explain xkcd - User contributions [en]

2198: Throw

2019-09-09T09:45:44Z

172.68.110.70: /* Formulas */

{{comic
| number = 2198
| date = September 3, 2019
| title = Throw
| image = throw.png
| titletext = The keys to successfully throwing a party are location, planning, and one of those aircraft carrier steam catapults.
}}
<div class="toclimit-3">{{TOC}}</div>
*To experience the interactivity of this game, visit the {{xkcd|2198|original comic}}.
==Explanation==
{{incomplete|Created by THOR, GOD OF THUNDER. Add the equation for throwing, done... Now explain them (what is the unit of the dragC and how does it work)? Could we add the animation of the throwers? Transcript of the possible sentences in a table on an extra page/possible pictures also. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This is an interactive comic made to celebrate the release of [[Randall|Randall's]] new book, ''[[How To]]''. The comic is based on a chapter in the book.

As the comic celebrates the book, which was released on Tuesday, September 3rd, 2019, the comic was thus also released on a [[:Category:Tuesday comics|Tuesday]] to coincide with the release day, replacing that week's normal Wednesday release. This was the same timing used for another of Randall's book releases, when [[1608: Hoverboard]] came out on the Tuesday when [[Thing Explainer]] came out. Although the Hoverboard comic is much more complex than this one, they are both [[:Category:Dynamic comics|dynamic]] and [[:Category:Interactive comics|interactive]], with [[:Category:Comics with animation|animations]] a part of them. Also the [[xkcd Header text]] changed to [[xkcd_Header_text#2019-09-04_-_Happy_Release_Day_-_bookstore|promote the release]] creating a large [https://www.explainxkcd.com/wiki/images/0/08/2198_Throw_-_Front_page_promotion.PNG combined promotion] of the book during the three full days the comic was on the front page (see more [[2198:_Throw/Screen-shots#Entire_xkcd_page_with_promotion|here]]).

In this comic the viewer can select a thrower and an object to be thrown, see this [[#Throwers and throw items|table]], and get an [[2198:_Throw/Screen-shots#Animation|animation]] of how the selected throw would work out, along with an estimated distance of the throw (both in the SI unit meter (m) and in other very arbitrary units; see this [[#Table of distance units|table]] below) if the throw was possible. Impossible throws include those where the thrower is not strong enough to thrown object, or when the thrower tries to throw themselves, which is possible as four "objects" are also listed as throwers. Most prominent {{w|George Washington}}. As the comic picture above cannot show all the possible selections in the two windows, pictures of all can be found [[2198:_Throw/Screen-shots#Throwers_and_Objects|here]]

The formula/guideline is apparently based on chapter 10 from the new ''How to'' book, see more under [[#Formulas|Formulas]].

It seemed though, that there was a special case to the calculations with {{w|Thor|Thor's}} hammer ({{w|Mjolnir}}). Because this comic obviously refers to the {{w|Thor (Marvel Comics)|Thor}} from the {{w|Marvel universe}}, played by another possible thrower, {{w|Chris Hemsworth}} in the {{w|Marvel_Cinematic_Universe}}, and {{w|Mjolnir (comics)|his hammer}}, which is enchanted such that only those deemed "worthy" are able to lift it. As such, despite its mass in principle being liftable by many of the characters, only Thor, God of Thunder (who is canonically worthy), is able to throw it. Also Thor is the only one who uses {{w|furlongs}} to measure his distances among the standard throwers. However, it is not a canonical part of this comic that only he can throw it, and its mass is not realistic, see more below.

[https://www.explainxkcd.com/wiki/images/f/f3/2198_Throw_-_Original_without_you.PNG Originally], when the comic was just released, there where only 7 throwers and 15 things to throw, giving a total of 105 different combinations; see the [[#Table of throw distances|table]] below. But only Thor can throw all 15, with three of the objects (George Washington, Thor's hammer, and the car) unthrowable by any of the other throwers. The smaller critters can throw only a few things, so the total number of throws is much less than 105. Still, there is an animation for all 105 combinations, but with no throw distance for many of these.

But already on day one the comic was out, a new thrower was added with the standard name "You", and this person, with black hair and a [[1350:_Lorenz#Knit_Cap_Girl|knit cap]], was also added to the objects that can be thrown increasing the number of throwers to 8 and objects to be thrown to 16. However, it would not be true to say that the number of options now would be 8 x 16 = 128, since the "You" can be customized when selecting it in the throwers menu (nuy not when selecting You in the object menu). When doing so a new window called [https://www.explainxkcd.com/wiki/images/thumb/4/48/2198_Throw_-_Custom_thrower.PNG/835px-2198_Throw_-_Custom_thrower.PNG Costume thrower] will open up over the comic. The "You" option can then be customized by changing the name (from the default "You"), and defining the height (default 5.8 ft = 1.77 m) and weight (default 160 lb = 72.57 kg), where ft (feet) can be changed to m (meter) and lb (pound) can be changed to kg (kilograms). But when doing so the window will not correct the number from feet to meter etc. but stay the same.

Below the above options there is line with four persons above it, defining a scale of ''athleticism'', the default second option being the drawing of "you" which represents ''Decent'' form (i.e. a normal person). The first on the scale is [[Black Hat]], who thinks moving things is for suckers, thus representing minimal athleticism. "You" in second position is in decent shape and pretty good form, representing decent athleticism. George Washington in third position represents extremely high athleticism, and as he states he threw so well they made him President. Finally the fourth position, representing a champion athlete, shows a person with a helmet with chin strap and googles who states that he trains 36 hours a day by using a time machine. It is thus indicated that such athletes can only be so good by training more than is possible; for instance, if he travels 24 hours back every day, he could use 12 more of these to practice, making it 36 hours on that "normal day" and he would then still have 12 hours to eat and sleep/restitution before his next 36 hours training pass.

Changing away from the decent "You" to one of the other three characters on the athleticism scale does, however, not change the character used for the animation, which stays the same. But still this gives a very large number of different "yous" that can both throw and be thrown.

A self-created character, unrealistically tall and heavy well over the human records for height ({{w|List of tallest people|272 cm}}) and/or weight ({{w|List of heaviest people|635 kg}}), can actually be able to [https://www.explainxkcd.com/wiki/images/e/e3/2198_Throw_-_You_throw_hammer_settings.PNG throw Thor's hammer] (For instance 4m and 1000 kg, see more [[2198:_Throw/Screen-shots#Hammer_throw|here]]. So it is not because it is magically inclined to only be thrown by Thor, it is just that the weight is set to 2000 kg, and only Thor of the standard characters have the strength (1000 times normal human strength) to throw such a heavy object. But if the "You" is big enough the lover athleticy difference to Thor will be compensated by shear wight and height. See this table of [[2198:_Throw#Data_from_xkcd_code|data from the comic]] for the above mentioned numbers.

Interestingly, Thor can throw a squirrel 257 meters. If a Custom Thrower is created, and they are 200 meters tall and 150 KG, they can throw the squirrel 256 meters (1 meter less than Thor). Thor can throw an acorn 136 meters, and the Custom Thrower will throw it 133 meters. Now, Thor can throw Thor's Hammer 19 meters. The Custom Thrower can throw it 44 meters! Apparently there is more to the enchantment of Thor's Hammer than meets the eye, as it would have been expected that if Thor can throw a squirrel and an acorn farther than an extraordinary human, then certainly he could throw his own enchanted Hammer a longer distance. This is, of course, because the Custom Thrower now throws from much higher than Thor. As to why the height doesn't affect the acorn or squirrel throwing distance in the same way it does Thor's Hammer, we'll leave that to you, the reader.

The title text refers to throwing a party (a colloquial synonym of hosting a party) and first makes the assumption of actually giving hints for giving a party, and then switching to suggest a mechanism to literally throw a huge object, such as a house with a party going on inside. An {{w|Aircraft_catapult#Steam_catapult|aircraft steam catapult}} is a mechanism to launch aircraft from ships, typically used on aircraft carriers.

==Safety Considerations==
Many of the items, even if technically possible to throw, may not be able to be thrown safely.

For example:
* Depending on how the microwave oven is damaged when it hits the ground, it may still be able to appear to function, but no longer seal properly, and therefore leak dangerously high amounts of microwave radiation.
* Blenders have blades and glass. Even if no one is struck by the flying blender, the broken pieces would be hazardous later if they are not properly disposed of.
* Cars have gasoline and battery acid which may spill if one is thrown.
* A squirrel might bite the person attempting to throw it, which is dangerous as some squirrels have rabies.
* Pikachu could shock (possibly fatally) someone trying to throw it.
* If a person is thrown, that person may be badly injured.

==Throwers and throw items==
*Here is a table with first the throwers and then the objects to be thrown.
**George Washington, Pikachu, and the squirrel are both throwers and throwable objects, as are the costumed option "You".
**For these four this is noted in the explanation. The "You" is also the first object, Washington and Pikachu is no. 11-12 and the Squirrel is also the last object (no. 16) in the object list.

