Quote:
Originally Posted by Rockstar
Im pretty sure nothing can travel faster than light in its own frame of reference. The Alcubierre drive theory (warp bubble) is one thought how an object of mass may one day may travel faster than the speed of light without throwing out the laws of physics.
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The Alcubierre drive still violates causality, even if the ship doesn't travel faster than light in its own frame of reference.
Quote:
Originally Posted by Catfish
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Ok let's say a spacecraft would be able to reach 1/2 of the speed of light, or maybe a bit more. Lots of reaction mass or a buzzard ram drive required, but theoretically possible.
Now you have two of them, and let them start in opposite directions ..
When each reaches 1/2 c, one is travelling at the speed of light, relatively to the other.
Not relatively to the starting point, of course, but ..
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Actually, in this case special relativity says that each ship would see the other travelling at only...0.8
c relative to its own frame of reference, I believe.