Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!whuxl!houxm!ihnp4!pesnta!hplabs!sri-unix!knutsen From: knutsen@sri-unix.ARPA Newsgroups: net.physics Subject: Re: Light Message-ID: <345@sri-arpa.ARPA> Date: Mon, 1-Jul-85 18:14:01 EDT Article-I.D.: sri-arpa.345 Posted: Mon Jul 1 18:14:01 1985 Date-Received: Thu, 4-Jul-85 04:08:07 EDT Lines: 15 From: knutsen (Andrew Knutsen) The Michelson Morley experiment showed that the speed of light is independent of direction. If the influence was being transmitted thru a medium, this would only happen if the source were at rest with respect to the medium. Since the earth cannot at all times be at rest with respect to such a medium (due to its rotations and orbits), MM called the aether into question and was one of the stepping-stones leading to special relativity. The speed of light is slowed in glass because it is absorbed and re-emitted by the glass atoms. No such thing seems to happen in a vacuum. Andrew