIKE IT SHOULD WORK BUT DOESN'T. Do NOT delete this tag too soon.}}

[[Cueball]] is standing at a lectern on a [[1661: Podium|podium]], addressing a large crowd. He is describing the program of some event, listing the different topics that will be covered. These appear to be random, but the caption gives the punchline: it is a conference on things that seem like they shouldn't work but do.

By "things that seem like they shouldn't work", it means things that the average person would have some intuitive sense that the function of thing was impossible, and yet ample real-world experience shows that they do, and may become a routine function that people depend upon. TTSLTSWBD in the title and the banner is the abbreviation for "Things That Seem Like They Shouldn't Work, But Do".

{{w|Organ transplantation}}, where a functioning organ is cut out of one person (possibly a dead person) and put into another person where it will continue to operate. Given the very complex and delicate nature of living tissue, it's rather surprising that this could work at all. In reality, it's not a simple process, and a lot of things could go wrong, but modern medicine is advanced enough that organ transplantation is widely accepted and regularly practiced, usually functioning well enough to extend life.

{{w|Airship|Airships}}, or dirigibles, are [[https://upload.wikimedia.org/wikipedia/commons/e/ee/Giant_Aircraft_Comparison.svg 1 huge]], rigid structures which are filled with bags of lighter-than-air gas, which causes the entire structure to float, and could carry both passengers and significant loads. The idea of such a huge vessel traveling, able to both move rapidly and float in place, would be hard to imagine if it didn't exist, yet zeppelins functioned and were a practical mode of transportation for a time. Unlike the other things mentioned, airships are largely obsolete (having lost favor due to {{w|Hindenburg_disaster|safety concerns}} and surpassed by other technologies)

{{w|Lunch|Lunch}} is listed as if it was another topic of the TTSLTSWBD, but it actually just means that after discussing airships, the conference will take a break to eat lunch, as many [[1530:_Keyboard_Mash|humans]] usually do.[[[285: Wikipedian Protester|''citation needed'']]] Because lunch is a relatively modern construction, filling a niche that grew after dinner shifted later into the day, it may defy one's intuition. In this sense, a three-meal day may seem like it shouldn't work, but most who observe all three meals on schedule would likely argue that it does.

{{w|Gyroscope|Gyroscopes}} are simple devices consisting of a spinning disc mounted inside three concentric {{w_Gimbal|gimbals}}. The rotational inertia of the disc resists change in orientation, and the gimbals allow it to remain in a single orientation, even when it's mounted to something that's moving. The notion that a disc can remain steady, even when everything around it is moving can be counterintuitive even to those who understand the physical principles. This weirdness has been previously referenced in [[332: Gyroscopes]].

{{w|Butterfly|Butterflies}} fly with an unusual fluttering pattern, which works in part due to the {{w|Ornithopter#Aerodynamics|notoriously complex principles of fluid dynamics}} that may look like uncontrolled fluttering but yet somehow allows the creature to land directly on specific flowerheads to feed. This is not as intuitively understandable as the flight of larger creatures such as birds.

The title text refers to {{w|Rotary hook|rotary hooks}} on sewing machines, which are a complicated (and complicated looking) mechanism whose purpose is to feed one thread in a loop around a whole spool of another thread, to the extent that the conference feels they need a whole day to cover them.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Cueball stands at a lectern gesturing with one hand held out, speaking to an audience. A banner hangs on the wall with the acronym "TTSLTSWBD" displayed in large text, with illegible smaller text under it.]
:Cueball: Next we have a session on organ transplants and another on airships.
:Cueball: Then lunch, then we'll have one on gyroscopes and one on butterflies.
:[Caption below panel:]
:The first annual conference on Things That Seem Like They Shouldn't Work But Do

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Animals]]

Talk:2534: Retractable Rocket

2021-10-28T19:58:19Z

172.70.34.165: /* 0% Penis Joke? */

However it is done, note that the base of the 'first stage' extends/retracts in advance of the bit further up, as can be seen by the panelling position in the standing/extending/extended/retracted frame-sequence. Which might be worth noting if you're wanting to copy the technology. [[Special:Contributions/172.70.85.185|172.70.85.185]] 03:09, 28 October 2021 (UTC)

: I think this might be theoretically possible, ignoring the apparently topological outer skin of the "rocket", with some kind of steerable [https://en.wikipedia.org/wiki/Space_fountain space fountain]. Accelerating the astronauts at 10g for about two minutes might be survivable, and could limit the overall length to just over 800 miles. Though the shroud only has to extend to where the atmosphere is "sufficiently" thin. No idea whether this kind of design would tend to fall over when finished or not. -- [[User:Ken g6|Ken g6]] ([[User talk:Ken g6|talk]]) 04:24, 28 October 2021 (UTC)
::I believe it is 100% impossible. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:45, 28 October 2021 (UTC)

If (as it appears) the Bot created the page with various references to "Retract'''i'''ble" rarher than "Retract'''a'''ble", does this mean Randall made that error initially? (I say this as the guy who failed to notice he'd put "re'''su'''able" in his Transcript edit. ;) ) [[Special:Contributions/172.70.162.129|172.70.162.129]] 03:54, 28 October 2021 (UTC)

: Looks like yep, Randall originally made that error persistently, as the image here still has "retractible" in the comic, but the image on xkcd.com has been updated. Not sure how this is usually handled, I think it's mentioned in the FAQ.
: Edit: okay, I've uploaded the new image, and added a trivia bit about the original. No idea how to update the page URL, that'll have to be someone else. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 04:02, 28 October 2021 (UTC)

In my own opinion I think this is actually a brilliant idea, if you think outside the box. Imagine those floppy noodle blow up baloons they use at car dealerships and the like. Now replace the continuous membrane with a membrane combined with multiple stages of internal baffles that can collapse and move around vertically, and scale the whole thing up. Now think about a straw. What if we engineered a straw that reaches all the way to the target (and then back into the atmosphere), and inflate it? we could have [https://en.wikipedia.org/wiki/ThothX_Tower] the ThothX tower but that is a stacked kevlar cell system that only reaches 12 miles in height. The weight is not truly supported by the air, but rather by the tensile strength of the membranes. The question is how much air we'd need to move and how big would it need to be to function. [[Special:Contributions/172.69.69.182|172.69.69.182]] 04:45, 28 October 2021 (UTC)

Is there a compelling reason to refer to the countdown as spoken by "Tannoy" rather than "PA" or "Loudspeaker" or something? I had to look up what that was. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 05:09, 28 October 2021 (UTC)
:I have correct to a count down voice. We have no idea how it emanates. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:44, 28 October 2021 (UTC)

I tried to update the page and image URLs to fix the misspelling, and I think it mostly worked. But if you click the "Next" button from the previous comic it doesn't work so smoothly. Anyone know how to fix that?? [[User:Orion205|Orion205]] ([[User talk:Orion205|talk]]) 05:40, 28 October 2021 (UTC)
: <strike>Erm, this seems to have broken the main page as well. I've found [[https://www.mediawiki.org/wiki/Special:MyLanguage/Help:Moving_a_page]], which says to use the "Move" option in the "More" menu at the top of the page. Did you use that?</strike> Never mind, I think I was just the victim of cache weirdness. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 05:51, 28 October 2021 (UTC)

As a rule, when you’re correcting someone else’s mistake, proofread your correction, or you might make a new mistake that will leave “it is” mark on explainxkcd. [[Special:Contributions/162.158.106.105|162.158.106.105]] 09:13, 28 October 2021 (UTC)

When I first read this comic, I thought it was a KSP reference. I feel like half the rockets I build do that if I don’t add struts. I realized in a second it was extending and not just noodling but it made me laugh, and then I laughed again after understanding the real joke. I got two jokes out of one. --[[User:BlackBeret|BlackBeret]] ([[User talk:BlackBeret|talk]]) 11:36, 28 October 2021 (UTC)

=== 0% Penis Joke? ===
It's hard for me to believe this is in no way a penis joke; particularly with the falling over rather than gracefully retracting, afterward. Is everyone truly certain there's ''not'' a penis joke intended, here? 
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:06, 28 October 2021 (UTC)
:I don\'t think so. --[[User:GcGYSF(asterisk)P(vertical line)e|GcGYSF(asterisk)P(vertical line)e]] ([[User talk:GcGYSF(asterisk)P(vertical line)e|talk]]) 18:29, 28 October 2021 (UTC)
:Me neither. randall hasn't done anything even remotely like that since over a thousand comics ago. kinda sad, really [[Special:Contributions/172.70.34.165|172.70.34.165]] 19:58, 28 October 2021 (UTC)Bumpf

406: Venting

2021-10-27T20:17:08Z

172.70.34.165:

{{comic
| number = 406
| date = April 4, 2008
| title = Venting
| image = venting.png
| titletext = P.P.S. I can kill you with my brain.
}}

==Explanation==
This is yet another xkcd comic referencing ''{{w|Firefly (TV series)|Firefly}}'', but it's not so much about ''Firefly'' itself as about {{w|Summer Glau}}. Summer Glau is an American actress best known for playing {{w|River Tam}} in ''Firefly'' and ''{{w|Serenity (film)|Serenity}}'', as well as Cameron in the ''{{w|Terminator: The Sarah Connor Chronicles}}'' series.

[[Cueball]] claims that he gives a long and seemingly well-researched reply to a stupid comment on a blog, just to let out his anger. In this particularly long comment, at first he becomes what is known over the internet as a 'Grammar Nazi'. Then, he proceeds to rip apart the commenter by citing their historical and political ignorance. He signs his comment as 'Summer Glau', after which he reminds the blogger to watch the next season of ''Terminator: The Sarah Connor Chronicles series''.

One likely reason that he uses 'Summer Glau' is that she is worshiped by geeks the world over, even those incapable of writing coherent blog posts. CrackMonkey74 would not risk responding negatively to the post, just in case it was actually written by Summer Glau, and by so doing, he would ruin any kind of respect by everyone. In this way, Cueball is assured of the last word in this argument, which makes for a most satisfying vent.

Another possible explanation is that River Tam has a genius-level intellect and is also mentally disturbed. Given xkcd's trend of comparing ''Firefly'' characters to their respective actors (Especially [[The Race]]), Cueball is probably using Summer Glau's name simply because an exhaustively researched blog comment seems like something River Tam -- and thus possibly Summer Glau -- would do.

The title text refers to the famous dialogue delivered by River Tam in ''Firefly'' Episode 11: "{{w|Trash (Firefly)|Trash}}".

==Transcript==
:When I need to blow off steam, I find a particularly stupid blog comment and reply with an exhaustively researched word-by-word rebuttal, which I sign 'Summer Glau'.
:Cueball (typing): In conclusion, on examining the above post by CrackMonkey74, after carefully working my way through the haze of spelling errors (documented in section 3), abuse of capitalization (section 4), and general crimes against grammar and syntax (sections 7-8), I have demonstrated that, beneath it all, the work betrays the author's staggering ignorance of the history and the workings of our electoral system. While the author's wildly swerving train of thought did at one point flirt with coherence, this brief encounter was more likely a chance event (see statistical analysis in table 5) than a result of even rudimentary lucidity.
::-Summer Glau
:P.S. Don't forget to check out the next season of the ''Sarah Connor Chronicles'' this fall on Fox!

==Trivia==
*Cueball's statement has been widely reused by many bloggers after the release of this comic.
*The name ''CrackMonkey74'' also appears in [[202: YouTube]] as one of the clueless YouTube commentators, and later appears in [[574: Swine Flu]].

