explain xkcd - User contributions [en]

User:Kynde

2024-10-23T11:16:16Z

141.101.98.61:

oh my god
Please send the capital letter "R" to (+86) 10683743173327888106

2951: Bad Map Projection: Exterior Kansas

2024-08-26T07:53:27Z

141.101.98.61: Undo revision 349388 by PaulEberhardt (talk) Try again. Use the Preview button..?

{{comic
| number = 2951
| date = June 26, 2024
| title = Bad Map Projection: Exterior Kansas
| image = bad_map_projection_exterior_kansas_2x.png
| imagesize = 740x706px
| noexpand = true
| titletext = Although Kansas is widely thought to contain the geographic center of the contiguous 48 states, topologists now believe that it's actually their outer edge.
}}

==Explanation==
{{incomplete|The title text isn't explained}}
This is the seventh comic in the series of [[:Category:Bad Map Projections|Bad Map Projections]] displaying Bad Map Projection #45: Exterior Kansas.

[[File:Exterior_Kansas_Azimuthal_Projection.png|thumb|left|Projection of the world from the same perspective as the comic. This uses an azimuthal equidistant projection, so distances from the center point (39°50′S 98°35′E) are correct but areas are distorted.]]

This comic portrays an unusual projection of a map of the contiguous United States based loosely on an {{w|azimuthal projection}}. Maps of individual countries are common, especially in academic settings. It is typical for such maps, which only display a limited area of the globe, to use a projection that does not severely distort the shape of the country or its internal borders, but a country that is large enough (as with the United States) will always noticeably suffer from certain distortions of at least one element chosen from distances, areas or angles. This usually occurs at its extremities (though some projections can be made more faithful to its extremities at the expense of distorting its interior).

Here, however, Randall has opted for a much different projection. Rather than placing the geographical center of the country in the middle and the borders on the outside, this map has gone the opposite direction, with the border of the US toward the center, and the geographical center of the contiguous US (Kansas) and surrounding states distorted to surround the entire map. This, understandably, results in the shape of both the national and state borders being largely unrecognizable as it effectively puts ''every'' bit of the chosen map features out towards the distorted extremities. Much of the internal area of Kansas itself (should one wish to display further internal features) may be located far beyond the comic's edges, perhaps even to infinitely far away on the projected plane.

[[File:Azimuthal_equidistant_projection_SW.jpg|300px|thumb|right|Polar {{w|azimuthal equidistant projection}}, as on the {{w|flag of the United Nations}}, but with an "exterior Antarctica"]]

If Alaska and Hawaii were present in this map and represented in geographically accurate locations (as opposed to inset, as is common in many maps of the United States), Alaska would in the upper right of the empty space, between Minnesota and Washington, while Hawaii would be in the center to the right, off the coast of California. Both would be rather small, with Hawaii particularly compressed (to an extent dictated by the exact projection method used). Additionally, if all 50 states were included, the geographical center would be further to the northwest, resulting in an "Exterior South Dakota" projection.

The title text refers to the fact that {{w|Geographic center of the United States#Contiguous United States|the geographic center of the contiguous United States}} is within Kansas. This map projection instead causes Kansas to show up as the exterior of the US, which makes it the outer edge.

[[File:now.gif|325px|thumb|left|The map in [[1335: Now]] shows an exterior {{w|Arctic Ocean}} and Antarctica in the center]]
{{Clear}}

==Transcript==
{{incomplete transcript|Map description could be improved? Do NOT delete this tag too soon.}}

:[A distorted map of the contiguous United States with the states labeled, where the Atlantic and Pacific coasts and the Canadian and Mexican borders are located closest to the center, with there being a gray void in the middle of the map, while the central U.S. states are distributed in the edges of the panel, with Kansas being in all of the four corners of the map.]

