Re: SCI: slow light

KPJ (kpj@sics.se)
Mon, 22 Feb 1999 11:45:03 +0100

It appears as if <EvMick@aol.com> asked:
|"Nothing can exceed the speed of light".......
|
|I've heard that many times. Well apparently that is not true. Since soon a
|turtle will be able to do it.
|Only kidding here...since I've neglected the "in a vacumn" part of that
|quote".
|However...that leads to a question. If light is "slowest" in a Bose-Einestein
|Condesate...and "fastest" in a vacumn......is there anything "less" than a
|vacumn? It is possible to slow light down...is it even theoretically
|possible to speed light up?
|No clue here...a vacumn is a vacumn right?

It appears if <retroman@together.net> answered:
|
|Yes. It is. c in a vacuum is as high as anything can go. If you put more
+ energy
|into the photon, it simply increases in frequency. This is why the researchers
|knew they had measured an extremely slow speed in the condensate, because if
+ they
|had just drained energy from the light, it would have changed frequency. What
+ it
|did do was retain its energy at the same frequency, which told them they were
|getting a refractive phenomenon.

Why would one assume that nothing can travel faster than c except for the relativity theory postulate simply stating so?

The theory summarizes what ``we'' knew about motion at various speeds in vacuum and matter at the point in spacetime when mr Einstein formulated the theory.

If ``we'' could create a specific matter/space configuration with less density than vacuum, then ``we'' would need to update the theory to handle this new case, as it probably would allow for FTL motion.

As far as I know, nobody has discovered such a case yet.

Therefore, currently it appears as if nothing can move faster than c.