You can't have faster than light travel without violations of causality. And while the equations of General Relatively allow for universes where causality is routinely violated, the probability that we are in such a universe seems vanishingly small. E.g., just because you can violate causality does not mean that you can go back in time and kill your grandfather. If you were to try, something would stop you, as a universe in which you kill your own grandfather is not consistent with General Relativity.
A universe that gives you the means to go back in time and try to kill your grandfather, but then somehow always thwarts you, would be a very strange universe indeed.
Edit: To whoever down-voted me, have you taken any classes on General Relativity? I have.
In any case this is from Wikipedia:
Causality is not required by special or general relativity[citation needed], but is nonetheless generally considered a basic property of the universe that cannot be sensibly dispensed with. Because of this, most physicists[who?] expect that quantum gravity effects will preclude this option.[citation needed] An alternative is to conjecture that, while time travel is possible, it never leads to paradoxes; this is the Novikov self-consistency principle.
The "Novikov self-consistency principle" is the the one that states that you could try to create a time paradox, but that you would never be able to succeed. I.e., the universe would be a very strange place!
We aren't talking about time travel. So many people confuse the idea of FTL with time travel. General Relativity talks about frames of reference.
Suppose you had a base on Mars and sent a radio signal to it from Earth. It would take between 4.3 to 21 minutes to reach Mars, depending on its distance from Earth at the time.
If you simultaneously jumped in your 10x warp drive and set out, you would arrive at Mars in 25.8 seconds to 1min 26 seconds, again depending on distance.
In this scenario, there has been no violation of causality. You aren't arriving before you sent your radio signal. All that is happening is that you're arriving before your radio signal does. From the perspective of a telescope or radio antenna at the Mars base, you would view Earth in its state 4.3 to 21 minutes before, because it simply takes that long for the electromagnetic waves to get to you.
So yes, you can travel faster than the speed of light without violating causality. If you travel in a relativistic way, i.e. speed all the way up to 99.99999% of light speed, you will most certainly run into time slowing down in your local frame, while it continues at a normal frame back at your departure point.
But with a warp drive that works as described in the article, there is no changing of reference frames. Since you're warping space itself, the spacecraft isn't actually undergoing acceleration in the relativistic way of a rocket. For passengers on board, the clocks are going to run at the same rates as back home.
A lot of people responding to this thread do not understand relativity. The OP is correct, the fundamental problem is causality, relativity and FTL do not mix. The common way of saying it is that you can have two of the three: FTL, causality, or relativity. You cannot have all three. Here is a very nice explanation of why:
Also, I've never understood how the Novikov self-consistency principle would work in reality. Causality violations can be a lot simpler than killing your grandfather. Say, for example, you set up a pool table with a pool ball and hit it through a time machine such that it went back in time and hit itself, making it miss the time machine? Would the pool ball be suddenly acted on by some invisible force? Would it explode? Would the universe just end? The whole scenario seems so implausible that addressing this theoretical concern is a lot more relevant than worrying about the energy levels required to manipulate space time.
[Background note: I'm a physics professor with a background in string theory and relativity.]
You're raising a sensible point, and most of the objections raised here are invalid. But it nevertheless turns out (surprisingly, to me!) that your argument doesn't work. This topic came up a lot during the short-lived superluminal neutrino excitement last year, and one good discussion of it by Sean Carroll can be found at:
That post includes a link to a paper by Bob Geroch that goes into the topic in detail. The very short summary is that there is no mathematical necessity for "causality" to be defined just by relativity: the union of the relativistic definition and some other well-defined causal theory can work just as well, even if that theory involved faster-than-light travel.
So thank you for raising a very good point about this topic, even if it wasn't quite accurate. And to those who've objected here: unless your objection explicitly quoted Geroch, odds are very good that they're wrong.
In General Relativity, Faster-Than-Light travel is only prohibited locally. Its possible for space-time itself to expand and shrink faster than light. This is why distant-enough galaxies are receding from us at faster than the speed of light.
Mathematically, the structure of the proposed warp-drive is such that the spaceship is moving at << c locally, so no causality is violated. See the author's answer here:
I'm not the down-voter, but I think you were likely down-voted because this article/discussion is not about time travel. And your first statement is that "you can't have faster-than-light travel..." is precisely what this paper discusses -- that with certain loopholes in physics (and consistent with General Relativity), faster-than-light travel is at least theoretically possible.