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Summer Glau]]
[[Category:Language]]
[[Category:Terminator]]

Talk:2533: Slope Hypothesis Testing

2021-10-27T19:42:25Z

172.70.34.165:

In the line "Randall has repeatedly made comics about this hopeful error", should specific examples be provided? I know /882 is one, but I'm blanking on any others. [[Special:Contributions/172.68.132.114|172.68.132.114]] 10:21, 26 October 2021 (UTC)
:Definitely, otherwise it would not be very useful. --[[Special:Contributions/162.158.203.54|162.158.203.54]] 13:10, 26 October 2021 (UTC)
:hi, I added the line. <thinking-out-loud removed in copyediting>. I think there was one where article titles that blatantly used poor statistical techniques were listed, not sure. [[Special:Contributions/172.70.114.3|172.70.114.3]] 14:40, 26 October 2021 (UTC)
I love it. [[User:Fwacer|Fwacer]] ([[User talk:Fwacer|talk]]) 02:52, 26 October 2021 (UTC)

I imagine that the problem here is that the errors are not independent. I can't find anything else wrong with this, but I feel like there's something obvious I'm not seeing. They might revoke my statistics degree if I miss something big here, hehe.--[[User:Troy0|Troy0]] ([[User talk:Troy0|talk]]) 03:06, 26 October 2021 (UTC)
:The scores are clearly the one score they originally (sometime prior to the expanded test) received. Either that or multiple tests with the same exam questions without having given them enough feedback to change their answer-scheme at all. The volumes are probably a "good go at screaming" on demand, belying any obvious "test result -> thus intensity of scream" (what might be expected if the scream(s) of shock/joy/frustration were recorded immediately upon hearing a score).
:What they have here is a 1D distribution of scream-ability/tendency (which was originally a single datum), arbitrarily set against test scores. (Could as easily have been against shoe-size, father's income-before-tax, a single dice-roll, etc.)
::I initially assumed that the participants are screaming in response to learning their scores, so the relationship is not arbitrary -- the students with good scores sceam loudly with joy. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:45, 26 October 2021 (UTC)
:::Perhaps it was that (except the screaming volume is clearly confounded by other factors, such as how loudly they normally scream) but asking them to "scream again" seems to show far more personal correlation than emotional attachment, for they are the same people but time has passed to reduce the spontenity of the response and their newer submissions are ''at best'' "try to scream like you did when you heard your score the first time". Which is problematic and not really a valid new response to add to the list. At best, it's a test of replay consistency (now unlinked from the original feeling). [[Special:Contributions/172.70.85.185|172.70.85.185]] 15:57, 26 October 2021 (UTC)
:Whether there ''was'' an original theory that grades correlated with intensity of vocalisation is perhaps a valid speculation, but clearly the design of the test is wrong. Too few datum points, in the first instance, and the wrong way to increase them when they find out their original failing.
: The true solution is to recruit more subject. (And justify properly if it's intensity of spontaneous result-prompted evocations or merely general ability to be loud that is the quality the wish to measure. Either could be valid, but it's not obvious that the latter is indeed the one that they meant to measure.) [[Special:Contributions/141.101.77.54|141.101.77.54]] 04:21, 26 October 2021 (UTC)
: It's pretty straightforward. This is a simple linear regression, Y = α + βX + ε, where α and β are parameters and ε is a random variable (the error term). Their point estimations for α and β are correct. But their confidence intervals (and thus p-values) are wrong, because they are based on a false assumption. They constructed their intervals assuming ε was normally distributed, which it clearly is not. ε will always be approximately normally distributed if the central limit theorem applies, but it does not apply here. The central limit theorem requires that the samples be independent and identically distributed. Here, they are identically distributed, but they are not remotely independent. After all, the same people were selected over and over again. Therefore ε will probably not be randomly distributed (it isn't even close), and the confidence intervals (and so p-values) are wrong. [[Special:Contributions/172.70.178.47|172.70.178.47]] 09:10, 26 October 2021 (UTC)
:: You seem to be the only person so far who's learned in academia why this is wrong. Is the current state of the article correct? [[Special:Contributions/172.70.114.3|172.70.114.3]] 14:31, 26 October 2021 (UTC)
: The scientific error isn't quite what people are saying it is. The issue here is not "reusing a single test score" or an issue with non-normality of errors, the issue is that the data are *nested* within participants and that isn't being accounted for. There are fairly standard ways of managing this, at least in the social science literature (and these ways are statistically valid), most commonly the use of multilevel modeling (also known as hierarchical linear modeling). This accounts for the correlated nature of the errors. Now, even using the right method they're not going to attain statistical significance, but at least they aren't making a statistical mistake.
:: You can look at it in different ways. Obviously the error they made in their research was sampling the same people repeatedly and assuming that could increase the significance of their result. But mathematically, the analysis fails because the errors are not normally distributed. The math doesn't care about how you gather data. If the random variables ε is normally distributed, you can calculate confidence intervals for the parameters and for predictions exactly. The sum of squared residuals will have a chi square distribution. In particular, this means the estimator for beta will be normally distributed, and therefore the standard error in the point estimator will have a (scaled and translated) t distribution. Knowing this, you can use the CDF for the t distribution to compute the p-value exactly. To explain what's wrong with this, we need to spot which assumption was in error. Here, the false assumption was the normality of ε. Even if ε is not normally distributed, as long as it has finite mean and variance, the mean of n independent samples will converge in distribution to z as n goes to infinity. But here, the samples are not independent. So even if you sampled these same kids infinitely many times, the distribution of errors will not converge to the normal distribution, so the assumption of normality remains false. (BTW, this is the same IP as before, just from my phone this time.) [[Special:Contributions/172.70.134.131|172.70.134.131]] 19:40, 27 October 2021 (UTC)

I don't think the title text speakers are unidentified, I'm pretty sure it's a direct continuation of the dialogue in the last panel. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 04:11, 26 October 2021 (UTC)
:I agree. the second speaker starts to say "I said, are you sure--", this is the start of Cueball's last line. I think this is intended to be Cueball and Megan trying to talk about the results while the students are still screaming. [[User:TomW1605|TomW1605]] ([[User talk:TomW1605|talk]]) 06:45, 26 October 2021 (UTC)
::It could also be the case that their hypothesis was true and they failed so badly at statistics, that their voices are inaudible now.
:::Because, since they didn't write that test, their score is zero. [[Special:Contributions/108.162.241.143|108.162.241.143]] 14:29, 26 October 2021 (UTC)

Is there a polynomial that better fits this data? [[Special:Contributions/108.162.241.143|108.162.241.143]] 14:29, 26 October 2021 (UTC)
:Given three points, there's a ''circle'' that exactly fits them... ;) [[Special:Contributions/172.70.85.185|172.70.85.185]] 15:57, 26 October 2021 (UTC)
:Also, infinite number of polynomials which fits this data exactly. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:06, 26 October 2021 (UTC)
::But ''exactly one'' circle (assuming all mutually different, and not already upon a line), in an {{w|Circumscribed_circle#Triangles|elegantly obvious}} manner. Therefore clearly the more individually significant statistical match for three datum points. :P [[Special:Contributions/172.70.162.173|172.70.162.173]] 11:50, 27 October 2021 (UTC)

Speaking as the person who wrote the explanation for "slope hypothesis testing," we need someone to write a better explanation for it. It's just a placeholder meant to patch a gap until someone who knows what they're talking about (or what to google) can write a better one. [[User:GreatWyrmGold|GreatWyrmGold]] ([[User talk:GreatWyrmGold|talk]]) 14:30, 27 October 2021 (UTC)
:My (armchair) summary(!) would be that a general proposition is that there is a simple linear relationship between two factors (or their logs/powers/whatevers, reformulated as necessary) so those are plotted and their conformity to a gradient(±offset) is evaluated.
:The slope is defined by just two values which can, if necessary*, be emperically tested against the 'wrongness' of the points against the line (including error allowances) to find that line which is itself therefore minimally 'wrong', and that remaining wrongness (including how much of the possible error may need to be accepted) conveys the conformity or otherwise and you have also tied down the possibly unknown relationships - as best you are allowed to.
: * - though there are doubtless many different direct calculation/reformulation methods that don't require progressive iterations towards a better solution. And identify where multiple minima might lie in the numeric landscape.
: (Summary, indeed! This is why I didn't myself feel the need to try to do anything with the Explanation. It just seems like a typical Munrovian mash up of {{w|Statistical Hypothesis Testing}} and working with a slope. If I was ever taught this Slope-specific one (other than assessment by inspection, to preface or afterwards sanity-check loads of Sigma-based mathematics/etc that one can easily mess up by hand, or GIGO when plugged into a computer wrongly) then I've forgotten its name.) [[Special:Contributions/172.70.91.50|172.70.91.50]] 15:19, 27 October 2021 (UTC)

700: Complexion

2021-10-23T13:28:18Z

172.70.34.165: /* Explanation */ Added link

{{comic
| number = 700
| date = February 10, 2010
| title = Complexion
| image = complexion.png
| titletext = Why do all my attempts at science end with me being punched by Batman? (P.S. benzoyl peroxide soap works great.)
}}

==Explanation==
[[Cueball]] suffers from {{w|acne}}. Like many others afflicted with the same condition, he uses skin care products designed to treat acne. Unlike most other people, he does his own controlled trial by using them on only one half of his face and measuring the effects; the blemishes on the treated half of his face are noticeably diminished, while the untreated half remains the same, allowing him to isolate the effects of the cream versus the effects of time.

He convinces his friends to try the same experiment with different treatments so they can find out which works the best. In order to properly randomize the trials, he flips a coin. However, because half of his face is "scarred" (with acne blemishes), he's flipping a coin, and appears to be threatening someone with acid, he's mistaken for the Batman villain {{w|Two-Face}}. (Two-Face flips a coin to decide whether his victims will live or die, and was badly burned by acid on exactly one half of his face.) Cueball is subsequently punched by Batman; the title-text implies this has happened before.

{{w|Salicylic acid}} and {{w|benzoyl peroxide}} are both chemicals known for their skin care effects (salicylic acid in particular is also used to treat {{w|psoriasis}}).

==Transcript==
:I get frustrated trying to judge whether acne creams are having any effect. In the spirit of a controlled trial, I used one on just half my face for a few weeks.
:[A graph shows pimples vs. time, with two lines: one remains one steady, and one is declining.]

:It was cool seeing the effects so clearly, so I got some friends to try different treatments in an impromptu study.
:[Cueball looks in a mirror, sees a half-pimpled face, and applies a treatment.]

:[Cueball is talking to Ponytail and Megan, each with some pimples also.]
:Cueball: Okay, you try the salicylic acid first.
:Ponytail: Wait, we should randomize the trials. Got a coin?

:Cueball: Okay, call it. Heads, she gets the-
:(Off-panel): YOU!

:[Batman runs into frame and punches Cueball. The coin goes flying.]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics with color]]
[[Category:Line graphs]]

2529: Unsolved Math Problems

2021-10-16T21:07:49Z

172.70.34.165:

{{comic
| number = 2529
| date = October 15, 2021
| title = Unsolved Math Problems
| image = unsolved_math_problems.png
| titletext = After decades of studying the curve and the procedure that generates it, the consensus explanation is "it's just like that."
}}

==Explanation==
{{incomplete|Created by a EULER FIELD GÖDEL-ESCHER-KURT-HALSEY STRANGE "CURVE" WALKING RANDOMLY ON A HYPERDIMENSIONAL FOUR-SIDED QUANTUM KLEIN MANIFOLD. Do NOT delete this tag too soon.}}

Math has many problems that remain unsolved. Some problems are easy to understand, but difficult to form a proof for, such as the {{w|Collatz conjecture}}. Others are unsolved because they require an extremely high level of knowledge just to recognize the parts, so there are few people who can work on them and even they have trouble.

In mathematics, a concrete problem is one that is very obviously connected to a real world process while an abstract problem is one which seems unconnected to actual problems. In modern math many problems tend to be very abstract requiring complicated notation to adequately state the problem in the first place like many of the {{w|millennium problems}}. On the other hand many unsolved problems are very concrete, for example there are very many problems related to packing objects into spaces which are very difficult to solve, although quite easy to state. Finally cursed problems are problems that have strange, seemingly random behavior such as, for example the collatz conjecture or the distribution of primes.

