[sentientbicycle]

OOoohhhh. I totally get it now. You are an unpublished internet stranger and the Alcubierre drive has been scrutinized by some of the top minds in physics. But your criticisms are more important for some reason I don't know. Mkay, going to bed now.

Edit: By the way. I did read the thing about point A and B and understand it completely. The thing is, it doesn't matter. This is why I'm absolutely sure now that you haven't got a clue as to what the drive actually does. Here let me explain it to you like you are 5. If you send a packet of information from point A to point B, and it goes faster than light, then yes that will screw with causality. But if instead you bring point A closer to point B, it will appear as though it is "traveling" (notice the quotes) faster than light. It is however not traveling. it isn't moving. No movement through space. Freefall. zero movement. Stillness. Think about that for a moment. Absolutely positively no movement. Complete stillness. There is a lack of motion with this drive relative to the speed of light. Mind you this isn't a wormhole because even wormholes can screw with causality. This is a space creator/destoyer. Destroys in the front, creates in the back. No movement is involved. I know it's really hard to wrap your head around but just think about it for a couple of days. think about bringing point A closer to point B instead of going through all the trouble of sending the information. Remember, doesn't move.

[nessus42]

Where do any of these top minds of physics say that this drive does not violate causality??? They DON'T! If they asserted such a nonsensical thing, they would be the laughing stock of the scientific world and would no longer be considered any kind of mind, other than a quack. The only reason that you don't see much talk about this violation of causality is that it's just a fact that all physicists know. One physicist doesn't have to tell another physicist that an FTL drive violates causality; it just goes without saying. It would be like one physicist telling another physicist that 1 + 1 = 2. It doesn't need to be said!

It doesn't matter ONE TINY BIT to Special Relativity how it appears to YOU that you got information from point A to point B. What matters is how it appears to an OUTSIDE OBSERVER. If Earth and Mars are still 8 light minutes apart from some point of view, and you managed to transmit information from Earth to Mars in only 4 minutes, then there are frames of reference in which your message arrived at Mars BEFORE it left Earth.

This is just freshman-level Special Relativity. I guarantee you, that no one has found a work-around for that, especially since it is a matter of LOGIC. It follows LOGICALLY from the assertions of Special Relativity. If you wish to deny this conclusion, then you would have to deny Special Relativity.

If on the other hand, you have used your drive to permanently shred up space and time, rapidly crashing Mars into Earth and destroying all life on both planets, leaving the mess like that, and then stating you have successfully transmitted a message at FTL speeds, then more power to ya!

[sentientbicycle]

Alcumbierre himself states that it does not violate causality. from: http://www.npl.washington.edu/av/altvw81.html > The possibilities for FTL travel or communication implicit in the Alcubierre drive raise the possibility of causality violations and "timelike loops", i.e., back-in-time communication and time travel. Alcubierre points out that his metric CONTAINS NO SUCH CLOSED CAUSAL LOOPS, and so is free of their paradoxes. However, he speculates that it would probably be possible to construct a metric similar to the one he presented which would contain such loops.

    So either he's a laughing stock and nobody is talking about that or (more likely) you are wrong.

[nessus42]

He has only stated that there are no closed causal loops for one particular use-case of his drive. He never stated either that causality was not violated from the point of view of a distant observer in a different frame of reference. Nor did he state that such a drive would not allow closed causal loops to be generated. In fact, he implied the opposite.

[lmm]

I'm sure the authors of the paper know that the warpdrive violates causality.

It doesn't matter that you're warping space to move points A and B closer from your perspective. If an outside observer can see you at point A at time t, and at point B at distance d away at time <t+d, you have violated causality, and an observer moving at a suitable velocity will see you arrive at B before you left A. That is a basic, irrefutable fact of special relativity.