Causality, though, is a postulate in the system. If you start with the assumption that faster-than-light is impossible and build a system around that, the system you build around that assumption will always prove that it's impossible -- until something else proves otherwise.
I'm glad you brought this up. I got into this same argument on a Star Trek fan site and my opinions on the feasibility of FTL travel were not popular with that crowd. I would like to know what Alcubierre himself thinks about the causality issue. You simply can't wish it away.
It's not that the universe might "literally" prevent you from performing an action. It's just that our universe doesn't allow it in the first place. The coherence of the universe is a biproduct of its inherent order.
I guess what I mean, without sounding too pseudo-scientific, is I believe the way it works is that, if, say, you go back in time and kill your grandfather, then what is actually happening is you are killing the person you thought was your grandfather, but they were not, in fact, your grandfather to begin with.
In fact, all you would know going back is that your grandfather was murdered by someone. Let's say you believe it was you, and you have a change of heart. Decide it's not in you to kill someone, even to prove a scientific point. That doesn't mean he doesn't get killed. Nothing's changed. It's simply that someone else killed him.
The answer to the question of Schroedinger's cat isn't that the cat is dead or alive, it's that it is.
Since QED and relativity aren't consistent, and QED says that can photons travel at speeds less than and greater than c, isn't it possible that relativity is just probabilistically true but not "enforced" to be true?
I feel like a lot of people here misunderstand the speed of light as a cosmic speed limit. The speed of light as a speed limit is a local constraint. On a larger scale there is no such speed limit. Just because you travel faster than light on a non-local scale does not mean you break causality.
For example, light "travels" more slowly through water than vacuum. Well, actually, photons travel at c always -- it's just that light gets bounced around by water molecules, getting absorbed and reabsorbed many many times before arriving at the destination. It's like driving to a destination as opposed to running to it. If the roads are curvy enough, the runner will win because he is not constrained by roads. Could it be that the Alcubierre drive gets past the roads of empty space in a way light cannot?
The fact that galaxies we see now are moving away from us faster than the speed of light has some bleak consequences, however. Astronomers now have strong evidence that we live in an "accelerating universe," which means that the speed of each individual galaxy with respect to us will increase as time goes on. If we assume that this acceleration continues indefinitely, then galaxies which are currently moving away from us faster than the speed of light will always be moving away from us faster than the speed of light and will eventually reach a point where the space between us and them is stretching so rapidly that any light they emit after that point will never be able to reach us.
In other words, vacuum fills in between us and far away galaxies faster than light can traverse it. Again, locally, the derivative of position with respect to time is c, but the universe is able to "cheat" by messing around with the definition of position. If the Alcubierre drive messes with the fabric of the universe in a similar way, I don't see any reason why it cannot succeed.
Technically speaking, the speed of light limit only applies when you are in an "inertial frame" -- that is, sitting where you are, without any forces acting on you, and measuring the speed of an object that moves past a ruler and clock that you are holding in your hand. Across the large distances in the universe, however, we have a very different set of circumstances. No one is in an inertial frame, because everyone is being accelerated with respect to everyone else, due to the universe's gravitational field and the fact that the universe is expanding. In effect, the universe's expansion isn't really due to galaxies moving "through space" away from each other, but rather due to the stretching of space itself, which isn't governed by the same limits that we are.
I'm not sure whether the Alcubierre drive contradicts causality, but if it does, I highly doubt that it is because of the arguments presented on this forum.
As much as it pains me to say this, but I think we have to invent some more advanced weapons before we start poking our heads out of our galaxy. Don't get me wrong, this is fantastic and I'm all tingly from excitement (this is the first time I've read about warp drives in the context of real science) ... but like I said, taking a stroll trough the galaxy with our bombs and finding a hostile alien world. Well we'd be screwed.
Just food for though here; this is from the Halo universe, where the timeline goes something like this: humans invent "warp drives", they colonize other worlds, soon this colonies start to rebel which leads to a massive space civil war. Later the aliens arrive and set to destroy all of humanity. Now, if it waren't for the civil war, humans would have no experience in space combat, and they wouldn't have developed more advance weapons which would later allowed them to defeat the alien threat.
1000 years is the blink of an eye compared to the lifetime of our galaxy or the amount of time it took life to evolve intelligence on Earth. There's no good reason to expect that humanity's age will be within 1000 years of an alien race's. Consider how little chance an army behind 1000 years technologically would stand against a modern army.
