explain xkcd - User contributions [en]

1179: ISO 8601

2023-12-14T17:36:39Z

172.68.110.171: Format fix

{{comic
| number = 1179
| date = February 27, 2013
| title = ISO 8601
| image = iso_8601.png
| titletext = ISO 8601 was published on 06/05/88 and most recently amended on 12/01/04.
}}

==Explanation==
When abbreviating the date into numerical form, {{w|Date format by country|various areas of the world}} tend to list the year, month, and day in different orders (as well as with different delimiting symbols), which can cause confusion particularly when the day value is 12 or lower allowing it to be easily interpreted as the month and vice versa. As a {{w|public service announcement}}, this comic states that there is in fact one international standard for writing numeric dates, set by the {{w|International Organization for Standardization}} in its {{w|ISO 8601}} standard: YYYY-MM-DD.

The comic then proceeds to list several discouraged ways of writing out the date of the comic's publication, as they do not match the standard. It begins with several commonly used ones in countries around the world but then begins to list increasingly uncommon ways, ranging from strange (Roman numerals) to quirky (binary, Unix time) to essentially impossible (painting the numbers onto a black cat).

The title text provides a perfect example of the kind of ambiguity that can arise when non-standard formats are used. The ISO standard was in fact published on 1988-06-05 and amended on 2004-12-01. This is mentioned in the title text in MM/DD/YY format; however, there is no way to naturally figure this out, particularly with the second date.

With the year truncated to two digits and all three numbers at 12 or lower, the date referring to December 1, 2004 (the digits pairs 12, 01 and 04) has a number of misinterpretations. Usually 12th Jan '04 (if written as US-style but read as European, or vice-versa) but with ISO-influenced "YY MM DD" ordering as one side or other of the misunderstanding it can easily become the 12th day of April 2001, the 4th day of December 2001 and the 4th of January 2012. It takes two such communication errors to 'become' the 1st day of April 2012.

Date formats were again the subject in [[1340: Unique Date]] and [[2562: Formatting Meeting]].

The other mentioned formats are:

