duntemann.wbst@PARC-MAXC.ARPA (01/19/84)
---------- Subject: Undelivered mail From: BacoNoir.ms (a Grapevine mail server) To: duntemann.wbst Date: 18-Jan-84 15:42:21 EST The message sent by duntemann.wbst at 18-Jan-84 15:41:35 EST could not be delivered to the following recipients because they were rejected by the MTP server "Maxc". The reason given was: Domain missing in ARPA recipient name "JAFFE&RUTGERS" JAFFE&RUTGERS.ARPA ---------------- From: duntemann.wbst Date: 18-Jan-84 15:37:40 EST Subject: FTL To: JAFFE&RUTGERS.ARPA The beauty of special relativity and time dilation is that it does NOT completely outlaw FTL travel. It only outlaws FTL with respect to an external reference frame. If you abandon external reference frames, you can travel as quickly as you like. With the exception of Anderson, few SF writers have picked up on this, and none that I know of treat it as a normal, useful effect. For example, assume you have a total conversion drive which accelerates all particles within a given volume equally--no stresses are placed on the substance of the starship or the people inside. With total conversion of matter, accelerations of 2000 or 3000 G should be easy enough to achieve. This violates no physical laws that I know of; obviously we don't know how to do it yet nor will we for some time. But that magnitude of acceleration would make a trip to the nearer stars a matter of weeks or months rather than centuries. So who gives a damn if the universe ages a millenium in the process? If the idea is to get a boatload of colonists somewhgere, timeslips like that are trivial--the planet won't change noticeably in the meantime. If we can ever perfect a "thruster" as Niven called them, we will travel as fast as we like--as long as we never look back. Godspeed, Jeff Duntemann duntemann.wbst@PARC-MAXC
stern@bnl.UUCP (Eric Stern) (01/22/84)
> For example, >assume you have a total conversion drive which accelerates all >particles within a given volume equally--no stresses are placed >on the substance of the starship or the people inside. With >total conversion of matter, accelerations of 2000 or 3000 G should >be easy enough to achieve. This violates no physical laws that I know >of; obviously we don't know how to do it yet nor will we for some >time. Actually, to do this would require communicating a change in velocity instantly over a nonzero distance, which is prohibited by special relativity. This is the cause of the large-stick-in-the-small-garage special relativity so-called paradox. The point is, that any FTL scheme would require that special relativity be extended in a radical way, and we would probably need a new way of looking at space-time in order to resolve all the causality paradoxes that arise in special relativity from FTL communications. That is why this is science fiction right now. Eric G. Stern
cooley@nmtvax.UUCP (03/21/84)
FTL travel has interesting possibilities when you consider time as a series of events perceived by the senses and strung together as a continuous line by consciousness. This is the same as saying that time is simultaneous and all events happen at the same "time". If such is the case than the likely place to go when one passes the speed of light is into a different probability system. Note: I'm not saying that the speed of light is a barrier, but merely that as you approach the speed of light, your perceptual network becomes discontinuous with the networks of those at different speeds (relative to you). If you were a telepath traveling at very near the speed of light, and you tuned in to a telepath moving at a relatively slow speed, would you be able to read his/her thoughts or would they be too fast? After all, if two photons are traveling towards each other at the speed of light, isn't the distance between them shrinking at twice the speed of light? Both the photons and the distance between them are perceptual objects: In one framework we are measuring spped of travel from point A to point B, in the other we are measuring rate of shrinkage. 1 = 1c, 2 = 2c. Michael Cooley Socorro, NM c/o twilight zone
Donald.Schmitz%CMU-RI-ARM@sri-unix.UUCP (03/27/84)
Re the post by Michael Cooley in which he gives the example of two photons approaching each other and claims the distance between them shrinks at speed 2c. This seems like an example used to explain relativity that I've read somewhere before, and the results are not exactly what are expected, as what happens depends on the point of view. If viewed from a coordinate system attached to either photon, the other appears to be approaching at a speed just under c. If viewed from a coordinate system attached to say the point of collision of the two photons, the distance between the two is shrinking at speed 2c, however this does not imply that any physical object or information is traveling at speed greater than c. If I've gotten any of the details wrong here (I'm working completely from memory and can remember the text) please let me know. Also, regarding the question of one telepath traveling at relativistic speeds compared to the other, Heinlein wrote a story based on just such a premise many years back (one of his juvenile books I read in about 8th grade), with exactly what was described happening. The telepaths, taken along on the first star trip for communication, had to concentrate on one idea for hours so that their earth bound receptors could catch what they were sending, and had to use hypnosis to pay attention to the return transmission long enough to understand it (although transmission time was instantaneous). Don
Edward.Tecot@CMU-CS-H.ARPA (05/23/84)
Einstein *could* be wrong.
SRA@MIT-XX.ARPA (07/21/85)
From: Rob Austein <SRA@MIT-XX.ARPA> Of *course* Niven's FTL drive had no relation to the other space drives in use and hasn't been well explained. If we understood it why would we have to buy it from the Outsiders??? For that matter, if we understood it we would probably understand why intelligent races like the Outsiders and the Puppeteers won't ride in the damned things. --Rob -------