Computer strategy games (I'm specifically thinking of Master of Orion and Galactic Civilizations) often make the assumption that all the races that are going to come into contact with each other have the same technological starting point. This is for the good and simple reason of game balance: Nobody would want to play the game if one race started with a game-winningly huge technological advantage due to random luck.
Many other games and science fiction settings make a similar assumption: That alien and Terran technology are on roughly equal footing, because a situation where everyone has a fighting chance simply makes a better narrative.
Seeing how if we use our warp drives to 'colonize' space, other creatures would have far more to fear from us than we from them (think Independence day with roles reversed). If a space faring species encounters non-space faring species, the one with warp is probably (not necessary) in the better position. Even without the weapons, FTL drive implies a magnitudes greater technology than anything a non-FTL race would have. In fact atm we might be the most dangerous creature out there, so in future (if we get that far) I probably see human species branching out into several subspecies and then waging endless war against each other.
Halo is a work of fiction, not a real life based drama. We'll probably be lucky if we find anything more interesting than a microbe. First encounter will probably be more like Solaris than Halo. We'll most likely find an organism that we can't even perceive as one.
So no, we don't need guns in space. Best weapon in space is Newton's second law (i.e. Kinetic bombardment). Cheap and easy to set up, hard to defend if your target is in a gravitation well.
I think that developing "advanced" weapons in isolation would be an exercise in futility. If there's a race that's experienced in interstellar war out there, their weapons would be much more refined than ours. You can't create any product independent of its context.
If we were to meet a hostile alien race, unless they were at a similar developmental stage (which seems unlikely), we'd be at their mercy either way due to the extent of the other side's settlements.
Such an investment would almost certainly skew the probabilities in the other direction. So far we know of exactly one species that has both taken the initiative to develop weapons that could exterminate humanity and has made threatening gestures with said weapons: us.
If the human race gets destroyed by mega-weapons, it'll almost certainly have been a human that pulled the trigger.
There are a lot of challenges we have to overcome to travel to the stars, but this is certainly not one of them.
What weapon system would be "good enough" anyway? A potential other civilization could be completely primitive, or it could have faster-than-light travel for millions of years by now.
To me it seems entirely absurd to consider this as one of the major problems.
For anyone interested in the (just for fun) topic of technological advancement, weaponry, and encounters with other civilizations, you should check out Vernor Vinge's Zone of Thought novels, a Fire Upon the Deep and A Deepness in the Sky. I can't recommend them enough.
In particular, he assumes that all civilizations will follow roughly the same arc of technological discovery, and that once they hit their information age, it's all about computational power and software. Which, of course, expand in power exponentially with time.
As for us explicitly preparing for that kind of encounter, sorry but if we run into hostiles we're screwed. Take any tech of your choosing and extrapolate. For example, a civilization a few hundred years more advanced than us could easily hit Earth with a custom-made virus or nanobots and wipe out humanity in a day. And if they were a few hundred thousand years more advanced? Impossible to say, but I think our only hope is think that we're too low-level for them to bother messing with.
Interesting thoughts you bring up there, and if we ever did colonize other planets, I've absolutely no doubt they would all start warring and civil warring and fighting each other. All one needs for evidence of this fact is a quick look at how we behave on planet Earth, and what we do with just one planet...
Fear not. Despite the science behind the OP, faster than light travel will not turn out to feasible. Those who think it will be, haven't really thought through the ramifications of what a world in which causality is routinely violated would be like.
If this is really possible, it should increase the probability of having been contacted by advanced extraterrestrial civilizations. Maybe we're really alone after all :( http://en.wikipedia.org/wiki/Fermi_paradox
This is all but a necessary step. If you work out the conventional rocket equations assuming a perfect translation of mass into momentum, to get to appreciable fractions of lightspeed still requires absurd amounts of propellants. At the moment we haven't even got a faint idea as to how we might obtain such total conversion. That's why there's so much interest in designs where you don't carry your fuel with you, like laser-driven solar sails and such.
I assume travelling near speed of light with conventional physics is impossible, since the ship's mass would crush itself as it increased infinitely.
Warp drives, on the other hand, seem to work by moving space-time, not the ship. So in theory the ship is left intact, without the people inside feeling any acceleration whatsoever.
I skimmed through the responses, which seemed to be all about the execution, with little or no discussion or debate questioning if this is a good thing or not.
