I've just read the following quote from the Wikipedia page on Hawking Radiation...
In order to preserve total energy, the particle that fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole).
From my understanding this is based on the law of Conservation of Energy.
E.g. an observer from outside the black hole will note a small area near the event horizon as initially having zero total energy, then within this area, virtual particles (or vacuum fluctuations) appear (which are allowed by the uncertainty principle), then the force of gravity pulls one virtual particle into the black hole while the other escapes. The observer now notes the particle escaping from the small area they are monitoring and that it has positive energy and concludes that the particle that fell into the black hole must have had negative energy (negative mass) to balance the positive.
From this it is concluded that the negative energy annihilates/cancels positive energy within the black hole and by this mechanism black holes can evaporate or loose mass.
I'm assuming that the particle and anti-particle (e.g. with positive and negative charge) are different from energy and negative energy and that it's just as likely that the anti-particle escapes the black hole as the particle (as both are effected by gravity equally).
So my questions are:
Is my summary above correct?
Is there any empirical evidence for negative energy (negative mass)?
There seems to be a very large (and IMO unproven) assumption that there was no energy coming into the small area being observed. So...
Is it possible that the virtual particles are being created by something coming into the area from outside and colliding, e.g. neutrinos, dark matter, or some other charge-less particle?
If we can't rule out external energy sources for the virtual particles then by Occam's razor shouldn't we take that as the simplest explanation and say that negative energy doesn't exist and black holes don't evaporate?