AncapFTW Posted July 14, 2015 Posted July 14, 2015 I know it has nothing to do with politics, but: Why would a warp drive violate causality? I understand that a person from an external frame of reference behind you would see you as moving backward in time, and from in front of you they would see you as arriving before they saw you leave. Isn't that really a matter of the limitation of your detection equipment, though? After all, if I tried to track a super-sonic jet with sonar, or tracked the location of its sonic boom, I would get the same effect. And if you could travel FTL, wouldn't that mean you could transfer information FTL, making the person's perception meaningless?
WasatchMan Posted July 15, 2015 Posted July 15, 2015 I think FTL has actually now been shown to be theoretically possible. Right now it is not practically possible because you need more mass and/or negative mass then could ever be gathered, however, you know humans - we'll find a way
SigmaTau Posted July 15, 2015 Posted July 15, 2015 warp drives dont violate causality at all. You need retarded amounts of energy though.
AncapFTW Posted July 15, 2015 Author Posted July 15, 2015 I think FTL has actually now been shown to be theoretically possible. Right now it is not practically possible because you need more mass and/or negative mass then could ever be gathered, however, you know humans - we'll find a way The improved version Nasa is working with only requires about a ton of negative matter/energy. Of course, that's more than the world's yearly output of energy by quite a bit, but at least it's not as bad as it used to be. I've just heard several people saying that it would violate causality, so I was wondering how that could be possible.
Guest Gee Posted July 16, 2015 Posted July 16, 2015 The common expression for mass-energy equivalence, E=mc2 is a simplified version for when the velocity is much less than the speed of light in a vacuum. The full expression is E=gmc2 where g, gamma, is equal to 1/(1-(v2/c2))1/2, one over the square root of one minus the square of the velocity divided by the square of the speed of light in a vacuum. For a mass m to be moving at velocity v such that v=c must mean that v2/c2 = c2/c2 = 1 so gamma reduces too 1/(1-1)1/2 = 1/0. 1/0 means the energy E would be infinite. This is interpenetrated as the energy required to accelerate a mass m to a velocity v such that v = c is infinite and therefore unnphysical. It can't happen, it's a boondoggle. 2
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