In the first panel, Ponytail describes a weird abstract problem. Her description seems to be a meaningless jumble of terms that are either mathematical or just ''sound'' mathematical. And the mathematical terms are from disparate branches of mathematics: group theory, topology, calculus. It's full of what seem to be [[Malamanteau|malamanteaus]]: "quasimonoid" combines the prefix "quasi" (meaning "partially" or "seemingly") and "monoid" (an object from group theory) and is probably meant to evoke the character {{w|Quasimodo}} from ''The Hunchback of Notre-Dame'' (although quasimonoids are a type of algebraic object, namely a non-associative {{w|monoid}}); "Gödel-Klein" combines {{w|Kurt Gödel}}, a 20th-century mathematician who studied logic and philosophy (he's most well known for {{w|Gödel's incompleteness theorems}}) and {{w|Felix Klein}}, a 19th century mathematician who studied group theory and geometry, who probably never collaborated; "sondheim calculus" refers to {{w|Stephen Sondheim}}, one of the most successful composers and lyricists of American musical theatre -- the producer of his musical "Into the Woods" once [[https://www.indiewire.com/2015/01/watch-singing-sondheim-is-like-calculus-in-into-the-woods-behind-the-scenes-video-exclusive-189507/ remarked]] that “Singing Stephen Sondheim is like calculus for singers and actors.”; and "conjection" may combine conjecture and conjunction, or be a joke on pros and cons plus projection. Finally she asks whether the problem statement is ill-formed; considering that it's mostly gibberish, this may be true.

Many real unsolved math problems appear similarly abstract. One example is the Hodge Conjecture, a Millenium Prize problem. It states "Let X be a non-singular complex projective manifold. Then every Hodge class on X is a linear combination with rational coefficients of the cohomology classes of complex subvarieties of X." These words may appear nonsensical to a layman.

In the second panel, Cueball describes a concrete {{w|random walk}} problem, and then mentions that this somehow has applications in three unrelated fields. This is actually not uncommon. The Wikipedia article says "random walks have applications to engineering and many scientific fields including ecology, psychology, computer science, physics, chemistry, biology, economics, and sociology."

In the final panel, Megan is looking at a strange curve that seems to have no consistent pattern. At the bottom it's mostly straight, with a few little wobbles. In the middle it looks like a wild, high-frequency wave that suddenly bursts and then dies down. And the top is a spiral that looks like a question mark or a Western-style {{w|Crosier}}. She wonders if this could even be mathematical. Considering the weird shapes that come from plotting some mathematical processes (e.g. the {{w|Mandelbrot set}}), it could well be.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

The Three Types Of Unsolved Math Problem

:First: Weirdly Abstract
:[Ponytail stands in front of an equation]
:Is the Euler Field Manifold Hypergroup Isomorphic to a Gödel-Klein Meta-Algebreic ε<0 Quasimonoid Conjection under Sondheim Calculus?
:Or is the question ill-formed?
:⬙ℝंℤ/Eℵ₅ The Z is raised and underneath it is a double-ended arrow bent at a right angle. One points toward the R the other toward the Z. The ₅ is double-struck like the ℝ and ℤ

:Second: Weirdly Concrete
:[Cueball stands in front of a grid with 6 columns and 7 rows]
:If I walk randomly on a grid, never visiting any square twice, placing a marble every ''N'' steps, on average how many marbles will be in the longest line after N*K steps?
:Somehow the answer is important in like three unrelated fields.
:[The path starts in the 3rd row and 3rd column, a small circle indicates the start. It takes the path: North, East, North, East (a black dot representing the 1st marble is placed here, so N=4), South, East, South, South (2nd marble), West, South, West, North (3rd marble), West, South, South, South (4th Marble), West, North, West, West (this goes offgrid to the West. There is no visible line or marble outside the grid). The 1st, 3rd, and 4th marbles are colinear and there is a dotted line connecting them. The line's slope is 3.]

:Third: Cursed
:[A Megan with unkempt hair stands next to a curve]
:What in god's name is going on with this curve?
:Is it even math?
:[The curve starts at the bottom of the screen, rises straight upward, begins to wobble left and right a little. It lists to the left and the left-right motion increases, then decreases. It begins a large counter-clockwise arc, spiraling inwards twice, then ends]

{{comic discussion}}
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring Megan]]
[[Category: Comics featuring Ponytail]]
[[Category: Math]]

2520: Symbols

2021-09-30T03:10:00Z

172.70.34.165: Deleted the words "this definition has fallen out of regular usage." Re is in fact the usual symbol for earth radius in the space physics field (and probably other fields as well).

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by VERY EXPENSIVE EQUIPMENT - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to elements of (mostly mathematical or engineering) notation commonly used in various fields of math and science. Each piece of notation is presented as "symbolizing" not what it specifically means, but a typical ''context'' in which it might be encountered. Many of the individual descriptions look like verbiage that might be found on informational or warnings signs or placards, although typically with a silly edge.

*d⁄dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is one of the basic operations in {{w|calculus}} and consequently is ubiquitous in the work of undergraduates in the sciences. A hard-working undergraduate in the relevant fields would churn through exercises using this symbol.

*∂⁄∂x: A grad student is working very hard
The replacement of the standard "d" letters with the curly letters "∂" denotes the partial derivative, which generalizes the ordinary derivative to multi-variable calculus. Problems with partial derivatives, especially partial differential equations, can be extremely challenging. Although PDEs would typically be first taught at an undergraduate level, difficult partial derivatives would be encountered in graduate-level work.

*ħ: Oh wow, this is apparently a quantum thing
ħ (pronounced "h-bar") is a symbol used for (the reduced) {{w|Planck's constant}}, a universal, fundamental constant in quantum physics. ħ is equal to the energy of a photon divided by its frequency, and angular momentum in quantum mechanical systems is measured in quantized integer or half-integer units of ħ.
Classical physics appears as a limit of quantum physics if all "actions" (quantities of dimension energy * time, momentum * length, or angular momentum) are much larger than ħ. Conversely you can also formally set ħ=0 to get classical results from quantum formulae. This means that effects which are proportional to some power of ħ cannot be explained classically, and instead are "a quantum thing".

*Rₑ: Someone needs to do a lot of tedious numerical work; hopefully it's not you
The {{w|Reynolds number}} (which is actually usually denoted by "Re," not "Re" as it appears in the comic) is the most important dimensionless group in fluid mechanics. Named for Osborne Reynolds, Re characterizes the relative sizes of inertial and viscous effects in a moving fluid. Large values of Re are indicative of turbulent flow, which cannot usually be solved for analytically, and so numerical modelling is necessary. Accurate numerical studies of high-Reynolds-number flows are notoriously difficult to create and program.

Alternatively, Rₑ could stand for electronic {{w|transition dipole moment}} in a molecule. This appears in quantum-mechanical calculations of transition probabilities and also includes a lot of unpleasant numerical work. Rₑ is also a term used for the radius of the Earth at mean sea level, though this is not necessarily a complex term in and of itself.

Another alternative is that Rₑ could refer to Relative Error, a measurement of precision or accuracy. Used often in the analysis of scientific data and in numerical analysis.

*(Ta⁴ - Tb⁴): You are at risk of skin burns
The {{w|Stefan-Boltzmann law}} says that a perfectly absorbing ("black body") source emits electromagnetic radiation with a power per unit area of σT4, where σ is a known constant and T is the absolute temperature. The quantity (Ta4 – Tb4) thus appears in any calculation of purely radiative energy transfer between two bodies, one at temperature Ta and the other at Tb. When radiative transfer is large enough to be the most important form of heat interchange, it is normally also large enough to sear the skin with thermal or ultraviolet burns.

*NA: You are probably about to make an incredibly dangerous arithmetic error
NA, or {{w|Avogadro's number}}, is the number of molecules in a mole of a substance—roughly the number of protons plus neutrons in 1 gram of matter. This is an enormous number, exactly 6.022 140 76 × 10²³, or 602 214 076 000 000 000 000 000. Adding up molecular weights and converting between grams and moles of several substances is a lot of arithmetic on a scale where intuition won't help you catch mistakes. Working with NA, it is easy to make errors of one or more powers of ten without noticing. If this kind of error is made in the calculation of the stoichiometrically correct amount of a reagent in a chemical reaction, it is possible to accidentally create dangerous amounts of unwanted chemical products.

*µm: Careful, that equipment is expensive
{{w|Micrometre|Micrometer}}s are a very small unit of distance. Micrometers are commonly used to measure wavelengths in the infrared, and infrared detectors are very expensive, compared with visible wavelength counterparts. Of course, micrometers are used as a measurement of distance in other contexts, but any distance-measuring device capable of accurately measuring micrometer distances would also be expensive. Similarly, tools used to create or calibrate items within micrometer tolerances can also be expensive.

*mK: Careful, that equipment is very expensive
Kelvin is a temperature scale proportional to Celsius, but taking absolute zero as its zero point instead of the freezing point of water. {{w|Millikelvin}}s (1/1000 of a Kelvin) are used for high precision temperature work. Frequently this is used in processes of cooling temperatures to near absolute zero - such as superconductors or other quantum effects that occur when atoms are almost still. This is suggesting that the symbol appears on a sensitive experimental system probing quantum mechanical behavior that would likely only exist in an advanced laboratory. Any equipment that works down at mK temperatures, or at least to mK precision and accuracy, is likely to be very expensive.

*nm: Don't shine that in your eye
{{w|Nanometer}}s are frequently seen in the listed wavelengths for lasers. Pointing a visible or infrared laser at someone's eye is notoriously dangerous; the tightly-focused coherent light can cause permanent damage very quickly.

*eV: Definitely don't shine that in your eye
{{w|Electron volt}} energies are typical of moderate-energy particle beams, produced by accelerating electrons (or protons) over macroscopic voltages. These particle beams can be {{w|Anatoli Bugorski|even more damaging}} to soft tissues than optical-wavelength lasers.

*mSv: You are about to get into an Internet argument
The {{w|millisievert}} is a unit of radiation dose absorbed. It is actually a very small dosage, but the joke refers to Internet trolls debating the effects of low-dose radiation sources, such as 5G wireless networks. [[Randall|Randall's]] comment may also be referring to [https://xkcd.com/radiation/ this chart].

*mg/kg: Go wash your hands
This unit measures the dose of a drug or other chemical in milligrams per kilogram of body mass. If the appropriate dose - or worse, the lethal dose - is measured in mg/kg (parts per million), then the substance may be quite toxic.

*µg/kg: Go get in the chemical shower
A unit 1/1000 times the size of mg/kg. If a dosage is measured in micrograms per kilogram (parts per billion), any accident probably requires whole-body decontamination procedures.

*π or τ: Whatever answer you get will be wrong by a factor of exactly two
π is defined as the ratio of a circle's circumference to its diameter, while τ is defined as the ratio of a circle's circumference to its radius (and is therefore equal to 2π). {{w|pi|π}} has been used as the primary constant for describing the circumference and area of circles for millennia, but proponents of {{w|Turn (angle)|τ}} claim that τ is actually more natural in most contexts, since it makes working in radians more straightforward. The joke here is that whichever constant you use, it will probably be the wrong one (off by a factor of two, one way or the other) for the formula you are trying to use. The debate over Tau vs Pi was solved by Randall in this compromise: [[1292: Pi vs. Tau]].

The title text refers to two non-SI units of radiation measurement, {{w|Roentgen (unit)|röntgen}} and {{w|Roentgen equivalent man|rem}}. In the mid-20th century when they were in use, the dangers of radiation weren't as well understood as today, so an area with radiation that was noteworthy back then is probably dangerous ( https://www.bloomberg.com/news/articles/2019-08-28/france-is-still-cleaning-up-marie-curie-s-nuclear-waste ), hence the no trespassing part.

