From: utzoo!decvax!cca!REM@MIT-MC@sri-unix Newsgroups: net.space Title: Article-I.D.: sri-unix.2457 Posted: Thu Aug 5 03:32:33 1982 Received: Sun Aug 8 01:03:19 1982 From: Robert Elton MaasMy understanding of general relativity slightly contradicts what was said in this digest by menlo70!sri-unix!hplabs!menlo70!sytek!zehntel!teklabs!tekmdp!dadla-b!dadla-a!steve at Ucb-C70. Accelleration and gravity are indistinguishable locally, i.e. if a single measurement is made at a point . But if measurements are made at different points then indeed a global picture may be obtained which can possibly separate gravity and centrifugal force from true delta-vee/tee. Note that this global analysis isn't trivial, for example mascons can create gravity measurements that look more like non-gravity, and there's no such thing as absolute space and absolute time so you can't arrange measurements to be "simultaneous" so if forces are changing with time you may have trouble getting any consistent global picture at all. But at least with multiple measurements you can distinguish the simple cases from each other. Re sf, I see no reason sf has to contradict known and well-established scientific theories. What's wrong with sticking to known science and postulating new engineering uses for these, such as black-hole mass-to-energy conversion, Dyson spheres, encyclopedia gallactica, etc.? I'd rather see a good story about how to maintain a stable economy when major shipments of precious metals arrive from the asteroid mining colonies once every 14 months, bigger each time, sort of like the bonus armies in the game of Risk; than read somebody's idlebrained speculation about how if we could only go faster than light we could ...