explain xkcd:Museum

Welcome to the explain xkcd wiki!
We have an explanation for all xkcd comics, and only 46 (1.4%) are incomplete. Help us finish them!

Latest comic

Go to this comic explanation

Particle Census

|< < Prev #3247 (May 18, 2026)

Title text: Remember, your answers to the physics census are confidential; we will not be issuing Pauli exclusion principle citations.

|< < Prev Random Explanation

Explanation

This is incomplete: This page was created at an UNCERTAIN TIME. Don't remove this notice too soon. If you can fix this issue, edit the page!

This comic references the Heisenberg uncertainty principle of quantum mechanics. Put simply, it states that we can't know both the position and momentum of a particle -- the more accurately we know one, the less we know the other. Megan says they're taking a census of the positions of all particles in the universe, so they'll be known precisely; therefore, all their momenta will be unknowable. And by the time we use the census results we won't know where any of the particles are, we'll just know where they were at the instant their positions were recorded by the census.

In the United States, the Constitution mandates that a population census of people living in all the states be taken every ten years. This is primarily for the purpose of apportioning representatives to Congress, but it has come to be used for many other demographic purposes. There's no legal requirement for a decenial physics census; if physicists want to do this, it's their own decision. However, it's not really possible to measure the positions of all particles in the universe - Because there are a lot of particles in the universe, and many are quite difficult to reach.^{[citation needed]} As well as that, saying where some of the particles are, at least when you get to more spacebound areas, would be difficult too. And unless the particles happen to be at absolute zero, they will be moving around a lot. So a needlessly difficult census.

In the third panel, someone speaks up and is worried about what they will do with the particles in the potential “disruption”. Randomly taking someone’s particles and relocating them would be considered unpleasant,^{[citation needed]} even if you tell them where the particles are going.

The title text refers to the Pauli exclusion principle. This states that no two fermions can occupy the same quantum state. As the results of the census are confidential, physics officials will not use it to determine if any particles are violating it and issuing citations. This confuses physical laws, which describe how the universe works, with societal laws, which state what is allowed or required by the government.

Trivia

When this comic was uploaded the normal sized image was incorrectly 2x size. It still shows up at 2x size on unixkcd.

Additionally, "indeterminate" is spelt "indeterminite" in the second panel text.

Transcript

This is one of 45 incomplete transcripts: Don't remove this notice too soon. If you can fix this issue, edit the page!

[First Panel. Megan is standing at a lectern, presumably talking to an audience.]

Megan: Remember, Tuesday is the decennial particle census.

Megan: Physicists will be recording the location of all particles in the universe.

[Second Panel. Zooms out to show the stage Megan is on]

Megan: Of course, this will cause their momenta to become indeterminite, so please plan for some disruption.

[Third Panel. An audience member pipes up from off-panel.]

Audience member: Wait, disruption? Where will my particles go?

Megan: No one can say, but you'll know exactly where they were.

  Add comment        Create topic (use sparingly)       Refresh 

Discussion

Maybe it's more of statistics than exhibitions. --While False (speak|museum) 21:17, 3 October 2022 (UTC)

pixels-assembly-3.png

how is it 0 bytes?? i see that it is shown as 0 bytes on the wiki, but the file itself, when downloaded is 5kb! how???108.162.221.209 16:41, 4 October 2022 (UTC)Bumpf

If the question is how it can be written like that here, the answer is that I used the numbers of the wiki. —While False (speak|museum) 19:18, 4 October 2022 (UTC)

Sorry, should have made it more clear. Do you know why it is shown as 0 bytes on the file page? 172.70.134.103 12:37, 7 October 2022 (UTC)Bumpf

There's always the possibility that this is actually the Null image under the .png file format. Every other .png is defined by the delta required to display the desired graphic when starting from the baseline of this 'ur'-image, but if you ever wanted to display that graphic the undocumented format specifications allow you to omit all unnecessary bytes (including the magic header bytes) and it will happily produce its hardcoded "it's a PNG!" preprocessing template, which happens to be this image. Obviously, the PNG spec (and, ultimately, the original ancestor of the detailed source code tree for every subsequent implementation) was written before Randall ever got anywhere near to drawing this image so the chances are slim that he just happened to luck upon the exact image that happens to have a 100% compression rate because it just happened to consist of something Randall wanted to draw, and in the manner of Randall's artistry. But it's a non-zero likelihood that an arbitrary artist might draw exactly the same image as a purely arbitrary "index null" page's collection of pixels and so... This might not be the Best Of All Worlds, but there has to be some highly fortunate occurance to balance out all the unfortunate ones, statistically, and this is ours!

(Or maybe there's a minor bug/data-error in the way the wiki database serves the front-end webserver, but I can't ask you to believe something as trivially random as that!)) 172.70.90.245 15:03, 7 October 2022 (UTC)
        Add comment

Is this out of date? .

New here?

Last 7 days (Top 10)

Rank Score Pages Changes Username 1 59 52 63 Ally 2 51 44 55 SomebodyElse 3 32 27 33 TheusafBOT 4 28 16 50 GSLikesCats307 5 27 16 49 DollarStoreBa'al 6 20 17 19 FaviFake 7 19 14 21 YZ100 8 8 3 10 Barry Margolin 9 8 3 9 Trimutius 10 7 4 7 BunsenH

Lots of people contribute to make this wiki a success. Many of the recent contributors, listed above, have just joined. You can do it too! Create your account here.

You can read a brief introduction about this wiki at explain xkcd. Feel free to sign up for an account and contribute to the wiki! We need explanations for comics, characters, themes and everything in between. If it is referenced in an xkcd web comic, it should be here.

• If you're new to wiki editing, see the explain xkcd:Editor FAQ for a specific guidance to this Wiki and the more general help on how to edit wiki pages. There's also a handy wikicode cheatsheet.

• Discussion about the wiki itself happens at the Community portal.

• You can browse the comics from List of all comics or by navigating the category tree at Category:Comics.

• There are incomplete explanations listed here. Feel free to help out by expanding them!

Rules

Don't be a jerk!

There are a lot of comics that don't have set-in-stone explanations; feel free to put multiple interpretations in the wiki page for each comic.

If you want to talk about a specific comic, use its discussion page.

Please only submit material directly related to (and helping everyone better understand) xkcd... and of course only submit material that can legally be posted (and freely edited). Off-topic or other inappropriate content is subject to removal or modification at admin discretion, and users who repeatedly post such content will be blocked.

If you need assistance from an admin, post a message to the Admin requests board.