{| class=wikitable
! Date !! Explanation
|-
| 02/27/2013
| MM/DD/YYYY, used mostly in the [https://www.trustedtranslations.com/blog/how-are-dates-written-in-different-countries United States, Belize and Micronesia].
|-
| 02/27/13
| MM/DD/YY, same as above but with the year shortened to two digits.
|-
| 27/02/2013
| DD/MM/YYYY, used variously in South America, Canada ({{w|Date_and_time_notation_in_Canada|officially uses ISO 8601}}), Australia, New Zealand and much of Europe.
|-
| 27/02/13
| DD/MM/YY, same as above but with the year shortened to two digits.
|-
| 20130227
| YYYYMMDD, same as ISO 8601 without delimiting punctuation. Allowed by the standard. Technically not ambiguous but is hard to read as a date at first glance.
|-
| 2013.02.27
| YYYY.MM.DD, used in Japan, South Korea and Hungary. Same as ISO 8601 except with different punctuation.
|-
| 27.02.13
| DD.MM.YY, used in Germany, Russia, and others.
|-
| 27-02-13
| DD-MM-YY, used in Denmark, Netherlands, Indonesia, India, Bangladesh, and others.
|-
| 27.2.13
| D.M.YY. It is common in several areas to abbreviate the month or day to a single digit and drop the leading zero when possible.
|-
| 2013. II. 27.
| YYYY. MM. DD., with month as {{w|Roman numerals}}, used in Hungary. In this format, February and November are prone to be confused with each other: "II" vs. "11". Similar formats with the opposite ordering (27. II. 2013) existed historically in various European countries like France, Germany and Italy.
|-
| 27⁄2-13
| D⁄M-YY, traditional format in Denmark, Norway and Sweden
|-
| 2013.158904109
| Year and decimal fraction of year. 0.158904109 is a decimal approximation of 58/365, with February 27 being the 58th day of the year. This format may be easier to read for computers/programs in some contexts, but is difficult for humans to interpret.
|-
| MMXIII-II-XXVII
| The ISO 8601 standard but written in Roman numerals. Never used as a traditional standard anywhere as it is hard to read, parse, and interpret for no benefit.
|-
| MMXIII LVII⁄CCCLXV
| Year followed by its partial fraction 57/365, all in Roman numerals. Equally useless as the above. As a note, apparently this 'standard' is different from the decimal fraction two rows above, as the decimal fraction notation uses the ''end'' of the day (first day of the year is 1/365 while the last is 365/365), while this uses the ''beginning'' (first day is 0/365 and last is 364/365).
|-
| 1330300800
| {{w|Unix time|UNIX Timestamp}}, a standard method of storing absolute time in many computer systems and defined as the number of seconds since 00:00:00 on 1970-01-01 (UTC). The Unix time listed here appears to mistakenly be for '''2012'''-02-27, which is also mentioned by [[Randall]] in the original transcript. The Unix Timestamp for 2013-02-27 would be 1361923200.
|-
| ((3+3)×(111+1)-1)×3/3-1/33
| A useless format where the numbers 2013, 2, and 27 written as needlessly long arithmetic expressions using just the digits 1 and 3. For additional confusion, the values are delimited by slashes, enabling confusion with the fraction bar. (If evaluated literally, the entire expression evaluates to 670.963, or 671 minus one twenty-seventh.)
|-
|    2  272013
| A nearly impossible to read date "format" that can be considered a parody "compromise" between different formats: rather than argue about the order in which the year, month, and day should be, they are simply all written on top of each other. As a "bonus", there is also no arguing over which separator character to use.
|-
| 10/11011/1101
| The US mm/dd/yy format in {{w|Binary number|binary}}, corresponding to 2/27/13. Never used for obvious reasons.
|-
| 02/27/20/13
| MM/DD/CC/YY, where CC stands for century. This format is never used.{{Citation needed}} Note that while months and days count starting from 1, centuries and years in this format count from 0 for extra confusion. But the CC value is widely used on many operating systems to distinguish between the 20th and 21st century, represented by the values "19" and "20" because 1950 belongs to the 20th century.
|-
| 2053112674378
| An obfuscated format where the small numbers indicate the positions where the large digits should be placed. In this reading, 0 is used at positions 2 and 5, 1 is used on position 3, etc.; the result being 20130227
|-
| [A hissing black cat with "2-27-13" painted on it]
| In Western cultures, black cats and the number 13 are associated with bad luck. The cat might also just be angry that someone covered it in paint.
|}

==Transcript==
:Public Service Announcement:

:Our different ways of writing dates as numbers can lead to online confusion. That's why in 1988 ISO set a global standard numeric date format. This is '''''the''''' correct way to write numeric dates:

::2013-02-27

:The following formats are therefore discouraged:
:*02/27/2013
:*02/27/13
:*27/02/2013
:*27/02/13
:*20130227
:*2013.02.27
:*27.02.13
:*27-02-13
:*27.2.13
:*2013. II. 27.
:*27⁄2-13
:*2013.158904109
:*MMXIII-II-XXVII
:*MMXIII LVII⁄CCCLXV
:*1330300800
:*((3+3)×(111+1)-1)×3/3-1/33
:*   2  272013 [the numbers 2013, 02, and 27 written overlapping each other]
:*10/11011/1101
:*02/27/20/13
:*2053112674378
:*[A black cat with 2-27-13 scrawled across its body in dripping white paint.]
:**Cat: ''Hissss''

{{comic discussion}}
[[Category:Math]]
[[Category:Calendar]]
[[Category:Binary]]

Talk:2710: Hydropower Breakthrough

2022-12-13T10:35:12Z

172.68.110.171: A real breakthrough

ChatGPT sez:
:The comic depicts Beret Guy, a character known for his expertise in science and engineering, standing on a podium and announcing that their hydroelectric dam has achieved a level of efficiency greater than one, producing more water than was fed into it. This is cause for celebration, as it indicates that the dam is functioning properly and efficiently. However, the second off-panel voice raises a question, suggesting that there may be more to the situation than initially thought.
:The title text adds further information by revealing that a hydroelectric dam is also known as a heavy water reactor. This suggests that the dam may not be operating in the traditional way, but rather may be using a different type of technology, such as nuclear power, to produce the excess water. This could raise concerns about safety and the potential risks associated with this type of technology.
Meh. [[Special:Contributions/172.69.33.45|172.69.33.45]] 03:44, 13 December 2022 (UTC)

