Faster than light travel?

[blike]

Einstien's theory of special relativity says nothing can travel faster than the speed of light. BUT, special relativity only applies when space time is flat.

 

So, for example, could a ship be built that bends space time around the ship, and therefore allowing faster-than-light travel relative to an outside observer?

[fafalone]

No, superluminal motion is not neccessarily a violation of special relativity. Special relativity states that all observers view an event in the same order based on a subluminal signal, but if the signal was superluminal it would appear to some to travel back in time. However, this does NOT create a causal paradox. In order for one to occur, a time-reversed path must exist in the emitters past light cone; something that is garunteed by global inertial frames in special relativity. With gravity being part of the space-time curvature, gravitational birefringence allows photon paths to depend only on the curvature, and a straight line isn't always the shortest path. In fact, along the event horizon of black holes, if one polarization of a photon is subluminal, the other is superluminal. As far as we know right now, superluminal motion is only possible because of a quantum violation of the strong-equivalence principle with photons.

[fafalone]

...bump...

 

[MajinVegeta]

What about a closed time loop? Ftl is possible then, right?

 

So like, ftl is relative?(ah, a stroke of genius!)

[MindOfChaos]

...bump...

 

 

Bump

[5614]

When spacetime becomes curved light will travel along the curved spacetime. This seems to have the effect of bending light, and because it is travelling in a curve (and not a straight line) it seems to slow down ie. it takes longer to get from A to B if the spacetime between A and B is bent (it's not taking the shortest possible route - although technically it is because the shortest route is to follow the contours of spacetime).

[amrit]

photon is a mass less particle, it travel with light speed

any mass particle will have a less speed than light speed

faster than light is only a "gedanken experiement" and will always lead to the wrong conclusions

 

amrit

[Daecon]

So' date=' for example, could a ship be built that bends space time around the ship, and therefore allowing faster-than-light travel relative to an outside observer?[/quote']

You mean like "Warp Speed" travel, or like creating a mini-wormhole for the ship to travel through?

[SmallIsPower]

FTL travel through warp drive has already been proposed, and is theorectically possible, however, not currently technically feasable.

[Klaynos]

Yeah if we can create this magical thing that is the single missing part...

 

If you notice the last paragraph says that there are several theoretical arguments against it, so saying that it's "theoretically possible" is as true as to say "it's theoretically imposible"...

 

</skeptic>

[Severian]

So' date=' for example, could a ship be built that bends space time around the ship, and therefore allowing faster-than-light travel relative to an outside observer?[/quote']

 

This was actually the old explanation used for warp drive in Star Trek. They would fire gravitons out the front of the ship, which warp space making the distance shorter - they then move over it at a speed <c and space re-expands behind them, making it seem that they were travelling faster than light.

 

Unfortunately this won't work because you can't warp the space in front of you faster than c. In other words, the space distortion wave you are riding is also restricted to speeds <c. (I do wish the BBC would report real science rather than picking up on the work of cranks.)

[Ragib]

I wish i was born when Star Trek was running... Anyway, O, the question is fundamentally wrong, Sure the speed of light barriar was formulated then, without including warped spacetime, but later General Relativity was formulated which incorporated it. Anyway, an outside observer wouldn't see you if you were travelling faster than light. To them you dont exist.