| From: Brent | 1/04/99
23:18:50 |
| Subject: FTL communication | post id:
5446 |
| I wonder if this would
work: Imagine (for a moment if you will) that humans had established a colony in another star system. Communication by conventional means would be limited by the speed of light, so your looking at years before a signal can conceivably get there. How about this. If a rigid pole could be constructed between the two star systems, and the pole was then pulled on at one end... would the spatial translation be observed at the other end of the pole instantly? Is there a relatavistic delay on the propogation of spatial position information through a rigid media? If not, that would facilitate faster-than-light communication. Brent. | |
| From: James Richmond (Avatar) | 2/04/99
12:11:43 |
| Subject: re: FTL communication | post id:
5455 |
| A signal sent by moving one end
of the pole would travel between the ends at the speed of sound in
the pole, which is significantly less than the speed of light. In other
words, when you move one end of the pole, the other end doesn't know about
it instantly. A compression or expansion wave has to travel from one end
to the other, and this happens at the speed of sound in the material of
the pole. Relativity doesn't affect the situation unless you start moving the pole at speeds close to the speed of light. Then things become more complicated, but you still won't be able to transmit a signal faster than light. JR | |
| From: Mal | 3/04/99
16:54:49 |
| Subject: re: FTL communication | post id:
5489 |
| I'm afraid I'd have to disagree
with the above comment. Sound is a type of compression wave but it isn't
the only one by any means and if the piece of material was "uncopressable"
then the movement would be effectively instantanious. What would make this
slower than the speed of light would be that the material would have such
a huge length to compress over. Another way to make the message
intantaneous would be to oscillate the rod with a greater amplitude than
it is able to absorb in the material. Just as a complete asside any astrophysisist worth his salt will tell you that things travel faster than light all the time | |
| From: Terry Frankcombe | 3/04/99
18:49:45 |
| Subject: re: FTL communication | post id:
5491 |
| I'm afraid I'd
have to disagree with the above comment. Sound is a type of compression
wave but it isn't the only one by any means and if the piece of material
was "uncopressable" then the movement would be effectively
instantanious. The speed of sound in any material is the natural maximum speed for a compression wave, and depends largely on the intermolecular potential of the material. I don't know what you are refering to when you say that there are other types of compression wave to sound. An example? There is no such thing as a truely uncompressable material. Sure, thangs can get pretty rigid, but there are no irresistable forces in this universe that we are aware of. What would make this slower than the speed of light would be that the material would have such a huge length to compress over. Can you explain this thought for me? Another way to make the message intantaneous would be to oscillate the rod with a greater amplitude than it is able to absorb in the material. You simply cannot do this. If you attempt to shock a material into compressing faster than its speed of sound it will break. Just as a complete asside any astrophysisist worth his salt will tell you that things travel faster than light all the time Do you mean faster than light or faster than light in a vacuum? A recent celebrated experiment had light travelling at 40 mph. Easy to travel faster than that. Or are you refering to some thought experiment in which incorrectly applying simultaneity gives FTL results? | |
| From: Cass | 3/04/99
22:03:22 |
| Subject: re: FTL communication | post id:
5516 |
| Mal said: Just as a
complete asside any astrophysisist worth his salt will tell you that
things travel faster than light all the time Don't take this the wrong way, Mal, but that's the funniest spelling mistake/typo I have seen all day! =) Cass | |
| From: Chris (Avatar) | 6/04/99
10:01:31 |
| Subject: re: FTL communication | post id:
5594 |
| Incompressible objects are
forbidden by the special and general theories of relativity. End of story.
If you want to assert otherwise, then you will have to show me where those
theories are wrong, and how you intend to replace them. FTL travel is possible, but not in the linear sense you describe. FTL communication is not yet possible, by any means. If you have seen/read/heard/believe otherwise, then (as usual) "show me the money"! Hope this helps! Chris btw, I'd like to think I am worth my salt...(whatever that worth may be!) :o) | |
| From: Terry Frankcombe | 6/04/99
14:08:32 |
| Subject: re: FTL communication | post id:
5647 |
| FTL travel is
possible, but not in the linear sense you describe. Well then, in which sense are you refering to? Jumping trough wormholes or something of that ilk? | |
| From: Chris (Avatar) | 6/04/99
15:00:04 |
| Subject: re: FTL communication | post id:
5661 |
Come on Terry! You know all the cheats! Local FTL travel is forbidden but a global average is possible. Eg wormholes, warp drives, laser scissors, etc. In fact FTL travel is not forbidden by SR, only acceleration to FTL speeds from sublight. | |