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From: peter@micomvax.UUCP
Newsgroups: net.space
Subject: Re: Light Sails
Message-ID: <400@micomvax.UUCP>
Date: Thu, 28-Feb-85 16:43:55 EST
Article-I.D.: micomvax.400
Posted: Thu Feb 28 16:43:55 1985
Date-Received: Mon, 4-Mar-85 07:56:17 EST
References: <722@mordor.UUCP> <133@uwvax.UUCP>
Reply-To: peter@micomvax.UUCP (Peter Ruhe)
Organization: Philips Information Systems - Montreal, Canada
Lines: 7
Summary: 


On the question of how photons can impart energy to a light sail,
I imagine a reflected photon would lose energy to the sail, so it
(the photon) would go to a lower frequency, longer wavelength, etc.
You shine blue light at a receding light sail, and get red light back.
For a sail starting from rest, the photon wavelength shift would probably
be immeasurably small, but still non-zero.