:[Caption below the panel:]
:Bad Map Projection #45:
:Exterior Kansas

{{comic discussion}}

[[Category:Bad Map Projections]]
[[Category:US maps]]

Talk:2829: Iceberg Efficiency

2023-09-15T15:22:36Z

141.101.98.61:

BH clearly isn't Freudian. For the {{w|File:Structural-Iceberg.svg|Iceberg of the Mind}}, the most important part is the 90% of it that is ''hidden''. Which makes for a totally ''different'' (and potentially more implementable) solution whenever you happen to consider that the most important function of an iceberg is to sneak up on ships... ;) [[Special:Contributions/172.71.178.68|172.71.178.68]] 13:26, 15 September 2023 (UTC)

i added a transcript hopefully it isn't horrible [[User:Certified_nqh|Me]]<sup>[[[285: Wikipedian Protester|''citation needed'']]][[Category:Pages using the "citation needed" template]]</sup> 13:47, 15 September 2023 (UTC)
:Tweaked (slightly, to personal descriptive tastes), but definitely not horrible. [[Special:Contributions/172.70.86.7|172.70.86.7]] 14:07, 15 September 2023 (UTC)

Does anyone have knowledge of aerogels being infused with helium? I'm assuming it wouldn't be too outlandish to do so, but honestly don't have a lot of experience with them. [[User:Fifteen12|Fifteen12]] ([[User talk:Fifteen12|talk]]) 14:39, 15 September 2023 (UTC)
:It'd be complex. Most are 'open cell', so need an external coating. Or "pockets of helium" could mean small helium-filled ballonettes embedded within aerogel; being uniformly externally supported by the aerogel, these pockets could be structurally less bulky than traditional bladders of lift-gas (still need to be impermeable, but without the inflate-stretching of rubber, can be a more 'delicate but efficient' material, perhaps [https://pubs.aip.org/physicstoday/online/27257/Graphene-displays-unexpected-permeability graphene]). You could (also?) coat the outside of the aerogel, but adding an arbitrarily large envelope of such a membrane around helium-infused aerogel and then adding more (normally aerated) aerogel onto the outside as additional buffer/structural precaution might be wise(r), as you go ship-hunting... [[Special:Contributions/141.101.98.61|141.101.98.61]] 15:22, 15 September 2023 (UTC)

Talk:2462: NASA Award

2021-05-13T12:39:33Z

141.101.98.61:

Possibly a reference to this? (I'm sure there are other examples, though.) https://en.wikipedia.org/wiki/Cydonia_(Mars) [[Special:Contributions/172.70.34.100|172.70.34.100]] 04:25, 13 May 2021 (UTC)
:More likely it's this recent nonsense: https://www.popularmechanics.com/space/moon-mars/a36356445/mushrooms-on-mars-nasa-photos-life-on-mars/ [[Special:Contributions/162.158.187.229|162.158.187.229]] 05:42, 13 May 2021 (UTC)

Ironically, while many of us are still holding out for visible space fauna, practically every test we've constructed to check for the biochemical ''signs'' of life has returned positive results. Even as far back as the Viking landers, we've been sending out probes & conducting tests, designed to detect trace compositions ''only known to form via biological processes'', & over & over we find those traces right where one would expect. From otherwise inexplicably high methane production, to complex sugars forming around a distant star, it often appears that the universe may be ''teeming'' with life, & we simply haven't collected it somewhere so observable as a petri dish, yet. As near as I can tell, the only reason we haven't declared "extraterrestrial life confirmed" is because we keep raising the bar for proving it. At this rate, I feel like we could discover martian sunflowers & honeybees, & somehow there would still be some question of "Yeah, but are they really truly technically & inarguably ''alive'', exactly? What is life, anyway?" ... So far, I'm not aware of many chemical tests performed to check for signs of life in space which ''didn't'' detect signs of life?
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 08:12, 13 May 2021 (UTC)

Ponytail gives a rock as a prize, but tells Hairy that from an angle it can look like a Nobel. She is using the same semantics when people look at Mars photos and recognize structures or figures in oddly shape rocks. [[Special:Contributions/162.158.158.131|162.158.158.131]] 09:30, 13 May 2021 (UTC)
:I'm surprised there's no wikilink to https://en.wikipedia.org/wiki/Pareidolia yet, in the explanation (or straight to the #Mimetoliths section, even, though that's a slightly different aspect of the same coin as the comic intends). But the rewrite I'd want to do to the Explanation is far more extensive (shuffling, mostly, with only minor editorialising and 'correction') than the time I have right now, if I want to do it well, so I'll leave this until later or let someone else grasp the nettle and perhaps add Pareidolia/similar references themselves? (Honestly, I keep getting YouTube 'recommendations' of stuff like "We've found a pipe* on Mars!" (*i.e. the tobacco kind) which is basically just someone doing the equivalent of saying that a particular cloud in the (Earthly) sky looks like an elephant. Sorta-maybe-for-a-few-seconds-before-it-doesn't-again.) [[Special:Contributions/141.101.98.61|141.101.98.61]] 12:39, 13 May 2021 (UTC)

893: 65 Years

2016-10-27T20:47:28Z

141.101.98.61: Added some details to explain the mouse over text that thos comic has, I would suggest that that mouseover text is a truly excellent quote

{{comic
| number = 893
| date = May 2, 2011
| title = 65 Years
| image = 65 years.png
| titletext = The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision.
}}
==Explanation==
[[Randall]] is showing the number of still living humans who have walked on another world for the 65-year period that begins in 1969 (when a human first walked on the moon). Up to 2011 (when the comic was drawn), he has drawn a single line for the actual figures.

