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friend
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I'm wondering if black holes radiate antimatter as well as matter? If they radiate antimatter in equal amounts to matter, then would it all cancel out?
friend said:I'm wondering if black holes radiate antimatter as well as matter?
friend said:If they radiate antimatter in equal amounts to matter, then would it all cancel out?
friend said:I suppose that black holes do radiate both matter and antimatter in equal amounts and that they do annihilate into photons leaving for the most part photons that radiate away from the BH. Is this right?
I'm not well educated on black holes. The "negative energy particles" are not real. I am more familiar with vacancies and holes which are also not real. For example we can put boron into a silicon crystal lattice. The "hole" is a point on the lattice missing an electron. Engineers talk about "holes" as if they were a thing and that works well for designing integrated circuits. A "hole" is not the same thing as an anti-electron or positron. Current really does flow through circuits when electrons and holes meet and annihilate each other.friend said:As I understand it, there are virtual particle pairs formed just outside the BH horizon. Positive energy particles radiate out, and "negative energy" particles fall into the BH and reduce its total energy. My question is what's the difference between antimatter and negative energy particles? Antimatter is sometimes described as having negative mass or as traveling negatively through time. What constant gets the negative sign in negative energy particles?
friend said:I suppose that black holes do radiate both matter and antimatter in equal amounts and that they do annihilate into photons leaving for the most part photons that radiate away from the BH. Is this right?
Hawking radiation will contain both matter and antimatter in equal amounts, and it does not cancel out, because the particles and antiparticles both have positive mass-energy.friend said:I'm wondering if black holes radiate antimatter as well as matter? If they radiate antimatter in equal amounts to matter, then would it all cancel out?
Nugatory said:... "equal amounts" are both zero, because the energy available for Hawking radiation is so small that only very long-wavelength low-energy photons have any probability of emission.
That is a pop-science myth. It is not what actually happens.friend said:As I understand it, there are virtual particle pairs formed just outside the BH horizon.
That is completely wrong.friend said:Antimatter is sometimes described as having negative mass
mfb said:...
Everything emitted will just fly away, matter and antimatter fly away in exactly the same way.
Hawking radiation is emitted. It flies away because otherwise it wouldn't be Hawking radiation. There is also no process that would lead to orbiting particles.stefan r said:Why would it fly away instead of orbiting?
That is a possible process if there is something orbiting the black hole.stefan r said:How would a charged particle avoid interacting with nearby charged particles that are orbiting?
mfb said:...There is also no process that would lead to orbiting particles...
There is a central black hole, and a few stars are directly orbiting this central black hole, but the mass of the black hole is tiny compared to the total mass of the galaxy. Most parts of the galaxy wouldn't even notice if the central black hole wouldn't be there.stefan r said:I thought the entire galaxy is orbiting a black hole.
This has nothing to do with Hawking radiation either.stefan r said:Radiation from accretion disks is emitted by particles orbiting.
mfb said:This has nothing to do with Hawking radiation, where things are emitted from the black hole.This has nothing to do with Hawking radiation either.
There is no such thing.stefan r said:A particle that was inside the event horizon and finds itself outside the event horizon
No. They travel in different directions, and at different speeds for massive particles. In addition, Hawking radiation for massive black holes is exclusively electromagnetic radiation, while the particles in the accretion disk are massive - there are no stable orbits for light.stefan r said:If other particles near the black hole are orbiting and gradually making their way into the hole via friction then one of Hawking's particles does the same.
I need some help understanding this negative energy going into the BH. I'm thinking that the Hawking radiation is similar to the Unruh radiation, both being produced by accelerated reference frames. Does Unruh radiation produce negative energy "particles"? What is negative energy? Isn't this the stuff needed to keep worm holes open for which we really have no hope of producing? Why not?mfb said:That is completely wrong.
There is no such thing.friend said:I need some help understanding this negative energy going into the BH.
No.friend said:Does Unruh radiation produce negative energy "particles"?
It is unclear if things can have negative energy at all. Probably not.friend said:What is negative energy?
What about gravity? Doesn't gravity have "negative energy"? Would gravitons be particles with negative energy?mfb said:It is unclear if things can have negative energy at all. Probably not.
mfb said:There is no such thing.No.It is unclear if things can have negative energy at all. Probably not.
Gravity is not an object. Asking about its energy is about as meaningful as asking about the energy of the concept of sweetness.friend said:What about gravity? Doesn't gravity have "negative energy"? Would gravitons be particles with negative energy?
