3263: Baryon Asymmetry

Baryon Asymmetry

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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

This is one of 39 incomplete explanations: This page was created recently, but was recently annihilated by its anti-matter counterpart, and needs recreating. Don't remove this notice too soon. If you can fix this issue, edit the page!

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 — that is, 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. (Due to its CP-violating properties, the weak force can create some imbalance, but not enough to explain the observed asymmetry.) 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 intended, only to create a massive explosion as large parts of the universe, possibly including Cueball, experience annihilation.

The carelessness of adding in the forgotten antimatter without considering the widespread impact it would have on the current state of the universe is strange. A being with the power to create the universe might be assumed to have comparable abilities to observe and understand its state, and should not be oblivious to its not having been working as intended (missing around half of its mass), nor to realizing that the forgotten feature was actually a bad idea after all. 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 (a differing substance, that is thought to exist but remains considerably less well understood even than antimatter) mysteriously interacts via gravity but not, as far as we know, via electromagnetism. The creator is surprised that we call something 'dark matter', but somehow understands what Cueball is referring to and reveals that this 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. 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.

Electron/positron annihilation will produce gamma rays with energy approximately 0.5MeV. The implication is that the two errors are related - if the creator added enough antimatter then the result would have been gamma rays, which would have interacted with the 'dark' matter during the 'BOOM' in the final panel.

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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Discussion

Randall made a what if? blog Article and video on antimatter. YZ100 4:34, 25 June 2026 (UTC)

If I had a dollar for ever floating black sphere that talks in XKCD, I'd have 4 bucks. Which isn't alot, but it's weird that it's becoming a recurring subject. RG (talk) 06:21, 25 June 2026 (UTC)

Why would you only ask the all-powerful floating black sphere for a dollar? 82.13.184.33 08:23, 25 June 2026 (UTC)

It'd be safer! Probably. (Unless the theory about him being a Black Hat-by-proxy is correct, in which case all bets are off.) 82.132.239.58 14:12, 25 June 2026 (UTC)

I'm the gate! I'm the key! I'm...in the wrong comic! 2A02:2455:1960:4000:E16D:EF33:CC13:79C9 07:19, 25 June 2026 (UTC)

This is a great SMBC. 2A0D:6FC7:622:BB15:9189:B3E6:8C3:779E 09:38, 25 June 2026 (UTC)

There's another comic with the Creator of the universe I'm sure. It's the one where they made a bunch of nice clouds I think. Does anyone know what that is? GSLikesCats307 (talk) 10:20, 25 June 2026 (UTC)

That would be 3222. A similar sphere also appears in 1173 and 3085, but it looks a little different. 2A00:FBC:E87A:6682:FA9C:C595:1673:92DB 12:56, 25 June 2026 (UTC)

I think there's a good chance that the Creator with the clouds-fixation is this one too (similarly short-sighted and/or forgetful of the necessary implications). The "About 20 Pounds" one seemed positively competent, by comparison. Also, while that one's statement about dark matter isn't totally incompatible with this one's, they seem to have different perspectives on it, unless that was just due to the different style of questioning about it.

But there are also the probably different Time Travelling Spheres (maybe what they look like as Futurekind, if they aren't really the Kang-and-Koloth-type tentacle-monsters and these were just their temporal avatars), various 'out of the box' AIs, etc. You could go so far as to do a Grand Unified Charscter Theory to make them all the same (with time-travel abilities, room for anachronistic order of characterisation, gaining and/or losing competency/knowledge/Creator-abilitors accordingly and even changing their manifestation appearance somewhat (dark/light, the nature of their 'glow') according to how they do. So the AI-in-the-box (that likes being in the box) could eventually decide to make their own entirely new box, in the form of the universe. But only after some mild senility has perhaps set in. 82.132.239.58 14:12, 25 June 2026 (UTC)

