dopey (08/30/82)
Sitting in church and listening to a <long> sermon, I started thinking about physics... As far as I have been able to tell, all particles and all energy is effected by gravity (nothing (?) can escape from a black hole except by tunnelling maybe (not too probable), and nothing can pass through one, even neutrinos, etc, that I have heard of). So if "gravitons" really exist, and have energy/momentum because they're moving, how could they get out? Also, do particles emit a characteristic spectrum when they fall into a black hole? If so it would seem that you could determine the existence of arbitrary particles from the spectrums they emit falling into black holes (or neutron stars, or whatever). Just wonderin' james blasius ihps3!ihuxq!dopey
CSvax:Physics:retief (09/07/82)
The question is why can gravitons (if they exist) escape from black holes. That's a pretty interesting question. I asked a friend of mine who is doing a Ph.D. in theoretical physics that question and his answer was "I don't know". It seems that a black hole distrupts space-time so much that it is hard to do Quantum Field theory in its neighborhood. It is field theory that will tell you what a graviton might do. Oh well. If you don't worry about gravitons, gravity from a black hole can be thought of as a massive distortion of space-time due to the hole's great mass. Another guy said that physist's knew the answer, but are keeping everybody in the dark. - Dwight -
JGA@MIT-MC@sri-unix (09/08/82)
From: John G. Aspinall <JGA at MIT-MC> The question of "do gravitons escape from a black hole" brings another related question to mind. Since charge is conserved also, when you drop an object into a black hole, could we not ask the same question about virtual photons, which are considered to carry the electric field? We all "know" that real photons don't escape (tunneling aside) from the black hole, but apparently virtual ones do. Perhaps the gravitons that carry the gravitational field behave analagously. As an aside to the questions about radiation - the spectrum is determined by the acceleration of the charge. Synchrotron radiation has a characteristic spectrum because the acceleration is the circular motion of a charge in a magnetic field. But a particle dropping into a black hole also feels gravitational acceleration. So I suspect there's very little you could see from a spectrum - it'd be pretty smeared. John Aspinall.