RE: Solar sailing vs. laws of physics ?

From: Paul Grant (shade999@optonline.net)
Date: Wed Jul 09 2003 - 09:36:03 MDT

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    As an aside that might be relevant ;)
    Somebody up at MIT (THANK GOD!)
    is working on using a shockwave moving
    through a crystalling matrix to generate
    any frequency of light; the way it works
    is this: the crystal is transparent to a
    particular frequency of light; when
    the crystal is distorted, it ceases to become
    tranlucent, and instead opaque. If you
    zap the crystal (with a moving [active] light beam)
    with a precisely timed signal, you can have it
    reflect off the moving shockwave front; the
    result - you can modulate the resulting "frequency"
    of the exiting lightbeam :)

    Pretty kean gear, and very elegant :) They've
    managed to build a simple version of it, but
    now they're working on extending the work.

    How it relates to this particular discussion, is of course,
    the fact that the shockwave front acts as a moving mirror :)

    omard-out

    -----Original Message-----
    From: owner-extropians@extropy.org [mailto:owner-extropians@extropy.org]
    On Behalf Of Spike
    Sent: Thursday, July 03, 2003 11:00 PM
    To: extropians@extropy.org
    Subject: RE: Solar sailing vs. laws of physics ?

    I was in a hurry when I posted my one-liner.
    Let me deal with this in a little more detail.

    from: Jeff Davis
    Subject: RE: Solar sailing vs. laws of physics ?

    --- Spike <spike66@comcast.net> wrote:
    >
    > Subject: Solar sailing vs. laws of physics ?
    >
    > The reflected photon would have the same
    > frequency as the pre-reflection photon
    > only if the light source and the reflector
    > are stationary with respect to each other.

    ...Is this actually the case?...

    Ja.

      ...Has it been
    observed experimentally with stationary
    versus moving mirrors?...

    Ja.

      ...Certainly we've
    heard of radiation that has been Doppler-shifted
    red or blue from radiation sources moving
    towards or away--respectively--from the
    observer. Is a moving reflector equivalent to a
    moving emitter?...

    Ja.



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