Even more than the idea excites me, I hope this fails miserably. We're at the Avatar stage of our evolution, not Star Trek.
> The only problem is, previous studies estimated the warp drive would require a minimum amount of energy about equal to the mass-energy of the planet Jupiter.
Uh, no. The "only problem" is that the concept relies on exotic matter, a hypothetical matter with 0 evidence for its existence (so far). See http://en.wikipedia.org/wiki/Exotic_matter
> Uh, no. The "only problem" is that the concept relies on exotic matter, a hypothetical matter with 0 evidence for its existence (so far). See http://en.wikipedia.org/wiki/Exotic_matter
There are multiple routes here though. They could also find an "exotic spaceship" that already has a warp drive.
That was my main problem with this article. http://en.wikipedia.org/wiki/Exotic_matter You could simulate the effect using metamaterials probably, but you couldn't break the real speed of light with it because you don't have real negative mass.
I don't understand how the warp-bubble would itself travel through space-time faster than C (it's effects are inside of it), only that the space-craft traveling through that warp-bubble would. But the space-craft is stationary / in the center of it?
Well if you read the paper the effective speed is 10c, not .1c. They postulate 'boosting' the effective speed by contorting space-time around the craft, see this quote in the paper:
"assume the spacecraft heads out towards Alpha Centauri and has a conventional
propulsion system capable of reaching 0.1c. The spacecraft initiates a boost field with a value of 100
which acts on the initial velocity resulting in an apparent speed of 10c. The spacecraft will make it to
Alpha Centauri in 0.43 years as measured by an earth observer and an observer in the flat space-time
volume encapsulated by the warp bubble. "
[+] [-] nostromo|13 years ago|reply
[+] [-] mvzink|13 years ago|reply
[+] [-] pixie_|13 years ago|reply
[+] [-] nessus42|13 years ago|reply
A universe that gives you the means to go back in time and try to kill your grandfather, but then somehow always thwarts you, would be a very strange universe indeed.
Edit: To whoever down-voted me, have you taken any classes on General Relativity? I have.
In any case this is from Wikipedia:
Causality is not required by special or general relativity[citation needed], but is nonetheless generally considered a basic property of the universe that cannot be sensibly dispensed with. Because of this, most physicists[who?] expect that quantum gravity effects will preclude this option.[citation needed] An alternative is to conjecture that, while time travel is possible, it never leads to paradoxes; this is the Novikov self-consistency principle.
The "Novikov self-consistency principle" is the the one that states that you could try to create a time paradox, but that you would never be able to succeed. I.e., the universe would be a very strange place!
[+] [-] geuis|13 years ago|reply
Suppose you had a base on Mars and sent a radio signal to it from Earth. It would take between 4.3 to 21 minutes to reach Mars, depending on its distance from Earth at the time.
If you simultaneously jumped in your 10x warp drive and set out, you would arrive at Mars in 25.8 seconds to 1min 26 seconds, again depending on distance.
In this scenario, there has been no violation of causality. You aren't arriving before you sent your radio signal. All that is happening is that you're arriving before your radio signal does. From the perspective of a telescope or radio antenna at the Mars base, you would view Earth in its state 4.3 to 21 minutes before, because it simply takes that long for the electromagnetic waves to get to you.
So yes, you can travel faster than the speed of light without violating causality. If you travel in a relativistic way, i.e. speed all the way up to 99.99999% of light speed, you will most certainly run into time slowing down in your local frame, while it continues at a normal frame back at your departure point.
But with a warp drive that works as described in the article, there is no changing of reference frames. Since you're warping space itself, the spacecraft isn't actually undergoing acceleration in the relativistic way of a rocket. For passengers on board, the clocks are going to run at the same rates as back home.
[+] [-] jxcole|13 years ago|reply
http://thebestforumever.com/community/threads/tachyon-pistol...
Also, I've never understood how the Novikov self-consistency principle would work in reality. Causality violations can be a lot simpler than killing your grandfather. Say, for example, you set up a pool table with a pool ball and hit it through a time machine such that it went back in time and hit itself, making it miss the time machine? Would the pool ball be suddenly acted on by some invisible force? Would it explode? Would the universe just end? The whole scenario seems so implausible that addressing this theoretical concern is a lot more relevant than worrying about the energy levels required to manipulate space time.
