Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site micomvax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!panda!talcott!harvard!seismo!cmcl2!philabs!micomvax!peter 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.