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If hawking radiation is the result of a pair of virtual particles popping into existence just outside the event horizon, and then one falling into the black hole through the event horizon, and the other escaping, how can this process reduce the mass of the Black Hole?

Charles Bretana
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  • Maybe this question on Hawking Radiation will first help you to understand a bit more about it as a first step. The popular view of it can be misleading as you can see. – Triatticus Nov 16 '23 at 17:15
  • Strong electromagnetic fields and gravitational fields (in the case of black hole) can give rise to pair production of particles. If particles are able to annihilate,- they return energy to the field. But black hole, often catches 1 of particle , while second escapes. So this process drains BH gravitational energy faster, compared to emitting "raw" gravitational waves without disturbance. Hence by loosing gravitational energy, BH looses mass altogether due to $E=mc^2$. – Agnius Vasiliauskas Nov 16 '23 at 17:36
  • Btw, usually blackhole sucks-in more matter from regions around event horizon than it looses energy due to Hawking radiation. So, no worries. Black holes will live until almost all universe becomes empty. Or some blackhole may die, if in some collision event it is thrown into deep outerspace where there is no matter to attract into BH. – Agnius Vasiliauskas Nov 16 '23 at 17:39
  • read this https://en.wikipedia.org/wiki/Hawking_radiation#Black_hole_evaporation . only for small mass black holes the radiation can reduce the mass – anna v Nov 16 '23 at 18:08
  • If nothing ever falls through the horizon, how do they grow? – Charles Bretana Nov 16 '23 at 20:45
  • Considering the time issue, where we imagine that from our external perspective, nothing appears to fall through the horizon, then is it the case that the horizon grows in size from the mass "deposited" on the holographic surface of the horizon, and not from the mass that (apparently) does not actually pass through the old horizon? – Charles Bretana Nov 16 '23 at 20:50
  • Then, if I can restate this, the local density of infalling materiel, right above the horizon, is sufficiently high enough that the Schwartzchild radius based on the total mass including the infalling materiel just outside the old horizon is large enough to encompass the added materiel. – Charles Bretana Nov 17 '23 at 01:42
  • CharlesBretana When a star collapses, its matter remains on the outer surface of the horizon in our view. When a new object falls in, the horizon expands toward it while the star matter remains on the outer surface. The new radius of the horizon is based on the total mass. Here is a video for two black holes, but the idea is the same for other objects: https://m.youtube.com/watch?v=Y1M-AbWIlVQ&feature=youtu.be – safesphere Nov 17 '23 at 23:02

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