For the subsequent years, he has drawn three lines using {{w|actuarial table}}s or life tables (such tables show, for each age, the probability that a certain person will die within the next year).

The line marked "5TH PERCENTILE" indicates that there is a 95% probability that the number alive in a given year will be above that line and a 5% probability that the number alive will be below that line. For example, this line indicates a 5% chance that all Apollo moon walkers will be dead by 2023, and a 95% chance that at least one will still be alive by that year.

The line marked "95TH PERCENTILE" indicates that there is a 5% probability that the number alive in a given year will be above that line and a 95% probability that the number alive will be below that line. For example, this line indicates a 95% chance that all Apollo moon walkers will be dead by 2035, and a 5% chance that at least one will still be alive by that year.

The middle line is not identified, but is probably the "50TH PERCENTILE" (see [http://blog.xkcd.com/2012/07/12/a-morbid-python-script/ these tables]). If so, it indicates that there is a 50% probability that the number alive in a given year will be above that line and a 50% probability that the number alive will be below that line. For example, this line indicates a 50% chance that all Apollo moon walkers will be dead by 2028 (see previous link), and a 50% chance that at least one will still be alive by that year.

Although the term ''other world'' would include all other worlds on which humans have walked, there is currently only one other world on which humans have walked, which is the moon. The humans that have walked there are the 12 {{w|List of Apollo astronauts#Apollo astronauts who walked on the Moon|Apollo astronauts}} who landed on the Moon between 1969 and 1972.

In particular, {{w|Neil Armstrong}} and {{w|Buzz Aldrin}} landed in July 1969. {{w|Pete Conrad}} and {{w|Alan Bean}} landed in November. {{w|Alan Shepard}} and {{w|Edgar Mitchell}}: February 1971. {{w|David Scott}} and {{w|James Irwin}}: July 1971. {{w|John Young (astronaut)|John Young}} and {{w|Charles Duke}}: April 1972. {{w|Eugene Cernan}} and {{w|Harrison Schmitt}}: December 1972.

Irwin died in 1991. Shepard and Conrad died in 1998 and 1999 respectively, making the total 9 as of the date this comic was published. Armstrong died in 2012 and Mitchell in 2016, so the current number is 7. The oldest living person to have landed on the moon is Aldrin, 86. There is one 86-year-old, one 85, two 83s, one 81 and two 80s.

The chart assumes that no other humans will go to walk on another world within the time-frame plotted and the title text implies that this is primarily an economically determined decision. While noting that not exploring space is a justifiable and sensible decision which may also be made by many hypothetical cultures on other worlds, the text implies a grandness to a civilization that would be given the opportunity to discover, study and memorialize the 'one-world graves' of other civilizations by choosing to explore space despite the economic difficulty. This also implies that the likely consequence of not exploring space is that a civilisation which chooses to do this is doomed to go extinct fairly rapidly while those which do explore and colonise may last long enough to be safely established on multiple worlds and discover the remains of civilisations which acted on a purely economic basis and hence ensured their own collapse. High five for exoplanet archaeology.

==Transcript==
:[A graph titled 'Number of Living Humans Who Have Walked on Another World' - its y-axis is numbered 5, 10, 15, its x-axis increments every ten years from 1960-2040. The line of the graph has a bracket above it that says '65 Years', starting at 1969, ending in 2034.
:The line starts at 1969 and increases steeply to 12 by 1972. It then plateaus until the early nineties declines gradually to 9 between 1991-1999, and then plateaus again.
:From 2011-2035, which is labeled 'Projected Actuarial Tables', the line branches into three and begins to decline more steeply to zero. The area between the first and second branch is shaded and labeled '5th percentile' and the area between the second and third branch is shaded and labeled '95th percentile.']

