Matter predominates b/c anti-matter fell into black holes?

[swampwiz]

I was reading an article about the great Steven Hawking, and it seems to say that matter & anti-matter can be created in space, but that one of them can fall into a black hole, thus leaving the other around in a higher preponderance, which of course matter is. So it would seem that a good explanation for why there is an imbalance of matter to anti-matter is that the anti-matter fell into black holes.

https://www.theatlantic.com/science/archive/2018/03/stephen-hawking-is-still-underrated/555590/

 

[Orodruin]

That is a highly popularised article and you should not look to learn actual physics from it. In particular, the popularised description of Hawking radiation that is provided is the typical one and Hawking himself said that, while inaccurate, it was the closest analogy he could find that would be understandable by laymen.

However, even within the popularised description, there is no guarantee that it is the anti-particle that "falls into" the black hole. It would be equally likely that it was what we call a particle that does that. Hence, you cannot use Hawking radiation to explain the matter-antimatter asymmetry.

 

[mfb]

In addition to Hawking radiation having nothing to do with pairs:
- Hawking radiation is completely irrelevant in the current universe. It is too weak to have any impact.
- As far as we know all black holes have at least stellar masses, there Hawking radiation is exclusively made out of photons, gravitons and maybe neutrinos - none of them contribute to the matter/antimatter asymmetry
- Even hypothetical smaller black holes, small enough to have other particles in the Hawking radiation, should radiate matter and antimatter in equal amounts

 

[ohwilleke]

- As far as we know all black holes have at least stellar masses, there Hawking radiation is exclusively made out of photons, gravitons and maybe neutrinos - none of them contribute to the matter/antimatter asymmetry.

There can be matter-antimatter asymmetry in neutrinos and one of the more important cosmology measurements which has not yet been made is the ratio of neutrinos to antineutrinos in the universe. It doesn't contribute to baryonic matter/antimatter asymmetry, but that isn't the only possible kind of matter/antimatter asymmetry. In fact, if the number of antineutrinos outnumbers the number of ordinary matter neutrinos by even 1% (and there are hints that it might) then the number of anti-leptons in the universe vastly exceeds the number leptons and non-antimatter baryons in the universe by a substantial amount.

 

[mfb]

but that isn't the only possible kind of matter/antimatter asymmetry

I'm sure it is the asymmetry OP was asking about. And it is unlikely that these black holes emit neutrinos at all - one mass eigenstate would have to be exceptionally light compared to the other two.

How could Hawking radiation emit different amounts of neutrinos and antineutrinos, by the way?