Comment by terryf | Hacker News Reader

Comment by terryf | Hacker News Reader

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Right, but the charges of particle-antiparticle pairs do cancel out, so there is no net energy produced.

Quick thought experiment: two particle-antiparticle pairs get created:

p1-ap1, p2-ap2

In regular space, after a very short amount of time p1 annihilates with ap1 and p2 with ap2. Net result is zero additional matter and energy, otherwise we'd just be creating random matter and/or energy everywhere.

If the same happens at the event horizon of a black hole and let's assume purely by chance, p1 and ap2 fall in and p2 and ap1 do not. After a short while, p1 and ap2 annihilate inside and p2 and ap1 outside. The result should be effectively the same as in the previous case, thus zero net energy and/or matter on either side. Thus, also no radiation and mass loss.

It'd be nice if an actual physicist chimed in at this point and told me where I went wrong :)

Ahem! Net result is photons, which have energy.

The actual physicist is Richard Feynman, and here is a Feynman diagram of a particle-antiparticle annihilation.

* https://commons.wikimedia.org/wiki/File:Mutual_Annihilation_...

Well, the virtual p-ap creation happens everywhere, all the time. Why aren't there a large number of photons happening everywhere all the time?

Look at the PBS Space Time video previously linked in other comments. It will help.

nocturnial's other comment: https://news.ycombinator.com/item?id=19643999 .

The epistemological reality of those events are not as simple as you assume. For the most part, that annihilation event is a short-hand analogy for a term in an equation. Another way to think of it is that this 'happening everywhere' style of particle-anti-particle annihilation relies on the inherent uncertainty of energy over short time scales, and thus it 'borrows' energy that doesn't exist in order to precede, but under any measurable timescale the energy must be conserved, and so these events are likewise unobservable. So it's not a simple matter to assume they happen, or that they are the same phenomenon as annihilation in general.

What is the charge of a photon?

For the charge to matter, you're saying that charges infer positive or negative mass. But that's original responder's point.... both the particle and anti-particle both have positive mass regardless of their charge, which is a different attribute.

Consider how it is you are conserving energy/mass in your thought experiment. Seems like you might be creating a back door whereby that mass/energy is not conserved in order to preserve charge conservation.

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