We don't have a definite answer to this question because we don't have a theory of quantum gravity. Possible answers which have been proposed in the literature are:dsaun777 said:As Hawking radiation does away with black holes in the eons of time it takes to evaporate, what is the limiting mass at the final stages of the black hole evaporation? Is it Planck mass? or some fractional mass of the initial BH?
TbhkB=hc3/GM8π. Temperature is the average of the kinetic energy of Hawking radiation. What are the limits of frequencies for the Hawking radiation? I hear there is a problem with trans-Planckian wavelengths when you trace back a "photon" to the horizon of the black hole. Has this issue been resolved where energy divergences happen near the horizon?PeterDonis said:We don't have a definite answer to this question because we don't have a theory of quantum gravity. Possible answers which have been proposed in the literature are:
(1) The hole evaporates completely; nothing is left behind.
(2) A remnant of something like the Planck mass is left behind.
(3) Something more exotic happens.
This is a heuristic belief currently, yes, but we have no microphysical model of how Hawking radiation is emitted to back it up, because, as I said, we don't have a theory of quantum gravity.dsaun777 said:Temperature is the average of the kinetic energy of Hawking radiation.
We don't know. That's one of the open questions we have yet to get a definite answer for.dsaun777 said:What are the limits of frequencies for the Hawking radiation?
"I hear" is not a valid reference. Do you have one?dsaun777 said:I hear there is a problem with trans-Planckian wavelengths when you trace back a "photon" to the horizon of the black hole.
"Evading the Trans-Planckian problem..."PeterDonis said:This is a heuristic belief currently, yes, but we have no microphysical model of how Hawking radiation is emitted to back it up, because, as I said, we don't have a theory of quantum gravity.We don't know. That's one of the open questions we have yet to get a definite answer for."I hear" is not a valid reference. Do you have one?
Yes, this is one speculative resolution. But it's speculative, as all proposals in this area are, because we have no evidence in this regime and won't get any any time soon.dsaun777 said:Addresses the problem
Is all of theoretical physics at this point a race to come forward with a testable prediction that can confirm any "quantum gravitation" theory? Eric Weinstein may be onto something in his recent rants about physics. His arguments are a bit dramatic and even wrong in some instances though. To put his thoughts simply, he does not support the direction of physics and string theory because it lacks anything testable.PeterDonis said:Yes, this is one speculative resolution. But it's speculative, as all proposals in this area are, because we have no evidence in this regime and won't get any any time soon.
Not at all. There is plenty going on other than that. Also, we have no prospect of getting any test of quantum aspects of gravity any time soon; we would have to be able to probe the Planck scale regime and that is many orders of magnitude away from our experimental capability.dsaun777 said:Is all of theoretical physics at this point a race to come forward with a testable prediction that can confirm any "quantum gravitation" theory?
I share his misgivings about string theory, but there is a lot of work going on in physics other than string theory.dsaun777 said:he does not support the direction of physics and string theory because it lacks anything testable.
The limiting mass at the final stages of black hole evaporation is theoretically very small, often approaching the Planck mass, which is approximately 2.18 × 10^-8 kilograms. At this scale, quantum gravitational effects become significant, and our current understanding of physics is incomplete.
The Planck mass is significant because it represents a scale where the effects of both quantum mechanics and general relativity are equally important. As a black hole evaporates and its mass decreases, it approaches this scale, making the behavior of the black hole highly uncertain and not well described by current physical theories.
Hawking radiation causes a black hole to lose mass over time. This process occurs because particle-antiparticle pairs near the event horizon can result in one particle falling into the black hole while the other escapes, effectively reducing the black hole's mass. Over extremely long timescales, this can lead to the complete evaporation of the black hole.
At the very end of the evaporation process, the black hole's mass becomes extremely small, potentially reaching the Planck mass. At this point, it is hypothesized that the black hole might disappear entirely, leaving behind a burst of high-energy particles. However, the exact nature of this final stage is still unknown due to the lack of a complete theory of quantum gravity.
As of now, there is no direct observational evidence for black hole evaporation. The process is expected to be extremely slow for large black holes, making it difficult to observe within the current age of the universe. However, future observations and advancements in technology may provide indirect evidence or help confirm the theoretical predictions.