starship-design: Light is not a constant, apparently...

["Kyle R. Mcallister" <stk@sunherald.infi.net>]

Very interesting...according to relativity, the speed of light can not
be slowed down at all. The only 'apparent' slowing is caused by
refractivity changes. This is quite strange. According to science editor
Michael Guillen on Good Morning America, this is very bad news for
relativity as we know it. I tend to agree, however I am biased due to
the fact that I have seen FTL effects myself...;) See below:

The Electronic Telegraph

ISSUE 1364 Thursday 18 February 1999

Scientists put brakes on light

By Roger Highfield, Science Editor

SCIENTISTS have managed to slow down the speed of light so that it
can be overtaken by a bicycle.

By passing it through an illuminated atomic cloud, they have cut the
speed of a pulse of yellow laser light from 186,000 miles per second
to 0.01 mile per second and plan to reduce it further to a crawl of
about half an inch a second.


 This puts the speed of light in the shade when compared with the
 world-record cyclist Bruce Bursford, who has clocked up 207 miles per
 hour or 0.057 miles per second.

The feat is reported today by Dr Lene Hau of the Rowland Institute for
Science, and Harvard University, Cambridge, Massachusetts, and
colleagues. Light is already known to slow down a little when it
enters a piece of glass, because glass has a refractive index which is
larger than that of free space.

Dr Hau said: "We are using a much more interesting mechanism to slow
light down by a factor of 20 million." The trick is to use one light
beam to alter the refractive index of an unusual medium - a cloud of
sodium atoms cooled to ultra-low temperatures known as a
"Bose-Einstein condensate" - in such a way that it can slow down a
second pulse of light.

The trick has a number of applications, Dr Hau said, such as
converting infra-red light into blue light. "In the future, this could
be of importance for laser light projectors - it is hard to generate
blue light otherwise."

Another possible use is in night vision. She said: "This technique can
be used to convert infrared light to the visible spectrum (so we can
see it) at low power cost." The technology could also help to reduce
the noise in communications, and create switches that can control
light. These may be useful in computers that work on light rather than
electricity.

Dr Hau said: "These possible applications are of course for the future
- perhaps 10 years down the line if we get to work on it. Right now we
have an experimental set-up where we are pushing technology to the
outermost limit. We'll have to figure out how to make this into a
practical instrument."