[+] [-] Steuard|13 years ago|reply
You're raising a sensible point, and most of the objections raised here are invalid. But it nevertheless turns out (surprisingly, to me!) that your argument doesn't work. This topic came up a lot during the short-lived superluminal neutrino excitement last year, and one good discussion of it by Sean Carroll can be found at:
http://blogs.discovermagazine.com/cosmicvariance/2011/09/24/...
That post includes a link to a paper by Bob Geroch that goes into the topic in detail. The very short summary is that there is no mathematical necessity for "causality" to be defined just by relativity: the union of the relativistic definition and some other well-defined causal theory can work just as well, even if that theory involved faster-than-light travel.
So thank you for raising a very good point about this topic, even if it wasn't quite accurate. And to those who've objected here: unless your objection explicitly quoted Geroch, odds are very good that they're wrong.
[+] [-] pessimist|13 years ago|reply
Mathematically, the structure of the proposed warp-drive is such that the spaceship is moving at << c locally, so no causality is violated. See the author's answer here:
http://www.icarusinterstellar.org/daydreaming-beyond-the-sol...
[+] [-] nlh|13 years ago|reply
[+] [-] stan_rogers|13 years ago|reply
[+] [-] rootbear|13 years ago|reply
[+] [-] unknown|13 years ago|reply
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[+] [-] dclowd9901|13 years ago|reply
I guess what I mean, without sounding too pseudo-scientific, is I believe the way it works is that, if, say, you go back in time and kill your grandfather, then what is actually happening is you are killing the person you thought was your grandfather, but they were not, in fact, your grandfather to begin with.
In fact, all you would know going back is that your grandfather was murdered by someone. Let's say you believe it was you, and you have a change of heart. Decide it's not in you to kill someone, even to prove a scientific point. That doesn't mean he doesn't get killed. Nothing's changed. It's simply that someone else killed him.
The answer to the question of Schroedinger's cat isn't that the cat is dead or alive, it's that it is.
[+] [-] jonmrodriguez|13 years ago|reply
[+] [-] stryker|13 years ago|reply
For example, light "travels" more slowly through water than vacuum. Well, actually, photons travel at c always -- it's just that light gets bounced around by water molecules, getting absorbed and reabsorbed many many times before arriving at the destination. It's like driving to a destination as opposed to running to it. If the roads are curvy enough, the runner will win because he is not constrained by roads. Could it be that the Alcubierre drive gets past the roads of empty space in a way light cannot?
For a better example, consider the expansion of the universe. Link: http://curious.astro.cornell.edu/question.php?number=575. I quote:
The fact that galaxies we see now are moving away from us faster than the speed of light has some bleak consequences, however. Astronomers now have strong evidence that we live in an "accelerating universe," which means that the speed of each individual galaxy with respect to us will increase as time goes on. If we assume that this acceleration continues indefinitely, then galaxies which are currently moving away from us faster than the speed of light will always be moving away from us faster than the speed of light and will eventually reach a point where the space between us and them is stretching so rapidly that any light they emit after that point will never be able to reach us.
In other words, vacuum fills in between us and far away galaxies faster than light can traverse it. Again, locally, the derivative of position with respect to time is c, but the universe is able to "cheat" by messing around with the definition of position. If the Alcubierre drive messes with the fabric of the universe in a similar way, I don't see any reason why it cannot succeed.
Here's a related link: http://curious.astro.cornell.edu/question.php?number=56. I quote:
Technically speaking, the speed of light limit only applies when you are in an "inertial frame" -- that is, sitting where you are, without any forces acting on you, and measuring the speed of an object that moves past a ruler and clock that you are holding in your hand. Across the large distances in the universe, however, we have a very different set of circumstances. No one is in an inertial frame, because everyone is being accelerated with respect to everyone else, due to the universe's gravitational field and the fact that the universe is expanding. In effect, the universe's expansion isn't really due to galaxies moving "through space" away from each other, but rather due to the stretching of space itself, which isn't governed by the same limits that we are.
I'm not sure whether the Alcubierre drive contradicts causality, but if it does, I highly doubt that it is because of the arguments presented on this forum.
[+] [-] CWIZO|13 years ago|reply
Just food for though here; this is from the Halo universe, where the timeline goes something like this: humans invent "warp drives", they colonize other worlds, soon this colonies start to rebel which leads to a massive space civil war. Later the aliens arrive and set to destroy all of humanity. Now, if it waren't for the civil war, humans would have no experience in space combat, and they wouldn't have developed more advance weapons which would later allowed them to defeat the alien threat.