==Transcript==
:[A list with 14 different scientific constants/symbols are shown. Next to each symbol is a description. Above the list is a heading and beneath that a subheading.]
:::::<big>Symbols</big>
::::And what they mean

:::d⁄dx    An undergrad is working very hard
:::∂⁄∂x    A grad student is working very hard
:::ħ       Oh wow, this is apparently a quantum thing
:::Rₑ     Someone needs to do a lot of tedious numerical work; hopefully it's not you
:(Ta⁴ - Tb⁴)    You are at risk of skin burns
:::NA    You are probably about to make an incredibly dangerous arithmetic error
:::µm    Careful, that equipment is expensive
:::mK    Careful, that equipment is very expensive
:::nm    Don't shine that in your eye
:::eV     '''''Definitely''''' don't shine that in your eye
:::mSv  You are about to get into an internet argument
::mg/kg      Go wash your hands
::µg/kg      Go get in the chemical shower
::π or τ      Whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

[[Category:Math]]
[[Category:Physics]]
[[Category:Chemistry]]
[[Category:Biology]]
[[Category:5G]]

Talk:2521: Toothpaste

2021-09-28T18:02:19Z

172.70.34.165:

The editing done so far looks fairly good. Hopefully not too many reversions, or it might be like moving the deckchairs back to their original locations on the Titanic! [[Special:Contributions/172.70.35.70|172.70.35.70]] 05:46, 28 September 2021 (UTC)

Was Megan going to say: "It's just like- putting toothpaste back in the tube"? If so this should go into the description (and if not then what was she going to say?) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:40, 28 September 2021 (UTC)

Putting the mouth over the tube? It is not the tooth paste in your mouth that needs to get back. It is that on the tooth brush... I think it is possible (although not sanitary) to get tooth paste still in a blob on the tooth brush into the tube if it is a soft plastic tube. Because then when you press it together, the air comes out, and then when you release it will suck air back in (I have seen how the paste coming out gets sucked back in if it is not put on the brush). But if you then put the end of the tube onto the blob of toothpaste on the brush, it would suck the paste right back in. So I think it is true that you can get the paste back in the tube. But not by blowing, and of course there are many kinds of toothpaste containers, and not all of them could suck it back in. You should not put it back but you could! So it is a bad saying, and Megan is correct in pointing that out. What she suggest is disgusting, though, for sure. If that is the worst she ever said, though, she has been too kind to Cueball :-D In some ways it is not a very great comic, but I guess the fun part is when she assumes that she can take something bad said back because Cueball states you can do with things said like tooth paste back in a tube, and since you can put toothpaste back in the tube, she must be able to take her words back. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:50, 28 September 2021 (UTC)
:The tubes I have experience with may be able to suck a bit of paste back, but not much of it - they have little to no elasticity or how it's called, you permanently deform them when squeezing paste out. You would need to apply pressure, which, well, you either need some machine for or blow into them. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 16:09, 28 September 2021 (UTC)

I disagree that blowing paste into tube is disgusting. Now, reusing such paste, sure, although it's unlikely to be that much unhygienic as I don't think the bacteria can survive in tooth paste for long. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 16:09, 28 September 2021 (UTC)

Putting toothpaste back in the tube is easy with a syringe or an icing gun. But I want to know what happened at the 10th dentist's office? [[User:Cwallenpoole|Cwallenpoole]] ([[User talk:Cwallenpoole|talk]]) 16:58, 28 September 2021 (UTC)

I always heard it as "you can't put the genie back in the bottle". [[Special:Contributions/172.70.34.165|172.70.34.165]] 18:02, 28 September 2021 (UTC)

2521: Toothpaste

2021-09-28T05:33:04Z

172.70.34.165: /* Explanation */ Rephraseing. Hard to keep consistent the ambiguity of if there's just one (in ten) or a number (out of ~10 times that number).

{{comic
| number = 2521
| date = September 27, 2021
| title = Toothpaste
| image = toothpaste.png
| titletext = "9 out of 10 dentists have banned me from their offices."
}}

==Explanation==
{{incomplete|Created by a THE 10th DENTIST - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

Here, we see more of [[Megan]]'s "wordplay". Unlike in [[2352: Synonym Date]] and [[2245: Edible Arrangements]], she's not trying to make her friend uncomfortable -- it just happens anyway.

Putting toothpaste back in its tube is often used as an analogy for something irreversible, such as how you can't undo speaking. Megan rejects this assertion and says that you actually ''can'' put toothpaste back in its tube. She still believes that the analogy holds, and therefore she ''can'' unsay something - which she attempts to do to her description of returned toothpaste when Cueball is disgusted by it.

Toothpaste is normally loaded into the tube from the back, before it is crimped shut. However, it should ''technically'' be possible to push an extruded amount of paste back in from the front by wrapping one's lips around the whole front of the tube and blowing, provided the paste still covers the hole. This positive pressure can reinflate the tube the same way one blows up a balloon. However, blowing the toothpaste back into the tube would be highly unsanitary, and as the main purpose of toothpaste is to clean teeth, the end result is both counterproductive and disgusting.

It is common advertising practice to state that a good proportion of relevent experts (typically something like the significant but plausible 8 or 9 out of every 10) support your product, such as toothpaste, or other service - though hopefully only once such a claim is fulfilled. The titletext may be echoing this, but in the context of ''dis''satisfaction with Megan's approach. It may actually say more about any dental establishment that does ''not'' disapprove of what she apparently is not just theorising about doing.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Cueball: I can't believe she said that.
:Cueball: She apologized, but you can't put the toothpaste back in the tube.
:Megan: Sure you can; it's easy. You just put your mouth over the opening.
:Cueball: Well, ''that's'' the worst thing you've ever said.
:Megan: Sorry, I can take it back. It's just like-
:Cueball: NO!

:Title text: 9 out of 10 dentists have banned me from their offices.

{{comic discussion}}

2520: Symbols

2021-09-24T21:43:16Z

172.70.34.165: /* Explanation */

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by an internet argument - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to elements of (mostly mathematical or engineering) notation commonly used in various fields of math and science. Each piece of notation is presented as "symbolizing" a typical context in which it might be encountered. Many of the individual descriptions sounds look like verbiage that might be found on informational or warnings signs or placards, although typically with a silly edge.

*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is a mathematical operation that, while difficult, is one of the most basic operations in calculus and consequently well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*∂/∂x: A grad student is working very hard
The replacement of the standard "d" letters with the curly letters "∂" denotes the partial derivative, which generalizes the ordinary derivative to multi-variable calculus. Problems with partial derivatives, especially partial differential equations, can be extremely challenging—appropriate for hard graduate-level work.

*ħ: Oh wow, this is apparently a quantum thing
ħ (pronounced "h-bar") is a symbol used for (the reduced) Planck's constant, a universal, fundamental constant in quantum physics. ħ is equal to the energy of a photon divided by its frequency, and angular momentum in quantum mechanical systems is measured in quantized integer or half-integer units of ħ.

*Re: Someone needs to do a lot of tedious numerical work; hopefully it's not you
The Reynolds number (which is actually usually denoted by "Re," not "Re" as it appears in the comic) is the most important dimensionless group in fluid mechanics. Named for Osborne Reynolds, Re characterizes the relative sizes of inertial and viscous effects in a moving fluid. Large values of Re are indicative of turbulent flow, which cannot usually be solved for analytically, and so numerical modelling is necessary. Accurate numerical studies of high-Reynolds-number flows are notoriously difficult to create and program.

*(Ta4 – Tb4): You are at risk of skin burns
The Stefan-Boltzmann law says that a perfectly absorbing ("black body") source emits electromagnetic radiation with a power per unit area of σT4, where σ is a known constant and T is the absolute temperature. The quantity (Ta4 – Tb4) thus appears in any calculation of purely radiative energy transfer between two bodies, one at temperature Ta and the other at Tb. When radiative transfer is large enough to be the most import form of heat interchange, it is normally also large enough to sear the skin with thermal or ultraviolet burns.

*NA: You are probably about to make an incredibly dangerous arithmetic error
NA, or Avagadro's number, is the number of molecules in a mole of a substance—roughly the number of protons and neutrons in 1 gram of matter. This is an enormous number, approximately 6.02 × 1023. Working with NA, it is easy to make errors of one or more factors of ten without noticing. In this kind of error is made in the calculation of the stoichiometrically correct amount of a reagent in a chemical reaction, it is possible to accidentally created dangerous amounts of unwanted chemical products.

*µm: Careful, that equipment is expensive
Micrometers are a very small unit of temperature. Any equipment that is operating in these units will be incredibly finely calibrated and thus very expensive.

*mK: Careful, that equipment is very expensive
Millikelvin temperatures are very cold, barely above absolute zero, suggesting sensitive experiments probing quantum mechanical behavior that would likely only exist in an advanced laboratory. Any equipment that works down a mK temperatures is likely to be very expensive.

*nm: Don't shine that in your eye
Nanometers are most frequently seen in the listed wavelengths for lasers. Pointing a visible or infrared laser at someone's eye is notoriously dangerous; the tightly-focused coherent light can cause permanent damage very quickly.

*eV: Definitely don't shine that in your eye
Electron volt energies are typical of moderate-energy particle beams, produced by accelerating electrons (or protons) over macroscopic voltages. These particle beams can be even more damaging to soft tissues than optical-wavelength lasers.

*mSv: You are about to get into an Internet argument
The millisievert is a unit of radiation dose absorbed. It is actuality a very small dosage, but the joke refers to Internet trolls debating the effects of low-dose radiation sources, such as 5G wireless networks. Randall's comment may also be referring to [https://xkcd.com/radiation/ this chart].

*mg/kg: Go wash your hands
This measures the dangerous dose of a chemical per kilogram of body mass. If the dose is measured in mg/kg (parts per million), then the substance is quite toxic.

*µg/kg: Go get in the chemical shower
If the dosage is measured in micrograms per kilogram (parts per billion), the substance is extremely toxic.

*π or τ: Whatever answer you get will be wrong by a factor of exactly two
π is defined as the ratio of a circle's circumference to its diameter, while τ is defined as 2π times two (the ratio of the circumference to the radius). π has been used as the primary constant for describing the circumference and area of circles for millennia, but proponents of τ point out that τ is actually more natural in most constants, since it makes working in radians more straightforward. The joke here is that whichever constant you use, it will probably be the wrong one (off by a factor of two, one way or the other) for what you are trying to calculate.

The title text refers to two non-SI units of radiation measurement. An area with significant amounts of radiation is probably dangerous, hence the no trespassing part.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:An undergrad is working very hard
;∂/∂x
:A grad student is working very hard
;ħ
:Oh wow, this is apparently a quantum thing
;Re
:Someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:You are at risk of skin burns
;NA
:You are probably about to make an incredibly dangerous arithmetic error
;µm
:Careful, that equipment is expensive
;mK
:Careful, that equipment is very expensive
;nm
:Don't shine that in your eye
;eV
:Definitely don't shine that in your eye
;mSv
:You are about to get into an internet argument
;mg/kg
:Go wash your hands
;µg/kg
:Go get in the chemical shower
;π or τ
:Whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

2520: Symbols

2021-09-24T21:41:50Z

172.70.34.165: /* Explanation */

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by an internet argument - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to elements of (mostly mathematical or engineering) notation commonly used in various fields of math and science. Each piece of notation is presented as "symbolizing" a typical context in which it might be encountered. Many of the individual descriptions sounds look like verbiage that might be found on informational or warnings signs or placards, although typically with a silly edge.

*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is a mathematical operation that, while difficult, is one of the most basic operations in calculus and consequently well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*∂/∂x: A grad student is working very hard
The replacement of the standard "d" letters with the curly letters "∂" denotes the partial derivative, which generalizes the ordinary derivative to multi-variable calculus. Problems with partial derivatives, especially partial differential equations, can be extremely challenging—appropriate for hard graduate-level work.

*ħ: Oh wow, this is apparently a quantum thing
ħ (pronounced "h-bar") is a symbol used for (the reduced) Planck's constant, a universal, fundamental constant in quantum physics. ħ is equal to the energy of a photon divided by its frequency, and angular momentum in quantum mechanical systems is measured in quantized integer or half-integer units of ħ.

*Re: Someone needs to do a lot of tedious numerical work; hopefully it's not you
The Reynolds number (which is actually usually denoted by "Re," not "Re" as it appears in the comic) is the most important dimensionless group in fluid mechanics. Named for Osborne Reynolds, Re characterizes the relative sizes of inertial and viscous effects in a moving fluid. Large values of Re are indicative of turbulent flow, which cannot usually be solved for analytically, and so numerical modelling is necessary. Accurate numerical studies of high-Reynolds-number flows are notoriously difficult to create and program.

*(Ta4 – Tb4): You are at risk of skin burns
The Stefan-Boltzmann law says that a perfectly absorbing ("black body") source emits electromagnetic radiation with a power per unit area of σT4, where σ is a known constant and T is the absolute temperature. The quantity (Ta4 – Tb4) thus appears in any calculation of purely radiative energy transfer between two bodies, one at temperature Ta and the other at Tb. When radiative transfer is large enough to be the most import form of heat interchange, it is normally also large enough to sear the skin with thermal or ultraviolet burns.

