Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 (Tek) 9/26/83; site shark.UUCP Path: utzoo!watmath!clyde!burl!mgnetp!ihnp4!houxm!vax135!cornell!uw-beaver!tektronix!orca!shark!hutch From: hutch@shark.UUCP (Stephen Hutchison) Newsgroups: net.sf-lovers Subject: Re: Conservation of Momentum (and MT) Message-ID: <1036@shark.UUCP> Date: Thu, 6-Sep-84 14:35:15 EDT Article-I.D.: shark.1036 Posted: Thu Sep 6 14:35:15 1984 Date-Received: Wed, 12-Sep-84 01:30:04 EDT References: <161@vaxwaller.UUCP> Organization: Tektronix, Wilsonville OR Lines: 42 | One problem with interstellar travel that I've hardly ever seen | addressed (maybe because sf-writers aren't LOOKING for problems, just | trying to explain away the ones people are already likely to know) is | that of conservation of momentum. Isaac Asimov did make some use of | the concept in 'The Gods Themselves', but otherwise it has been | ignored, even by people like John Campbell, who generally seems very | conscientious about scientific accuracy. | | Carl Weidlin Well, actually, Larry Niven dealt with the conservation of momentum in all the Known Space series. Matter transmission is defined as impractical outside a gravity well, so interplanetary is out. Then he has the transmitters take all the momentum relative to the receiver and transmit it instead to a large set of heavy barges set in the middle of Lake Michigan. If momentum has to be added, it jerks the barge one way, if it has to be removed then it jerks it another way. Simple. Another series dealing with conservation of momentum is the series "The Journeys of McGill Feighan" whose author I forget the name of. Matter transmission is psionic (read magic for you materialists) and limited by several physical factors. First, a person with the knack for sending matter has a 914 kg limitation on the mass that can be moved. Second, kinetic energy has to be equalized and this is done by drawing or dumping momentum from a "hyperspace" which the transport apparently deals with. Third, the power MUST be trained. If you aren't trained and you have the power, it eventually kills you when you flip to someplace without equalizing kinetic energy. Fourth, you cannot "transmit" to anyplace you haven't been to. So, there is a fleet of ships travelling sublight, reaching various planets VERY SLOWLY. I don't know if you can transmit to a ship or not, the author didn't say. Anyway, most authors I've read who deal with matter transmission toss off conservation of momentum as something that's already been worked out. Hutch