Scientific Rules Of Evidence.

I believe that the speed of light IS constant...in a vacuum. The operative word here is "vacuum." If i am not mistaken they were able to slow down light in some kind of condensate (bose-einstien? (sp?))?

I'll need to check my physics book, but I was under the impression that light moving through a prism or atmosphere doesn't "slow-down" but loses energy and changes frequency?(edited because of my error )I did some armchair research and I see that my thinking above was mostly wrong. While the light wave propogates at c, the phase velocity of the wave is either faster or slower than light due to interference from atoms in the material. It is this apparant speed that we treat as a slowing down of light.Thanks to Jesse Clair at Mount Allison U. Why does light slow down when entering a prism but speed up when it exits? Where does it get the energy to increase it's velocity?[This message has been edited by DBlevins, 09-25-2003]