*NA: You are probably about to make an incredibly dangerous arithmetic error
NA, or Avagadro's number, is the number of molecules in a mole of a substance—roughly the number of protons and neutrons in 1 gram of matter. This is an enormous number, approximately 6.02 × 1023. Working with NA, it is easy to make errors of one or more factors of ten without noticing. In this kind of error is made in the calculation of the stoichiometrically correct amount of a reagent in a chemical reaction, it is possible to accidentally created dangerous amounts of unwanted chemical products.

*µm: Careful, that equipment is expensive
Micrometers are a very small unit of temperature. Any equipment that is operating in these units will be incredibly finely calibrated and thus very expensive.

*mK: Careful, that equipment is very expensive
Millikelvin temperatures are very cold, barely above absolute zero, suggesting sensitive experiments probing quantum mechanical behavior that would likely only exist in an advanced laboratory. Any equipment that works down a mK temperatures is likely to be very expensive.

*nm: Don't shine that in your eye
Nanometers are most frequently seen in the listed wavelengths for lasers. Pointing a visible or infrared laser at someone's eye is notoriously dangerous; the tightly-focused coherent light can cause permanent damage very quickly.

*eV: Definitely don't shine that in your eye
Electron volt energies are typical of moderate-energy particle beams, produced by accelerating electrons (or protons) over macroscopic voltages. These particle beams can be even more damaging to soft tissues than optical-wavelength lasers.

*mSv: You are about to get into an Internet argument
The millisievert is a unit of radiation dose absorbed. It is actuality a very small dosage, but the joke refers to Internet trolls debating the effects of low-dose radiation sources, such as 5G wireless networks. Randall's comment may also be referring to [https://xkcd.com/radiation/ this chart].

*mg/kg: go wash your hands
This measures the dangerous dose of a chemical per kilogram of body mass. If the dose is measured in mg/kg (parts per million), then the substance is quite toxic.

*µg/kg: go get in the chemical shower
If the dosage is measured in micrograms per kilogram (parts per billion), the substance is extremely toxic.

*π or τ
π is defined as the ratio of a circle's circumference to its diameter, while τ is defined as 2π times two. π has been used as the primary constant for describing the circumference and area of circles for millennia, but proponents of τ point out that τ is actually more natural in most constants, since it makes working in radians more straightforward. The joke here is that whichever constant you use, it will probably be the wrong one (off by a factor of two, one way or the other) for what you are trying to calculate.

The title text refers to two non-SI units of radiation measurement. An area with significant amounts of radiation is probably dangerous, hence the no trespassing part.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:An undergrad is working very hard
;∂/∂x
:A grad student is working very hard
;ħ
:Oh wow, this is apparently a quantum thing
;Re
:Someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:You are at risk of skin burns
;NA
:You are probably about to make an incredibly dangerous arithmetic error
;µm
:Careful, that equipment is expensive
;mK
:Careful, that equipment is very expensive
;nm
:Don't shine that in your eye
;eV
:Definitely don't shine that in your eye
;mSv
:You are about to get into an internet argument
;mg/kg
:Go wash your hands
;µg/kg
:Go get in the chemical shower
;π or τ
:Whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

2520: Symbols

2021-09-24T21:40:58Z

172.70.34.165: /* Explanation */

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by an internet argument - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to elements of (mostly mathematical or engineering) notation commonly used in various fields of math and science. Each piece of notation is presented as "symbolizing" a typical context in which it might be encountered. Many of the individual descriptions sounds look like verbiage that might be found on informational or warnings signs or placards, although typically with a silly edge.

*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is a mathematical operation that, while difficult, is one of the most basic operations in calculus and consequently well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*∂/∂x: A grad student is working very hard
The replacement of the standard "d" letters with the curly letters "∂" denotes the partial derivative, which generalizes the ordinary derivative to multi-variable calculus. Problems with partial derivatives, especially partial differential equations, can be extremely challenging—appropriate for hard graduate-level work.

*ħ: Oh wow, this is apparently a quantum thing
ħ (pronounced "h-bar") is a symbol used for (the reduced) Planck's constant, a universal, fundamental constant in quantum physics. ħ is equal to the energy of a photon divided by its frequency, and angular momentum in quantum mechanical systems is measured in quantized integer or half-integer units of ħ.

*Re: Someone needs to do a lot of tedious numerical work; hopefully it's not you
The Reynolds number (which is actually usually denoted by "Re," not "Re" as it appears in the comic) is the most important dimensionless group in fluid mechanics. Named for Osborne Reynolds, Re characterizes the relative sizes of inertial and viscous effects in a moving fluid. Large values of Re indicative of turbulent flow, which cannot usually be solved analytically, and so numerical modelling is necessary. Accurate numerical studies of high-Reynolds-number flows are notoriously difficult to create and program.

*(Ta4 – Tb4): You are at risk of skin burns
The Stefan-Boltzmann law says that a perfectly absorbing ("black body") source emits electromagnetic radiation with a power per unit area of σT4, where σ is a known constant and T is the absolute temperature. The quantity (Ta4 – Tb4) thus appears in any calculation of purely radiative energy transfer between two bodies, one at temperature Ta and the other at Tb. When radiative transfer is large enough to be the most import form of heat interchange, it is normally also large enough to sear the skin with thermal or ultraviolet burns.

*NA: You are probably about to make an incredibly dangerous arithmetic error
NA, or Avagadro's number, is the number of molecules in a mole of a substance—roughly the number of protons and neutrons in 1 gram of matter. This is an enormous number, approximately 6.02 × 1023. Working with NA, it is easy to make errors of one or more factors of ten without noticing. In this kind of error is made in the calculation of the stoichiometrically correct amount of a reagent in a chemical reaction, it is possible to accidentally created dangerous amounts of unwanted chemical products.

*µm: Careful, that equipment is expensive
Micrometers are a very small unit of temperature. Any equipment that is operating in these units will be incredibly finely calibrated and thus very expensive.

*mK: Careful, that equipment is very expensive
Millikelvin temperatures are very cold, barely above absolute zero, suggesting sensitive experiments probing quantum mechanical behavior that would likely only exist in an advanced laboratory. Any equipment that works down a mK temperatures is likely to be very expensive.

*nm: Don't shine that in your eye
Nanometers are most frequently seen in the listed wavelengths for lasers. Pointing a visible or infrared laser at someone's eye is notoriously dangerous; the tightly-focused coherent light can cause permanent damage very quickly.

*eV: Definitely don't shine that in your eye
Electron volt energies are typical of moderate-energy particle beams, produced by accelerating electrons (or protons) over macroscopic voltages. These particle beams can be even more damaging to soft tissues than optical-wavelength lasers.

*mSv: You are about to get into an Internet argument
The millisievert is a unit of radiation dose absorbed. It is actuality a very small dosage, but the joke refers to Internet trolls debating the effects of low-dose radiation sources, such as 5G wireless networks. Randall's comment may also be referring to [https://xkcd.com/radiation/ this chart].

*mg/kg: go wash your hands
This measures the dangerous dose of a chemical per kilogram of body mass. If the dose is measured in mg/kg (parts per million), then the substance is quite toxic.

*µg/kg: go get in the chemical shower
If the dosage is measured in micrograms per kilogram (parts per billion), the substance is extremely toxic.

*π or τ
π is defined as the ratio of a circle's circumference to its diameter, while τ is defined as 2π times two. π has been used as the primary constant for describing the circumference and area of circles for millennia, but proponents of τ point out that τ is actually more natural in most constants, since it makes working in radians more straightforward. The joke here is that whichever constant you use, it will probably be the wrong one (off by a factor of two, one way or the other) for what you are trying to calculate.

The title text refers to two non-SI units of radiation measurement. An area with significant amounts of radiation is probably dangerous, hence the no trespassing part.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:An undergrad is working very hard
;∂/∂x
:A grad student is working very hard
;ħ
:Oh wow, this is apparently a quantum thing
;Re
:Someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:You are at risk of skin burns
;NA
:You are probably about to make an incredibly dangerous arithmetic error
;µm
:Careful, that equipment is expensive
;mK
:Careful, that equipment is very expensive
;nm
:Don't shine that in your eye
;eV
:Definitely don't shine that in your eye
;mSv
:You are about to get into an internet argument
;mg/kg
:Go wash your hands
;µg/kg
:Go get in the chemical shower
;π or τ
:Whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

Talk:2519: Sloped Border

2021-09-23T12:05:01Z

172.70.34.165:

I would make the country's border an Alexander horned sphere. [[Special:Contributions/108.162.221.245|108.162.221.245]] 03:21, 23 September 2021 (UTC)

At least this border doesn't have [https://youtu.be/Mw44wHG4KOc thickness]. --[[User:Angel|Angel]] ([[User talk:Angel|talk]]) 04:48, 23 September 2021 (UTC)
-yet [[Special:Contributions/172.69.55.107|172.69.55.107]] 05:46, 23 September 2021 (UTC)

GIS: Geographic Information System, that are the systems where maps (and the borders) are defined. They won't care much though, because for them the ground information is the relevant one.
Once you get into air, you'll get a problem, because if the border is very sloped, and not in average straight, then an airplane might still be in the airzone of a different country than where it's flying over. Which will cause all kinds of problems, security wise.
Liechtenstein might loose all control over its airspace, yet their inhabitants want safety even from aircraft flying above them.
Can't imagine that going well, but bureaucrazy is that: it creates paperwork when it is not busy enough with the procedures it already created. [[Special:Contributions/172.69.55.107|172.69.55.107]] 05:46, 23 September 2021 (UTC)

Liechtenstein and air control is a bad example for the problems with sloped borders because it's quite often the case that the air space of one country is done by air space controllers of another country. In the case of Liechtenstein this is done by SKYGUIDE in Switzerland that is also doing it for southern parts of Germany (being responsible for the collision of two planes near Überlingen: https://en.wikipedia.org/wiki/2002_%C3%9Cberlingen_mid-air_collision) [[Special:Contributions/162.158.89.156|162.158.89.156]] 06:34, 23 September 2021 (UTC)

Wouldn't sloped borders also have interesting consequences underground when mining, building tunnels etc. ? [[Special:Contributions/162.158.88.239|162.158.88.239]] 08:39, 23 September 2021 (UTC)

I introduced into the explanation a hint of the more precise problem with airborne geometry upon spherical (or, possibly, geodesic) coordinates. The shallower the angle, the more possible that the 'curves with the ground' altitude calculation is to actually wrap itself all the way round the Earth before (presumably), whatever altitude limit there is to make space the same upper edge as International Waters are to horizontal edges. Taking the Liechtenstein case, as above, you could easily enclose them in a 'pyramidal' (or wedged, if not applied from all around them) air-claim by angling over them - ''or'' greatly increase their air-claim over neighbours if the angle is away. With inverse issues for the Mineral Rights issue. You need to agree in advance what happens when angled boundaries hit perpendicular ones, ''and'' whether the 'rhumbs' projected from the border mash together when equidistant points on a crinkly border project their own air-distance line. ''And'' if it is from an agreed surface level datum or local ground level, with the complications that arise from both cases. (Yeah, I originally thought there were about four different bones of contention that need to be ironed out in the codicil on curvature, but I now think there's about six of them needing strict definition, not counting the compound cases which further may need specifying in advance or forever requirev adhoc arbitration.) And none of this even takes account of Relativity and curved ''space'' frame of reference that might very subtly shift whatever reference you just agreed upon, if you let it go high enough. [[Special:Contributions/172.70.34.165|172.70.34.165]] 12:05, 23 September 2021 (UTC)

Talk:1735: Fashion Police and Grammar Police

2021-09-15T21:38:16Z

172.70.34.165:

This sentence of the explanation is confusing: "Grammar police are people who are 'sticklers' to grammar rules and get mad or contradictory if someone uses non-standard grammar in a sentence." What is meant by the grammar police getting 'contradictory' when non-standard grammar is used? [[Special:Contributions/108.162.237.140|108.162.237.140]] 19:44, 20 September 2016 (UTC)->

I added a basic explanation to this comic. I also changed the incomplete to say "Needs more on the explanation". Maybe you guys can help connect the dots and extend the explanation? --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 14:45, 19 September 2016 (UTC)

It should be noted that he uses literally wrong, just to anger the grammar police he's mocking, it's a nice touch.[[User:Trives|Trives]] ([[User talk:Trives|talk]]) 14:59, 19 September 2016 (UTC)
: What? He's using literally because it is literally "literally." He just listed 8 traits which both sides supposedly share. The joke/comment isn't that they are practically the same; it is that they are the identical same group of people.