{| class="wikitable" |
! Image
! Name
! Explanation
|-
|[[File:2198 Throw - you.png]]
|'''{{w|human|You}}'''
|'''Can also be thrown'''. The viewer may also choose to create a custom thrower, for instance, themself, inputting a name, height, weight, and general level of athleticism, as measured on a scale from "[[Black Hat]]" to "championship athlete" (a swimmer is pictured). The custom thrower is also selectable as a throwing item, presumably to provide more variety compared to the fixed values of George Washington.
|-
|[[File:2198 Throw - george.png]]
|'''{{w|George Washington}}'''
|'''Can also be thrown'''. He was the first president of the United States of America. There is a myth that a young George Washington threw a silver dollar across the Potomac River, which is more than a mile wide for much of its length; or alternatively that he would throw rocks across the Rappahannock River, which was about 300 feet wide near George's boyhood home. http://kenmore.org/education/kidstuff/legends.html. He is also used as a throwing item to represent the likelihood of a thrower distance with an average human as the projectile. George Washington is shown as a very powerful thrower; the comic makes fun of the flagrant embellishment of Washington's life.
|-
|[[File:2198 Throw - quarterback.png]]
|'''An NFL {{w|quarterback}}'''
|A quarterback in the National Football League is a highly athletic individual. Gridiron football is a full-contact sport that requires durability, speed, and precision. One of the primary skills required of quarterbacks is to be able to throw the football far with precision accuracy.
|-
|[[File:2198 Throw - pikachu.png]]
|'''{{w|Pikachu}}'''
|'''Can also be thrown'''. Pikachu is a species of Pokémon and the mascot of the Pokémon franchise as a whole. Although Pikachu are not normally shown to throw things, the ''Super Smash Bros'' series shows they are perfectly capable of picking things up that do not significantly out-size them. That said, Pikachu is capable of throwing a wide variety of objects through the move Fling, which allows the user to deal damage by throwing its held item (and, incidentally, a Fling TM). Its presence as a throwing item appears to reference the most recently released Pokémon games as of the comic's release, ''Pokémon Let's Go Pikachu'' and ''Pokémon Let's Go Eevee'', where the partner Pokémon of the respective title is not kept in a Poké Ball but thrown into battle when deployed. According to Pokédex entries throughout the series, the average Pikachu is 1'04" (0.4m) tall and weighs 13.2 lbs (6kg). Randall appears to have done his research, as a custom thrower with these stats and default athleticism will have near-identical results to Pikachu for both thrower and thrown item.
|-
|[[File:2198 Throw - carly.png]]
|'''{{w|Carly Rae Jepsen}}'''
|A Canadian music artist with [https://www.youtube.com/watch?v=AgwAywJlo1M marginal throwing ability.]
|-
|[[File:2198 Throw - thor.png]]
|'''{{w|Thor}}'''
|Thor is the god of thunder in Norse mythology, wielding a hammer that returns to its wielder when thrown. He is also {{w|Thor (Marvel Comics)|featured in Marvel comics}} and is portrayed by Chris Hemsworth (listed below) in the Marvel Cinematic Universe series of films. Thor was previously referenced in [[2097: Thor Tools]].
|-
|[[File:2198 Throw - chris hemsworth.png]]
|'''{{w|Chris Hemsworth}}'''
|He is an Australian film actor, best known for his role as Thor in the Marvel Cinematic Universe.
|-
|[[File:2198 Throw - squirrel.png]]
|'''A {{w|squirrel}}'''
|'''Can also be thrown'''. It is a small mammal of the family ''Sciuradae'', known for hoarding acorns. Squirrels have been a [[:Category:Squirrels|recurring topic]] on xkcd and have been used in ''What if?'' in lieu of a subject that Randall really doesn't want to draw. Due to their small size, a squirrel is also selectable as a throwing item.
|-
|[[File:2198 Throw - microwave.png]]
|'''A {{w|microwave oven}}'''
|A common household appliance in most American homes, used to heat or reheat food for consumption.
|-
|[[File:2198 Throw - basketball.png]]
|'''A {{w|basketball (ball)|basketball}}'''
|An inflated sphere used as a projectile in the sport of the same name.
|-
|[[File:2198 Throw - blender.png]]
|'''A {{w|blender}}'''
|It is a common household appliance in most American homes, used to shred food or ingredients into slush for consumption or baking.
|-
|[[File:2198 Throw - gold_bar.png]]
|'''A {{w|gold bar}}'''
|It is the form in which gold is cast for storage.
|-
|[[File:2198 Throw - cake.png]]
|'''A {{w|wedding cake}}'''
|It is traditionally a layer cake used for wedding receptions with copious amounts of frosting and figurines of the bride and groom standing upon the top layer. The figurines appear to have been removed before the cake is thrown, as they are before the cake is cut and served.
|-
|[[File:2198 Throw - pingpong.png]]
|'''A {{w|ping pong ball}}'''
|A small plastic sphere designed to bounce, used as a projectile in the sport of table tennis or "ping pong". Notably the ball is much more difficult to throw than the acorn, as its larger size yet much lighter weight causes it to lose more momentum due to air resistance.
|-
|[[File:2198 Throw - acorn.png]]
|'''An {{w|acorn}}'''
|A small nut which serves as a squirrel's primary form of nourishment.
|-
|[[File:2198 Throw - hammer.png]]
|'''{{w|Mjolnir (comics)|Thor's hammer}}'''
|This hammer refers to Mjolnir, an enchanted hammer in the {{w|Marvel universe}} which belongs to {{w|Thor (Marvel Comics)|Thor from Marvels comics}} and can only be lifted by those deemed worthy. It is based on {{w|Mjölnir}} the hammer of Norse God {{w|Thor}}, God of Thunder. In this comic, though, it appears that Mjolnir is just incredibly heavy, and Thor is able to throw it because he is very strong. The custom thrower is also able to throw it if their size and strength are set high enough. Setting aside this customization, Thor is the only standard thrower to be able to throw Thor's hammer. In the movies based on the Marvel universe, Thor is played by Chris Hemsworth, who is also one of the throwers, but in real life, he would of course not be able to throw such a weighty hammer.
|-
|[[File:2198 Throw - javelin.png]]
|'''A {{w|javelin}}'''
|An aerodynamic polearm thrown in Olympic sport.
|-
|[[File:2198 Throw - silver_spin.png]]
|'''A {{w|Dollar coin (United States)|silver dollar}} spinning'''
|A silver coin representing one (1) US dollar in value, as would have been common when George Washington was president. The coin is given two trajectories to choose from when thrown; Here '''spinning''', as one would properly throw a discus.
|-
|[[File:2198 Throw - silver_tumble.png]]
|'''A {{w|Dollar coin (United States)|silver dollar}} tumbling'''
|The coin's other possible trajectory, '''tumbling''', as might result from flipping a coin to make a decision. The spinning coin always goes farther than the tumbling one, since facing the air edge-on leads to a smaller area facing the wind and therefore less air resistance.
|-
|[[File:2198 Throw - car.png]]
|'''A {{w|car}}'''
|It is the most common form of long-distance transport in several well-developed countries.
|}

===Table of throw distances===
{| class="wikitable"
!Item / Thrower
!NFL Quarterback
!George Washington
!Pikachu
!Carly Rae Jepsen
!Thor
!Chris Hemsworth
!Squirrel
|-
|rowspan="2"|'''Microwave oven'''
|10.32 m
|7.76 m
|N/A
|3.67 m
|181.57 m
|6.15 m
|N/A
|-
|33.85 feet
|25.46 feet
|N/A
|82.65 rack units
|1.99 football fields
|138.40 rack units
|N/A
|-
|rowspan="2"|'''Basketball'''
|40.18 m
|33.22 m
|2.34 m
|19.11 m
|113.67 m
|27.99 m
|N/A
|-
|16.74 horses
|19.54 smoots
|75.90 attoparsecs
|11.24 smoots
|1.42 Manhattan blocks
|16.46 smoots
|N/A
|-
|rowspan="2"|'''Blender'''
|16.58 m
|12.45 m
|N/A
|5.89 m
|333.25 m
|9.86 m
|N/A
|-
|9.75 smoots
|40.85 feet
|N/A
|132.51 rack units
|1.66 furlongs
|32.34 feet
|N/A
|-
|rowspan="2"|'''Gold bar'''
|9.73 m
|7.23 m
|N/A
|3.36 m
|549.28 m
|5.69 m
|N/A
|-
|31.93 feet
|23.73 feet
|N/A
|75.65 rack units
|2.73 furlongs
|128.11 rack units
|N/A
|-
|rowspan="2"|'''Wedding cake'''
|8.96 m
|6.75 m
|N/A
|3.2 m
|146.25 m
|5.35 m
|N/A
|-
|29.40 feet
|22.14 feet
|N/A
|72.00 rack units
|1.60 football fields
|120.45 rack units
|N/A
|-
|rowspan="2"|'''Ping-pong ball'''
|11.8 m
|11.63 m
|9.28 m
|11.25 m
|12.53 m
|11.41 m
|4.95 m
|-
|38.72 feet
|38.17 feet
|30.46 feet
|36.92 feet
|41.10 feet
|37.44 feet
|111.37 rack units
|-
|rowspan="2"|'''Acorn'''
|83.00 m
|75.84 m
|28.16 m
|62.85 m
|135.98 m
|67.91 m
|6.53 m
|-
|1.04 Manhattan blocks
|0.95 Manhattan blocks
|16.57 smoots
|26.19 horses
|1.49 football fields
|28.30 horses
|146.85 rack units
|-
|rowspan="2"|'''Thor's Hammer'''
|N/A
|N/A
|N/A
|N/A
|19.32 m
|N/A
|N/A
|-
|N/A
|N/A
|N/A
|N/A
|11.36 smoots
|N/A
|N/A
|-
|rowspan="2"|'''Javelin'''
|56.10 m
|42.04 m
|N/A
|20.12 m
|3028.75 m
|33.09 m
|N/A
|-
|23.37 horses
|17.51 horses
|N/A
|11.84 smoots
|15.06 furlongs
|19.46 smoots
|N/A
|-
|rowspan="2"|'''George Washington'''
|N/A
|N/A
|N/A
|N/A
|136.65 m
|N/A
|N/A
|-
|N/A
|N/A
|N/A
|N/A
|1.49 football fields
|N/A
|N/A
|-
|rowspan="2"|'''Pikachu'''
|15.22 m
|11.41
|N/A
|5.39 m
|332.52 m
|9.03 m
|N/A
|-
|49.94 feet
|37.45 feet
|N/A
|121.18 rack units
|1.65 furlongs
|29.63 feet
|N/A
|-
|rowspan="2"|'''Car'''
|N/A
|N/A
|N/A
|N/A
|27.22 m
|N/A
|N/A
|-
|N/A
|N/A
|N/A
|N/A
|16.01 smoots
|N/A
|N/A
|-
|rowspan="2"|'''Spinning dollar'''
|177.09 m
|143.96 m
|16.91
|92.63 m
|1331.21 m
|115.89 m
|2.20 m
|-
|1.94 football fields
|1.57 football fields
|9.95 smoots
|1.16 Manhattan blocks
|6.53 furlongs
|1.45 Manhattan blocks
|71.41 attoparsecs
|-
|rowspan="2"|'''Tumbling dollar'''
|58.17 m
|53.77 m
|13.92 m
|44.08 m
|84.82 m
|49.03 m
|2.14 m
|-
|24.24 horses
|22.41 horses
|45.67 feet
|18.37 horses
|1.06 Manhattan blocks
|20.43 horses
|69.42 attoparsecs
|-
|rowspan="2"|'''Squirrel'''
|58.64 m
|46.92 m
|2.92 m
|25.44 m
|256.54 m
|38.50 m
|N/A
|-
|24.43 horses
|19.55 horses
|65.71 rack units
|14.97 smoots
|1.28 furlongs
|16.04 horses
|N/A
|}

