Why does matter always escape while antimatter falls into black holes?

In summary, the conversation discusses the concept of Hawking radiation and its relation to black hole evaporation. The idea of virtual particle-antiparticle pairs and their behavior near the event horizon is described, but it is noted that this is a simplified and heuristic explanation. The possibility of Hawking radiation containing antimatter and its effects on the black hole's mass are also discussed. However, the conversation concludes that nature does not conform to assumptions and that a deeper understanding of quantum gravity is needed to fully comprehend the phenomenon.
  • #1
fairtrax
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TL;DR Summary
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.
 
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  • #2
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.
 
  • #3
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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  • #4
Yes.
 
  • #5
Orodruin said:
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?
 
  • #6
fairtrax said:
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.

fairtrax said:
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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  • #7
fairtrax said:
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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  • #8
Virtual particles can have negative mass, or no defined mass at all.
 
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  • #9
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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  • #10
fairtrax said:
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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  • #12
Orodruin said:
Nature does not care about your assumptions.
Neato! I almost want to steal that for a sigline. 😉
 
  • #13
fairtrax said:
Summary: 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 tdhese pairs.
You might be erroneously assuming that during particle-antiparticle pair formation that the net mass of the black hole increases in the case where the particle falls in and the antiparticle escapes, and that the mass of the black hole decreases when antiparticle falls in and the particle escapes.

Think of it more in terms of net mass & energy escaping the black hole: if you didn't know anything about the particle-antiparticle formation, you would see a body emitting both particles and antiparticles. These will either fly away into the universe or annihilate each other and emit a gamma photon, either way it boils down to a net loss of mass and energy from the body.

Hope this helps.
 
  • #14
Elias1960 said:
I'm essentially free to use whatever background I like to illustrate the problems
Sure, you can use whatever background you like if what you are doing is essentially just some mental self-pleasuring.

If the goal is to convince other people rather than just please yourself then you need to use a background that those other people accept. Your argument violates the usual energy conditions so I don’t find it convincing, regardless of what you claim that you are free to use. You can declare by fiat that you are free to discard the energy conditions but I can and do equally declare by fiat that I am free to accept them.

At best you have shown that one or more proofs may have an unstated assumption, and it is hardly an objectionable assumption. As mentioned earlier, there are many proofs, so your argument likely does not apply to all of them anyway. And the proofs where your argument does apply can simply be modified by explicitly stating the energy conditions as an assumption. I would find such modified proofs as compelling as I found the originals.
 
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1. What is the process of evaporation of black holes?

The process of evaporation of black holes is a theoretical concept proposed by physicist Stephen Hawking. According to his theory, black holes emit particles and energy over time, causing them to gradually lose mass and eventually evaporate completely.

2. How does the evaporation of black holes affect their size?

The evaporation of black holes causes them to shrink in size over time. As they emit particles and energy, they lose mass and therefore their gravitational pull weakens, causing them to become smaller.

3. Can black holes completely evaporate?

According to current theories, black holes can eventually evaporate completely. However, this process would take an incredibly long time, as larger black holes would take much longer to evaporate than smaller ones.

4. What happens to the information inside a black hole during evaporation?

This is still a topic of debate and research among scientists. Some theories suggest that the information inside a black hole is lost during evaporation, while others propose that it is somehow preserved and released back into the universe.

5. Is there any evidence for the evaporation of black holes?

While there is no direct evidence for the evaporation of black holes, there are some observations that support the theory. For example, the detection of high-energy particles and radiation coming from black holes could be a result of the evaporation process. However, more research and observations are needed to fully understand this phenomenon.

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