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Baryon Asymmetry

|< < Prev #3263 (June 24, 2026)

Title text: Wait, what do you mean, 'dark matter'? It's not dark, it interacts with high-energy gamma rays ... right? Oh jeez, did I forget to make it interact?

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Explanation

In this comic, Cueball talks with the creator of the universe (possibly the one previously seen in another recent comic). Cueball wants to know why the universe has baryon asymmetry, which refers to the fact that the observable universe contains much more matter than antimatter. Current physical theories imply that matter and antimatter should have been created in roughly equal amounts. The fact that antimatter is extremely rare is very fortunate for humans and other objects made of matter, given that matter/antimatter reactions destroy both substances with a violent release of energy.

As it turns out, though, the creator of the universe, far from being wise and all-knowing, simply forgot to add a roughly equal amount of antimatter. Realizing their mistake, they proceed to add the antimatter that they originally forgot, only to create a massive explosion as large parts of the universe experience annihilation.

The creator seems to have been careless about the workings of their own created universe, only now adding in the forgotten antimatter without considering the widespread impact it would have on the current state of the universe. This is strange, given they created the universe, and they would surely not be oblivious to the fact that it either has not been working as intended (missing around half of its mass) or any realization that the forgotten feature was actually a bad idea after all. Although as they are conversing with Cueball, who has exhibited similar degrees of personal ineptitude, and as this might or might not be the same entity as seen getting things 'wrong' in 3222: Star Formation, this might just go to show that it is a shared trait to have so much ability but so little foresight and understanding.

An alternative explanation could be that the sphere is an equivalent to Black Hat, who knows all about the impact and yet 'corrects' the situation anyway, simply not caring about destroying the universe they created, or even deliberately choosing to worsen the situation.

The title text resolves another physics mystery in a similarly unexpected way. Dark matter, another substance that is thought to exist but is considerably less well understood than antimatter, mysteriously interacts via gravity but not, as far as we know, via electromagnetism. The creator seems to reveal that dark matter was supposed to interact with high-energy gamma rays, a form of electromagnetic radiation (which, at least as far as the creator is concerned, would not make it 'dark'), but they forgot to add that property to the substance that we had consequently called "dark matter". Exactly how this follow-up issue was posed is unknown, following the sudden annihilation of much (if not all) matter in Cueball's vicinity, and likely also his own body. However, there is a chance Cueball is safe from this, as the void shown is unknown, and the last panel could display events happening elsewhere in the universe, where the void is safe from such things.

It is uncertain if any more questions could be asked, after this other apparently-intended situation was properly implemented, but they might include something about the nature of dark energy, yet another mystery regarding the nature of the universe in which various after-market 'fixes' could also be particularly problematic.

The creator of the universe in this comic might be the same floating sphere featured in 3085: About 20 Pounds. Talking to a floating sphere/orb or some similarly non-corporeal entity is a recurring subject in xkcd.

Transcript

[Cueball is floating in a void. He is speaking with the creator of the universe, who appears as a black sun symbol.]
Cueball: So you're the creator of the universe?
Creator of the Universe: That's me! So, got any questions?

[Cueball puts his hand to his face as he floats upright.]
Cueball: Oh man, so many. What's the reason for baryon asymmetry? Why is most of the universe matter and not antimatter?

[Cueball's hand is back down he resumes his previous position.]
Creator of the Universe: Crap. Did I forget the antimatter? One sec, let me just…

[Many explosions fill the panel, including a large explosion in the centre.]
BOOM

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