===Table of distance units===
*This is a table of the alternative distance units shown and their lengths in meters.
**Three of the units shown here are listed in the Wikipedia articles {{w|List of humorous units of measurement}}
**Five the units shown here are listed in the Wikipedia article {{w|List of unusual units of measurement}}.
***Only furlong and foot/feet are not in any of the lists (although a different type of feet is in the last list).
**There are ten alternative units in the source code for the comic. However, the wiffle unit cannot be used, and the light-nanosecond unit is inaccessible except by customization.
**Two of the units are off by an order of magnitude.
{| class="wikitable"
!Unit name
!Length in comic in meters
!Explanation
|-
|{{w|List_of_humorous_units_of_measurement#Wiffle|Wiffles}}
|0.0089
|A Wiffle, also referred to as a WAM for Wiffle (ball) Assisted Measurement, is equal to a sphere 0.089 m (3.5 inches) in diameter – the size of a {{w|Wiffle ball}}, a perforated, light-weight plastic ball frequently used by marine biologists as a size reference in photos to measure corals and other objects. Randall is thus a factor 10 off. While wiffles should be the next unit after rack-units and before feet, the unit conversion typo seems to prevent it from being accessible by any thrower-object combination, as it is now even smaller than the wrong measure for light-nanoseconds. Wiffles have thus only been discovered in the data of the comic, as it seems to be impossible to get it displayed in the comic itself.
|-
|{{w|List of unusual units of measurement#Light-nanosecond|Light-nanoseconds}}
|0.0299
|The light-nanosecond was popularized by Grace Hopper, referring to the length light could travel in a nanosecond. The actual length of a light-nanosecond is 0.299 m, about a foot long, but it seems that [[Randall]] was off by an order of magnitude. This measurement is used for lengths from 1 to 1.06 m, but none of the standard throwers or objects can be thrown for this short a distance, so it is not included in the table above. But with the custom user it is [https://www.explainxkcd.com/wiki/images/a/a5/2198_Throw_-_Light_nanoseconds_1m.PNG possible to get down to 1 m] where it will then be used, but of course, since it says 33 light-nanoseconds instead of 3 it is wrong. See some examples [[2198:_Throw/Screen-shots#Light_nanoseconds_error|here]].
|-
|{{w|List_of_humorous_units_of_measurement#Attoparsec|Attoparsecs}}
|0.03086
|The parsec is a unit of length used to measure large distances to astronomical objects outside the Solar System. A parsec is defined as the distance at which one {{w|astronomical unit}} subtends an angle of one {{w|arcsecond}}. One parsec is equal to about 3.26 light-years or 31 trillion kilometers (31×1012 km) or 19 trillion miles (19×1012 mi). Atto- is a unit prefix in the metric system denoting a factor of 10−18 or 0.000000000000000001. Together the two-unit exponents will almost cancel out, as 31 trillion kilometers can be written as 3.1×1018cm, meaning that an attoparsec is 3.1 cm. The unit is only used three times in non-customized settings: once for Pikachu and twice for the squirrel. This measurement is used for lengths from 1.06 to 2.69 meters. See [https://www.explainxkcd.com/wiki/images/7/79/2198_Throw_-_Attoparsecs_107cm_setings.PNG example here].
|-
|{{w|List_of_unusual_units_of_measurement#Rack_unit|Rack units}}
|0.0445
|A {{w|Rack unit}} (abbreviated U or RU) is a unit of measure defined as 1 3⁄4 inches (44.45 mm). Mainly used to measure the overall height of the likes of {{w|19-inch rack}} frames or the equipment put in there. It is used for lengths from 2.69 to 6.67 meters.
|-
|{{w|Foot (unit)|Feet}}
|0.3048
|One foot is defined as 0.3048 meters. In customary and imperial units, the foot comprises 12 inches and three feet compose a yard. This measurement is used for lengths from 6.67 to 16 meters.
|-
|{{w|List_of_humorous_units_of_measurement#Smoot|Smoots}}
|1.7000
|The {{w|Smoot}} is a nonstandard, humorous unit of length created as part of an MIT fraternity prank. One smoot is equal to {{w|Oliver Smoot}}'s height at the time of the prank, 5 feet 7 inches (1.70 m). Mr. Smoot was used to measure the length of the Harvard Bridge (connecting Boston and Cambridge) by being repeatedly laid down along the length of the bridge; the markings indicating distances in smoots along the bridge have been maintained by the fraternity. This measurement is used for lengths from 16 to 36 meters. While the smoot is a nonstandard unit of length, Oliver Smoot has been chairman of the American National Standards Institute (ANSI) and President of the International Organization for Standardization (ISO). ANSI and ISO are among the world's main standardizing bodies, so Randall may indirectly be making the pun that while Smoot's body isn't a standard measure, Smoot has been in charge of bodies that standardize measurements.
|-
|{{w|List_of_unusual_units_of_measurement#Horse|Horses}}
|2.4
|The length of a {{w|horse}} varies a lot with the horse type, breed, age, and genes. In the Wikipedia article on horses, the length of a horse is not even mentioned, only the height and weight. But Randall has used horses for measurements before. A {{w|horse length}} is approximately 8 feet (2.4 m). This measurement is used for lengths from 36 to 75 meters.
|-
|{{w|List_of_unusual_units_of_measurement#Block|Manhattan blocks}}
|80.0
|The numbered streets in {{w|Manhattan}} run east-west and are generally 60 feet (18 m) wide, with about 200 feet (61 m) between each pair of streets. With each combined street and {{w|City block|block}} adding up to about 260 feet (79 m), there are almost exactly 20 blocks per mile. The typical block in Manhattan is 250 by 600 feet (76 by 183 m). When driving in a grid-like city, the {{w|Manhattan distance}} between two points is a concept, although it is also called {{w|Taxicab geometry}}. It seems like it is indeed the combined street and block distance. This measurement is used for lengths from 75 to 131 meters.
|-
|{{w|List_of_unusual_units_of_measurement#Football_field_(length)|Football fields}}
|91.44/109.728
|A football field in the comic is 100 yards or 91.44 m long. An {{w|American football field}} is 100 yards between the end zone although by including those it is actually 120 yards or 109.728 m. Although it is an American comic, it doesn't state that it is an American Football field. A {{w|Football pitch}} in {{w|Association football}} (Soccer) is also often used, and although the length of those varies the usual size for champions league matches is 105 m. This measurement is used for lengths from 131 to 201 meters.
|-
|{{w|Furlongs}}
|201.168
|A furlong is a measure of distance in imperial units and U.S. customary units equal to one-eighth of a mile. It is part of the {{w|List_of_humorous_units_of_measurement#FFF_units|FFF_units}} of the {{w|FFF system}} for furlong/firkin/fortnight, length, mass and time. One furlong should therefore be 201.168 meters, though the United States does not uniformly use this conversion ratio. Older ratios are in use for surveying purposes in some states. Only Thor's distances are given in furlongs. This measurement is used for lengths of 201 meters (1 furlong) and up. For the standard throwers and items only Thor can throw over 200 m, thus only he uses Furlongs to measure his throws. Given that this is an old unit, and Thor is based on ancient Nordic Mythology, this may seem appropriate.
|}

===Data from xkcd code===
*A user got this data from the code (and added it to the comments).
**But it makes sense to include here:
*From this it can be seen that:
**Thor's Hammer is not special, just very heavy, 2000 kg despite being rather small.
**Thor has the same stats as Chris, except he has 1000 times more Throw power (10,000 vs 10).
*The custumizeable You can have Throw power of 5, 10, 15 and 20, and wight and height can be set along with the name.
**The diameter is calculated from the formula given, so in the standard setting it is about 0.5 m.

{| class="wikitable"
! id
! name
! canThrow
! canBeThrown
! length (m)
! diameter (m)
! mass (kg)
! dragC
! throwPower
|-
| microwave
| A microwave oven
| false
| true
| 0.406
| 0.406
| 10.591
| 0.8
|
|-
| basketball
| a basketball
| false
| true
| 0.243
| 0.243
| 0.624
| 0.3
|
|-
| blender
| a blender
| false
| true
| 0.203
| 0.203
| 5.216
| 0.8
|
|-
| gold_bar
| a gold bar
| false
| true
| 0.0535
| 0.0535
| 12.4
| 0.8
|
|-
| cake
| a wedding cake
| false
| true
| 0.51
| 0.51
| 13
| 0.8
|
|-
| pingpong
| a ping pong ball
| false
| true
| 0.04
| 0.04
| 0.003
| 0.5
|
|-
| quarterback
| an NFL quarterback
| true
| false
| 1.905
| 0.584
| 102.058
| 0.6
| 20
|-
| acorn
| an acorn
| false
| true
| 0.0191
| 0.0191
| 0.0045
| 0.3
|
|-
| hammer
| thor's hammer
| false
| true
| 0.5
| 0.15
| 2000
| 0.4
|
|-
| javelin
| a javelin
| false
| true
| 1.8
| 0.0254
| 0.8
| 0.1
|
|-
| george
| George Washington
| true
| true
| 1.829
| 0.562
| 90.718
| 0.6
| 15
|-
| pikachu
| Pikachu
| true
| true
| 0.4
| 0.3
| 5.9874
| 0.4
| 10
|-
| car
| A car
| false
| true
| 4.5
| 2.134
| 1179.34
| 0.25
|
|-
| silver_spin
| a silver dollar (spinning)
| false
| true
| 0.04
| 0.011
| 0.027
| 0.5
|
|-
| silver_tumble
| a silver dollar (tumbling)
| false
| true
| 0.04
| 0.04
| 0.027
| 0.66
|
|-
| carly
| Carly Rae Jepsen
| true
| false
| 1.575
| 0.46
| 49.895
| 0.6
| 10
|-
| thor
| thor, god of thunder
| true
| false
| 1.91
| 0.59
| 91
| 0.6
| 10000
|-
| chris hemsworth
| chris hemsworth
| true
| false
| 1.91
| 0.59
| 91
| 0.6
| 10
|-
| squirrel
| A squirrel
| true
| true
| 0.203
| 0.096
| 0.454
| 0.6
| 10
|-
| you (can change)
| You
| true
| true
| 1.77
| (mass^(1/3))/8
| 72.5
| 0.6
| 10
|}

===Formulas===
* Used Formulas:
<math>\begin{align}g = 9.805 \frac{\mathrm m}{{\mathrm s}^2} = 9.805 \frac{\mathrm N}{\mathrm{kg}}\\
A = \sqrt[3]{3 * \mathrm{thrower\_length} * \mathrm{thrower\_throwPower} * \frac {\mathrm{thrower\_mass}} {\mathrm{object\_mass} + \mathrm{thrower\_mass} / 1000}}\\
B = \sqrt{\frac{2 * \mathrm{object\_mass} * g}{\pi * {(\mathrm{object\_diameter} / 2)}^2 * 1.2041 \frac{\mathrm{kg}}{{\mathrm m}^3} * \mathrm{object\_dragC}}}\\
\mathrm{distance} = \frac{A^2 * \sqrt2} {g * \sqrt{\frac{A^4} { B^4} * 0.8 + \frac{A^2} {B^2} * 3 + 2}}\end{align} </math>
* Used constants and units:
** g is in m/s², or equivalently in N/kg, and is the acceleration by gravity (on earth)
** 1.2041 is in units of kg/m³ and is the density of air at sea level
** Both A and B are in units of speed m/s
** A is the formula for throw speed regardless of direction, if you assume constant throw power in Watts and the body length as acceleration distance (arm has half the body length and goes from back to front)
** B is the possible throw speed, which still does not air brake the object too much. Thrown at speed B, the distance is reduced to 58,7%. B is only dependent on the object. If B was set to infinite, the air resistance would be removed from the formulas.
** throwPower is in m²/s³, or equivalently W/kg (Watts per body mass)
** dragC is without unit and signifies the roundness of the object

==Extra pages==
As this comic is very complicated several screen shots and tables are needed for the full explanation. In order to keep this main page easy to use, these pictures and possibly some of the tables will be placed on some extra pages, as has also been done with [[:Category:Comic subpages|other complex comics]] in the past:
*[[2198: Throw/Screen-shots]]

==Transcript==
:[As this is an interactive comic, not all possible text should be given in this transcript. Also, it is not possible to see all the different throwers or objects in one image. This transcript here includes the text that can be found when loading the page, without changing the thrower or object (the default), but also includes the text that can be found by scrolling in the two select "windows" as that would be similar to a long comic where you need to scroll as well as customization options. For further differences that occur by changing the objects refer to a table of all combinations.]