It *is* possible. All Beret Guy has to do is use the electricity to run air conditioners, which will have one side condensing water from the atmosphere, ergo more water coming out than went in. [[User:SDSpivey|SDSpivey]] ([[User talk:SDSpivey|talk]]) 04:00, 13 December 2022 (UTC)

Considering that he phrases it "more water than we fed into it" in the past tense, it might just be that there's a leak in the dam.
[[Special:Contributions/172.69.33.19|172.69.33.19]] 04:06, 13 December 2022 (UTC) mraction

More variation: "more water than *we* fed into it" ie not counting water from the river that feeds it, or rainfall. There's also the title text turn of phrase "heavy water reactor". "heavy" could refer to either the "water" (in the sense of gravity, or deuterium passing through), or the "reactor" (as in its mass) - [[Special:Contributions/172.70.210.242|172.70.210.242]] 05:43, 13 December 2022 (UTC)

"Another member of audience, who is presumably familiar with regular physics, says "Wait.", because conservation of mass usually applies to water such that a dam should produce the same amount of water as that fed into it. That said, for a regular dam in a natural valley like the one shown in this comic, it is entirely normal for the dam to "produce" more water than input in the sense that in addition to water from upstream rivers, the dam will also output any "unofficial" inflow from direct rainfall above and from uncharted sources of groundwater below." 
I thought that the "Wait" comment was in relation to the fact that the announcement, although achieving something that was not achieved so far, is impractical. As the power plants are expected to produce energy, announcement that they produce additional water is irrelevant, and the "wait" comment indicated that they have missed the point. {{unsigned ip|172.68.50.204}}

Given the title of ''Hydropower Breakthrough'', is a possible interpretation that the dam is just about to fail? --[[Special:Contributions/172.68.110.171|172.68.110.171]] 10:35, 13 December 2022 (UTC)

2671: Rotation

2022-09-13T09:46:55Z

172.68.110.171: ...

{{comic
| number = 2671
| date = September 12, 2022
| title = Rotation
| image = rotation.png
| titletext = It's okay, we can just feed the one-pixel image into an AI upscaler and recover the original image, or at least one that's just as cool.
}}

==Explanation==
{{incomplete|Created by an IMAGE UPSCALER. Do NOT delete this tag too soon.}}

Another of [[Randall]]'s [[:Category:Tips|Tips]], this tip claims that rotating a phone and taking a screenshot too many times will cause an image to disappear into nothingness as it will become smaller than the planck length, and warns the user against doing so. This is absurd because the camera and the display both have limited resolutions. The detail of the original screenshot at the center of the image will be aggregated out as it approaches the range of a few pixels, hence the original image will be lost before it reaches the sub-pixel range. Camera phone users are unlikely to do this, they are usually less aware of the optimal resolution for their intended purposes than they could be. A phone's "auto-rotation" feature will automatically rotate an image to the fit the phone's current orientation based on {{w|accelerometer}}s.

[[Image:World lines and world sheet.svg|thumb|200px|{{w|String theory}} describes the {{w|worldline}}s of point-like particles as {{w|worldsheet}}s of "closed strings," forming a topological foam.]]

For a fuller explanation of the concepts involved, including {{w|Planck units}}, often associated with the topological {{w|quantum foam}} of {{w|string theory}}, please see [https://www.youtube.com/watch?v=pUF5esTscZI this CGP Grey video.] For an explanation of topological string theory, see [[2658: Coffee Cup Holes]].

