the speed of light is constant in a vacuum only. It cannot get faster but it
can be slowed for example when traveling through Gallium phosphide it slows significantly
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HIIHIIH,
Mon 3 Nov 2003, 15:18,
archived)
You get crazy radiation
emitted when light goes too fast in a medium - Cerenkov Radiation or something like that. Shine a laser into certain materials and you get random light emitted as the stuff goes 'err, you shouldn't be moving that fast in here'
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jacko_here just here has some ducks,
Mon 3 Nov 2003, 15:20,
archived)