Can Black Holes Die? - Exploring Their Nature

[Monsterboy]

In simple terms without going into virtual particles and etc...
The Hawking radiation is emitted from very slightly outside of the event horizon and is thus is able to escape.
Since mass and energy are equivalent, the lost energy is equivalent to lost mass.

Drakkith said the same thing, the mass of a black hole is the mass and/or energy that has entered the singularity or atleast entered the event horizon right ? So, for it to lose mass something will have come out of the event horizon and/or the singularity that is impossible right ? That goes against the definition of event horizon right ? Without using virtual particles and negative energy things etc (which I don't really understand), it's not possible to explain right ? like mfb said physics doesn't answer "how" questions on a fundamental level or maybe its more appropriate to say that our current understanding of physics cannot answer some "how" questions.

 

[rootone]

It took somebody of the calibre of Stephen Hawkins to deduce from quantum math how it is that these virtual particle (pairs) could pop into existence and some of them end up becoming real particles emitted as radiation.
It took quite a while for him to convince others at his own level that this is likely.
Without the complicated math, and I am no math genius anyway, the key point to grasp is that the particles are not particles which have traveled from inside of the horizon to outside.
They literally just appear outside the horizon 'from nowhere', pairs of them having equal and opposite properties.
Yes, quantum mechanics is weird like that.

 

[PeterDonis]

the mass of a black hole is the mass and/or energy that has entered the singularity or atleast entered the event horizon right ?

Not quite. To an observer 'hovering" anywhere outside the horizon, the "mass" of the hole is whatever mass is at a smaller radial coordinate than he is. So if matter falls into the hole, you, as an observer "hovering" outside the horizon, will measure the hole's mass to be larger as soon as the falling matter passes you.

for it to lose mass something will have come out of the event horizon and/or the singularity

No. See below.

Without using virtual particles and negative energy things etc (which I don't really understand), it's not possible to explain right ?

Not really, but the quantum explanation of Hawking radiation does violate key assumptions of the theorem (due to Hawking, btw) that says a classical black hole can't lose mass and a classical event horizon can't decrease in area. That theorem requires that certain conditions called "energy conditions" are assumed to hold. The quantum fields that produce Hawking radiation violate the energy conditions, so the theorem no longer applies and it is possible for Hawking radiation to cause a black hole to lose mass and its event horizon to decrease in area. This is a quantum effect and it doesn't involve anything classical "coming out" of the horizon.

Violating the energy conditions does not require "virtual particles and negative energy things" (those are just interpretations of the quantum physics involved, and other interpretations are possible), but it does create some counterintuitive possibilities--though no more counterintuitive, IMO, than anything else in QM.

 

[mfb]

like mfb said physics doesn't answer "how" questions on a fundamental level or maybe its more appropriate to say that our current understanding of physics cannot answer some "how" questions.

It is not just a limit of our current understanding, it is a fundamental limit. You can replace theories by theories that are more fundamental, unify more effects, require fewer free parameters and so on, but they will always stay theories.

 

[Monsterboy]

It is not just a limit of our current understanding, it is a fundamental limit. You can replace theories by theories that are more fundamental, unify more effects, require fewer free parameters and so on, but they will always stay theories.

Is that because we have not been able to test these theories with a real black hole ? If we manage to create micro black holes in LHC then will those fundamental "how" questions be answered ?

 

[Chronos]

Even if [a very big if] the LHC could produce a micro black hole, it is believed they would instantaneously evaporate. Any testing would be like trying to play ping pong in a hurricane

 

[mfb]

Is that because we have not able to test these theories with a real black hole ? If we manage to create micro black holes in LHC then will those fundamental "how" questions be answered ?

It is a general limit of physics everywhere. You cannot describe "how" things are attracted by Earth on a fundamental level, for example. You can say "spacetime curvature!" but then the follow-up question is "how does mass bend spacetime?" and you are back to the same type of question.