Quantum field theory doesn't have these solutions any more, they are proper particles with positive energy.Kevin McHugh said:I must be deficient in my understanding of the negative energy solutions to the Dirac and KG equations. Do they not predict negative energy solutions?
mfb said:Gravity is not an object. Asking about its energy is about as meaningful as asking about the energy of the concept of sweetness.
Gravitons, if they exist, have positive energy.Quantum field theory doesn't have these solutions any more, they are proper particles with positive energy.
Apples grow in whole numbers. I can take 3 apples out of a basket. That is not the same as saying that "negative apples exist". Eating the apples is a type of negative apple production. We can prove that the operation (eating) is happening without having to believe that negative apples exist.friend said:What about gravity? Doesn't gravity have "negative energy"? Would gravitons be particles with negative energy?
So how do black holes evaporate? Is it simply matter inside quantum tunneling out?mfb said:It is unclear if things can have negative energy at all. Probably not.
Yes, I understand this is similar to radiation associated with Unruh radiation and reheating after inflation. But if all that is produced because of curved space is positive energy particle radiation, then wouldn't some of this positive radiation fall into the BH and make it bigger?mfb said:The radiation is produced outside, simply because spacetime is curved there.
If all that is produced near the event horizon is positive energy particles, it seems natural to assume that some of them would fall into the BH and make it grow. Or are you saying in general that in curved spacetime the radiation that is produced always only goes in one direction wrt the curvature?mfb said:No. Where would the energy come from to make it bigger?
I guess I'm looking for the mechanism that transfers the mass of the BH to the energy of the particles that escape such that the mass of the BH decreases in the process. What do you mean they can only leave? Why can't they go in? Do the particles that would otherwise go inside get reflected back out because it is more dense nearer the BH?mfb said:The energy to make these particles comes from the black hole mass - even if the particles could fall in they wouldn't change the energy there. And the particles can only leave anyway.
Go in from where? It is the black hole that produces them. What would "go in" even mean?friend said:Why can't they go in?
mfb said:There is no meaningful way to assign the mass of a black hole to specific locations in space.Go in from where? It is the black hole that produces them. What would "go in" even mean?
Imagine a decay process in particle physics: A->B+C. Do you ask if C can "go in" there as well?
Larger black hole -> little bit smaller black hole + photon. Same idea.
Don't take the analogy to particle physics too far.friend said:So there is just some coupling constant between BH and radiation?
I don't know which effect you expect to see. The "horizon" for accelerated reference frames doesn't have a radius, mass, or other properties that could change.friend said:Shouldn't we then see the same affect with Unruh radiation?
What numbers do you put on the 'extremely low frequencies'? one hertz? That would be low in my book:) Or do you mean IR frequencies? Also do you really mean black holes in your first example of 1/10,000,000 th solar mass? Don't you mean 10 MILLION solar masses. 10^7 and so forth? Well I guess you really mean 10^-7 looking at it closer. Sorry.mfb said:That is a pop-science myth. It is not what actually happens.That is completely wrong.
All the black holes we know are so massive (3+ solar masses) that they only emit electromagnetic radiation with extremely low frequencies. There is a theoretical chance that they emit massive particles, but the probability that any black hole in the observable ever did that in the history of the universe is below 0.000000001%, so why bother.
At 10-7 solar masses we get a few neutrinos in addition.
At 10-16 solar masses or 1014 kg we get some electrons and positrons - in equal amounts for an uncharged black hole. A black hole with this mass has a Schwarzschild radius of just a few hundred femtometers, smaller than an atom.
At 1011 kg we also get pions as the lightest hadrons. A black hole with this mass is smaller than a proton and emits Hawking radiation at a power of a few GW. It still has a lifetime of about a billion years.
Everything emitted will just fly away, matter and antimatter fly away in exactly the same way.
Antimatter is a type of matter that has the same mass as regular matter but has the opposite charge. It is believed that black holes, due to their immense gravitational pull, can create and emit antimatter particles.
Black holes are surrounded by a disk of material called an accretion disk. As matter falls into the black hole, it is accelerated to extremely high speeds and collides with other particles in the disk. This collision can create pairs of matter and antimatter particles, with the antimatter particles being ejected from the black hole as radiation.
Yes, we can detect the radiation emitted by black holes, including the antimatter particles. However, it is difficult to distinguish between regular matter and antimatter particles, so further research and technology is needed to accurately measure and study this radiation.
If confirmed, the discovery of black holes emitting antimatter could have significant implications for our understanding of the universe. It could help explain the abundance of matter in the universe compared to antimatter, and could also have practical applications in energy production and space travel.
While there is currently no direct evidence of black holes emitting antimatter, there have been observations of high-energy radiation from black holes that could potentially be attributed to antimatter particles. Further research and observations are needed to confirm this theory.