explain xkcd - User contributions [en]

2526: TSP vs TBSP

2021-10-09T00:22:00Z

162.158.90.157: /* Explanation */ corrected conversions (exponents…)

{{comic
| number = 2526
| date = October 8, 2021
| title = Tsp vs Tbsp
| image = tsp_vs_tbsp.png
| titletext = It's like one teraspoon / when all you need is a kilonife
}}

==Explanation==
{{incomplete|Created by ALANIS TURINGETTE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic plays a joke on the common liquid measurements of {{w|teaspoon}}s (tsp) and {{w|tablespoon}}s (tbsp), which are commonly confused. In the US, a teaspoon is defined as 4.9 mL (0.18 imp fl oz; 0.17 US fl oz) while a tablespoon is defined as 14.8 ml (0.50 US fl oz; 3 tsp).

It also plays a joke on metric prefixes (based on powers of 10) versus binary prefixes (based on powers of 2), which are also a common source of confusion (see also [[394: Kilobyte]]). In the International System of Units (SI), T (for ''tera-'') signifies a multiplier of 1012 (that is, 1 000 000 000 000), while Ti (''tebi-'', for ''terabinary''), and not Tb, is an ISO standard binary prefix meaning 240 (that is, 10244 = 1 099 511 627 776).

The title text is a play on a lyric from the Alanis Morissette song "{{w|Ironic (song)|Ironic}}": "It's like ten thousand spoons when all you need is a knife." Randall changes the line to "teraspoon" and "kilonife". The knife being translated as k nife with k meaning kilo, hence kilonife instead of kiloknife!

If "spoon" is understood as US teaspoon, then one teraspoon will be 4 928 922 cubic meters (1.302 billion US gallons or 3996 acre-feet) and a binary teraspoon will be 5 419 407 cubic meters (1.432 B gal or 4394 acre-ft). If the US tablespoon is taken as base unit, a teraspoon will be 14 786 765 cubic meters and a binary teraspoon 16 258 220 cubic meters – roughly equivalent to six thousand Olympic-size swimming pools and slightly more than six times the volume of the Pyramid of Giza.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Cooking tips: tsp vs tbsp

:[left column:]
:<big>Tsp</big>
:Teraspoon
:1,000,000,000,000
:(1012) spoons

:[right column:]
:<big>Tbsp</big>
:Binary tsp
:1,099,511,627,776
:(10244) spoons

{{comic discussion}}
[[Category:Computers]]
[[Category:Tips]]
[[Category:Math]]
[[Category:Food]]

Talk:893: 65 Years

2021-10-05T14:04:05Z

162.158.90.157:

I wonder if it would be possible to identify ''individual people'' who are behind those vertical jumps in the graph (in the not projected part)... --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 19:18, 14 December 2012 (UTC)
*Glad you asked! </Information Hen> Neil Armstrong and Buzz Aldrin landed in July 1969; that's two. Pete Conrad and Alan Bean joined the group that November; that's four. Alan Shepard and Edgar Mitchell in February '71; that's six. David Scott and James Irwin in July '71; that's eight. John W. Young and Charles Duke in April '72; that's ten. Eugene Cernan and Harrison Schmitt in December '72; that's twelve. Irwin died in '91, dropping it to 11. Shepard and Conrad died in '98 and '99 respectively, making it 9 as of the date this comic was published. Armstrong died in '12, so our current number is 8. The oldest living person to have landed on the moon is Aldrin, 83. There are two 82-year-olds, two 80s, one 78 and two 77s. [[User:Ekedolphin|Ekedolphin]] ([[User talk:Ekedolphin|talk]]) 13:28, 27 January 2013 (UTC)

Almost prophetic and very, very sad. RIP Neil Armstrong ------

Can we add the 5% and 95% columns to the table? [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]])
::i dont feel like this would add to the explanation of the comic and would require us to know a great deal about the author's calculations. rather than attempt to redo the actuarial calculations performed to make the chart and assign this to the individuals in the table we should rather explain the concepts behind the 5% and 95% and preserve the intention of actuarial information as applying to demographic groups. 5% of people in the demographic the author selected live to _ age 95% of those people live to _ age and how this affects our subject population. [[User:Mrarch|Mrarch]] ([[User talk:Mrarch|talk]]) 21:43, 6 December 2013 (UTC)

Why is this explanation incomplete? The second paragraph does a good job explaining what the 5th percentile and 95th percentile are referring to. [[User:String userName = new String();|String userName = new String();]] ([[User talk:String userName = new String();|talk]]) 23:35, 19 June 2015 (UTC)

I prefer to think of the inhabitable planets as extensions to earth reserved for when we have learned not to kill all the inhabitants of the only inhabited planet in the universe.

