Imagine a material in which light travels slowly. (I don't know much about quantum mechanics, but I think this is a Bose-Einstein condensate.) From my knowledge of electromagnetic radiation, this material would have a very high index of refraction. I have some questions: Is classical electromagnetism (like refractive indices) sufficient to model a material in which light travels at, say, 17 meters per second? (I read about this somewhere) If not, at what level of QM will I be able to model such materials? Back to the story. Imagine that you have a slab of this light-slowing material on a table, with an extremely powerful loaded rifle aimed at the slab. You fire the rifle, and the bullet burrows into the slab with enough energy to maintain a speed always greater than 17 meters per second. This means that within the slab, the bullet is traveling faster than the speed of light. More questions: Is this possible? If not, why not? If so, what would happen? Thanks. This situation just popped into my head, and I wanted to know how I could model it with physics.