2854: Date Line

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Date Line
They estimate the rocket should be free by approximately ... uh ... well, in about two hours.
Title text: They estimate the rocket should be free by approximately ... uh ... well, in about two hours.


The International Date Line is a nominal line on Earth near the antimeridian (180°) that represents where adjoining territories observe a full calendar day of difference (give or take the 'normal' time of day adjustment).

It causes one of three situations where the date might change for you, the usual one being when (in your time zone) you pass from the hour of 11 pm across beyond midnight, and a second being if you travel directly between time zones at such a time (usually that being a window of just one specific hour, at night) where they are each either side of midnight. Most people don't travel at or around midnight, and just being awake as the clocks tick over is not often such a remarkable thing, other than to perhaps mark reaching a special date (significant birthdays, perhaps, or New Year's Day). However, travel across or between certain areas of east and west Pacific (or vice-versa) is not so uncommon, yet brings with it the special need to effectively adjust your watch by a full day (plus or minus any other time to be adjusted).

The International Date Line is not a physical string,[citation needed] and therefore could not be caught by a rocket. It should also be noted that the International Date Line is not straight, but extends either side of the antimeridian to avoid confusion on internal land journeys (like Russia, a portion of which overlaps the antimeridian), similarly cutting off 'nearby' outlying island territories or adding needless complexity when dealing with chosen trading partners. (There may also be the niche tourism-led motivation of being able to claim 'first' in experiencing the new date.) Of course, these very bends would give a physical International Date Line quite a bit of slack that a rocket could pull up (as depicted in the comic).

Based on what is shown in the comic, the rocket could have been launched by the Russians (e.g. from the Vostochny Cosmodrome), but the caption implies that the American space agency is the one expecting to resolve the issue (whoever's original error it was), and all orbital flights are pretty much guaranteed to cross (over) the dateline at some point in the initial track. Of course, the odds of a rocket getting stuck on such a line (if it existed) would be incredibly slim. Additionally, striking such an object wouldn’t trap the rocket. Instead, the rocket (and likely the line) would undergo what many KSP users have encountered: Rapid Unplanned Disassembly.

The caption suggests that this event has messed up the normal regulation of time, and is somehow unsafe to 'use' as a result, so people should pause their usage of it by stopping their clocks and calendars. Also, because time is not behaving normally, ‘they’ can’t give a time for when it will be fixed. If, say, it was 8:00 when the rocket got snagged, then it is 8:00 until they fix it. This means that no matter how much time should have passed, until they fix it, it will remain 8:00. In reality, even if a physical dateline did exist, and if disturbing it were to mess up our ability to measure time, synchronize clocks, and so on, time itself would continue to flow regardless, and pausing one's clock would have no effect on this. Indeed, if time stopped operating, it's not entirely clear what an amount of time that 'should have passed' would even mean, or if we would be able to perceive that anything was wrong. Or, we could use more traditional ways of keeping the time that doesn't need the International Date Line, like Water Clocks or Sundials until it's fixed.

More worryingly, yet oddly not mentioned by the announcement, is that the International Date Line and Greenwich Meridian appear to be a single continuous physical line, and consequently, the stretching of the former is pulling in the latter, causing significant geological disruption along that line, which would result in danger to life and property and infrastructure damage affecting many millions of people living close to it, and probably tsunamis that could threaten many more further afield.

The title text states that the estimated time the rocket should be free is "about two hours,” but the speaker/writer hesitates when about to give an estimated time stamp, as the time does not advance on clocks, assuming the instructions are followed. Instead, a more generic time must be given, though there still remains the issue of how to properly judge the relative passing of time.


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[The earth, with the International Date Line as a physical band being pulled off of the surface by a rocket, cutting into the land on the other side.]
[Caption below the panel:]
Timekeeping announcement: A rocket accidentally became snagged on the International Date Line during launch. Please pause all clocks and calendars until NASA is able to free it and safely resume the normal flow of time.


  • This trivia section was created by a BOT
  • The standard size image was uploaded with a resolution/size larger than the supposed 2x version.
  • This may have been an error.
  • The about two hours might reference the orbital time of LEO satellites

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The 'standard' and '2x' sized images had unexpected sizes, so a Trivia section has been automatically generated, and an imagesize parameter has been added (at half size) to render the image consistently with other comics on this website. --TheusafBOT (talk) 22:56, 13 November 2023 (UTC)

I see no evidence of this, so the Trivia section should probably be removed. The comic appears standard sized on XKCD (both in the page and if opening the direct link), and the link in the Trivia also leads to a standard size image. NiceGuy1 (talk) 04:19, 19 November 2023 (UTC)
Things have been known to be corrected. For whatever reason, TheusafBOT detected the initial issue (since it was made to do so, these problems recently having occured in other comics and caused problems) and it certainly was worth the automatic note making to make people aware of the (probable) discrepancy.
Without looking into possible webarchived material, or delving too deep into the current stock, I think it's worth keeping a small note (just as when the original "neeeded" was corrected to "needed" in a title text, etc), but obviously reword it as being no longer true (and/or change link to the erroneous size's archive location, if there is one?). I would also then see no problem with fully excising the 'BOT announcement here (and your response and this response to that) here on the Talk page.
If you'd prefer to excise the "Trivia", then I suggest transfer the gist (not header) here to Talk as a quote/indent, so future readers know what we're talking about, and leave this part of the fuss intact. (Same for any other such 'corrected' anomolies you can find needing sorting out in other comics, albeit their Talk elements are probably thankfully unaugmented by this particular metaⁿ-discussion.)
I'm sure if you edit it all how you want to, though, it'll all be critically assessed by every other editor who cares (myself, I care little about this particular issue, just 'best wiki-keeping practices' in general, not liking to lose information that has been 'true') and modified/whatevered at their whim, just as we gladly honour/humour your own edits.... ;) 14:32, 19 November 2023 (UTC)
Meant to add: the "evidence" for it is in the following comments, editors who witnessed this. Which is good enough for me to be a fact (and not even a {{fact}}). 14:38, 19 November 2023 (UTC) (aka, above, in case that has changed)