:[A heading with a subheading is above a line, beneath which are a sentence, that is generated by the selections in the two windows beneath this sentence:]
:<big>'''Throw Calculator'''</big>
:This calculator implements the approximate throwing distance estimation model from ''How To'' Chapter 10: ''How to throw things''.

:How far could George Washington throw a Microwave oven?

:[Beneath this sentence are two "windows" with a frame around them, one to the left and one to the right, each with a heading breaking the top frame. Each also has a scroll bar to the right, which allows one to scroll down through 8 different possible selections in the left window and 16 in the right window. There are, depending on the browser zoom level, one or two selections on each line. Each window's content is given here under their respective headings. Each possible selection is a drawing with a caption beneath it.]
:Select a thrower

:*You
:*An NFL Quarterback
:*George Washington
:*Pikachu
:*Carly Rae Jepsen
:*Thor, God of Thunder
:*Chris Hemsworth
:*A squirrel

:Select an object to be thrown
:*You
:*A microwave oven
:*A basketball
:*A blender
:*A gold bar
:*A wedding cake
:*A ping-pong ball
:*An acorn
:*Thor's Hammer
:*A javelin
:*George Washington
:*Pikachu
:*A car
:*A silver dollar (spinning)
:*A silver dollar (tumbling)
:*A squirrel

:[Below the two windows is the result of the animation that will happen when a selection has been made. An animation of the selected thrower throwing (or failing to throw) the selected object is shown, and the object's traveling distance is measured out both in meters (SI units) and in some other unit in brackets below. If the distance is not too long compared to the size of the object and thrower, then both can be seen, and in case the object is soft it may break from the throw.]

:[In the pre-selected version, George Washington throws a microwave oven, which ends up several meters from him lying on a corner broken with its wire lying beneath it. The distance is given under the ruler along which the throw has occurred, with markings for approximately every meter. In this case, there are seven steps even though the distance is above 7 meters:]
:7.76 meters
:(25.46 feet)

:[Clicking on "You" in the thrower box opens a new window over the above described comic parts. some of the comic can still be seen including the thrower and his item, and a new throw occurs every time something is changed in this new window. It is a customization box with several options shown below.]

:Your Name
:____You_____ [can be changed]

:Height
:5.8 ft [number can be changed; ft can be changed to m]

:Mass
:160 lb [number can be changed; lb can be changed to kg]

:Athleticism
:[Below is a scale showing Black Hat, the character depicting You with a knit cap, George Washington, and a person with goggles and a helmet. A marker is set at You, but can be changed. Below the characters are descriptions.]
:Black Hat: Moving objects around is for suckers.
:Minimal
:You: I'm in decent shape and have pretty good form.
:Decent
:George Washington: I'm so good at throwing they made me president.
:Extremely High
:Goggles: I use a time machine to train for 36 hours a day.
:Champion Athlete

:[Once done the box can be clicking on a cross at the top right or just clicking outside the window on the comic behind it. Now the thrower you (and the object you) will have the weight, length and strength chosen and will be able to throw (or be thrown) with these stats. ]

==Trivia==
*The comic refers to Thor as the character from the Marvel comics and movies (and other media), who is himself a reference to the ancient Norse god. In Marvel Cinematic Universe movies, Thor is played by Chris Hemsworth.
*Thor's hammer, Mjölnir, bears an enchantment that prevents any living being from lifting it unless they are "worthy." This is reflected in the simulation by giving Mjölnir a mass of 2,000 kg.
**In-universe, Thor's hammer weighs [https://urbandud.files.wordpress.com/2011/08/detail-128-thors-hammer.jpg?w=550 42.3 pounds].
*The option to customize your own character was added to the comic later.
*Due to a bug, the calculations for the customized person ('you') are incorrect when the mass is specified in pounds
*When the comic came out there was a mistake so the item to be thrown was named the same as the thrower, except for the coins and for when Pikachu and George Washington tried to throw themselves in which case it for instance said:
**[https://www.explainxkcd.com/wiki/images/9/93/2198_Throw_-_Original_error_George_Himself.PNG How far could George Washington throw himself?]
**But if he picked another object it would write:
***[https://www.explainxkcd.com/wiki/images/c/c9/2198_Throw_-_Original_error_George_George.PNG How far could George Washington throw George Washington?]
**See more examples [[2198:_Throw/Screen-shots#Errors|here]]
*A one foot tall Champion Athlete You with a mass of over 524,644.3 pounds can throw the car 44 feet. In fact, the mass can be defined to 70 or more decimal places, with each incremental change allowing You to throw the car 44 feet, as long as the addition is sufficient
**Tester used trial and error and became bored after inputting the mass below:
***524,664.3134471218218095600605010996328125[35 zeroes]1
*A one pound Champion Athlete You with a height of 480,651 feet, 1 and 9/64th inches can also throw the car 44 feet
**Subtracting 1/64th of an inch prevents the CAY from throwing the car

{{comic discussion}}

[[Category:Comics with animation]] 
[[Category:Dynamic comics]]
[[Category:Interactive comics]]
[[Category:Physics]] 
[[Category:American football]] 
[[Category:Comics featuring politicians]] 
[[Category:Pokémon]]
[[Category:Comics featuring real people]] 
[[Category:Religion]] 
[[Category:Squirrels]]
[[Category:Food]] 
[[Category:Basketball]]
[[Category:Sport]] 
[[Category:Book promotion]]
[[Category:How To]]

2198: Throw

2019-09-04T08:59:32Z

172.68.110.70: Changed to values used in Javascript code (the previous values deviated to due rounding)

Talk:2188: E Scooters

2019-08-13T12:36:06Z

172.68.110.70:

This comic came out early. They don't usually go live till around noon my time. It's 1:20 AM. [[User:Blacksilver|Blacksilver]] ([[User talk:Blacksilver|talk]]) 05:21, 12 August 2019 (UTC)
:Yes, quite early, but about once a month or something it happens. Randall never has fixed upload times. So it is not really uncommon. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 07:46, 12 August 2019 (UTC)
::It used to be that the comics would come online in the early US hours (morning for Europe), but about 1 year ago this shifted to morning US / mid-afternoon Europe, with some exceptions.[[Special:Contributions/141.101.99.203|141.101.99.203]] 10:26, 12 August 2019 (UTC)

Please tell me I'm not the only one who thought Cueballs first "sound" in panel 6 was 20000000M and was wondering what that number meant? :D [[User:Bischoff|Bischoff]] ([[User talk:Bischoff|talk]]) 09:29, 12 August 2019 (UTC)
:You [where] were the only one I think :-p --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:55, 12 August 2019 (UTC)
he wasn't

I have noticed that in several comics Randall doesn't draw a frame around every panel, like panel 5 in this case. Is there any meaning behind this or is it just a random artistic choice? [[User:Bischoff|Bischoff]] ([[User talk:Bischoff|talk]]) 09:32, 12 August 2019 (UTC)
:I think it is a choice, but not random. It gives a certain flow to the comic. He does this a lot. I have begun writing it in the transcript, as I did here (someone else did it partially but I corrected it to "frame-less panel". A quick search [https://www.explainxkcd.com/wiki/index.php?title=Special:Search&limit=500&offset=0&profile=default&search=%22frame-less+panel%22 showed 79 pages] using this sentence. So it is quite common, as I have certainly not been around all of the comics doing this. However, I'm probably the one that have edited most transcripts (as the one with the most edits on this wiki, who on top of that has specialized in making the transcripts complete. ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:55, 12 August 2019 (UTC)
:In this instance it could mean "Zoom Out" again after panel 4 zoomed in (so basically it looks like a combined panel 4+5 with the zoomed in panel framed). Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 12:36, 13 August 2019 (UTC)

I didn't really get this explanation. It doesn't really _explain_ why the response is made of whizzing sounds, no? Wouldn't the point of the explanation be to explain the comic? [[Special:Contributions/162.158.114.52|162.158.114.52]] 16:10, 12 August 2019 (UTC)

: Why seemed obvious to me. It could be that there is no *serious* reason for it, that he did it for fun.
[[Special:Contributions/108.162.245.184|108.162.245.184]] 17:24, 12 August 2019 (UTC)

:I added an explanation for his sounds.

2014: JWST Delays

2019-06-17T19:10:54Z

172.68.110.70: fix categorization

<noinclude>:''"2014", this comic's number, redirects here. For the comic named "2014", see [[1311: 2014]].''</noinclude>
{{comic
| number = 2014
| date = July 2, 2018
| title = JWST Delays
| image = jwst_delays.png
| titletext = Since delays should get less likely closer to the launch, most astronomers in 2018 believed the expansion of the schedule was slowing, but by early 2020 new measurements indicated that it was actually accelerating.
}}

==Explanation==

The {{w|James Webb Space Telescope}} (JWST) is a {{w|space telescope}} created to be the successor of the {{w|Hubble Space Telescope}}.

The telescope has been in development since 1996, but has been plagued by numerous delays and cost overruns. This comic was likely inspired by the most recent [https://nasa.gov/press-release/nasa-completes-webb-telescope-review-commits-to-launch-in-early-2021 delay announcement], which was posted on June 27, 2018. As of July 3, 2018, the JWST is scheduled to launch on March 30, 2021.