[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 22:39, 23 January 2015 (UTC)

I see no reason this is marked as incomplete; I've tidied up the percentile explanations, but haven't really added much more. I think it's fine, and will remove the incomplete tag in a few days if nobody objects. [[User:Cosmogoblin|Cosmogoblin]] ([[User talk:Cosmogoblin|talk]]) 13:53, 24 June 2015 (UTC)

'''UPDATED GRAPH:''' I've updated the image with a red line showing actual moon walker deaths. View here: [https://i.imgur.com/G7DbbBi.png]. Sadly, it's right on track. [[Special:Contributions/172.68.58.59|172.68.58.59]] 22:19, 9 August 2018 (UTC)

As of mid April, 2020, this prediction is still accurate, but I'm really scared of what it'll be by the end of 2020 or 2021. Stay healthy everyone, astronaut or not! [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 07:04, 22 April 2020 (UTC)

Interesting that 6/12 of all the people who walked on the moon were born in 1930, and all bar Alan Shepard was born 1930-1935. Reminds me of some of the ideas in Malcolm Gladwell's *Outliers* about there being especially good birth years to succeed at high levels in given fields. It seems you want to have been mid-30s to early-40s (Shephard the outlier at 47) in the late 60s/early 70s. This also makes the comic more dramatic - if there had been a wider spread of ages, then the "death curve" would be a lot more gradual. -[[User:Honeypuppy|Honeypuppy]] ([[User talk:Honeypuppy|talk]]) 01:15, 30 September 2020 (UTC)

Honorary mention: Michael Collins (1930-2021), RIP this date. [[Special:Contributions/162.158.158.104|162.158.158.104]] 17:44, 28 April 2021 (UTC)

IMO the saddest part isn't astronauts dying - it's lack of any new people getting to walk on another planet. [[Special:Contributions/162.158.90.157|162.158.90.157]] 14:04, 5 October 2021 (UTC)

407: Cheap GPS

2021-09-27T19:25:18Z

162.158.90.157: /* Explanation */ Correctness

{{comic
| number = 407
| date = April 7, 2008
| title = Cheap GPS
| image = cheap gps.png
| titletext = In lieu of mapping software, I once wrote a Perl program which, given a USB GPS receiver and a destination, printed 'LEFT' 'RIGHT' OR 'STRAIGHT' based on my heading.
}}

==Explanation==
{{w|GPS}} is a system allowing people to find their location and from that, speed on Earth. It was first developed for the U.S. military, but now it sees international usage for everyday navigation. Many motorists today have GPS devices (sometimes just called GPS's) that can give driving directions electronically.

{{w|Hunt the Thimble|Hot and Cold}} is a children's activity/game where one person searches for an unknown object, and the rest must respond "Hot" or "Cold." Other words, such as "warm" and "cool" can be used to describe their distance more accurately. The closer the player is to the mystery object, the "hotter" they are.

This GPS would be extremely difficult to use, as it gives no directions, only telling you how close you are to reaching your destination. The series of instructions spoken ("cold," "warm," "hot," then "cold" again) suggests that Cueball either missed a turn, or that he just passed his destination.

Randall describes a past engineering project of his that can only describe turns "as the crow flies." So, for example, if he was driving north with the destination to the northeast, the GPS would tell him to turn right even if no such turn was legally possible. Perhaps not very functional, but it ''is'' a pretty cool thing to build.
While cars go fast and are only allowed to, or able to, use a very limited number of all roads and trails in the world, this is less so for pedestrians. As a consequence, for hikers, an app that just shows the direction you should be walking in 'as the crow flies' is actually quite a common and useful tool, since a lot of small roads suitable for pedestrians do not show up on maps. Of course, just printing 'left' or 'right' is much more primitive than showing an arrow in the correct direction (compass-like), and often less helpful since on one cross section there can be multiple trails to the right.

