Sure, as long as negative mass exists and you never want to interact with "normal" space-time again once the thing is switched on. "Ok, you can travel FTL with these magic beans but you can never stop traveling FTL." Also, it does nothing to avoid the causality violations implicit in special relativity.
Yes, and that is understood. nevertheless this is a viable enough solution that Nasa are taking it seriously. Besides, it is not the writer's job to solve science's problems. But given the author is writing a work a fiction, Alcubierre is the best chance we have 'at the moment' to deliver the goods. Writers have always taken what is 'possible' and extrapolated a possible extension or adaptation. Look at how wormhole theory spawn hyperspace gates, stargates etc etc.
A writer does not need to come up with a workable theory of FTL travel. He or she only needs to come up with FTL behavior that is plausible to the readers. Preferably, the writer will know enough physics to avoid glaring errors. It's best not to use specific theories to justify your FTL behavior. Many theories are convincing bullshit. Many others are highly speculative, and likely to be disproven in under a decade, either by continuing research or by mathematicians finding logical flaws in the math the theory is based on. You need to establish the behavior only to the extent that it impacts your plot. For example, in a novel I am working on, the consequences of the FTL theory used is that interstellar travel still requires a couple years and a lot of fuel to travel between systems, so my colonists are for all practical purposes completely cut off from Earth. Theirs is a one-way journey. Other novels will change the behavior of FTL travel to create different restrictions. And as in this novel, I never explicitly explain the restrictions. I simply make it apparent in context, unless there is some restriction that is necessary and defies intuition.
I'm with Cogito on this. I'm working on a series of short stories about humans visiting distant planets, and I need FTL travel. I'm trying to keep as close to modern science as I can, but I need FTL travel and I need FTL communications. This probably means my stories are science fantasy, or speculative fiction, rather than science fiction, but frankly, I don't care what they're called. I need my distant planets and I need my humans to be there, and it doesn't matter to me how they get there. I'm allowed, as a writer of fiction, to get them there. I establish rules governing this kind of travel in my stories. It costs a huge amount to achieve FTL travel, for example. It's not easy. Mounting an expedition to a planet light-years away is an enormous undertaking. Returning to Earth after making such a trip is almost impossible - most of these journeys are one-way trips. My plots depend on this. Obviously, I'm assuming some changes to the laws of physics that we understand today. I don't feel the need to explain them in mathematical detail - I'm writing fiction, after all. I just want the same license every science-fiction writer before me has claimed: My characters can get where they need to be, and THAT'S IT. As long as I'm consistent in my treatment of the science involved, then I'm okay. I'm only on thin ice if I change the rules as my story progresses, and I never do that.
I try, wherever possible, not to specifically break a well-known existing scientific principle (which is why I've recently had to do a bit of research into mass, gravity and orbits to fix a problem with the planetary system I had come up with for my novels). So, I wouldn't have my spaceships travelling at LS or higher in conventional space. I use a completely fictional variation on the hyperspace idea simply to avoid any direct breach of physical laws. (However, I think I must also point out that despite various theories espoused by science I don't believe time travel is or ever will be possible either in theory or practicality, and so I banned it from my writing - so I don't always follow accepted scientific views).
I wouldn't exactly say NASA is taking it "seriously". Alcubierre published a paper in '94, and now someone is looking at using lasers to make extremely small "bubbles". Actually using such things to transmit information FTL is a totally different story and flies in the face of accepted scientific principles (Special Relativity) so before it can be taken seriously whomever is doing the work would need to present extraordinary evidence and go through extensive peer review. Until then it's fringe science at best. There have been claims of FTL information before and they have roundly been discredited by the scientific community. "Wormholes" created by negative mass and separated at relativistic speeds, time travel included (with special sauce to avoid causality violation) is (very slightly) less problematic than Alcubierre.
White is a Nasa Physicist, and sure he is only trying to create the tiniest of shifts, but the fact they are pursuing that line of enquiry at all is intriguing. and seeing as we do not relaly have any other workable theories, if you are trying to extrapolate an FTL drive form existing theories, this is about all we have.
In general, yes. Although it's possible to carefully construct scenarios where FTL doesn't allow for causality violations, any arbitrary use of FTL can be used to time travel.
I didn't say it shouldn't be pursued in the interest of exploring distorted space-time, but the plausibility of using it for actual FTL is exceedingly low and really unsupported by science. Anyone, regardless of pedigree, who claims to be able to transmit information superluminally is operating outside the bounds of modern scientific theory.
You're right, that's futuristic fantasy (not sure "science fantasy" makes any sense) and despite the way fiction is currently categorized, it really should be labeled as such.
Because of the relativity of simultaneity from special relativity which states that there is no absolute simultaneous events (i.e. "now") everywhere at once; it's complete dependent on your inertial reference frame and all frames are equally valid. That means that any faster-than-light information will result in some inertial reference frames in which there will be disagreement about the ordering of events; i.e. the transmission will appear to go back in time. That's actually not too problematic all by itself, but if the FTL is cyclic in nature (leaving, traveling, returning to destination), there will also be frames in which the information returns to the origin before it left. It's difficult to describe exactly without light cones and Minkowski spacetime graphs. You can go through the thought experiment at http://www.theculture.org/rich/sharpblue/archives/000089.html and it should be fairly clear.
I have been looking up a number of references on the internet regarding SR, GR and causality and that was one of the pages I found. However, it still didn't quite add up for me. I know I must be missing something, so I'm now looking into the issue of relativity of simultaneity to see if I can find something that will explain it in terms I can get my head round. Edit: Just for reference, this is what I'm looking at at the moment: http://upload.wikimedia.org/wikipedia/commons/9/96/Einstein_train_relativity_of_simultaneity.png
Bypass Wikipedia, and look for primary sources. I hope you can read the language of mathematics. Without it, many of the explanations will not make intuitive sense.
Wikipedia is only a general starting point, and the article that jsiprell linked to isn't a Wikipedia one. However, I posted the link to the picture here so others like jsiprell could see what I was studying, in order that they could point out any errors in it if it was wrong and point me towards a better source. No-one's done that yet, so for now I'm happy to consider it a reliable interpretation of Einstein's, Minkowski's and Lorentz's work until proven otherwise. As for going to the sources, you're right, I'd have to have a very good understanding of scientific maths, which I don't. I'm not a scientist or mathematician and as such would probably never be able to explain why I feel things don't add up in a way that scientists would accept. That doesn't mean my disquiet over what I'm seeing is necessarily wrong, but as so many scientists and mathematicians accept these theories I have to believe I'm wrong in my interpretation and find out why.
