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Q-reeus is offline
Feb21-12, 08:53 AM
P: 1,115
Quote Quote by stevebd1 View Post
...Extract from 'How does the gravity get out of the black hole?'-
"...the gravitational field is a fossil field. The same is true of the electromagnetic field that a black hole may possess.
And that same source goes on to say:
Often this question is phrased in terms of gravitons, the hypothetical quanta of spacetime distortion. If things like gravity correspond to the exchange of "particles" like gravitons, how can they get out of the event horizon to do their job?
Gravitons don't exist in general relativity, because GR is not a quantum theory. They might be part of a theory of quantum gravity when it is completely developed, but even then it might not be best to describe gravitational attraction as produced by virtual gravitons. See the physics FAQ on virtual particles for a discussion of this.

Nevertheless, the question in this form is still worth asking, because black holes can have static electric fields, and we know that these may be described in terms of virtual photons. So how do the virtual photons get out of the event horizon? Well, for one thing, they can come from the charged matter prior to collapse, just like classical effects. In addition, however, virtual particles aren't confined to the interiors of light cones: they can go faster than light! Consequently the event horizon, which is really just a surface that moves at the speed of light, presents no barrier.
Nice try, but presenting the problems and pretending to answer them doesn't cut it imo. So the 'fossil field', be it gravitational or electric, is a source unto itself? Perhaps someone can enlighten me here. It is well known that in GR the stress-energy tensor T as source of gravity contains zero contribution from the field itself. Yet when we get to a notional BH, seems some kind of magic takes over and the 'fossil field' of necessity becomes it's own source. Pray tell how is this not an act of sweeping under the rug an embarrassing contradiction? Carefully avoiding the words 'field as source term' and vaguely substituting 'fossil field' is not simply calling a rose by another name?

Further, just how can there be a necessarily *continuous* virtual particle exchange process giving rise to an exterior electric field? Seems especially problematic to me given that all temporal processes for any and all objects at or interior to the BH EH have come to a screeching halt wrt the BH exterior, where the E field supposedly effortlessly extends. It surely takes two to tango if an exchange process is to occur. You can have a genuine exchange if at one end of the telegrapher's line the telegrapher is in deep suspended animation?! In other words, if the exchange *rate* is necessarily zero, how is any exchange at all taking place between an external 'hovering' entity and charged matter at or interior to the EH? What deep principle am I missing here?