==Transcript==
:[Cueball driving down the road, with a GPS reading "COLD."]
:GPS: COLD... WARM... HOT! COLD...

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Maps]]
[[Category:Programming]]

2517: Rover Replies

2021-09-23T10:13:30Z

162.158.90.157: /* Explanation */

{{comic
| number = 2517
| date = September 17, 2021
| title = Rover Replies
| image = rover_replies.png
| titletext = I'm so glad NASA let you take your phone to Mars!
}}

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

There is a [https://twitter.com/nasapersevere?lang=en Twitter account] for {{w|NASA|NASA's}} {{w|Perseverance (rover)|Perseverance Mars Rover}}, which recently collected samples. The Twitter account tweets in the first person like in the comic. Likely a human on earth is playing the role of the rover. While the exact post shown does not exist, it has posted a [https://twitter.com/NASAPersevere/status/1433334279937789954 similar tweet.]

The first four replies (in order of top-to-bottom) are likely just general compliments to the rover, demonstrating that the replies are indeed wholesome. Reply three in particular references rocks, as the main purpose of most Mars rovers is to perform Martian geology.

Reply five is a mashup of conspiracy theories, including about {{w|5G}} communications, {{w|Vaccine hesitancy|vaccines}}, and others. [[Ponytail]] then replies "Quiet, we're not doing that here", implying either that she doesn't want it in the replies to this, that she thinks that the rude reply should be posted somewhere else, that she's a NASA employee stating that NASA does not have a 5G vaccine-microchip factory, or that she also is a conspiracy theorist trying to redirect the fellow commenter to other forums with more susceptible audiences.

The next reply references people saying where they're from, then clarifying where that is in brackets, e.g. Wingerworth (England). This commenter expands that to clarify that they are from Earth, joking that the planet may be ambiguous as the Mars rover is not on Earth. In reality, this ambiguity does not exist as humans only live on Earth,{{citation needed}} thus contributing to the humor.

The second-to-last reply is likely a misunderstanding, with the commenter believing that the rover is digging to perform anthropology or paleontology, not geology. The commenter could, however, believe that there is/was complex life on Mars, thus allowing the possibility that there are Martian skeletons for the rover to find.

The final reply is a reference to {{w|Ingenuity (helicopter)|Ingenuity}} a small helicopter which Perseverance took to Mars as a [https://mars.nasa.gov/technology/helicopter/ technology demonstrator]. It has been very successful and completed many flights, [https://mars.nasa.gov/images/mepjpl/PIA24797-Flight12.jpg often taking it quite far from Perseverance.]

The title text is in the form of another reply. The character posting that reply believes that the rover has taken its phone to Mars, and has used that to take the pictures. This is likely because most photos on social media are taken on phones, and social media sites are often designed for phones. In addition, Perseverance and Curiosity differ from previous rovers in that they have cameras mounted on flexible arms, allowing them to take photographs of themselves - somewhat akin to a smartphone on a selfie-stick. In reality, Mars rovers don't have smartphones, and Perseverance is taking photos with an equipped camera.

While this comic is most likely referencing Perseverance, there is another small possibility that Curiosity is shown here, as Curiosity also has [https://www.space.com/19708-mars-rover-curiosity-rock-drill-sample.html collected samples]. This is unlikely though due to the timing of this comic.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A post of a rocky landscape and a close-up of a rock is next to a profile picture of the camera of a Mars rover.]
:Just collected a sample!

:[Comments below. Each comment has an icon of a person or other image next to it and an illegible name above the comment.]
:[face of Cueball-like character]: These pictures are great!
:[curved lines]: I'm so proud of you
:[Cueball-like stick figure]: Wow you know a lot about rocks
:[Megan]: Go go go go go!
:[spiral galaxy-like image]: More propaganda from NASA's 5G vaccine microchip factory
::[Ponytail]: Quiet, we're not doing that here
:[unidentified stick figure]: Hello from Missouri (Earth)!
:[Hairy]: Did you find any skeletons yet
:[Blondie]: I hope your helicopter comes back!

:[Caption below frame:]
:The most unexpectedly wholesome place on the internet is the replies to NASA's rovers on social media.
{{comic discussion}}

[[Category:Mars rovers]]
[[Category:Social networking]]