Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site looking.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!lll-crg!dual!qantel!ihnp4!cbosgd!looking!brad From: brad@looking.UUCP (Brad Templeton) Newsgroups: net.movies Subject: Why shouldn't time travel leave you in the same spot? Message-ID: <323@looking.UUCP> Date: Mon, 12-Aug-85 00:00:00 EDT Article-I.D.: looking.323 Posted: Mon Aug 12 00:00:00 1985 Date-Received: Sat, 17-Aug-85 05:59:58 EDT References: <9793@ucbvax.ARPA> Distribution: net.movies Organization: Looking Glass Software, Waterloo, Ont Lines: 19 Everybody goes on and on about how if you time travel, you should end up way out in space because the Earth is whizzing around the sun. Not quite true. Aside from the rotation of the Earth about its axis, the planet is in an inertial frame. To suggest a time traveller would appear where the Earth "was" implies some sort of absolute frame that the planet moves in. So in theory, if you come back at the same siderial time of day that you left, you would arrive at the same place. Of course, it's probably true that photon pressure and solar wind make the orbit of the Earth deviate slightly from an inertial frame. Does anybody know by how much? A time travel story where they claim they can only arrive at the same spot if they pick the exact time of day - that would impress me. -- Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473