The title text refers to producing photographically likely higher resolution images from lower resolutions, an active area of current research.[https://openaccess.thecvf.com/content/ICCV2021/papers/Liang_Hierarchical_Conditional_Flow_A_Unified_Framework_for_Image_Super-Resolution_and_ICCV_2021_paper.pdf] Because reducing the resolution of an image is a lossy process, results obtained through such processes will not be able to perfectly recreate the original. When scaled all the way down to one pixel, everything except a small amount of data about the image's overall color is lost, making reconstructing the original image impossible. The "[https://tvtropes.org/pmwiki/pmwiki.php/Main/EnhanceButton enhance button]" for upscaling images is a common trope in movies and television, especially in crime and science fiction stories.

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

:[A phone in portrait orientation shows an image of Cueball standing. It is then rotated, showing the image smaller with bars in landscape orientation, then the next phone is in portrait showing the entire screen of the previous rotated sideways, shrinking it every time. An arrow points from each phone to the phone with the next smaller image, until the last one. The labels, at the 9th, 25th, and 101st rotation, show the decreasing size of the original image as it goes through successive rotations.]

:[Labels:]
:9 rotations: original image is smaller than a pixel.

:25 rotations: original image is smaller than an atom.

:101 rotations: original image is smaller than the Planck length, at which the concept of distance may break down.

:[Bottom caption:]
:Phone tip: don't rotate and screenshot an image too many times or it will become lost in the quantum foam of the universe.

{{comic discussion}}
[[Category:Tips]]
[[Category:Smartphones]]
[[Category:Comics featuring Cueball]]

Talk:984: Space Launch System

2022-09-07T15:05:11Z

172.68.110.171:

But then we built a whole pile of rockets after that. Apollo, moon landing, mars rover, etc. Boo Black Hat.06:53, 2 February 2013 (UTC)
:"Apollo, moon landing" -- that is, in fact, the Saturn V, built by von Braun, captured Nazi scientist, and his team, largely captured Nazi scientists. Yes, other rockets were built after the Saturn V, but as pointed out in the strip, none have been bigger or more powerful. "Finally, rockets that improve on the ones we had 40 years ago."
:The first Mars lander (true, not a rover), Viking I, was launched on an Titan/Centaur. The Centaur was a co-creation of Krafft A. Ehricke, nazi scientist.
:Mars Sojourner, a rover, part of the Mars Pathfinder mission, was launched on a Delta II rocket. The Delta family of rockets are based on the Thor ballistic missile. The Thor was originally co-developed by Dr. Adolph K. Thiel, Nazi scientist.
:You see where this is going? {{unsigned|212.149.48.43}}

Technically, von Braun wasn't captured. He voluntarily defected. He was wandering Germany because he had chosen to no longer support Hitler, so to stay at the concentration camp where he worked, or anywhere where a Nazi soldier could find him was suicide, so he escaped and was wandering out alone. He surrendered and defected to the first allied troops he saw, which just happened to be American. This is why he worked on the space programme instead of being shot on sight. By the time he was building American rockets, he hadn't been a Nazi for years.[[Special:Contributions/76.29.225.28|76.29.225.28]] 14:40, 4 July 2013 (UTC)
:You're way off the mark. He was never opposed to the Nazis per se, but did understandably start grumbling a bit when he realized this Endsieg thing wasn't really working out. He and his team left the base because they, again understandably, did not want to be prisoners of the Red Army and Soviet Russia. Then, when the Americans finally caught up with them, he surrendered himself, avoiding execution by guards at the same time. --[[User:Qwach|Qwach]] ([[User talk:Qwach|talk]]) 02:19, 1 September 2013 (UTC)
:"He hadn't been a Nazi for years" -- really, this is begging the question of how you determine whether someone "is a Nazi" or not. Would you say that anyone who ever joined the Nazi party "is a Nazi," despite the fact that many of them probably did so for social expedience rather than because they actually agreed with Nazi philosophy? And would you then ignore the fact that many modern-day skinheads or neo-nazi's aren't formally registered with any national-socialist party? And, if you get around this problem by ignoring party registration altogether, and you simply say that someone "is a Nazi" if they hold views which concur with the views of the Nazi party, then how do you measure someone's views? How do you determine whether someone's views are sufficiently-similar to the Nazi party's to call them a Nazi? If someone were to say "sure, I hate Jews, but we probably shouldn't murder them all," would they be sufficiently Nazi-esque to "be a Nazi" or would their dissent make them "not a Nazi?" In conclusion, to say conclusively that von Braun "was a Nazi" or "wasn't a Nazi" at any particular point in time is probably nearly impossible, and not worth our time. [[Special:Contributions/108.162.221.249|108.162.221.249]] 19:12, 9 March 2015 (UTC)