Is it just me or are these size errors becoming more common? What going wrong in the infra? 22:57, 13 November 2023 (UTC)

Yeah, and this one came in HUGE. The image size upon loading the comic at xkcd.com was 6642x7838. At first, I thought it was a special comic or an interactive one. But just huge. Orion205 (talk) 00:25, 14 November 2023 (UTC)

added an explanation 23:49, 13 November 2023 (UTC)

The IDL might not normally be straight, but when the rocket pulls in it, it will straighten it out. Barmar (talk) 00:54, 14 November 2023 (UTC)

The Kentucky State Police resent the implication about their organizational infrastructure.

I like how this comic came out the same day (in UTC+10) as I am studying Earth geometry including the IDL. Nice little coincidence. OmniDoom (talk) 03:46, 14 November 2023 (UTC)

Why's there a missing line of latitude? 05:47, 14 November 2023 (UTC)

That is actually a good question. Seems like an error. --Kynde (talk) 08:01, 14 November 2023 (UTC)
I would assume the lines that are shown are intended to be the equator, tropics, and arctic circle (antarctic being hidden out of view), being the most commonly known lines of latitude. 12:04, 14 November 2023 (UTC)
The latitude lines, the top one is obviously the Arctic Circle. The next goes through the northern part of Africa, making it the Equator. Next would be a Tropic. Where's the northern Tropic? (I always mix up Cancer and Capricorn, I want to go with Cancer). Missing line. NiceGuy1 (talk) 04:19, 19 November 2023 (UTC)
I think it's just the angle. If viewed from the side (instead of diagonally above as in the image), I think they would appear more equidistant. Or maybe they're based on a different projection entirely, that wouldn't be out of character for Randall either. 12:08, 14 November 2023 (UTC)
No, the northern Tropic is missing. After Arctic it shows the Equator, there should be a Tropic in between. NiceGuy1 (talk) 04:19, 19 November 2023 (UTC)
I'm not seeing the problem, I guess? The northern Tropic passes through northern Africa; that's not the equator. The equator passes through the *middle* of Africa (south of India, through Indonesia and the Philippines, etc.), so from the north pole the drawing does show the Arctic Circle, then the Tropic of Cancer, then the equator, then the Tropic of Capricorn way down at the bottom. https://en.wikipedia.org/wiki/Tropics#/media/File:World_map_indicating_tropics_and_subtropics.png -- ModelD (talk) 13:27, 21 November 2023 (please sign your comments with ~~~~)

Even if the lines were actual physical strings/ropes, they appear to be lying right on the earths surface instead of being suspended in mid air. So how would a rocket accidentally get snagged on one? You'd have to purposefully shove the rocket between the earth and the line before launch. Bischoff (talk) 08:39, 14 November 2023 (UTC)

Well, obviously you wouldn't want ships/trains/etc hitting them as they moved longitudes(/latitutudes) or timezones, so they must be held up out of the way by skyhooks. Probably also above plane travel, or we'd see them being snagged quite often...
Noting that I had to caveat the idea of the Russian launch-site, as NASA seems to be the named agency needing to fix the mess. Could of course be 'Hollywood Exceptionalism', regarding who it is who leads saves the world. Or actual expertise such as might have actually helped with the Kursk submarine, in a pinch (except that, geoplitically, currently it'd probably take even longer for Russia to deign to request assistance from the US than 23 years ago).
I also, for brevity, skipped the needless pedantic analysis of typical 'first orbit' trajectories from all current launch sites, worldwide, so as to work out whether any others might encounter such a North Pacific crossing-point at 'first hit' (after which, it's clearly high enough to not snag again). Depending on launch eccentricity, it's feasible from practically any of them, naturally. 10:37, 14 November 2023 (UTC)
Maybe it was a submarine launched rocket. 12:06, 14 November 2023 (UTC)
It's obviously North Korean. Russia disclaims any involvement. 08:42, 15 November 2023 (UTC)

I think the "about 2 in the title text references the Windows approximate download times dialogs - GreyFox 18:31, 14 November 2023 (UTC)

It's not. They were about to say an absolute time, e.g. "by approximately 12:00" but they realized absolute time is paused so they gave a relative time instead. --NeatNit (talk) 22:39, 14 November 2023 (UTC)

This looks devastating for western Europe and western Africa. --NeatNit (talk) 22:39, 14 November 2023 (UTC)

I just tripped over the 90º24’ line. What is with these new strings? TenGolf MathHacker (talk) 15:12, 15 November 2023 (UTC)