This comic portrays the launch delays and the new predicted launch years and the times at which those predictions were made. There have been so many delays in this project that you can plot a line of best fit with a surprisingly high degree of accuracy. Randall says optimistically that the line’s slope is less than one (there is less than one year of ''new'' delay per year of elapsed time), implying, of course, that if events continue without further intervention, it will eventually be built, with a predicted date of late 2026.

The title text compares the famous research over the {{w|Accelerating expansion of the universe|universe’s accelerating expansion}} to the apparently ever-delaying schedule and observes that the delay per time does not decrease, although the date gets nearer (which should help to schedule the launch date, as research and unknown parameters are replaced with engineering and exact predictions and measurements).

The Wikipedia article linked above includes a {{w|James Webb Space Telescope#Cost and schedule issues|table}} which provides the data points for the chart:

{| class=wikitable
! width=35 | Year !! Planned launch !! Time left (years)
|-
| 1997 || 2007 || 10
|-
| 1998 || 2007 || 9
|-
| 1999 || 2007 to 2008 || 8-9
|-
| 2000 || 2009 || 9
|-
| 2002 || 2010 || 8
|-
| 2003 || 2011 || 8
|-
| 2005 || 2013 || 8
|-
| 2006 || 2014 || 8
|-
| 2008 || 2014 || 6
|-
| 2010 || 2015 to 2016 || 5-6
|-
| 2011 || 2018 || 7
|-
| 2013 || 2018 || 5
|-
| 2017 || 2019 || 2
|-
|2018 || 2020 || 2
|-
|2018 || 2021 || 3
|}

==Transcript==
:[Top caption, in the panel:]
:James Webb Space Telescope
:[Subtitle of top caption:]
:Launch Delays

:[There is a positive-quadrant only line graph. The x- axis is labeled 'Current Date' and the y axis is labeled 'Planned Launch Date'. The dates on both of the axes range from 1995 to 2030.]
:[In the graph are 15 points, starting at (1997,2007) and extending at a slope of a little less than one. The most recent one is labeled 'Now: 2021'.]
:[There are two lines on the graph: a red one and a dashed black one. The red one is a regression of the points on the graph. The black one is a line with a slope of one. They intersect at the point (2026,2026), marked by the label 'Late 2026'?]

:[Caption below the panel:]
:Look, at least the slope is less than one.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Astronomy]]
[[Category:Space probes]]
[[Category:Line graphs]]

2014: JWST Delays

2019-06-17T19:08:28Z

172.68.110.70: categorization

1342: Ancient Stars

2019-03-08T02:28:53Z

172.68.110.70: "1212: Interstellar Memes" added as it is another clever illustration of the actual *proximity* of visible stars

{{comic
| number = 1342
| date = March 14, 2014
| title = Ancient Stars
| image = ancient_stars.png
| titletext = 'The light from those millions of stars you see is probably many thousands of years old' is a rare example of laypeople substantially OVERestimating astronomical numbers.
}}

==Explanation==
[[Cueball]] makes the common observation that many of the visible stars in the sky are so distant that it takes thousands of years for light from that star to reach Earth. However, the brightest star {{W|Sirius}} is one of the nearest at a mere 8.6 {{W|Light-year|light-years}} distance. In other words, the light that was arriving from Sirius in March 2014, when the comic was posted, was emitted some time around August 2005. The previous US president, {{W|George W. Bush}}, was in office from 2001 to 2009 and [[Megan]] notes that this isn't a terribly impressive observation.

The title text references the fact that most normal people have a hard time imagining the large scale of astronomical numbers. For example, the distance between astronomical bodies or the size of the Sun are hard to imagine; they typically underestimate them by many orders of magnitude and think they are much smaller than they actually are. See {{tvtropes|SciFiWritersHaveNoSenseOfScale|Sci-Fi Writers Have No Sense of Scale}}

In this case, however, people instead overestimate both the number of visible stars and their distance by quite a bit. It's frequently cited that about 5,000 to 10,000 stars are visible in the sky by the naked eye. The {{W|Bright Star Catalogue}} is a star catalogue that lists all stars of {{W|apparent magnitude}} 6.5 or brighter, which is roughly every star visible to the naked eye from Earth. The catalog contains 9,110 objects, of which 9,096 are stars, ten are {{w|Nova|novae}} or {{w|supernovae}}, and four objects outside of our Milky Way (two {{w|globular cluster}}s and two {{w|open cluster}}s). To see most of these you need good eyes and a very dark night, and at any point you will only be able to see fewer than half of these as the rest are blocked by the Earth.

This list shows the {{W|Visible stars|91 brightest stars}}. Of these 59 are more than 100 light years away and only 6 are more than 1,000 light years away. The farthest on this list, {{W|Eta Canis Majoris|Aludra}}, is "only" 3,200 light years away. Our entire {{w|Milky Way}} contains up to 400 billion (400x10⁹) stars and has a diameter of 100,000 light years.

There are visible objects much farther away, like the {{w|Andromeda Galaxy}} which is 2.5 million light years away and made up of billions of stars. And a gamma ray burst {{w|GRB 080319B}} would have been briefly visible to the naked eye, despite being 7.5 billion light years distant.

See also [[1212: Interstellar Memes]], [[1644: Stargazing]].

==Transcript==
:All of the panels of this comic are white-on-black.

:[Megan and Cueball stand facing each other, looking up at the sky.]
:Cueball: Just think - the light from that star was emitted thousands of years ago. It could be long gone.

:[Cueball looks at Megan, who is still looking up.]
:Megan: That's Sirius. It's eight light-years away.

:[Cueball looks up again.]
:Cueball: Oh.

:[Both look at one another.]
:Cueball: Just think - the light from that star was emitted in the previous presidential administration.
:Megan: Hmm, doesn't pack quite the punch.

==Trivia==
*The star {{W|List of stars in Cassiopeia|V762 Cas}} in the {{W|Cassiopeia (constellation)|Cassiopeia constellation}} is listed as being 14818 light years away and still having an {{W|apparent magnitude}} of 5.87 - thus being within the visible 6.5 limit. If Cueball had been able to point this star out, he would have been correct. But it is only visible under perfect conditions.

{{comic discussion}}
[[Category:Comics with inverted brightness]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Astronomy]]

Talk:2118: Normal Distribution

2019-03-01T23:41:09Z

172.68.110.70:

Is there a statistician in the house? [[User:Hawthorn|Hawthorn]] ([[User talk:Hawthorn|talk]]) 15:32, 1 March 2019 (UTC)
I think they all got annoyed at the graph and left. [[User:Margath|Margath]] ([[User talk:Margath|talk]]) 15:46, 1 March 2019 (UTC)
Of course there is! [[Special:Contributions/162.158.214.22|162.158.214.22]] 15:44, 1 March 2019 (UTC)

As an example: When measuring the height of people in the same age bracket, then you'll expect the number of people at each height to look like this graph. There will be a lot of people around the average height, fewer a foot shorter/taller, some (but very few) exceptionally tall people, and some (but very few) exceptionally short people. The x-value represents the height, the y-value essentially represents the amount of population that share that height. When we measure the middle 50% of the population using vertical bars, then people at a certain height are either inside '''OR''' outside the middle. Randall uses horizontal bars here, which means some people at a certain height will be counted in the middle 50%, but other people with the same height won't be. In fact, some people with the exact average height of the whole population would fall outside the middle. [[Special:Contributions/108.162.241.214|108.162.241.214]] 16:01, 1 March 2019 (UTC)

Feel free to rip me apart for referring to it as the "number of people at each height", since y-axis is more complicated than a simple count. [[Special:Contributions/108.162.241.214|108.162.241.214]] 16:03, 1 March 2019 (UTC)

Just to say, Randall's horizontal slice isn't entirely meaningless. It's a calculation I've had to do, where I have a series of binned samples of a population (say I knew how many fell in -10..10, how many fell in -5..5, how many fell in -2..2) and wanted to combine them with an appropriate weighting to approximate a Gaussian. I was using it for filtering, but it's logically similar. [[User:Fluppeteer|Fluppeteer]] ([[User talk:Fluppeteer|talk]]) 16:19, 1 March 2019 (UTC)
::Also, the slice sampler for MCMC is a trick for sampling from a distribution by "turning it on its side". But I don't think the 50% figure would be meaningful in that context. [[Special:Contributions/172.68.54.136|172.68.54.136]] 21:16, 1 March 2019 (UTC)

Pedant: etymologically, there *is* actually a connection between a normal (to a surface or line) and the normal distribution; the former comes from the Latin for a set square (giving you perpendicular), and it later came to mean "standard". The "tangential distribution" certainly fits the etymology of "odd/unusual" though. [[User:Fluppeteer|Fluppeteer]] ([[User talk:Fluppeteer|talk]]) 16:26, 1 March 2019 (UTC)

This reminds me of the difference between Riemann(-Stieltjes) and Lebesgue integration. [[Special:Contributions/172.68.54.160|172.68.54.160]] 20:16, 1 March 2019 (UTC)

As the axis are not labeled (see comic 833) we could consider this a multivariate distribution where one parameter is uniform and the other is normal. That was my first thought when I saw this. [[Special:Contributions/172.68.34.88|172.68.34.88]] 18:43, 1 March 2019 (UTC)

Is there any meaning to midpoint: 52.7%? Maybe that is the arbitrary center he formed the horizontal bounds around? Maybe it relates to data? Is this a reference to something? It's certainly reminiscent of how normal distributions produce statistically meaningful numbers that have weird decimals in them (like the % represented by being within so many standard deviations). [[Special:Contributions/162.158.78.178|162.158.78.178]] 19:45, 1 March 2019 (UTC)
::Maybe it's because the meaning of "50% of the chart lies between these lines" specifically becomes roughly useless for discerning error if the lines are not centered around the origin. [[Special:Contributions/162.158.78.178|162.158.78.178]] 19:52, 1 March 2019 (UTC)
::I might get it!!! The area between the lines is 52.7% of the total area: which means that 50% is technically included in what lies between them. [[Special:Contributions/162.158.78.220|162.158.78.220]] 23:07, 1 March 2019 (UTC)

The correct way to do this is to have the topmost vertical line equal to or above the top of the normal plot. Then the bottom-most line would represent the same values as vertical lines would. [[Special:Contributions/162.158.78.220|162.158.78.220]] 23:32, 1 March 2019 (UTC)

Say I want to build a diverse team or a representative council. And it is more important that the selection is representative of several subpopulations (who should not be voted down by the majority) than that it gives an equal fair chance to anybody. I would cut away the absolute outliers and reduce the weight of the most abundant group - this gives just the area between the two lines. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 23:40, 1 March 2019 (UTC)

