> Jim Choate writes:
> > In the most striking of the new experiments a pulse of light that
> > enters a transparent chamber filled with specially prepared cesium gas
> > is pushed to speeds of 300 times the normal speed of light. That is so
> > fast that, under these peculiar circumstances, the main part of the
> > pulse exits the far side of the chamber even before it enters at the
> > near side.
>
Really. That explains how I got to work this morning while I was still
sitting at home eating my Wheaties. I'll rest easier now that I know
there's a >rational< explanation for my sensation of temporal
dislocation - a Cs cloud by Livermore Labs! Where is the EPA when you
need them?
> It is not exactly a well-kept secret that the envelope of a waveform may
> move at arbitrary velocity through a medium, even though the wave itself
> propagates at a much lower speed.
>
I'm a bit rusty but isn't it the other way around? Phase velocity may
exceed 55mph( 25 in a school zone ) but group velocity ( information,
energy ) is limited? I thought the envelope was what carried energy.
> This does not allow one to convey information at faster than light
> velocities, and is just an artifact produced by carefully interfering
> waveforms with closely spaced frequencies.
>
> It's a cute experiment, but I'm not buying stock in the IPO.
>
IPO's a bit out of fashion as of late?
Mike