In my eyes the 2 groups are not standing together in this comic. --[[User:DaB.|DaB.]] ([[User talk:DaB.|talk]]) 15:12, 19 September 2016 (UTC)
: Yeah I'd have said they were just being presented graphically, the intention isn't to display them as protesting alongside each other. [[User:Xseo|Xseo]] ([[User talk:Xseo|talk]]) 15:31, 19 September 2016 (UTC)

Is there an extra joke in the Title Text, "* Mad about jorts"? If it's something which both Grammar Police and Fashion Police would find distasteful, it would add an extra layer to the assertion that they are the same people. {{unsigned ip|172.68.35.71}}
:Yes for sure and this is now in the explanation. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:27, 19 September 2016 (UTC)

Incidentally, I find it ironic and probably unintentional that the Title Text demonstrates the importance of grammar and undermines Randall's own assertions that Grammar Police are superfluous and annoying. Is he saying that he really likes jorts, or is he saying that he is really angered by them? If only there was some formal ruleset which allowed meaning to be more effectively conveyed, rather than being a system of glorious chaos... https://xkcd.com/1576/ {{unsigned ip|172.68.35.71}}
:I think the comment above is inaccurate: "Title Text demonstrates the importance of grammar and undermines Randall's own assertions that Grammar Police are superfluous and annoying". The "*" represents a bullet point so it is clear that "* Mad about jorts" is an additional bullet point that both groups would find offensive. The irony now is that I'm not familiar with how to structure my wiki comments. ~~dizzydan~~ {{unsigned ip|108.162.221.103}}
::Yes very intentionally and thanks for pointing out it is an extra bullet point ;-) That is why the grammar police would hate that sentence where the other police just hate jorts. And would be mad if they realized it could be understood like they loved jorts. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:27, 19 September 2016 (UTC)

Technically, the grammar police wouldn't care about jorts, since that is a spelling error, not a grammatical error. Please contact the spelling police. Sincerely,
:The Semantics Police {{unsigned ip|108.162.237.216}}
::Jorts is not a spelling error it is a real term used on Wikipedia and now linked in the explanation. They are mad about the use of "mad about". Because in this case it can be misunderstood as either really loving jorts or being upset about jorts. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:27, 19 September 2016 (UTC)
:::Then it would be "* mad about 'mad about jorts'", thus I lean for the portmanteau explanation - Sebastian --[[Special:Contributions/162.158.86.167|162.158.86.167]] 03:07, 20 September 2016 (UTC)
::::When I first read it I just took it in the same context for both. I found it funnier to think that the "Grammar Police" are inexplicably mad at people wearing jean-shorts. [[User:Schiffy|Schiffy]] ([[User_talk:Schiffy|Speak to me]]|[[Special:Contributions/Schiffy|What I've done]]) 14:44, 20 September 2016 (UTC)

'''Judgemental''' A spelling of the word 'judgmental,' infrequently used in the UK (which is widely regarded to be more fashionable than the US)? 
'''Deeply Arbitrary''' Internally inconsistent? Arbitrary means based on random chance or whim and as such cannot be strong or deep? 
'''Appreciate . . . are . . . is ''' Subject/verb disagreement with a plural/singular shift? 
'''Cool and casual''' vague use of an indefinite pronoun & a 'cool and casual' fashion choice is likely entails a significant amount of work, meaning it is not casual at all.--[[User:GotWilLeibniz|GotWilLeibniz]] ([[User talk:GotWilLeibniz|talk]]) 18:43, 19 September 2016 (UTC)
:Arbitrary is more 'not based on physical phenomena', and is not necessarily based on chance. [[Special:Contributions/172.68.35.80|172.68.35.80]] 06:17, 20 September 2016 (UTC)

: 'judgment' v. 'judgement' - I was taught that the first is used as in "using one's judgment," while the latter is "the court issued a judgement." [[User:Miamiclay|Miamiclay]] ([[User talk:Miamiclay|talk]]) 08:22, 20 September 2016 (UTC)

"Fashion Police and Grammar Police and ExplainXKCD Contributors" {{unsigned ip|108.162.219.69}}
:True ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:27, 19 September 2016 (UTC)

Just dropping a couple links here re: the "uncomfortably transparent proxies for race and class" in language. [[Special:Contributions/162.158.214.227|162.158.214.227]] 21:20, 19 September 2016 (UTC)
http://wordtree.com/what-the-victorians-did-to-english-grammar/
http://www.languagejones.com/blog-1/2014/6/8/what-is-aave {{unsigned ip|162.158.214.227}}

Por simpliĝi gramatikon, nur lernu Esperanton! Ĝi ne havas arbitrajn regularojn. [[Special:Contributions/108.162.249.158|108.162.249.158]] 22:17, 19 September 2016 (UTC)

In reality, I support the grammar police. Language is a set of shared rules allowing us to understand each other. Speaking in improper grammar produces misunderstandings and throws off listeners/readers, as well as making the speaker sound incompetent. Imagine if people started piping garbage down TCP connections! Servers wouldn't understand a thing! [[Special:Contributions/108.162.215.190|108.162.215.190]] 22:50, 19 September 2016 (UTC)

Rich white people being in high places is not really the point. Classism is the easiest to demonstrate: the grammar police frown on non-prestige dialects, and the fashion police consider poor people's clothing to be unfashionable. Racism is harder to demonstrate simply, but with language you have AAVE being treated as just "bad English" and, to a lesser extent, fashion popular in certain races being considered bad. (See, the literal fashion police of some French towns in reaction to burkinis. [[User:Trlkly|Trlkly]] ([[User talk:Trlkly|talk]]) 03:24, 20 September 2016 (UTC)
:Hostility to burkini in France has nothing to do with fashion police. This is not a reaction to alleged bad taste in clothing (attemps to make them more fashionable are even well received), but to other things that the French are not comfortable with: public display of rigorist religious behaviour in a strongly secular country, perceived provocation by muslims in a context of islamist terror attacks, considerations around women's liberties (burkini seen as an enslavement to men/husbands)... Or for some it's simply knee-jerk racism... [[Special:Contributions/141.101.98.14|141.101.98.14]] 11:57, 20 September 2016 (UTC)

Isn't this an example of [https://en.wikipedia.org/wiki/Duck_typing Duck Typing]? [[Special:Contributions/141.101.104.21|141.101.104.21]] 10:17, 21 September 2016 (UTC)

Kudos to all who uses badder grammar for this explanations.[[User:Nerdman1|Nerdman1]] ([[User talk:Nerdman1|talk]]) 12:39, 21 September 2016 (UTC)

I'm all for using words in a way that makes them more performant, regardless of the rules, or whether or not they are in the dictionary. [[User:Psu256|Psu256]] ([[User talk:Psu256|talk]]) 15:28, 21 September 2016 (UTC)

'''Why hasn't anybody pointed out the most obvious fact?!'''
They are called 'Grammar Nazis'!!!! {{unsigned ip|198.41.243.240}}
: I have thought about that, but since this term doesn't show up neither in the comic nor in the title text I discarded the idea again. On the other hand, I've never heard of the term "Grammar Police" while "Grammar Nazi" is quite common to me and in Google the term "grammar nazi" has about twice as many results as "grammar police" - despite explainXKCD [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 06:49, 22 September 2016 (UTC)

Glamour and grammar ...
https://en.wiktionary.org/wiki/glamour {{unsigned ip|108.162.237.169}}

"...and attempts to do so send strong messages of their own" ....what? i dont understand this part. what did randall mean to say?? [[Special:Contributions/172.70.34.165|172.70.34.165]] 21:38, 15 September 2021 (UTC)Bumpf

2513: Saturn Hexagon

2021-09-09T14:22:19Z

172.70.34.165: /* Explanation */

{{comic
| number = 2513
| date = September 8, 2021
| title = Saturn Hexagon
| image = saturn_hexagon.png
| titletext = Sorry, in SI units that's "there's a big football in there."
}}

==Explanation==
{{incomplete|Created by CUEBALL'S POLAR HEXAGON - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{{w|Saturn's Hexagon}} is a cloud formation on Saturn centered on its north pole. Similar to Jupiter's {{w|Great Red Spot}}, Saturn's Hexagon has proven a persistent feature observed by multiple space probes. The cause was not known until recently, when data from the 2006-2009 {{w|Cassini–Huygens}} probe could be analyzed in depth. This finding was widely publicized in popular science media (see for example [https://www.sciencealert.com/astronomers-think-they-figured-out-how-saturn-s-giant-hexagonal-storm-could-have-formed]) and is related to how currents flow deep within Saturn's atmosphere.

Randall proposes an alternate explanation: it is the top of a {{w|Ball_(association_football)|soccer ball}}. Soccer balls have been made in the shape of a {{w|truncated icosahedron}}, where faces alternate between regular hexagons and regular pentagons to achieve a more uniform roll, since 1968 when the design was introduced as the {{w|Adidas Telstar}}, a design now considered the "traditional" soccer ball.

BSBIT stands for Bachelor of Science in Business Information Technology [https://www.acronymfinder.com/Bachelor-of-Science-in-Business-Information-Technology-(BSBIT).html], a relatively new specialization where business majors learn programming techniques [https://vt.edu/academics/majors/business-information-technology.html]. It could be used in the comic to imply that a graduate of this major came up with the soccer ball model listed in the presentation, but more likely BSBIT stands for "Big Soccer Ball In There".

Soccer is the name given in the United States to {{w|association football}}, the form of football practiced in most of the world. Since the imperial system (inches, feet, yards, miles, etc.) is also used in the United States whereas the SI/metric system (centimetres, metres, kilometres, etc.) is the system in use in most of the world, "football" is jokingly referred to in the title text as the SI name for "soccer". As much of the Web panders to a significantly US-based audience{{fact}}, many sites may use only Imperial measurements and omit metric equivalents, which might cause annoyed international users to respond; Randall parodies this by sarcastically and non-seriously apologizing.{{fact}}. Randall writes for his US-based college-educated community from Massachusetts.

Ironically, the UK is the birthplace of association football, and the origin of the term "soccer" — originally to {{w|Names_for_association_football#Background|distinguish it}} from rugby football (sometimes "rugger"), before soccer became the most common form of football and is now considered the default code of football for many, though particular regions and contexts may instead give {{w|Comparison_of_rugby_league_and_rugby_union#Naming|Rugby Union or League}} that soubriquet. Other international variations will usually be identified explicitly, as with 'American' football (gridiron, or jocularly "hand-egg"), '{{w|Australian rules football|Aussie Rules}}' (more rarely discussed, without Hollywood levels of cultural exporting) and {{w|Gaelic football}} (outwith its own dedicated celtic 'homelands').

The UK is also a partial hold-out for imperial measures. Officially many everyday measurements must now be primarily given in their metric forms, if not more specifically SI, but in the UK and the US road distances remain signed in miles (though horse racing distances remain in furlongs, and their prizes in guineas), with road-speeds in miles per hour; glasses of brewed alcohol and doorstep milk deliveries are in pints (indeed, it is ''illegal'' in the UK to sell draught beer or cider except as a ⅓ pint or multiple of a half-pint); feet (plus inches) and stones (plus pounds) are still commonly used for a person's height and weight. As a further sop to those who still think better in 'old money' measures (an allusion to how the currency itself was non-metric in nature until 1971), a weather presenter may add to their summary (with the windspeeds in mph, except when in Beaufort scale) the equivalent Fahrenheit temperatures involved, in addition to the more official (i.e. 'new money') Celsius variety, and perhaps also give the inches version of any rainfall mentioned.

Incidentally, the presentation of the truncated-icosahedral 'football', pressing one clear polygonal face up along the upper limit of the planetary sphere, has much in common with the (non-truncated) icosahedron that floats within a {{w|Magic 8-Ball}}, arranged to display just one random triangular face whenever its viewing window is upwards. This may be coincidence, without any obvious attempt to directly reference any of the [https://knowyourmeme.com/photos/1404098-safely-endangered popular memes] relating to this.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

[Cueball is presenting in front of a poster, which he is pointing at with a stick.]

