Question On Virtual Particles

[darkmatter4brains]

I've always understood that the "virtual" in virtual particles basically comes from the Heisenberg uncertainty principle, specifically the enery-time uncertainty relation - that you can create a particle of energy delta E out of "nothing" and this will not violate the conservation of energy as long as it disappears out of existence in a delta time (2 delta E / hbar). This is what virtual particles are doing all the time in the vacuum right? A particle-antiparticle pair comes into existence and they annihilate themselves before delta t.

Well, doesn't Hawking Radiation have one escaping to infinity and another falling into the black hole. If these guys don't annhilate before time delta t mentioned above, wouldn't they be violating the conservation of energy.

Another thread mentioned grabbing one in the lab - wouldn't this have the same problem.

Or, am I totally getting mixed up here .... it wouldn't be the first time!

Thanks!

 

[vogon13]

The particle pairs are divied by the blackholes' gravity, one escapes, one is snarfed. The snarfed one is deleted from the blackholes mass budget, and eventually, the black hole goes poof.

And that 'eventually' there might take 10^100 years. Make a bowl of popcorn and get a comfy chair . . .

 

[vogon13]

Also, consider the spectrum of wavelengths emitted by the blackhole via this process.

The wavelength of the escaping photon will be comparable to the size of the blackhole, so for big ones, the wavelength is really large. That means the energy of these photons is really low. As the blackhole gets smaller (slowly) the average wavelength decreases and the energy of the photon increases.

You will get to the point that towards the end of the process you will have some nasty flux zorching out of this thing.