B Evaporation of black holes

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I don't get it, why can we be sure, that black holes evaporate
Summary: I don't get it, why can we be sure, that black holes evaporate

My simplified imagination about Hawking radiation is that when the vacuum fluctuation creates a matter-antimatter particles pair at the event horizon, thay are ripped appart by the tidal force and do not manage to split and anihilate as usual.
It's clear, it can happen, that one particle flies away, the other falls into the hole. But why does always fly away the matter-particle, and the antimatter one falls into the hole to anihilate there with one particle inside and decrease the total mass of black hole? Should that be not statistically 1:1 also for the cases, when antimatter is radiated by the black hole and a matter particle falls into the hole? I do not understand the point, why black holes is evaporating and always devours the antimatter from these pairs.
 

Orodruin

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First of all, the description of Hawking radiation as virtual particle-antiparticle pairs is at best heuristic. Hawking himself stated it was not very accurate but the closest analogy he could think of that made some sort of sense in a popular scientific setting.

Second: what makes you think Hawking radiation would just be matter. It is not the case.
 
Second: what makes you think Hawking radiation would just be matter. It is not the case.
well, does it also radiate antimatter?
 
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Orodruin

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Yes.
 
then, my assumption would be, the matter particle from the virtual pair should fall into the hole and the mass should increase -> black hole mass should remain constant and should not evaporate.

On the other hand, I would also expect to receive a constant "rain of antimatter" from all the directions in the universe annihilating with matter on their way. What's wrong with my view?
 

Orodruin

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then, my assumption would be, the matter particle from the virtual pair should fall into the hole and the mass should increase -> black hole mass should remain constant and should not evaporate.
Nature does not care about your assumptions.

Again, the particle-antiparticle description is heuristic at best and even in that description, the particle can have negative energy.

On the other hand, I would also expect to receive a constant "rain of antimatter" from all the directions in the universe annihilating with matter on their way. What's wrong with my view?
Hawking radiation is certainly not strong enough to provide anywhere near the amount of antimatter you are thinking about.
 
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the matter particle from the virtual pair should fall into the hole and the mass should increase
I am not sure, but it sounds like you think that matter has positive mass and antimatter has negative mass. Both matter and antimatter have positive mass. Antimatter simply has the opposite charge.
 
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Virtual particles can have negative mass, or no defined mass at all.
 

PAllen

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Just as an aside, we cannot be sure black holes evaporate. There is, as yet, no observational evidence of this. There are a few serious physicists who think the various semiclassical derivations are not correct or consistent, and that until there is a more complete QG theory, there is no reason to expect evaporation.

Of course, most physicists are convinced by the multiplicity and generality of derivations that the hypothesized phenomenon must be real. There are also classical analog experiments that imply Hawking radiation should occur (under certain assumptions).
 
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My simplified imagination about Hawking radiation
"Simplified imagination" is not a good strategy for trying to understand physics in general, but it's a particularly bad strategy for trying to understand Hawking radiation. You marked this thread as level "B", but Hawking radiation can't really be understood without an "A" level (i.e,. graduate level) background in the subject. This is one of those cases where pretty much anyone's intuitive guess is going to be wrong, so it's better not to guess at all, but to wait until you have the proper background.
 

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