Cueball: We're proud to announce that our team has finally determined the origin and nature of Saturn's polar hexagon.

[The poster represents Saturn and its ring. There is a massive semi-transparent football/soccer ball inside of the planet, taking up slightly less than half of it by volume.
One of the ball's hexagons coincides with Saturn's polar hexagon, and is labelled "Hexagon". Other labels are illegible. 
The poster's title is "There's a Big Soccer Ball In There". The rest of the poster is illegible, except for a section heading that reads "BSBIT Model".]

{{comic discussion}}

2513: Saturn Hexagon

2021-09-09T04:44:28Z

172.70.34.165: /* Explanation */ Visually clashed with the bracketted "(non-truncated)".

{{comic
| number = 2513
| date = September 8, 2021
| title = Saturn Hexagon
| image = saturn_hexagon.png
| titletext = Sorry, in SI units that's "there's a big football in there."
}}

==Explanation==
{{incomplete|Created by SATURNS POLAR HEXAGON - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{{w|Saturn's Hexagon}} is a cloud formation on Saturn centered on its north pole. Similar to Jupiter's {{w|Great Red Spot}}, Saturn's Hexagon has proven a persistent feature observed by multiple space probes. The cause was not known until recently, when data from the 2006-2009 {{w|Cassini–Huygens}} probe could be analyzed in depth. This finding was widely publicized in popular science media (see for example [https://www.sciencealert.com/astronomers-think-they-figured-out-how-saturn-s-giant-hexagonal-storm-could-have-formed]) and is related to how currents flow deep within Saturn's atmosphere.

Randall proposes an alternate explanation: it is the top of a {{w|Ball_(association_football)|soccer ball}}. Soccer Balls have been made in the shape of a {{w|truncated icosahedron}}, where faces alternate between regular hexagons and regular pentagons to achieve a more uniform roll, since 1968 when the design was introduced as the {{w|Adidas Telstar}}, a design now considered the "traditional" soccer ball.

BSBIT stands for Bachelor of Science in Business Information Technology [https://www.acronymfinder.com/Bachelor-of-Science-in-Business-Information-Technology-(BSBIT).html], a relatively new specialization where business majors learn programming techniques [https://vt.edu/academics/majors/business-information-technology.html]. It is probably used in the comic to imply that a graduate of this major came up with the soccer ball model listed in the presentation. (Of course, BSBIT also stands for "Big Soccer Ball In There".)

Soccer is the name given in the United States to {{w|association football}}, the form of football practiced in most of the world. Since the so-called imperial system (inches, feet, miles, etc.) is also used in the United States whereas the SI/metric system (centimetres, metres, kilometres, etc.) is the system in use in most of the world, "football" is jokingly referred to in the title text as the SI name for "soccer". As much the web caters to a US-based audience many sites use only Imperial measurements and omit metric equivalents, which might cause annoyed international users to respond; Randall parodies this by sarcastically and non-seriously apologizing.

Ironically, the UK is the birthplace of association football, which is the default understanding of the term there, with rugby football (league or union) being the closest common cultural confusion between officionados of differing forms. Qualification is definitely needed for all other variations, such as 'American' football (gridiron, or jocularly "hand-egg"), 'Aussie Rules', etc. It is also a partial hold-out for imperial measures. Officially many everyday measurements must now be primarily given in their metric forms, if not more specifically SI, but: road distances remain signed in miles (though horse racing distances remain in furlongs, and their prizes in guineas), with road-speeds in miles per hour; glasses of brewed alcohol and doorstep milk deliveries are in pints; feet (plus inches) and stones (plus pounds) are still commonly used for a person's height and weight. As a further sop to those who still think better in 'old money' measures (an allusion to how the currency itself was non-metric in nature until 1971), a weather presenter may add to their summary (with the windspeeds in mph, except when in Beaufort scale) the equivalent fahrenheit temperatures involved, in addition to the more official (i.e. 'new money') celsius variety, and perhaps also give the inches version of any rainfall mentioned.

Incidentally, the presentation of the truncated-icosahedral 'football', pressing one clear polygonal face up along the upper limit of the planetary sphere, has much in common with the (non-truncated) icosahedron that floats within a {{w|Magic 8-Ball}}, ultimately to display just one random triangular face against its upturned viewing window. This may be coincidence, without any obvious attempt to directly reference any of the likely memes relating to this.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
{{comic discussion}}

2513: Saturn Hexagon

2021-09-09T03:53:28Z

172.70.34.165: /* Explanation */ A lot to pack in, showing a British POV about both 'soccer' (mostly that's unused, except as informally as "footie") and imperial vs. metric/SI (it's complicated!). ((Plus using non-US spelling of non-US measures.))

2512: Revelation

2021-09-08T15:29:47Z

172.70.34.165: /* Explanation */ Fixed an annoying spelling error.

{{comic
| number = 2512
| date = September 6, 2021
| title = Revelation
| image = revelation.png
| titletext = And the heaven departed as a scroll when it is rolled together, but then more heaven kept appearing to replace it, as if the scroll was infinite.
}}

==Explanation==
{{incomplete|Created by NEWSCASTER JOHN. Please please please please PLEASE (with a cherry on top!)do NOT delete this tag too soon!!}}
A user with a profile picture of a man, who could be on an island and is called John, posts the Bible text from [https://www.biblegateway.com/passage/?search=Revelation%206%3A12&version=KJV Revelation 6:12] on a social media website, making it likely that the user has the identity of {{w|John of Patmos}}, either as this biblical-era person themselves (online communities existing in their time, or vice-versa) or adopting the historic character name for parodic/interpretive reasons. The comic places a Biblical event in the modern day to portray what it would be like for apocalyptic miracles to happen nowadays.

A news channel's official social-media monitor understands this to be an actual natural disaster in progress and asks for permission to use the posted information in a broadcast. This could be what would have happened if John had been using Twitter in his own time, in which case his Revelation might have received this response from that time's similarly-connected reporters, perhaps not comprehending the observations to be 'prophetic visions of the future', with potentially a different level of significance altogether, rather than reports of events just happened.

If the monitor has just found some form of dislocated account (a ''very'' old message, a modern echo for proselytizing purposes or a jape of some kind) then they appear to have been drawn in, having not recognised it as historic text from the bible.

Whichever way, the response is typical of a 'foot in the door' approach probably used for any and all candidate 'breaking news' citizen-reports, identified by trawling and searching the media-feeds for newsworthy content by either reporters or an 'algorithm'. As well as trying to ask for republishing permission, as per the duty of care reporters should grant to their sources, it is couched behind a typically bland statement of concern.

The reply may seem underwhelming, given the Revelations-level nature of the scenario, but this early in the reporting cycle the researcher may not have enough facts from which to respond more empathetically. Without any 'empathy' the channel and its staff may look entirely uncaring, but anything too effusive would also look unprofessional. Whether the news-organisation and/or its staff could be truly concerned, or simply going through the motions, would highly depend upon their established reputation in the eyes of one viewing this exchange. Cynicism might be involved, all round.

The title text modifies verse 14 from "And the heaven departed as a scroll when it is rolled together; and every mountain and island were moved out of their places" to instead reference the {{w|scrolling#Film_and_television|infinite scrolling}} of a {{w|news ticker}}. Thus this news story would just be one on an infinite scroll page of ever-new stories.

Alternatively, a Biblical-level disaster actually IS occurring, in which case the newscaster's response is underwhelming, to say the least.

The described event happens at times. The sun is black during an eclipse, the moon is red when it sits at the horizon, and earthquakes happen on a frequent basis across the planet. When events happen together, it can have great import, and people may become more disconnected from what is real or common nature as lives become digitized.

==Transcript==
:[A Twitter-like page is displayed with a post and a comment nested beneath it. The top poster's profile image is of a man with wild hair, standing on hill near a coast looking out over the ocean. The beach is visible below him. His name is revealed in the comment as John. The poster of the comment's profile image is of a man with flat hair. There is a logo "9 News" at the bottom right. Beneath both pictures are unreadable text. There are also four icons with unreadable text beneath both posts. A line divides the original post and the comment.]
:John: And I beheld when he had opened the sixth seal, and lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood.

:Channel 9 News: Hi John, incredible story, hope you and your family are safe. Can Channel 9 News share your account in broadcast and print?

{{comic discussion}}

[[Category:Social networking]]
[[Category:Religion]]

875: 2009 Called

2021-09-08T02:01:04Z

172.70.34.165: /* Explanation */

{{comic
| number = 875
| date = March 21, 2011
| title = 2009 Called
| image = 2009 called.png
| titletext = 2017 called, but I couldn't understand what they were saying over all the screams.
}}

==Explanation==
The comic deconstructs a {{w|snowclone}} or common idiom - "X called, they want their Y back." Usually, X is a year (like 2009 here), and Y is something very popular in that year that is seen as ridiculous in the present day.

Here, [[Megan]] notices a Three-Wolf Moon T-shirt that [[Cueball]] apparently owns. The {{w|Three Wolf Moon|Three-Wolf Moon}} is a shirt of three wolves howling at the moon that reached meme status when several people posted ironic reviews giving it supernatural powers on {{w|Amazon}} around late 2008.

Megan says the snowclone, but before she can finish, Cueball pretends to take it literally (that is, that the year 2009 actually called her) and admonishes her for not telling them about {{w|2010 Haiti earthquake|the February 2010 earthquake in Haiti}} and {{w|2011 Tōhoku earthquake and tsunami|the March 2011 earthquake and tsunami in Japan}}. The comic was posted shortly after the latter, so it is reasonable to assume that it was created as a response to the disaster. Knowing Cueball, he's either preempting Megan's attempt to humiliate him and giving her a pretty good burn, or Cueball, being Cueball, actually thinks the past called.

The title text continues the snowclone by implying a terrible future awaits in 2017. Likewise, non-apocalyptic events, such as political protests, can generate "yelling and screaming". Given the public's general inclination to focus on the negative the prediction of a "bad future" may have worked with any date.

2017 has occurred, and the world hasn't exploded.{{Citation needed}} In hindsight, 2020 would work better for the joke. [insert hindsight is 2020 joke here]

==Transcript==
:[Cueball is at computer. Megan is standing behind him, looking at clothes on the floor.]
:Megan: Is this a three wolf moon shirt?
:Megan: Dude, 2009 called, and they-
:Cueball: ''OH MY GOD!''
:Cueball: ''DID YOU WARN THEM?''
:Cueball: ''ABOUT HAITI AND JAPAN?''
:Megan: What? No, I-
:Cueball: You ''ASSHOLE!''

==Trivia==
See also:
*[[102: Back to the Future]]
*[[1072: Seventies]]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]

2512: Revelation

2021-09-07T11:49:24Z

172.70.34.165: /* Explanation */ Because I couldn't explain how I was *not* intending to squash the thing I edit-conflicted, re-adding (minor changes) the bit I did not pre-empt already.

2512: Revelation

2021-09-07T11:46:28Z

172.70.34.165: /* Explanation */ Hard to say how genuine or mercenary the journo/channel is, but for a breaking story there'll be a standard set of first-contact phrases so that there is neither under- or over-'caring' an attitude before much else is known.

2512: Revelation

2021-09-07T11:10:49Z

172.70.34.165: /* Explanation */ Wikilink and interpretation

2511: Recreate the Conditions

2021-09-04T04:11:55Z

172.70.34.165: /* Explanation */

{{comic
| number = 2511
| date = September 3, 2021
| title = Recreate the Conditions
| image = recreate_the_conditions.png
| titletext = We've almost finished constructing the piña collider.
}}

==Explanation==
{{incomplete|Created by a BIG BANG FLAVORED PALM TREE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
{{comic discussion}}

2508: Circumappendiceal Somectomy

2021-08-28T01:45:30Z

172.70.34.165:

{{comic
| number = 2508
| date = August 27, 2021
| title = Circumappendiceal Somectomy
| image = circumappendiceal_somectomy.png
| titletext = Some personal news: After treating my first case a few years ago with antibiotics, I can report that I have now had appendicitis for the second and--unless something extremely unexpected happened with the surgery--final time.
}}

==Explanation==
{{incomplete|Created by a BODY REMOVED FROM AROUND THE APPENDIX OF A BOOK - Do NOT delete this tag too soon.}}

Breaking down the title: circum- means "around," -appendiceal means "the appendix," som(a)- means "the body," and -ectomy means "removal." Therefore, a circumappendiceal somectomy would be "a removal of the body from around the appendix." This appears to be the procedure that the doctor in the comic is describing.

