On Sun, 21 Feb 1999 06:57:16 EST CALYK@aol.com writes:
>In a message dated 2/21/99 4:25:35 AM Central Daylight Time,
><< It's 1999 all right. We'll have stardrives yet. Come to think of
> faster than light today. >>
>I was under the impression light always travels the same speed, but
>diverted on a longer path when it appears to be going slower?
The index of refraction of vacuum is 1. The index of refraction of air is a little more than 1. Glass is about 1.4. Diamond is about 2.4. The speed of light in a transparent material medium is slowed relative to the speed in vacuum in proportion to the refractive index. Light speed through a material with a refractive index of 2 is half the speed in a vacuum.