==Trivia==
*The theme of actuarial projections was explored earlier in [[493: Actuarial]]; Randall's morbid python script for both was given in [http://blog.xkcd.com/2012/07/12/a-morbid-python-script/ the blag].
{| class="wikitable"
|+Table of men who walked the moon
|- style="background:#ccc;"
| style="width:20px;"|
| '''Name'''
| '''Born'''
| '''Died'''
| '''Age at<br>first step'''
| '''Mission'''
| '''Lunar dates'''
| '''Service'''
| '''Alma Mater'''
|- style="background:#def;"
| 1. || {{w|Neil Armstrong}}|| 1930-08-05 || 2012-08-25 || 38y 11m 15d
|rowspan="2"| {{w|Apollo 11}} ||rowspan="2"| July 21, 1969 || {{w|NASA}} || {{w|Purdue University}}, {{w|University of Southern California}}
|- style="background:#def;"
| 2. || {{w|Buzz Aldrin}}|| 1930-01-20 || || 39y 6m 0d || {{w|United States Air Force|Air Force}} || {{w|United States Military Academy}}, {{w|MIT}}
|- style="background:#ffe8e8;"
| 3. || {{w|Pete Conrad}} || 1930-06-02 || 1999-07-08 || 39y 5m 17d
|rowspan="2"| {{w|Apollo 12}} ||rowspan="2"| November 19–20, 1969 || {{w|United States Navy|Navy}} || {{w|Princeton University}}
|- style="background:#ffe8e8;"
| 4. || {{w|Alan Bean}}|| 1932-03-15 || || 37y 8m 4d || {{w|United States Navy|Navy}} || {{w|University of Texas, Austin}}
|- style="background:#def;"
| 5. || {{w|Alan Shepard}} || 1923-11-18 || 1998-07-21 || 47y 2m 18d
|rowspan="2"| {{w|Apollo 14}} ||rowspan="2"| February 5–6, 1971 || {{w|United States Navy|Navy}} || {{w|United States Naval Academy}}
|- style="background:#def;"
| 6. || {{w|Edgar Mitchell}}|| 1930-09-07 || 2016-02-04 || 40y 4m 19d || {{w|United States Navy|Navy}} || {{w|Carnegie Mellon University}}, {{w|Naval Postgraduate School}}, {{w|MIT}}
|- style="background:#ffe8e8;"
| 7. || {{w|David Scott}} || 1932-06-06 || || 39y 1m 25d
|rowspan="2"| {{w|Apollo 15}} ||rowspan="2"| July 31 - August 2, 1971 || {{w|United States Air Force|Air Force}} || {{w|University of Michigan}} (freshman year, and later, an honorary doctorate), {{w|United States Military Academy}}, {{w|MIT}}
|- style="background:#ffe8e8;"
| 8. || {{w|James Irwin}} || 1930-03-17 || 1991-08-08 || 41y 4m 14d || {{w|United States Air Force|Air Force}} || {{w|United States Naval Academy}}, {{w|University of Michigan}}
|- style="background:#def;"
| 9. || {{w|John Young (astronaut)|John W. Young}}|| 1930-09-24 || || 41y 6m 28d
|rowspan="2"| {{w|Apollo 16}} ||rowspan="2"| April 21–23, 1972 || {{w|United States Navy|Navy}} || {{w|Georgia Institute of Technology}}
|- style="background:#def;"
| 10. || {{w|Charles Duke}} || 1935-10-03 || || 36y 6m 18d || {{w|United States Air Force|Air Force}} || {{w|United States Naval Academy}}, {{w|MIT}}
|- style="background:#ffe8e8;"
| 11. || {{w|Eugene Cernan}} || 1934-03-14 || || 38y 9m 7d
|rowspan="2"| {{w|Apollo 17}} ||rowspan="2"| December 11–14, 1972 || {{w|United States Navy|Navy}} || {{w|Purdue University}}, {{w|Naval Postgraduate School}}
|- style="background:#ffe8e8;"
| 12. || {{w|Harrison Schmitt}} || 1935-07-03 || || 37y 5m 8d || {{w|NASA}} || {{w|Caltech}}, {{w|University of Oslo}} (exchange), {{w|Harvard University}}
|}

{{comic discussion}}
[[Category:Line graphs]]
[[Category:Math]]
[[Category:Science]]
[[Category:Comics to make one feel old]]

Talk:1718: Backups

2016-08-12T00:35:16Z

141.101.98.61:

