Aucbvax.5827 fa.space utcsrgv!utzoo!decvax!ucbvax!space Sun Jan 17 11:33:10 1982 SPACE Digest V2 #82 >From OTA@S1-A Sun Jan 17 03:42:35 1982 SPACE Digest Volume 2 : Issue 82 Today's Topics: Absolute velocity of the Earth Re: life from comets Physical laws Firms sign up to use less costly European rockets Dean Machine History ---------------------------------------------------------------------- Date: 16 January 1982 17:56-EST From: Gene Salamin Subject: Absolute velocity of the Earth To: SPACE at MIT-MC The tenets of special relativity, that absolute velocity is physically meaningless and that there is no lumeniferous ether, are generally considered as established because of the agreement between the predictions of the theory and experimental results. Although there is no ether with respect to which we can measure the velocity of the Earth, the vacuum of space is actually filled with black body radiation at a temperature of 3 K, and it is possible to define one's velocity with respect to this radiation. An observer is at rest when the radiation is isotropic (independent of direction). An observer in motion with respect to the black body radiation will measure a higher temperature in the direction toward which he is moving, and a lower temperature in the direction opposite, as a consequence of Doppler shift. The optical absorption length for this radiation is larger than the radius of the known universe, so the reference frame defined by the radiation is of a cosmological scale (although not necessarily of the entire universe). Using balloon carried microwave sensors, the "absolute" velocity of the Earth has been measured. It is something like 300 km/sec. ------------------------------ Date: Sat Jan 16 01:46:57 1982 To: Space at MIT-MC From: decvax!watmath!jcwinterton at Berkeley Subject: Re: life from comets Source-Info: From (or Sender) name not authenticated. I wish people would not post newswire stuff to this network. It is not all that useful, and I am not even sure it can be legal. What about the copyright of the wire service? ------------------------------ Date: 16 Jan 1982 2028-EST From: Jon Webb Subject: Physical laws To: Space at MIT-MC The Michelson-Morley experiment was one of the major problems that led to the creation of the theory of special relativity, but if it turned out to be in error today we would still have to keep a lot of relativity around. This is because physicists observe every day things that are consistent with the "strange" predictions of relativity, like time dilation and increase in mass with velocity. They observe these things in particle accelarators. So just finding an error in M-M won't make it possible to build FTL ships after all. The same thing applies much more strongly to things like the Dean Drive, of course. If we're going to find ways around the obstacles we've encountered, those ways will probably be at the frontiers of science, not way back someplace which has been overlooked by mankind and Mother Nature all these millenia. Jon ------- ------------------------------ Date: 17 Jan 1982 0000-EST From: JoSH Subject: Firms sign up to use less costly European rockets To: space at MIT-MC According to a news story (Gannet) under this title, three US companies, Western Union, Southern Pacific Comm., and GTE have signed up for a total of 5 satellites so far on the "mostly-French" Ariane. At $20 million a shot that comes to $100 million, instead of spending $125 to $135 million at NASA (which would have used McDonnell-Douglass Deltas). "Despite the shuttle's potential as an efficient cargo carrier into space, America's space transportation system could price itself out of the market by the end of the decade if--as expected--NASA raises its shuttle cargo rates due to escalating costs of the external tanks and solid rocket boosters." The story says the French completed the Ariane test flight program last month after four launches. The satellites are scheduled to go up in 83 and 84. --JoSH ------- ------------------------------ From: Marvin Minsky@MIT-AI (Sent by MINSKY@MIT-AI) Date: 01/17/82 00:25:30 Subject: Dean Machine History Marvin Minsky@MIT-AI (Sent by MINSKY@MIT-AI) 01/17/82 00:25:30 Re: Dean Machine History To: space at MIT-MC, Pourne at MIT-MC, sf-lovers at MIT-MC Shortly after the Dean drive was described in Astounding, John Campbell published a picture of it. I examined the picture with a lens and managed to read the brand name of the bathroom scale used to measure the loss of weight of the machine. My college roommate, Roland Silver, and I conjectured correctly that this scale had a "diode" in it that coupled the platform and the reading device. So we went to Sears Roebuck in Porter Square, Cambridge and bought that very scale. When you stand on it it reads your weight fine, but if you pump your arms up and down -- just as did the dean machine itself -- then the weight fluctuates a lot -- with the mean weight (and even the maximum) far below the real weight. So then Clause Shannon and John Pierce and I wrote a sharp detailed letter to Campbell about this. John Campbell didn't print our letter, but he sent me (knowing I was the instigator) a long letter that I still have here, denouncing establishment scientists for their reactionary and unimaginative rigidity and general intolerance. Suitably chastened, I dropped yhe matter and continued with my reactionary, establishment-bound studies. Anyway, this incident jibes with Pournelle's account about Cambell seeing the machine which "jumped around a lot" on a bathroom scale. I checked out all the other scales, too, and finally found one that reads high when you bounce. But these were much less common. So, possibly, Dean was hoist by this pitiful petard. But I maintained that this was extremely unlikely since, obviously, he was all too familiar with flakey, vibrating, weighing mechanisms. -- marvin P.S.. I should add that much as we hated him, we loved him greatly too, and for all he did for all of us. And same for G. Harry Stine. ------------------------------ End of SPACE Digest ******************* ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.