Trent said: > If there is a wormhole and one extrinsic observer experiences 10 years > of subjective time and another extrinsic observer experiences 1000 > years of subjective time then the wormhole must experience no less > than 1000 years of subjective time.
What you've written is somewhat confused. Suppose there are two "wormhole clocks", Inside_1 and Inside_2, happily ticking away in the two mouths of the wormhole and two "exterior clocks", Outside_1 and Outside_2, ticking in the vicinity of the wormhole mouths. (This idea of "inside" and "outside" the wormhole is only an approximation!) Suppose further I stand by Outside_1. If I look into the wormhole, I see Inside_1 ticking at the same rate as my clock, Outside_1. If I look right through the wormhole, I see Inside_1, Inside_2 and Outside_2 ticking at the same rate as my clock, Outside_1. Now, suppose I train a powerful telescope on the ship carrying the second mouth. I then see Outside_2 running slowly with respect to my clock. Suppose further that the ship has set up a system of mirrors that let me use my telescope to look back through the wormhole. Then I see Inside_2 running at the same rate as Outside_2, which is to say slowly with respect to the clock sitting right next to me. But if I look more carefully, I also see Inside_1 running slowly with respect to my clock. Even more surprisingly, if I look through my telescope and the mirrors back through the wormhole at my own clock, I see it running more slowly than I do if I look at the clock sitting right next to me! All of this might be surprising, but it's not in any way paradoxical. It's just a consequence of relativity. The clocks can't tick out of sync with their own reference frames, because it's their ticking that defines the reference frames! Everything is fine as long as the two reference frames are in uniform motion with respect to each other. When the ship turns around and heads home, the problem arises. There will come a point at which a temporal loop forms. It's conjectured by people much smarter than me that quantum effects will collapse the wormhole just as this happens, so that causality can't be violated and so your warning from the future scenario isn't possible. The Orion's Arm idea of "empire time" arises from this restriction on the movement of wormholes. They think that the times of all the wormholes get locked together by the restrictions becoming more and more severe as more wormholes get added to the system. I'm not sure whether this is actually the case, but I haven't thought about the problem in any great depth. Rich _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