I think this makes more sense if only a small portion of all files from the laptop complete the ENTIRE loop. if the total percentage of files which complete the entire loop is 0.0004% , and he backups once a month, that should give him exponential growth slightly smaller than Moore's Law. At 18 months, his total file size would be about 168% of the original. [[Special:Contributions/172.68.58.245|172.68.58.245]] 22:03, 10 August 2016 (UTC)
: "Cueball: Wait. My laptop is backing up some folders to this server..." Because of that I agree with you. It's saying "Some" folders are being backed up. The wording heavily implies it's not everything in the computer being backed up just a part. [[Special:Contributions/141.101.98.61|141.101.98.61]]

Also, the title text my refer to that often when you lose a project and have to start over from scratch, the project become so much better. [[Special:Contributions/162.158.133.102|162.158.133.102]] 01:55, 11 August 2016 (UTC)



This happens. It can really surprise you when the exponential curve is flat enough. We had a case where we kept a log of the backups on a server that was backed up. This went fine for years, until at some point when we ran out of backup space we found that backups of the logs of backups consumed over 99% of our diskspace.[[Special:Contributions/162.158.87.11|162.158.87.11]] 10:04, 11 August 2016 (UTC)
:Tee hee! This is why the first thing I exclude from backup is the log directory, or the whole /var tree (with a few selected exceptions, like /var/spool/cron/crontabs - this is a royally misplaced location, it should go under /etc). The logs that need to be kept are sent to a log server, online, by the logger daemon itself. If there's no log server (small systems) at least send the logs to backup place during log rotation. -- [[Special:Contributions/162.158.203.151|162.158.203.151]] 18:59, 11 August 2016 (UTC)
:I once managed to backup / to the backup disk at /media/Backup Disk. D'oh. Backupception. --[[Special:Contributions/162.158.150.228|162.158.150.228]] 12:17, 11 August 2016 (UTC)

940: Oversight

2014-09-15T18:27:04Z

141.101.98.61: /* Explanation */

{{comic
| number = 940
| date = August 19, 2011
| title = Oversight
| image = oversight.png
| titletext = I felt so clever when I found a way to game the Fitocracy system by incorporating a set of easy but high-scoring activities into my regular schedule. Took me a bit to realize I'd been tricked into setting up a daily exercise routine.
}}

==Explanation==
[[Megan]] and [[Cueball]] having sex! Against a wall! Over a couch! In some sort of high flying sex swing! {{w|Fitocracy}} is a web site that turns workouts into a social game by awarding points, badges, levels and all sorts of other {{w|Gamification}}. However, according to this cartoon, Fitocracy does not consider sex to be an activity acceptable for its site, despite the high flying nature of Cueball and Megan's sexual workout.

The title text explains how sites like Fitocracy are so successful. Because human brains, especially the cynical ones, like to game the system whenever they can, they will find easy things to do that also score high. In the case of Fitocracy, these are simple exercises that add up a lot when applied daily. But the creators of Fitocracy (and other such successful sites, like Weight Watchers or Lumosity) know this, and, as in Soviet Russia, the system games you into adopting an exercise regimen, or losing weight, or getting smarter, or whatever else there is.

Sex does raise your breathing rate and heartbeat, but as sparkpeople<ref>Sparkpeople "Does sex count as cardio..." http://www.sparkpeople.com/blog/blog.asp?post=you_asked_does_sex_count_as_cardio_how_many_calories_does_it_burn</ref> (a similar site to fitocracy) notes, it is not as effective as a session at a gym, as it does not typically use the main muscle groups in their full range of motion, and doesn't sustain a raised heartbeat for a sufficient length of time. They consider sex to be less effective as cardio than brisk walking, as it burns only about 100-200 kcal per hour, which is little raised above a typical resting rate of about 60 kcal per hour.

==Transcript==
:[Megan and Cueball have sex up against a wall.]

:[Megan and Cueball have sex standing in an armchair.]

:[Megan and Cueball have sex in a swing, swaying above a table with a flower vase on it.]

:[Fitocracy. The search phrase is "sex" and the site returned "activity not found."]

:[Megan and Cueball stand in front of the computer, Megan is at the keyboard, Cueball stands back wearing a towel on his tail.]
:Megan: Come on! That was like two hours of cardio!
:Cueball: Hmm, let's see... The part on the dresser was ''kind'' of like skiing...

{{comic discussion}}
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Comics with color]]
[[Category:Sex]]
[[Category:Internet]]