So he was one of the good guys?
Not like the other guards and related personnel who didn't want anyone to know they were intimately involved in any of what they were so intimately involved with?
Someone tell me how the USA isn't a working example of Nazi Germany.[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 08:01, 22 January 2015 (UTC)

:This may be quite late but I'd like to point out that von Braun was not just member of the NSDAP (the Nazi party) but of the SS as well which goes beyond simple opportunism or group pressure. And he actually visited concentration camps and even selected "workers" (for V2 production) personally, so there is no doubt that von Braun was a Nazi war criminal. He was just never convicted because he was too useful (which was unfortunately the rule rather than an exception at the time). --[[Special:Contributions/162.158.90.78|162.158.90.78]] 19:45, 18 April 2018 (UTC)

As of September, 2021 (10 years after the comic was published0, the first SLS launch still has not taken place. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 14:29, 19 September 2021 (UTC)

;Incomplete

Oh, this comic is one of the "more complex" ones. The time line (not the comic sequence) is starting with the US failures to archive space flight in the 1950's, then referring to Nazis, and by the end we are on the current US space policy, which is also highly questionable.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 19:51, 4 July 2013 (UTC)

Not sure what you mean by one of the "more complex" ones, it is actually pretty straightforward. Some nitpicking though: there was no US failure to achieve space flight in the 50s; both the US and the USSR did it within 4 months of each other at the end of 1957/beginning of 1958. A little history lesson:
The Space Race didn't begin until July of 1955, when the US announced its intention to launch Earth-orbiting satellites sometime between July 1st 1957 and December 31st 1958. The USSR followed suit shortly afterwards, and by the end of August 1955 the Soviet Academy of Sciences created a commission (i.e. offered support and possibly some sort of incentive) for the sole purpose of beating the US into space - which they ended up doing with Sputnik 1 (10/04/57) and 2 (11/03/57). The creation of that commission is considered the start of the space race. The US launched its first successful satellite a few months after the Sputniks, the Explorer 1, on February 1, 1958, well within what most people would call the 1950s. [[Special:Contributions/108.162.216.80|108.162.216.80]] 19:53, 31 July 2014 (UTC)

Which is not to say that Maria Cary is a rocket scientist or not, as the case may be.[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 08:21, 22 January 2015 (UTC)
Doh Shania Twain. (It's amazing what you can learn when you check your spelling.)[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 08:21, 22 January 2015 (UTC)

Amazing how Randall can take heinous ideas of which any rational person would be ashamed to even think, put them in the mouth of Blackhat, and it's not only fine, but hilarious. Bravo. [[Special:Contributions/108.162.219.236|108.162.219.236]] 18:41, 3 August 2015 (UTC)

"Once the rockets go up, who cares where they come down? That's not my department..."[[Special:Contributions/173.245.50.174|173.245.50.174]] 04:40, 6 September 2015 (UTC)

Personally, I don't get why using Nazi scientists is considered abhorrent. The fuckers who gassed Jews just for the hell of it? Yes, they're despicable. But the rocket scientists who built spacecraft? Fact is, they knew what they were doing, and were good to further our technology. They're ability to advance science is a positive quality, which does not in any way diminish their horrible qualities. Like all human beings, they had a good part, even if their bad vastly overshadows it. [[User:HumaneEngineer|HumaneEngineer]] ([[User talk:HumaneEngineer|talk]]) 02:01, 27 September 2018 (UTC)
:They knew of, or at least delibretly closed their eyes on the working condidents of the consturcuction sites of the V2 rockets, where between 16,000 and 20,000 slave workers died under horrible circumstances. Also they knew exaclty that their rockets where used as an offensive weapon against civilians.