Another hawking radiation question

[jnorman]

i am trying to understand hawking radiation. in wikipedia, it states:

"In order to preserve total energy, the particle which fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process the black hole loses mass, and to an outside observer it would appear that the black hole has just emitted a particle."

please explain why the particle which falls into the BH must have negative energy. thanks.

 

[Chris Hillman]

Not a good way to think about it

Shouldn't this be in the "astrophysics" forum?

please explain why the [virtual] particle which falls into the BH must have negative energy. thanks.

(I added a crucial word which you omitted.)

The idea is to invoke conservation of energy, but you can look for some past discussions in sci.physics.research (from years ago when that group was populated by knowledgeable physicists) of why this "argument from virtual particles", often quoted in popular books, is deprecated by most knowledgeable theorists. Look for posts by Bill Unruh in particular.

Wikipedia is not a reliable source of information and should never be used by nonexperts except to gather keywords for searching the index of a conventional printed encyclopedia such as Encylopedia Britannica.