The joke is that such a procedure is functionally identical to a typical appendectomy, the removal of the appendix from the body - just viewed from a different perspective. It humorously implies that the entire body of the patient is the problematic part to be removed, in order to leave behind a healthy, functional appendix.

The title text provides personal insight into the comic. It appears Randall has gotten appendicitis before, which may have been the inspiration of [[2147: Appendicitis]] and was treated using antibiotics instead of surgery. However, his appendix became inflamed again, and this time it was removed. Randall's experience is not uncommon, as a [https://pubmed.ncbi.nlm.nih.gov/32074268/ 2020 study] found that nearly 40% of patients treated with antibiotics for appendicitis required an appendectomy for recurrent appendicitis within 7 years. As well, this should be the final time, as it is unlikely to get appendicitis without an appendix.{{Citation needed}} However, he does not rule out the possibility that something "extremely unexpected" happened during the surgery which could cause him to suffer from appendicitis again. Possible candidates for such an extremely unexpected event could include the surgeon faking the removal of Randall's appendix and leaving it intact, or removing only part of it, or removing Randall's appendix but transplanting someone else's appendix into him instead.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Cueball is sitting on a hospital bed, hands pushing on his stomach, where his appendix is. A doctor is speaking to him with one arm outstretched, palms upwards.]
:Doctor: Normally we would remove your appendix from your body.
:Doctor: But thanks to new surgical techniques, we're now able to remove your entire body from around your appendix!
{{comic discussion}}

[[Category: Comics featuring Cueball]]

1141: Two Years

2021-08-27T02:29:22Z

172.70.34.165: /* Trivia */ Added references to Ten Years

{{comic
| number = 1141
| date = November 30, 2012
| title = Two Years
| image = two years.png
| titletext = She won the first half of all our chemo Scrabble games, but then her IV drugs started kicking in and I *dominated*.
}}

==Explanation==
This comic marks the second year of [[Randall Munroe]]'s wife's battle with cancer, and appears to depict actual events from those two years. Randall is depicted as [[Cueball]] and his wife as [[Megan]], as usual for both.

This comic later became part of a [[:Category:X Years|series of comics]] directly continued in [[1928: Seven Years]] and later continued in [[2386: Ten Years]]. The first eight panels of this comic is included in the next two, although slightly grayed out.

[[Image:two years key.png|right]]

Explanations of the individual panels:
*Panel 1: Randall's wife-to-be (at that point) receives a diagnosis over the phone (from Dr. [[Ponytail]]) as Randall sits by her side supportively. His wife has Megan long hair at this time.
*Panel 2: His wife undergoes IV (intravenous) {{w|chemotherapy}}. Because of the hair loss that results from chemotherapy, many patients opt to shave their heads when they undergo chemotherapy. As can be seen from the stubble she did not shave her hair, but has lost almost all of it. Only the hair coming back between chemo sessions is the cause of the stubble. Her hair grows back over the course of the panels following the end of her chemo (from panel 7).
*Panel 3: The two of them spend time alone together, experiencing something beautiful in the world for it may be one of her last chances to do so. Randall reinforces this sentiment in panel 8. In this panel (#3) she wears a {{w|knit cap}} presumably because it is cold, as well as the fact that patients with hair loss from chemo are urged by doctors to keep their heads covered to protect their scalps from the sun.
*Panel 4: The couple waits for a phone call from her doctor to hear the results of a scan. Both are clearly impatient and anxious.
*Panel 5: More chemotherapy. The couple plays {{w|Scrabble}}, in which players use letter tiles to spell words in a cross-word style. She uses the fact that she has cancer as leverage to get Randall to ignore the fact that the word she has played ('''zarg''') is not a real word. It should be noted that "{{Wiktionary|zark}}" (with "k" instead of "g") is a fictional swear word from {{w|The Hitchhiker's Guide to the Galaxy}}.
*Panel 6: Someone suggests they come for a visit next year, but all they can think about are the words "next year." Their future is entirely uncertain because of her health, making long-term planning a consistent source of worry and doubt. In this panel she wears a knit cap to hide her missing hair.
*Panel 7: Randall and his fiancée marry. With the chemotherapy completed, her hair has grown back enough that she has stopped using her knit cap.
*Panel 8: The couple goes whale ({{w|humpback whales}}) watching, possibly on their {{w|honeymoon}}. In this panel, she again wears the knit cap either because it is cold or because she is weak.
*Panel 9: Randall paraphrases a line from the song "{{w|Still Alive}}" (watch the [http://www.youtube.com/watch?v=l_S0PGu-cH4 video]) from the video game ''{{w|Portal}}'' (''"I'm doing science and I'm still alive"''). He does this because his wife is again back at her laptop working.
*Panel 10: The two of them sit under a tree reflecting on the significance of the past two years.
*Panel 11: Randall and his wife go out to dinner to celebrate the fact that she has made it two years since her {{w|biopsy}}. This turns awkward for [[Hairy]], the waiter, since he had assumed it was an anniversary of their marriage.

The title text is referring to a possible {{w|Chemotherapy#Neurological adverse effects|side-effect of chemotherapy drugs}}, the inability to concentrate. It could also just be the fact that the chemo can make you feel just terrible. When whatever effect kicks in, she loses the rest of their Scrabble games for that day. However, as we see in panel 5, there is a reason why she wins ''all'' of the first half of their games. But this is not enough, or she even forgets to play on the cancer, when the drugs take effect.

The use of the asterisk in the title text for "*dominated*" might be a reference to the 1999 game {{w|Unreal Tournament}} in which the game announcer voice would from time to time use the words "dominating" or "dominated" in a deep tone when a player is doing really well in the game (for example being on a multi-kill strike). Example sound [https://www.youtube.com/watch?v=miS5lh9xq_g here].

Knit caps have only been used a few times in xkcd, most prominently on [[1350:_Lorenz#Knit_Cap_Girl|Knit Cap Girl]] in [[1350: Lorenz]], see her section for more details.

==Transcript==
:[Randall and Randall's fiancée sit on a bed, Randall's fiancée is talking on the phone. The person she is talking to, a doctor holding a clipboard, is shown inset.]
:Randall's fiancée: Oh god.

:[Randall and Randall's fiancée sit together while Randall's fiancée, now bald, is receiving chemotherapy. They are both on their laptops.]
:IV pump: ... Beeep ... Beeep ... Beeep ...

:[Randall and Randall's fiancée (who is wearing a knit cap) are paddling a kayak against a scenic mountain backdrop.]

:[Randall and Randall's fiancée sit at a table, staring at a cell phone. There is a clock on the wall. Her head is stubbly.]
:Randall's fiancée: How long can it take to read a scan!?

:[Randall and Randall's fiancée are back at the hospital again, Randall's fiancée receiving chemo. They are playing Scrabble.]
:Randall: "Zarg" isn't a word.
:Randall's fiancée: But ''caaaancer.''
:Randall: ...Ok, fine.

:[Randall and Randall's fiancée (wearing a knit cap) are listening to a Cueball-like friend. A large thought bubble is above their heads and it obscures the friends talk. The text below, split in three is the only part there can be no doubt about:]
:Friend: So next year you should come visit us up in the mounta
::a
::and
:Randall and Randall's fiancée (thinking): '''"Next year"'''

:[Randall and Randall's fiancée are getting married, with a heart above their heads. Randall's wife's hair is growing back.]

:[Randall and Randall's wife (wearing a knit cap) stand on a beach, watching a whale jump out of water.]
:''Fwoosh''

:[Randall's wife is sitting at a desk with her laptop standing on top of two books. Her hair has grown back a little more. Randall stands behind her.]
:Randall: Hey—
:Randall: you're doing science,
:Randall: and you're still alive.
:Randall's wife: Yeah!

:[Randall and Randall's wife sit under a tall tree on a hill.]
:Randall: It's really only been two years?
:Randall's wife: They were big years.

:[Randall and Randall's wife sit at a table in a fancy restaurant. Her hair has grown back even more. The waiter (Hairy) brings them a dish with a cover on it.]
:Waiter: Happy... Anniversary?
:Randall's wife: Biopsy-versary!
:Waiter: ...Eww.

==Trivia==
While it is known that Randall's wife has since survived more than two years past the date of the invitation in Panel 6, it is unknown whether the invitation was later accepted. The followup comic [[Seven Years]] does not seem to include a visit "up in the mountains" among its various other recreational activities, but the one after it, [[Ten Years]], does. However, since it is possible that the invitation was made up for the comic in order to represent the worry over any invitation envisioning the future at that time, it is possible that it was never proposed as depicted in the comic. Therefore, the real life invitation(s) which inspired the inclusion of Panel 6 in the comic could perhaps have referred in real life to an activity that is actually depicted in [[Seven Years]] or [[Ten Years]], or to some other activity, which then may or may not have been realized.

{{comic discussion}}

[[Category:X Years]]
[[Category:Comics featuring Randall Munroe]]
[[Category:Comics featuring real people]]
[[Category:Doctor Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairy]]
[[Category:Multiple Cueballs]]
[[Category:Cancer]]
[[Category:Romance]]
[[Category:Video games]]

2502: Every Data Table

2021-08-14T06:11:50Z

172.70.34.165:

{{comic
| number = 2502
| date = August 13, 2021
| title = Every Data Table
| image = every data table.png
| titletext = "I'm hoping 2022 is relatively normal because I don't know what symbol comes after the asterisk and the dagger."
| imagesize =
}}

==Explanation==
{{incomplete|Created by OBELISQUE ASSTRICKS. Do NOT delete this tag too soon.}}
This comic is part of a series of comics about the COVID pandemic

The COVID pandemic has had a large impact on the entire world and one way this can be seen is through strange stats resulting from the effects of the pandemic. Various statistics such as employment statistics, spending power, holiday miles, pet ownerships, births (or at least conceptions) and — naturally — deaths may have been either grossly suppressed/increased for the majority of 2020, and for 2021 may have hardly recovered, partially recovered, renormalised, bounced back with a vengeance or be over-compensated for in the effort to catch up.

It is hard to know what 2022 might be like. Nothing (at the time of this comic being published) is exactly back to normal and proper recovery or the resulting compensatory readjustment may not have concluded in time for 2022 to reflect the trends expected based upon pre-2020 figures, and the additional further years that future statistics will record.

As an example, the four-year rolling average of total number of Olympic Games per year (normally a steady 0.25, 0.5, 0.75 or 1, depending upon whether the Winter Olympics and/or (Winter) Paralympics are included) will actually show a discrepancy for the next few years of a type not seen since the 1990s (when the all the Winter games were shifted away from the Summer games' years), the 1960s (the start of the Summer Paralympics) or the 1940s (the last major interuption in the main Summer Olympic cycle).

Sometimes punctuation such as an asterisk (*) or a dagger (†, also called an obelisk) is used to denote an unusual entry in a table to be explained in a footnote with a matching symbol. Common symbols that are used if the first two are taken include multiple asterisks (such as ** or ***), or a series of further symbols such as a double dagger (‡), the section symbol/silcrow (§), the parallel/double-pipe (‖) and the paragraph symbol/pilcrow ( ¶ ) and double asterisk (**).

The author, however, seems to have forgotten the potential monkey's paw nature of his wish. Relative is a relative term. It could well be that the whole pandemic thing becomes the new normal, thus removing the necessity of using symbols to delineate such years.

== Transcript ==

:2017........ (scribble)
:2018....... (scribble)
:2019....... (scribble)
:2020*...... (scribble)
:2021†...... (scribble)
:2022....... (scribble)
:2023....... (scribble)
:2024....... (scribble)

Every data table from now on

{{comic discussion}}

[[Category:COVID-19]]