Has somebody measured or calculated (by assuming normal distribution) the areas? It seems that the upper area is way smaller than the lower one, but both having the same 'height' in the middle. Is the 52.7% graphically correct? I tried half of the height at 0: .398942 and integrated, then I get 52,6% for the white area and 47,4% for the gray area. On the y-axis it seems that the three visible ticks are .1, .2, .3, then the gray area would be a bit broader than .2 and centered at .1. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 23:40, 1 March 2019 (UTC)

Talk:2118: Normal Distribution

2019-03-01T23:40:25Z

172.68.110.70:

Is there a statistician in the house? [[User:Hawthorn|Hawthorn]] ([[User talk:Hawthorn|talk]]) 15:32, 1 March 2019 (UTC)
I think they all got annoyed at the graph and left. [[User:Margath|Margath]] ([[User talk:Margath|talk]]) 15:46, 1 March 2019 (UTC)
Of course there is! [[Special:Contributions/162.158.214.22|162.158.214.22]] 15:44, 1 March 2019 (UTC)

As an example: When measuring the height of people in the same age bracket, then you'll expect the number of people at each height to look like this graph. There will be a lot of people around the average height, fewer a foot shorter/taller, some (but very few) exceptionally tall people, and some (but very few) exceptionally short people. The x-value represents the height, the y-value essentially represents the amount of population that share that height. When we measure the middle 50% of the population using vertical bars, then people at a certain height are either inside '''OR''' outside the middle. Randall uses horizontal bars here, which means some people at a certain height will be counted in the middle 50%, but other people with the same height won't be. In fact, some people with the exact average height of the whole population would fall outside the middle. [[Special:Contributions/108.162.241.214|108.162.241.214]] 16:01, 1 March 2019 (UTC)

Feel free to rip me apart for referring to it as the "number of people at each height", since y-axis is more complicated than a simple count. [[Special:Contributions/108.162.241.214|108.162.241.214]] 16:03, 1 March 2019 (UTC)

Just to say, Randall's horizontal slice isn't entirely meaningless. It's a calculation I've had to do, where I have a series of binned samples of a population (say I knew how many fell in -10..10, how many fell in -5..5, how many fell in -2..2) and wanted to combine them with an appropriate weighting to approximate a Gaussian. I was using it for filtering, but it's logically similar. [[User:Fluppeteer|Fluppeteer]] ([[User talk:Fluppeteer|talk]]) 16:19, 1 March 2019 (UTC)
::Also, the slice sampler for MCMC is a trick for sampling from a distribution by "turning it on its side". But I don't think the 50% figure would be meaningful in that context. [[Special:Contributions/172.68.54.136|172.68.54.136]] 21:16, 1 March 2019 (UTC)

Pedant: etymologically, there *is* actually a connection between a normal (to a surface or line) and the normal distribution; the former comes from the Latin for a set square (giving you perpendicular), and it later came to mean "standard". The "tangential distribution" certainly fits the etymology of "odd/unusual" though. [[User:Fluppeteer|Fluppeteer]] ([[User talk:Fluppeteer|talk]]) 16:26, 1 March 2019 (UTC)

This reminds me of the difference between Riemann(-Stieltjes) and Lebesgue integration. [[Special:Contributions/172.68.54.160|172.68.54.160]] 20:16, 1 March 2019 (UTC)

As the axis are not labeled (see comic 833) we could consider this a multivariate distribution where one parameter is uniform and the other is normal. That was my first thought when I saw this. [[Special:Contributions/172.68.34.88|172.68.34.88]] 18:43, 1 March 2019 (UTC)

Is there any meaning to midpoint: 52.7%? Maybe that is the arbitrary center he formed the horizontal bounds around? Maybe it relates to data? Is this a reference to something? It's certainly reminiscent of how normal distributions produce statistically meaningful numbers that have weird decimals in them (like the % represented by being within so many standard deviations). [[Special:Contributions/162.158.78.178|162.158.78.178]] 19:45, 1 March 2019 (UTC)
::Maybe it's because the meaning of "50% of the chart lies between these lines" specifically becomes roughly useless for discerning error if the lines are not centered around the origin. [[Special:Contributions/162.158.78.178|162.158.78.178]] 19:52, 1 March 2019 (UTC)
::I might get it!!! The area between the lines is 52.7% of the total area: which means that 50% is technically included in what lies between them. [[Special:Contributions/162.158.78.220|162.158.78.220]] 23:07, 1 March 2019 (UTC)

The correct way to do this is to have the topmost vertical line equal to or above the top of the normal plot. Then the bottom-most line would represent the same values as vertical lines would. [[Special:Contributions/162.158.78.220|162.158.78.220]] 23:32, 1 March 2019 (UTC)

Say I want to build a diverse team or a representative council. And it is more important that the selection is representative of several subpopulations (who should not be voted down by the majority) than that it gives an equal fair chance to anybody. I would cut away the absolute outliers and reduce the weight of the most abundant group - this gives just the area between the two lines. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 23:40, 1 March 2019 (UTC)
Has somebody measured or calculated (by assuming normal distribution) the areas? It seems that the upper area is way smaller than the lower one, but both having the same 'height' in the middle. Is the 52.7% graphically correct? I tried half of the height at 0: .398942 and integrated, then I get 52,6% for the white area and 47,4% for the gray area. On the y-axis it seems that the three visible ticks are .1, .2, .3, then the gray area would be a bit broader than .2 and centered at .1. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 23:40, 1 March 2019 (UTC)

Talk:2107: Launch Risk

2019-02-06T07:30:42Z

172.68.110.70:

Gave a short explanation, but I think it would be good to mention probability based logical fallacies and https://what-if.xkcd.com/55/. Don’t know how to link without it looking bad. This is my first page! [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 17:28, 4 February 2019 (UTC)

Revised to a more extensive explanation including the fallacy that the second astronaut apparently realizes in mid-reply. [[User:SteveMB|SteveMB]] ([[User talk:SteveMB|talk]])

What are the odds that one or both astronauts are female? I see "he" being used to refer to the second astronaut, but we don't actually know the sex of either one. [[Special:Contributions/162.158.74.135|162.158.74.135]] 17:56, 4 February 2019 (UTC)
: Fixed [[Special:Contributions/108.162.246.95|108.162.246.95]] 18:07, 4 February 2019 (UTC)

This seems wrong, at least with the lightning explanation. I believe the joke is that since he already is an astronaut, being hit by lightning doesn’t seem unlikely. [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 18:03, 4 February 2019 (UTC)

Would be nice to add something about risk perception of common vs. uncommon and dramatic vs. more mundane seeming events. e.g. in US, lifetime chance of death from flu, 1 in 63; from automobile accident 1 in 84; from lightning 1 in 79,746; from shark attack, 1 in 3,748,067 https://www.floridamuseum.ufl.edu/shark-attacks/odds/compare-risk/death/ [[Special:Contributions/108.162.245.166|108.162.245.166]] 18:52, 4 February 2019 (UTC)
:I find it strange that 1 in 63 citizens die from flu, while 1 in 84 die in auto accidents. Those sound like old numbers to me.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:44, 4 February 2019 (UTC)

The risk to be killed as an astronaut should be add somewhere (it is easy to find number of death/total number of astronaut) if someone want to make the morbid calculation. [[User:Xavier Combelle|Xavier Combelle]] ([[User talk:Xavier Combelle|talk]]) 18:55, 4 February 2019 (UTC)

From some impatient Googling and Wikipedia scanning there have been just over 360 people in space and 18 deaths (excepting training including Apollo 1). That puts the death rate at just over 3%.

These were mostly Shuttle as the crews were larger. However,the title is Launch Risk, so the figure would be less than half that, but still about 1.5%. Furthermore, if you ignore the Space Planes the Launch Risk is probably very low. [[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 19:07, 4 February 2019 (UTC)

::Many of those 360 have been in space multiple times reducing the risk further. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 07:30, 6 February 2019 (UTC)

We should get a better source for the lightning info: The current citation is confirmed as a biased source owned and controlled by socialist Jews.
[[Special:Contributions/108.162.245.220|108.162.245.220]] 19:10, 4 February 2019 (UTC)
:I ''would'' like to hear some statistics on lightning-related death rates, as compiled by anarchist Buddhists.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:44, 4 February 2019 (UTC)

I'd say that part of the joke was the phrasing. The astronaut's friend said "You're more likely to be struck by lightning than selected as an astronaut," which isn't very reassuring; if the friend had said "You're more likely to be killed by a lightning strike than to die in spaceflight," it might have been a consolation (albeit a fallacious one).

Removed the shark death rate statistic, since it was 1) not typical, 2) not comparable to the other statistics in the paragraph. The statistic given was the percent of shark attacks that are fatal. It used reporting from one beach in Brazil, noted for having particularly high death rate statistics [https://en.m.wikipedia.org/wiki/Shark_attack]. The other rates listed are lifetime chance of death from particular cause - a totally different statistic.

The rocket closly resembels Soyuz. Might be this comic releted to recent Soyuz launch accident? If it is so, the one who is trolling is russian cosmonaut. And it also meeans some meta-trolling.
:It could be a Soyuz, thought it looks like the conical part just below the escape tower has windows. Soyuz has just a closed fairing. [[Special:Contributions/172.68.182.58|172.68.182.58]] 11:38, 5 February 2019 (UTC)

Launch pads usually have lightning protection systems, as a lightning strike on an assembled rocket would be bad news. See https://ams.confex.com/ams/pdfpapers/38831.pdf for example

2100: Models of the Atom

2019-01-18T23:30:16Z

172.68.110.70:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} came up with the most famous maxim of chemistry: "All stuff is made of atoms." Dalton used the idea to explain what is today known as {{w|stoichiometry}}. Thus humans thought up the idea of atoms – but in lieu of any ideas of how they work, the scientific community likely thought of them as "hard round balls"; thus the name described here.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.)

;Tiny bird model, Rutherford model
This was one of many competing ideas in the formative years of what-are-atoms-made-of-ology, where [[Randall]] claims a 1907 "tiny bird model" (the third model shown) would fit in well. But ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered that the positive charge seemed to be in the center of the atom, and put down his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a positive charge. This is the fourth model put down.

;Bohr model
But there were a few problems; {{w|Maxwell's equations}} complained, for instance, saying that accelerated (here: flying on the circle instead of a straight line) charges like the electrons would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. {{w|Niels Bohr}} patched the model up with the newfangled idea of quantum mechanics, creating his "{{w|Bohr model}}", the fifth model shown here, in 1913.

;Nunchuck model, Chadwick model
If this sounds like today's model, you didn't pay enough attention; note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. But more seriously, {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the the seventh model shown here.