Maybe the poor sphere is just going through some tough times, but by 3085, had figured all that out and was doing alright. RG (talk) 00:28, 26 June 2026 (UTC)

I don't think there's any indication that Black Hat has anything to do with this comic besides bad things happening; and that's not a very good justification for talking about him in the page IMO Jarochar (talk) 17:49, 25 June 2026 (UTC)

Some of the weird observations of the universe may be the observer-exists-therefore-your-options-are-limited effect: Assuming a bunch of values for things (universal gravitational constant, speed of light, etc) are possible, but only 1 set of those values result in human being (or any living thing) being around to observe it, then if you know human beings exist then the universe must have that set of values for those things, odds be damned. 64.201.132.210 18:08, 25 June 2026 (UTC)

That would be one or other of the anthropic principles, of course. 81.179.200.152 19:22, 25 June 2026 (UTC)

Might be worth a note (if not here, then in this site's what-if catalogue, which needs updating) that the issue of antimatter was raised in a YouTube/What-If video just a few days ago. Perhaps bringing this comic's general premise to mind. 81.179.200.152 19:39, 25 June 2026 (UTC)

The baryon asymmetry problem only exists if there isn’t a Creator. If there is a Creator, He wouldn’t have created half the universe in antimatter. Not sure if this should be stated in the explanation or not… Logalex8369 (talk) 20:02, 25 June 2026 (UTC)

I'm not sure you can say either of those things. Not with any of the knowledge we possess.

I can suggest several (currently highly uninvestigatable, but likely still being investigated) reasons for a Creatorless universe to (apparently, to our limited experience) be unbalanced. And name a few options that are (probably) ruled out.

And any Creator worth his pillar of salt is going to be able to deliberately set up a half-and-half universe that doesn't go as badly as with the comic version's belated efforts. 'Cos when you add an omniscient and omnipotent Creator, absolutely anything is possible if They desire it. (Though I prefer to think that one of those would deliberately set it up to look like it's not Created at all. Which is how it apparently turned out, give or take these other limits to our understanding...)

It's not so much a philosophical/theological black hole as one that's more rabbity, of course. Either way, easy to get lost if you forget about everything you can have a reasonable idea about. Either the remainder of the more easily confirmed reality, or at least enjoying the cosmic illusion of reality that was Created just for you. 81.179.200.152 22:46, 25 June 2026 (UTC)

Something I oftenh wonder about baryon assymetry is how can we be so sure that "most of the Universe is matter" without having interacted with most of the Universe, since from afar it should be impossible to distinguish between them. Something else I wonder sometimes about the matter is what happens when a particle meets its antiparticle, but there's a difference in energy levels. --94.73.49.104

See the this aforementioned summary, just for starters.

...as for energy levels, imagine (for simplicity) you're colliding a couple of free hydrogen atoms with an oxygen. So long as they do combine/combust, and don't spontaneously decompose again, any relative energy levels just averages out, the resulting water molecule still happens. And if it's technically even simpler when any particle annihilates with any suitable anti-particle (they can't be 'too cold' to not cooperate, at least not like that, nor 'too hot'). The varying energies that arrive in the form of the original components would manifest in whatever the annihilation products would be without so much care for whether it was originally any kind of 'anti-energy' or not (see the appropriate Feynman Diagram for details?) because it pretty much wasn't any such thing. At least in practical physics as we know it. 81.179.200.152 22:46, 25 June 2026 (UTC)

What would be the effect of suddenly 'correcting' things so that dark matter suddenly started interacting with gamma rays? Would it be similarly catastrophic to the sudden appearance of large amounts of antimatter? (Hard to imagine what could be as catastrophic as the mass annihilation of matter, but who knows?) 82.13.184.33 08:51, 26 June 2026 (UTC)

