> Light doesn't speed up or slow down when it passes through a
> gravitational field. It may gain energy or lose energy or change
> direction, but it doesn't change speed. You can arrange to emit two
> photons in different directions from the same point and have them both
> pass through another point at different times by having one pass through
> a region of greater spacetime curvature, but that doesn't mean one
> photon traveled faster than the other -- it means one traveled farther
> than the other. Both traveled at the same speed, and all observers will
> measure the same speed for both photons.
>
Based on the fact that a light beam exhibits properties of both waves and
particles, it is clearly obvious that a particle is accelerated or
decelerated by the affects of gravity.
> You need to read and understand a good book on relativity theory. I
> suggest _Spacetime Physics_ by Taylor and Wheeler for an introduction.
> If you are then able to understand _Gravitation_ by Misner, Thorne, and
> Wheeler you will be doing better than I am.
>
Most of what I'm talking about was presented in a Physics presentation
here some years a go by a visiting professor, I don't recall the name. I
also jsut recently saw a show on the Discovery channel last week and a
part of it was discussion this exact phenomenom, theoretically. I think
the show was Beyond 2000 or some such thing, anyway they were talking
about the possiblity of time travel. THis thoery about the speed of
light *not* being constant was the basis for the time travel discussion.
I wish I could take credit for such creative thinking, but, alas I'm only
restating some things I've heard over the years from other theorists.
_______________________________________________________________________
Mike Wangsmo, Graduate Student wanger@fubar.cs.montana.edu
Dept. of M&IE, MSU http://www.cs.montana.edu/~wanger
Bozeman, MT 59717 (406) 586-0690
"May the Force be with you, always"