;538 Model
The eighth model shown is a "538 model" in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}}. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]].

;Quantum model
But is the Chadwick model what scientists endorse today? No! Today physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons, there are quantum clouds, or more simply, the parts of the atom aren't in any particular point, but rather a probability field of possible locations. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model.

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 ||
|-
| π || The {{w|Pi|number pi}} present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Possibly a typo (could be 137) referring to the fine structure constant which value is approximately 1/137
|-
| √2 ||
|-
| 4i ||
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A circle, with (...)]
:Today Quantum model

:[A circle with surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Physics]]

Talk:2100: Models of the Atom

2019-01-18T07:39:47Z

172.68.110.70:

No mention of the Platonic solid model? [[User:DanielLC|DanielLC]] ([[User talk:DanielLC|talk]]) 05:56, 18 January 2019 (UTC)

Not yet. My favorite of those 5 is the double cube, AKA the Octahedron. [[User:Haph|Haph]] ([[User talk:Haph|talk]]) 06:35, 18 January 2019 (UTC)

:My good sir DanielLC: I presume that Randall neglected to mention it because the first evidence-based atom theory didn't come until 1810 and John Dalton. The atom theories of the ancient Greeks were mostly philosophical posturing, in my opinion.

According to [[https://www.ast.cam.ac.uk/~trentham/cosmology/lec6.pdf|cosmology lecture notes by the astronomer Neil Trentham]], mass in the universe ist 75% H (mostly 1p+0n=1) and 25% He (mostly 2p+2n=4). As He is 4 times as heavy and 3 times as seldom, there is 12 times more H than He => The ratio n/p is 1/7.
We can assume that in the 538 model the statistics was done on atoms comprising few Hydrogene, e.g. only the earth's mantle. In heavier elements the ratio n/p > 1. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 07:39, 18 January 2019 (UTC)

2070: Trig Identities

2018-11-28T09:54:00Z

172.68.110.70: /* Proof of algebraic mistakes in the comic */ format/syntax

{{comic
| number = 2070
| date = November 9, 2018
| title = Trig Identities
| image = trig_identities.png
| titletext = ARCTANGENT THETA = ENCHANT AT TARGET
}}

==Explanation==
{{incomplete|Math markup in a floating text is bad layout. Please only mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic shows several real {{w|List_of_trigonometric_identities#Trigonometric_functions|trigonometric identities}} at the first two lines and further below some identities "derived" by applying algebraic methods to the letters in the trigonometric function names, which is obviously nonsense.

The first line are the known trigonometric functions: sine, cosine and tangent, and the second line contains the reciprocals of the trigonometric functions from the first line: cosecant, secant, and cotangent.

The following identities are made up and are increasing in absurdity. The comic reflects on the confusion one gets when working more intensely with these identities, since there are a lot of hidden dependencies between them.

The third and fourth line is made by treating the trigonometric function as a product of variables rather than a function and then using the above identities to create words. e.g. sin = b/c -> cin = b/s (this could also be a reference to the C++ cin).

The second to last line performs some algebra on the individual letters of <math>(\mathrm{tan}\ \theta)^2=\frac{b^2}{a^2}</math> as a setup to the last line. The last line takes the formula <math>distance=\frac{1}{2}at^2</math> "from physics" and plugs it into the equation of the previous line, doing some algebra to replace <math>at^2</math> with <math>distance2</math> and expanding <math>(na)^2</math> into <math>nana</math> to get the final equation, <math>distance2banana=\frac{b^3}{\theta^2}</math> . This is valid algebra only if the trigonometric operators are taken as variable products rather than operators, but this is a common misconception encountered when people first learn trigonometry. The distance equation is the distance a constantly accelerating object initially at rest moves in a given length of time t, most often used to find how far an object dropped from rest will fall under the influence of gravity in a given amount of time (or how long it will take to fall a given distance).

There are a few formulas that have mistakes if you simply make algebraic manipulations to the six standard trigonometric functions.

* <math>\mathrm{cas}\ \theta=\frac{o}{c}</math> seems to be derived from <math>\cos\theta=\frac{a}{c}</math> but to reach "cas" from "cos" one has to divide by "o" and multiply by "a". This would lead to <math>\mathrm{cas} \theta = \frac{o}{c} \frac{a^2}{o^2}</math>.
* In the identity <math>\sin\theta\sec\theta=\mathrm{insect}\theta^2</math> one of the "s"'s has turned into a "t", however this may be reached by 'phonetic stretch' from the sound of saying 'sin sec' together being similar to the sound of the word "insect". Another possible conversion is if you treat "s" as seconds, then "t" could be time, which keeps with the identity theme.

The title text is an {{w|Anagram|anagram}}. Due to the commutative property of multiplication (which states that order does not affect the product), these equations are equivalent if treated as individual variables as earlier. Another layer of absurdity is added in that the variable Theta is spelled out and broken into its letters, which are then treated as individual variables. (The {{w|arctangent}} referred to here is the inverse tangent, a one-sided inverse to the tangent function. You would not normally write <math>\arctan\theta</math>, since the theta in the comic refers to an angle, and the arctangent has an angle as its ''value'' rather than as its ''argument''; however, using theta here is merely unconventional, not forbidden.) The arctangent generally produces theta, the meaning of it being taken on theta being poorly understood. Randall here elucidates, via tongue-in-cheek algebraic proof, that taking a second arctangent of theta produces magical effects.

===From physics (and beyond)===
The formula s=1/2 a t2 gives the distance an uniform accelerating object reaches over time. The second formula belongs to astronomy and the {{w|Kepler's laws of planetary motion#Third law of Kepler|third law of Kepler}} in which ''the square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit'', meaning the fraction of b3 and t2 is a constant (banana).

But using the angle ''θ'' as an argument leads to {{w|Richard Feynman}}, who did many famous ''{{w|The Feynman Lectures on Physics|Lectures on Physics}}'' and his lost lecture about the ''{{w|Feynman's Lost Lecture|Motion of Planets Around the Sun}}'' from 1964 in which he only used geometry, based on the orbital ellipse, a circle around, and matching right-angled triangles to illustrate this law from Kepler. For deeper understanding why it really does work there is a nice presentation at the "Journal of Symbolic Geometry": [http://ceadserv1.nku.edu/longa/classes/calculus_resources/docs/kep.pdf Feynman Says: “Newton implies Kepler, No Calculus Needed! (Brian Beckman, 2006)”]

===Proof of algebraic mistakes in the comic===
Some have tried to argue there are mathematical justifications for the errors in some of the formulas, by stating (without proof) that you could prove that valid solutions to the original six trig identities (where letters are taken to be variables multiplied together) can be manipulated to show that solutions must have
:<math>a=o</math> and <math>s=t</math>.
These proofs are incorrect and can be shown easily with a counterexample. If you make the following assignments of variables like
:<math>o=s=\frac{1}{2}</math> and set <math>c=e=2</math>
while leaving the other variables set to 1 (<math>a=b=i=n=t=\theta=1</math>). This variable assignment will simultaneously satisfy all six original trig identities:
:<math>\sin \theta = \frac{1}{2} = \frac{b}{c}</math>;
:<math>\cos \theta = 2\cdot \frac{1}{2}\cdot\frac{1}{2}=\frac{a}{c}</math>;
:<math>\tan \theta = 1 = \frac{b}{a}</math>;
:<math>\cot \theta = 2\cdot\frac{1}{2} = \frac{a}{b}</math>;
:<math>\sec \theta = \frac{1}{2}\cdot2\cdot2 = \frac{c}{a}=2</math>;
:<math>\csc \theta = 2\cdot\frac{1}{2}\cdot2 = \frac{c}{b} = 2</math>.
However in this valid assignment, we have
:<math>a\neq o</math> since
:<math>1 \neq \frac{1}{2}</math> and we have <math>s \neq t</math> as <math>\frac{1}{2} \neq 1</math>.
This demonstrates that you can not make a valid algebraic derivation of
:<math>\operatorname{cas} \theta = \frac{o}{c} \frac{a^{2}}{o^2} = \frac{o}{c}</math> or
:<math>\sin \theta \sec \theta = \operatorname{insect} \theta^{2}</math>
without additional assumptions beyond the six given trigonometric identities.

==Transcript==
:[Inside a single frame comic a right-angled triangle is shown. The shorter sides are labeled "a" and "b" and the hypotenuse has a "c". All angles are marked: the right angle by a square and the two others by arcs. One arc (enclosed by "a" and "c") is labeled by the Greek symbol theta (θ).]

:[Supposed trigonometric functions of the marked angle θ are shown:]

:sin θ = b/c
:cos θ = a/c
:tan θ = b/a

:cot θ = a/b
:sec θ = c/a
:csc θ = c/b

:cin θ = b/s
:cas θ = o/c
:tab θ = b²/na

:bot θ = a/c → boat θ = a²/c → stoat θ = a²/c · st/b

:tan θ ( = b/a = b/a · c/c = b/c · c/a = sin θ sec θ ) = insect θ²

:(tan θ)² = b²/a² ( → t²n²a⁴ = b²/θ² → at²ba(na)² = b³/θ²
:from physics: distance = 1/2 at² → ) distance2banana = b³/θ²

:[Caption below the frame:]
:Key trigonometric identities

{{comic discussion}}

[[Category:Math]]

Talk:2038: Hazard Symbol

2018-08-27T15:00:04Z

172.68.110.70:

When on xkcd, the emoji only shows up as an empty square. On this site, it shows up as a sigma, caputal Y with umlauts, tilde, and decree symbol. What is it actually supposed to be? [[User:Smperron|Kestrel]] ([[User talk:Smperron|talk]]) 12:46, 27 August 2018 (UTC)
It's https://emojipedia.org/face-with-open-mouth-and-cold-sweat/ this emoji. Shows up correctly for me on the actual site on android but not on the wiki [[Special:Contributions/141.101.98.28|141.101.98.28]] 13:04, 27 August 2018 (UTC)

It shows up OK (Albeit small) on Mac OSX [[User:BSchildt|BSchildt]] ([[User talk:BSchildt|talk]]) 13:21, 27 August 2018 (UTC)

Does anyone know the source of the slippery symbol? The other symbols seem to be common to most standards, but the slippery symbol seems to have various designs. ☠☢☣⚡︎? [[Special:Contributions/162.158.62.57|162.158.62.57]] 13:52, 27 August 2018 (UTC)

: https://www.amazon.com/NMC-FS1-Double-Sided-CAUTION/dp/B009RVF1DY <-- This one on Amazon.com seems pretty close. [[Special:Contributions/172.68.58.245|172.68.58.245]] 14:13, 27 August 2018 (UTC)