If 'interact with' is just absorbing, I think it'd make bits of space (wherever Dark Matter is densest) suddenly more opaque to those frequencies, which might not seem disasterous (just 'visual', for certain types of astronomy) but might interfere with nuclear processes. Gamma rays are what a star's core fusion process produces, which then gets converted into its more 'useful' light and heat as the original energy migrates outwards through to the photosphere and beyond. Assuming there's enough DM mingling in the star's volume (likely to be more if it's gravitationally inclined to clump just as 'normal matter'), it'd suddenly be dampner. Potentially less light, less heat, the stellar body (that was still there past the sudden antimatter infusion, of course) may even collapse. I'm imagining a rapid stellar evolution to maybe the brown dwarf stage, all over the place, if that's what happens, but it'll be highly dependent upon what stars directly sufcer what effects, so the cosmic-alocalypse (aside from having to happen after the already rather disruptive matter/anti-matter apocalypse, one assumes) coupd wildly vary.

But the absorbed energy must go somewhere (assuming the Creator-orb-thing isn't throwing a different physical concept out of the window, as well). So, alternatively, if it interacts by both absorbing the gamma rays and re-emiting them it might just confuse the radiation paths a little (slight dimming, minor change in stellar equilibreum at worst, might even be survivable).

If it's not supposed to be dark (as per the orb's apparent confusion about that) because it emits other energies (but only as a result of absorbing HEGR excitation, if I am properly comprehending the 'original' in-universe thinking/design behind its apparently incomplete implementation), then perhaps it's meant to produce smaller stars quicker. Meaning stars, as we currently have them under the 'under-implemented' status of Dark Matter, suddenly get more photospheric conversion, deeper, with either more acceleration towards expanding bright stars or even start to shrug off upper layers entirely. Something 'nova'ish, perhaps?

It could even be, in a call-back to the other comic, supposed to stop runaway fusion by nudging apart any proto-star material that had started to stop being 'just a nice pretty cloud', tuned to balance the gravitational collapse (of normal+dark matter clumps) with just enough conversion of fusion energy to disperse stellar-sized accumulations. But, not having been set up right, just created more tendency to clump (than normal matter alone) and no counteractive effect. Hence why the intended clouds thing went wrong for the orb, against expectations. (lipping the necessary behaviour on now, with stars actively pumping out gamma rays would not easily just get to pretty balanced quajtities of clouds. But, even if/when it did, goodbye to (whatever was left of!) our Goldilocks Zone.

Ultimately, I don't think Randall even needs to know what his off-hand hypothetical retuned dark-matter's effects would be. It's as likely a random throwaway punchline to a situation where the universe has quite probably already mutually-annihilated itself into just energy.

Though that also hints at what may (in Randall's mind,xat least) be a more fully Unified possibility: that normal-matter plus anti-matter (belatedly) got to mutually destroy each other to become mostly HE gamma rays. Then the so-called dark matter (still being around, presuming there was no anti-dark-matter it could interact with, in any non-gravitational manner) is what was always supposed to be there to mop up the HEGRs and then... ...'something' else happens. Don't know what the orb's design plan might have been, at this stage. Something metaphysical (or metacosmological?), no doubt. And probably (from humanity's perspective) merely the third thing to have rendered our (accidentally habitable) universe entirely unlivable — by our standards, anyway.

Sorry, necessarily fudged some of the detail, above. I'm sure others can spot the shorcuts of reasoning I took, and perhaps even 'correct' me. 82.132.237.37 13:00, 26 June 2026 (UTC)

Ask a stupid question, get a stupid answer :) "Oh, you want total universal annihilation? Alrighty do!" To be fair I think the Baryon asymmetry problem is interesting. But I feel like it's actually more a question of "how" than "why", and "why" gets you "well matter and antimatter can't coexist so much, can they?" Aaron Liu (talk) 17:00, 26 June 2026 (UTC)

The "That's me!" has me reading the Creator in the voice of Tommy Wiseau, and I'm not sure how I feel about that. Thanks, keep the change, hi doggy. RegularSizedGuy (talk) 20:35, 26 June 2026 (UTC)
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