[+] [-] csense|13 years ago|reply
Computer strategy games (I'm specifically thinking of Master of Orion and Galactic Civilizations) often make the assumption that all the races that are going to come into contact with each other have the same technological starting point. This is for the good and simple reason of game balance: Nobody would want to play the game if one race started with a game-winningly huge technological advantage due to random luck.
Many other games and science fiction settings make a similar assumption: That alien and Terran technology are on roughly equal footing, because a situation where everyone has a fighting chance simply makes a better narrative.
[+] [-] Ygg2|13 years ago|reply
Halo is a work of fiction, not a real life based drama. We'll probably be lucky if we find anything more interesting than a microbe. First encounter will probably be more like Solaris than Halo. We'll most likely find an organism that we can't even perceive as one.
So no, we don't need guns in space. Best weapon in space is Newton's second law (i.e. Kinetic bombardment). Cheap and easy to set up, hard to defend if your target is in a gravitation well.
[+] [-] aeturnum|13 years ago|reply
If we were to meet a hostile alien race, unless they were at a similar developmental stage (which seems unlikely), we'd be at their mercy either way due to the extent of the other side's settlements.
[+] [-] wheels|13 years ago|reply
If the human race gets destroyed by mega-weapons, it'll almost certainly have been a human that pulled the trigger.
[+] [-] anonymouz|13 years ago|reply
To me it seems entirely absurd to consider this as one of the major problems.
[+] [-] adastra|13 years ago|reply
In particular, he assumes that all civilizations will follow roughly the same arc of technological discovery, and that once they hit their information age, it's all about computational power and software. Which, of course, expand in power exponentially with time.
As for us explicitly preparing for that kind of encounter, sorry but if we run into hostiles we're screwed. Take any tech of your choosing and extrapolate. For example, a civilization a few hundred years more advanced than us could easily hit Earth with a custom-made virus or nanobots and wipe out humanity in a day. And if they were a few hundred thousand years more advanced? Impossible to say, but I think our only hope is think that we're too low-level for them to bother messing with.
[+] [-] ImprovedSilence|13 years ago|reply
[+] [-] olalonde|13 years ago|reply
[+] [-] nessus42|13 years ago|reply
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[+] [-] outworlder|13 years ago|reply
Obligatory Star Trek reference.
This seems close enough: http://www.ex-astris-scientia.org/schematics/surak-timur-niv...
[+] [-] olalonde|13 years ago|reply
[+] [-] johnnymonster|13 years ago|reply
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[+] [-] goldfeld|13 years ago|reply
Warp drives, on the other hand, seem to work by moving space-time, not the ship. So in theory the ship is left intact, without the people inside feeling any acceleration whatsoever.
[+] [-] gotrythis|13 years ago|reply
Even more than the idea excites me, I hope this fails miserably. We're at the Avatar stage of our evolution, not Star Trek.
I think this says it best: (no affiliation) http://www.facebook.com/ResurrectingtheGoddess/posts/3960760...
[+] [-] dholowiski|13 years ago|reply
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[+] [-] cryptoz|13 years ago|reply
Uh, no. The "only problem" is that the concept relies on exotic matter, a hypothetical matter with 0 evidence for its existence (so far). See http://en.wikipedia.org/wiki/Exotic_matter
[+] [-] hooo|13 years ago|reply
There are multiple routes here though. They could also find an "exotic spaceship" that already has a warp drive.
[+] [-] sp332|13 years ago|reply
[+] [-] randallsquared|13 years ago|reply
[+] [-] iRobot|13 years ago|reply
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[+] [-] heyrhett|13 years ago|reply
As far as some news about faster than light travel, refer to: http://xkcd.com/955/
[+] [-] ChuckMcM|13 years ago|reply
"assume the spacecraft heads out towards Alpha Centauri and has a conventional propulsion system capable of reaching 0.1c. The spacecraft initiates a boost field with a value of 100 which acts on the initial velocity resulting in an apparent speed of 10c. The spacecraft will make it to Alpha Centauri in 0.43 years as measured by an earth observer and an observer in the flat space-time volume encapsulated by the warp bubble. "
[+] [-] heyrhett|13 years ago|reply
[+] [-] rewind|13 years ago|reply
[+] [-] acqq|13 years ago|reply
http://hitchhikers.wikia.com/wiki/Infinite_Improbability_Dri...