: [https://en.wikipedia.org/wiki/ISO_7010 | ISO 7010] - W011 Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 14:59, 27 August 2018 (UTC)

Talk:2038: Hazard Symbol

2018-08-27T14:59:22Z

172.68.110.70:

When on xkcd, the emoji only shows up as an empty square. On this site, it shows up as a sigma, caputal Y with umlauts, tilde, and decree symbol. What is it actually supposed to be? [[User:Smperron|Kestrel]] ([[User talk:Smperron|talk]]) 12:46, 27 August 2018 (UTC)
It's https://emojipedia.org/face-with-open-mouth-and-cold-sweat/ this emoji. Shows up correctly for me on the actual site on android but not on the wiki [[Special:Contributions/141.101.98.28|141.101.98.28]] 13:04, 27 August 2018 (UTC)

It shows up OK (Albeit small) on Mac OSX [[User:BSchildt|BSchildt]] ([[User talk:BSchildt|talk]]) 13:21, 27 August 2018 (UTC)

Does anyone know the source of the slippery symbol? The other symbols seem to be common to most standards, but the slippery symbol seems to have various designs. ☠☢☣⚡︎? [[Special:Contributions/162.158.62.57|162.158.62.57]] 13:52, 27 August 2018 (UTC)

: https://www.amazon.com/NMC-FS1-Double-Sided-CAUTION/dp/B009RVF1DY <-- This one on Amazon.com seems pretty close. [[Special:Contributions/172.68.58.245|172.68.58.245]] 14:13, 27 August 2018 (UTC)

: [https://en.wikipedia.org/wiki/ISO_7010|ISO 7010] - W011 Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 14:59, 27 August 2018 (UTC)

2035: Dark Matter Candidates

2018-08-20T17:36:37Z

172.68.110.70:

{{comic
| number = 2035
| date = August 20, 2018
| title = Dark Matter Candidates
| image = dark_matter_candidates.png
| titletext = My theory is that dark matter is actually just a thin patina of grime covering the whole universe, and we don't notice it because we haven't thoroughly cleaned the place in eons.
}}

==Explanation==
{{incomplete|Every section needs to be filled and explained. Do NOT delete this tag too soon.}}
{{w|Dark matter}} is a hypothetical form of matter used by the vast majority of astronomers to explain the far too high apparent mass of objects at large scales in our universe. In galaxies, stars are orbiting faster than the gravitational force of the sum of the masses of visible matter in the galaxy could cause, and entire galaxies are observed moving much faster around each other than their visible masses could explain. In galactic collisions, the mass can appear to separate from the visible matter, as if the mass doesn't collide but the visible matter does. A small handful of galaxies have been observed to not have this property, suggesting that it is a *thing* that a galaxy can have more or less of and is separable from. At scales of our solar system those effects are too small and can't be measured. In cosmology, dark matter is estimated to account for 85% of the total matter in the universe.

This comic gives a set of possibilities of what dark matter could possibly be, charted by mass from smallest (given in {{w|Electronvolt#Mass|electronvolts}}) to largest (given in kilograms). Masses in the range 10-15 kg to 10-3 kg are given in grammes.

The joke in this comic is that the range of the mass of the possible particles and objects stretch over 81 powers of ten. [[Randall]] filled the gap between real small candidate particles and real large candidate objects with highly absurd suggestions.

;Axion
An {{w|Axion|Axion}} is a hypothetical elementary particle that might be a component of dark matter.

;Sterile neutrino
{{w|Sterile neutrino|Sterile neutrinos}} are hypothetical particles interacting only via gravity. It's an actual candidate for dark matter.

;Electrons painted with space camouflage
{{w|Electron|Electrons}} are fundamental particles which compose the outer layers of atoms. A large number of electrons in the galaxy would be relatively easy to detect, as they not only interact with light (which dark matter does not appear to), but have a strong electric charge. Presumably, space camouflage is a positively-charged coating which prevents electrons from interacting with light. (Needless to say, this is not an actual candidate for dark matter.) The mass of an electron is about 0.5 MeV which fits well into the graph.

;Neutralino
A {{w|Neutralino|Neutralino}} is a hypothetical particle from {{w|Supersymmetry|Supersymmetry}}, not something made up by Randall Munroe that sounds vaguely like one. It's an actual candidate for dark matter.

;Q-ball
In theoretical physics, a {{w|Q-ball|Q-ball}} is a stable group of particles. It's an actual candidate for dark matter.

In billiards, a cue ball is the white (or yellow) ball hit with the cue in normal play.

;Pollen
{{w|Pollen|Pollen}} is a joke candidate, though people with seasonal allergies may suspect that the universe genuinely is made up entirely of pollen in the springtime.

;No-See-Ums
{{w|Ceratopogonidae|No-See-Ums}}, also called Ceratopogonidae, a family of small flies (1–4 mm long) who can pass through most window screens. Another joke candidate.

;Bees

;8-balls
In pool, the {{w|Pool (cue sports)|8-ball}} is a black ball numbered 8. It's a pun with Q-ball/cue ball. Unless undetected aliens have discovered billiards and become addicted to it, 8-balls are found only on Earth and are, hence, unlikely dark matter candidates.

;Space Cows
Cows are Bovines extensively farmed on Earth for milk and meat. Although there is folk lore concerning cows {{w|Hey diddle diddle|acheiving circum-lunar orbits}}, they have yet to be found elsewhere in the Universe.

;Obelisks, Monoliths, Pyramids
While those human constructions are huge on a human scale, they're negligible at universe-scale. It would take a large number of such constructions, distributed through space, to replicate the effects of dark matter; while a scenario could be envisioned where enough such constructs existed, with properties and distribution allowing them to match observations, this is obviously not a likely explanation.
They often show up in fiction and pseudo-scientific literature as alien artifacts generating immense unknown power out of nowhere, with the most famous and influential example being the three monoliths from 2001: A Space Odyssey (with the largest TMA-2 having a mass of about 500,000 tonnes).

;Black Holes ruled out by:
{{w|Black hole|Black holes}} are known in sizes of a few sun masses (about 1030-1031 kg) as remnants of the core of former big stars and the real big ones at the centers of galaxies (millions or even billions of the mass of the sun.) But recent gravitational wave detection indicate that black holes at 50 or 100 sun masses also exist while their origin is still not understood. Randall doesn't mention this but some astronomers hope that these could fill at least a part of the gap.

Except the last item all range below the mass of the sun (2x1030 kg) while the smallest known black hole is about four sun masses.
* Gamma rays: If dark matter were black holes of this size, the black holes would be evaporating in bursts of {{w|Hawking radiation}}, and we'd see a buzz of gamma rays from every direction.
* GRB lensing: {{w|Gamma-ray burst|Gamma-ray bursts}} (GRBs) are the brightest events in the universe only been observed in distant galaxies. While gravitational microlensing (see below) is an astronomical phenomenon it doesn't make much sense here. GRBs are short (milliseconds to several hours) and often only detected by gamma-ray satellites in space but rarely at any other wavelengths. Measuring lensing effects would be very difficult. This [https://arxiv.org/abs/1406.3102 paper] discusses the probability of detecting lensing effects caused by Halo objects in the databases of GRB given sufficient objects to represent the missing mass.
* Neutron star data: {{w|Neutron star|Neutron stars}} aren't black holes but they're also small high compact objects at about 1.4 and 2.16 solar masses. While black holes can't be observed directly neutron stars are detectable in many wavelengths. The number of them gives a clue about the number of stellar black holes which is far too low.
* Micro lensing: {{w|Gravitational microlensing}} is a gravitational lens effect. This is a prediction by Einstein's General Theory of Relativity and was first confirmed in 1919 during a solar eclipse when a star nearby the sun was closer to the sun than it should be. Astronomers have found many so called {{w|Einstein ring|Einstein rings}} or Einstein crosses where a massive object in front of other galaxies bends the light toward us. Those massive objects may be black holes but the number is far too low to explain the dark matter.
* Solar system stability: Our {{w|Solar system|solar system}} is 4.5 billion years old and very stable since then. If not we wouldn't exist. If dark objects at 1024 kg - 1030 kg (mass of Earth until Sun) would resemble the dark matter there should be many of them even in the vicinity of our solar system and the system wouldn't be stable at all.
* Buzzkill Astronomers: Black holes above a certain size would be impossible to miss, due to the effects they have on nearby matter. But at the mass of some 1030 kg there must be many supernova remnants we still haven't found.

;Maybe those orbit lines on space diagrams are real and very heavy
Any diagram of our solar system (or any solar system) will show lines representing the path the planet takes around its sun. Since planets orbit in ellipses, there will be an ellipse for every planet. This lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be ''huge'' (Earth's would be 940 million km long (2π AU) and Neptune's would be 28 ''billion'' kilometers long. [https://www.youtube.com/watch?v=0fKBhvDjuy0 Powers of Ten (1977)] gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the inner four planets, including the Earth, which would be a problem. Overall, not a very likely candidate.

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

:Dark matter candidates:
:[A line graph is shown and labeled at left quarter in eV and further to the right in g together with some prefixes.]
:[The labels read:]
:µeV, meV, eV, keV, MeV, GeV, TeV, 10-18kg, ng, µg, mg, g, kg, TON, 106kg, 1012kg, 1018kg, 1024kg, 1030kg

:[All items are shown in bars ranging between two approximately values:]
:< 1 µeV - 10 meV: Axion

:1 eV - 10 keV: Sterile neutrino

:0.5 MeV (exactly): Electrons painted with space camouflage

:10 GeV - 10 TeV: Neutralino

:100 TeV - 10-17 kg: Q-ball

:1 ng - 100 ng: Pollen

:0.1 mg - 1 mg: No-See-Ums

:10-1 g (exactly): Bees

:10 g - 100 g: 8-balls

:100 kg - TON: Space cows

:TON - 109 kg: Obelisks, monoliths, pyramids

:109 kg - 1033 kg: Black holes ruled out by:
::109 kg - 1013 kg: Gamma rays
::1013 kg - 1017 kg: GRB lensing
::1015 kg - 1022 kg: Neutron star data
::1021 kg - 1030 kg: Micro lensing
::1024 kg - 1030 kg: Solar system stability
::1030 kg - 1033 kg: Buzzkill astronomers

:1033 kg - >1036 kg: Maybe those orbit lines on space diagrams are real and very heavy

{{comic discussion}}

[[Category:Science]]
[[Category:Physics]]
[[Category:Astronomy]]
[[Category:Line graphs]]

2035: Dark Matter Candidates

2018-08-20T07:40:56Z

172.68.110.70:

2035: Dark Matter Candidates

2018-08-20T07:38:57Z

172.68.110.70: