WARP DRIVE, AHEM!

Austin Stanley · 2007-09-04 18:35:10

How then do you explain the Inflation theory of the Universe? Parts of the Universe have had to be traveling faster than the speed of light relative to other parts, otherwise we would live in a universe that adhered to the Special Relativity in all things without exceptions.

Like I said before, if you would peruse the websites I linked, you WOULD find answers to all these questions. Nothing in special relativity prevents some objects from appearing to travel fast that the speed of light to some observers. If I got on a ship traveling at relativistic speeds to Alpha Centari or someplace, it might appear to me that I was infact traveling faster than the speed of light (as due to time dilation I might experience less time passage then it would take for light to cover the distance), but in fact I would still be traveling slower than light.

Or more to the point if I was to measure to rockets traveling in opposite directions a .6C each, I might say the distance between them is increasing at 1.2C. This is still not FTL travel and whats more is the incorrect [url=http://www2.corepower.com:8080/~relfaq/velocity.html]way to add relativistic velocities[/ur]

That the equations produce contradictory results when you introduce instantaneous communication either indicates that something is impossible or that the theory is flawed as Newtons was about relative motion.

Or it might indicate C. that, in fact instantaneous communication (and FTL travel) is impossible. I'm sure I don't need to remind you which way the evidence points...

Einsteins relativity may be a more accurate description of the universe, but this in now way means that it is the final arbitrator of what is possible. According to Newton's equations, the speed of light ought to be infinite, because if it were infinite then the speed of light would be the same for all observers, but the speed of light is not infinite, it has been observed to be not infinite, so therefore Einstein had to come along and explain how it could not be infinite yet the same for all observers.
Now I am not a mathematician, it is not for me to disprove Einstein, but from past experience, I doubt his theory is the final arbitrator of what is and isn't possible. After all the Universe didn't listen to Newton, so why should it listen to Einstein?

Well despite all your wishing for FTL travel to be possible, I don't think the universe is going to listen to you either

Everyone likes to harp on that fact that Special Relativity corrects a relatively small subset of the rules of Newtonian motion. And they often seem to forget that the first and second laws of Newtonian motion (the law of inertia and conservation of momentum) still remain valid with special relativity. Or the fact that their are countless other laws (like say Archimedes' principle) that remain unchallenged. In the end its pointless as the fact that a previous law was proved incorrect in now way proves that the law that supersedes it will then be proved incorrect as well. Only experimental evidence can prove that and, as I have said, that is firmly on Special Relativities side.

Tom Kalbfus · 2007-09-05 05:14:35

The first and second laws of Motion aren't quite correct under Einstein's equations. There are Einsteinian equations that substitute for Newton's laws of motion and gravity. One of the early indicators that Newton was wrong was the orbit of Mercury, and of course the observation that the speed of light was finite and constant, independent of the observer. One of the indicators that Einstein might be superseded is that the Universe is bigger than the observable universe. If the Universe expanded faster than light, then under a similar principle might a warp drive operate. If the equations don't make any sense, then maybe the equations are simply wrong when dealing with this particular circumstance. Perhaps anypoint is equaly valid so long as nothing goes faster than the speed of light, but if something does and the equations are incapable of dealing with that, that just implies that the equations are wrong. Newton's laws were inadequate for dealing with near light speed.

The various exceptions to the light speed limit, including the Universes near uniform background radiation seem to point to possibly something more than merely Einstein's equations. There may be a way of getting around them, I not one to prove it to you, but it is fairly Pre-Copernican to say that Einstein's equations are the ultimate limit and that there is nothing in the Universe that may supercede them. Observation and experimentation supercede mere mathematical exercises. If the math works in describing the Universe and then the Universe does something that the math does not describe, you change your math.

Austin Stanley · 2007-09-05 13:27:47

The first and second laws of Motion aren't quite correct under Einstein's equations. There are Einsteinian equations that substitute for Newton's laws of motion and gravity.

No, this is inncorrect. Newtons 1st law (the law of inertia) holds perfectly true at relativistic velocities. If a rocket traveling at .9c shuts off it's engine it doesn't start to speed up or slow down, it continues traveling along at .9c. Likewise, Newtons 3rd law (the law of conservation of momentum) also holds true at relativistic velocities. If to rockets smash into eachother at .9c conservation of momentum holds perfectly true for them as well. There masses are increased by relativisitc momentum, true, but Newtons 3rd Law (that for every action there is an equal and opposite reaction) still hold true.

Now, it is true that Newtons 2nd law (F=m*a) does not hold true at relativistic velocities. Or rather it only hold true if you correctly apply the Lorenz factor to the objects mass. Newtons Universal Gravitation has also been supplanted by General Relativity, but that hasn't been the subject we have been discussing.

In any case, as I said before, this argument is pointless. The fact that Newton's laws were suplanted by Einstein's does not prove that Einstein's will likewise be suplanted.

One of the indicators that Einstein might be superseded is that the Universe is bigger than the observable universe. If the Universe expanded faster than light, then under a similar principle might a warp drive operate. If the equations don't make any sense, then maybe the equations are simply wrong when dealing with this particular circumstance.

Or maybe, as I have pointed out several times to you before, and provided links with helpful explinations, that the rate of expansion of the universe is not indicative of FTL travel.

Perhaps anypoint is equaly valid so long as nothing goes faster than the speed of light, but if something does and the equations are incapable of dealing with that, that just implies that the equations are wrong. Newton's laws were inadequate for dealing with near light speed.

Or again, maybe nothing goes faster than the speed of light, and Special Relativity is correct. And all these so called examples of violation of this principle are merely misinterpeted or non-existant.

The various exceptions to the light speed limit, including the Universes near uniform background radiation seem to point to possibly something more than merely Einstein's equations. There may be a way of getting around them, I not one to prove it to you, but it is fairly Pre-Copernican to say that Einstein's equations are the ultimate limit and that there is nothing in the Universe that may supercede them. Observation and experimentation supercede mere mathematical exercises. If the math works in describing the Universe and then the Universe does something that the math does not describe, you change your math.

I don't know what exactly you are trying to say by accusing me of being "pre-copernican," but holding Special Relativity as truth is pretty much universal among scientists.

In any case as you say, Science is a matter of observation and experimentation, and ALL of that is on Special Relativities side. Indeed even if you found some strange exception to it, which allowed FTL travel or communication, you would have to fit it in with all the data which indicates that it would cause a causalilty paradox.

Maybe this is the point that you are having problems with. I think you would agree that at least some points of Special Relativity are true. Such as the fact that time dilates for objects moving at reltavistic speed (even if you don't observation clearly proves this is true). But, as I pointed out in an earler example, this is EXACTLY what leads to potential causality violations. FTL communications/travel allows informations to be transported to these observes past! Either this Time Dilation does not happen (it does), or FTL travel is not possible. Those are the only real options.

Tom, this is getting old. You keep repreating the same repative arguments, and I keep giving you the same reposnes, which you ignore.

Austin Stanley · 2007-09-05 13:29:19

Sorry, double post.

Tom Kalbfus · 2007-09-06 15:52:04

The first and second laws of Motion aren't quite correct under Einstein's equations. There are Einsteinian equations that substitute for Newton's laws of motion and gravity.
No, this is inncorrect. Newtons 1st law (the law of inertia) holds perfectly true at relativistic velocities. If a rocket traveling at .9c shuts off it's engine it doesn't start to speed up or slow down, it continues traveling along at .9c. Likewise, Newtons 3rd law (the law of conservation of momentum) also holds true at relativistic velocities. If to rockets smash into eachother at .9c conservation of momentum holds perfectly true for them as well. There masses are increased by relativisitc momentum, true, but Newtons 3rd Law (that for every action there is an equal and opposite reaction) still hold true.
Now, it is true that Newtons 2nd law (F=m*a) does not hold true at relativistic velocities. Or rather it only hold true if you correctly apply the Lorenz factor to the objects mass. Newtons Universal Gravitation has also been supplanted by General Relativity, but that hasn't been the subject we have been discussing.
In any case, as I said before, this argument is pointless. The fact that Newton's laws were suplanted by Einstein's does not prove that Einstein's will likewise be suplanted.

Does not prove that it won't be either. We think that Einsteins Laws will hold true, but they have not been tested in all cases. I would not rest easily that Einstein's laws will never be broken. The current theory on the formation of the Universe calls for it in fact.

If you assume that nothing can travel faster than the speed of light no matter what the circumstances, you must also assume that the radius of the Universe in light years must equal its age in years. The Universe would have to appear much more curved than it does for this to be true. We are looking outwards on a smaller universe after all.

Now if you believe in the Inflation theory, this may also open the way for a possible Warp Drive if we could do what the Universe is doing but on a smaller scale.

Tom Kalbfus · 2007-09-06 16:04:38

I don't know what exactly you are trying to say by accusing me of being "pre-copernican," but holding Special Relativity as truth is pretty much universal among scientists.

Yet the cosmologists that expound on the Inflation theory of the Universe open up the can of worms that suggests that space can expand faster than the speed of light.

So far no one has found a direction in time that is not statisitical. If a Universe can expand while obeying all the laws it can also contract; thus if you can expand the local fabric of space behind a spaceship and contract it in front of the spaceship you have a warp drive. Now that relativistic equations can't deal with this situation does not mean that a Warp drive is necessarily impossible.

What I'm trying to say is that the equations are models of the Universe, they seek to describe what's going on in the Universe, but they are not perfect and the Universe does not have to obey the equations on the chalkboard. No one has a complete theory on how the Universe works, we only have approximation, and because of that, we can never be completely sure that something is impossible.

How do we know there is not some alien race that is exploiting some loopholes in physics even as we speak? We can say things are likely and probable given what we know, but it would be a mistake to sit on our larels or lean against a blackboard and say with absolute confidence that the equations you wrote on the board prove that something in the Universe is impossible. For one the equations may be wrong, even if they are mathematically correct, for another they may only be almost right, and might apply in some situations but not others. And also the Einsteinain and Newtonian equations on motion and gravitation explain most of the same behavior given most normal circumstances. One can sit on his laurels like some arrogant Sir Isaac Newton and confidently proclaim some truth due to one's mathematical brilliance, but one also has to look at the real universe too and see what's going on. There is alot we don't know about the real universe and we don't know the portion of stuff that we don't know. We can only see whats visible to our eyes and out instruments, and we can only know what is known.

Austin Stanley · 2007-09-06 18:26:21

Does not prove that it won't be either. We think that Einsteins Laws will hold true, but they have not been tested in all cases. I would not rest easily that Einstein's laws will never be broken.

I'm not sure what 'cases' you think Special Relativity has not been tested in. Special Relativity simply calls for all observes to see the speed of light as being the same, this is true and has been tested to be quite true. As a consequence we find that some observes experience time dilation in relation to other observes. This has also been tested and proves to be true. Since this dilation is in proportion to the speed of light, violating that limit can causes information to travel backwards in time for some observers. All of this has been quite thoroughly tested and proved, except for the impossible bit (FTL) which, being impossible, obviously can't be tested.

The thing you don't seem to be getting is even if we do some hand-waving and allow FTL travel it will be in violation of principles we have already tested and are quite sure are true. It wouldn't be some funky "edge case." Quite simply you cannot have FTL travel, Causality (the principle that cause follows effect), and Special Relativity in the same physical model. If Time Dilation happens (and again, it does) FTL MUST send information into the past. There is no untested area of relativity that could allow it.

And again without any experimental evidence that SR is false we must hold it to be true. The past fate of other laws is irrelevant. Note that physicisit are quite aware of things like expansion of the universe and they are running around yelling "OMG! Einstein was wrong!"

If you assume that nothing can travel faster than the speed of light no matter what the circumstances, you must also assume that the radius of the Universe in light years must equal its age in years. The Universe would have to appear much more curved than it does for this to be true. We are looking outwards on a smaller universe after all.
Now if you believe in the Inflation theory, this may also open the way for a possible Warp Drive if we could do what the Universe is doing but on a smaller scale.

Or you might be misunderstanding inflation theory. True some models for the big-bang have the universe expanding faster then speed of light as we measure if now, but this isn't the whole story. What actually was happening was that the scale of the universe (measured by the Hubble Constant) was expanding at a much faster rate. Somewhat like the expansion of a balloon.

Imagine if you were to expand a balloon at a rate faster than the speed of light. Would this allow point on a balloon to travel between one another FTL? No, since they are all expanding at the same rate (or rather their scale is expanding at the same rate) This makes even more sense when you consider that the universe (by definition) encompasses everything that we see and measure, so its scale expands, so does our scale of measurement. In effect the apparent FTL travel is more an artifact of how we define Space and Distance today. If we were to measure the Universes expansion at that time, it would not be moving FTL.

Another point to consider is that the Inflationary model of the universe was developed to deal with Special Relativity violations in other models (the so called Horizon problem). Do a google on this or comoving distance for a more detail explanation.

Yet the cosmologists that expound on the Inflation theory of the Universe open up the can of worms that suggests that space can expand faster than the speed of light.

Maybe. For special definitions of the words "space." In general, however the cosmologists are quite unanimous that SR must have been withheld through out the universes entire life. Thats why they came up with the Inflation theory after all.

So far no one has found a direction in time that is not statisitical. If a Universe can expand while obeying all the laws it can also contract; thus if you can expand the local fabric of space behind a spaceship and contract it in front of the spaceship you have a warp drive. Now that relativistic equations can't deal with this situation does not mean that a Warp drive is necessarily impossible.

Note the subtle shift from the term "universe" to the term "space." The universe, by some measures might be allowed FTL. Space, as we locally measure it, certainly is not allowed. And again the relativistic equations deal with it just fine. You can use SR to describe your spaceship traveling faster than light all you want, it just interferes with the way we have observed the rest of the universe to be acting.

What I'm trying to say is that the equations are models of the Universe, they seek to describe what's going on in the Universe, but they are not perfect and the Universe does not have to obey the equations on the chalkboard. No one has a complete theory on how the Universe works, we only have approximation, and because of that, we can never be completely sure that something is impossible.
How do we know there is not some alien race that is exploiting some loopholes in physics even as we speak? We can say things are likely and probable given what we know, but it would be a mistake to sit on our larels or lean against a blackboard and say with absolute confidence that the equations you wrote on the board prove that something in the Universe is impossible. For one the equations may be wrong, even if they are mathematically correct, for another they may only be almost right, and might apply in some situations but not others. And also the Einsteinain and Newtonian equations on motion and gravitation explain most of the same behavior given most normal circumstances. One can sit on his laurels like some arrogant Sir Isaac Newton and confidently proclaim some truth due to one's mathematical brilliance, but one also has to look at the real universe too and see what's going on. There is alot we don't know about the real universe and we don't know the portion of stuff that we don't know. We can only see whats visible to our eyes and out instruments, and we can only know what is known.

Maybe so. I can't be sure that the sky wont be green and filled with flying pigs tomorrow either. Science is only concerned with making models that fit the observations we have made so far. Stating that tomorrow we might make an observation that makes our current model untrue is irrelevant. Science is only concerned with the observations we have actually made, not all the hypothetical (and unpredictable) things that might occur. In other words, we can only go by what we measure. The things we have not measured are irrelevant from a scientific viewpoint. And so far our measurements are certainly in agreement with SR.

Tom Kalbfus · 2007-09-07 05:37:58

So far no one has found a direction in time that is not statisitical. If a Universe can expand while obeying all the laws it can also contract; thus if you can expand the local fabric of space behind a spaceship and contract it in front of the spaceship you have a warp drive. Now that relativistic equations can't deal with this situation does not mean that a Warp drive is necessarily impossible.
Note the subtle shift from the term "universe" to the term "space." The universe, by some measures might be allowed FTL. Space, as we locally measure it, certainly is not allowed. And again the relativistic equations deal with it just fine. You can use SR to describe your spaceship traveling faster than light all you want, it just interferes with the way we have observed the rest of the universe to be acting.

That is the whole point of Warp drive, it does not allow for FTL travel locally, that is the space immediately around the ship. The ship does not in fact move at all, instead space outside a narrow bubble around the ship is manipulated to change the ship's position.

I have no problem with people saying that nothing can travel faster than the speed of light so long as its carried through the whole theory and that theory does not allow for the Universe to expand faster than the speed of light. The problem lies when scientists say, nothing can move faster than the speed of light but the Universe expands to millions of light years across in the first few seconds. But that FTL travel is not for you, you potential builders of warp drives, for you you can't go faster than the speed of light, but we leave this big exception for the universe. That is the inconsistency.

In a purely Einsteinian Universe, a universe that is only a few seconds old can only be a few light seconds across, the fact that modern theoriticians leave this big exception open for the entire universe makes me want to "drive a truck through it." I never said Warp drive would be easy, or that we should count on it as a means to travel to the stars in the foreseeable future. I think if it takes the entire universe to do it, then it may not be an easy thing to accomplish, but I don't like laws of the universe that apply to some but not to others. If there is a way to make FTL, then the Universe points to it in the way in which it began. If the physical laws changes and are different now than they were then, perhaps we could then locally change the laws of physics around a space ship, I not so quick to dismiss it as impossible as you. If there is a loophole that the universe uses to come quickly into existance, then I think it may be possible for us to exploit that loophole for FTL travel.

If this causes time travel, as you may well know, there are many possible resolutions to paradoxes besides [b]you can't get there in the first place. If space and time are relative to one's point of view, why not also one's history. Causality might be only local as well with regards to travelling backwards in time. There may be an infinity or worldlines splitting off from one another at all points in time with every decision we make or every random phenomina that occurs where more than one outcome occurs. If you go back and time and kill your grandfather, you do, you are not erased from existance because now you are on a different worldline that does not lead to yourself. This requires an infinity or infinities, so? Einstein was one who believed in an infinite and eternal Universe for one, he found the concept of an infinite universe the encompasses everything to be more philosophically "beautiful" to him than a finite Universe that was all there was, maybe he was wrong anout the "way" in which the Universe was infinite, and so proposed this repulsive force to keep the universe in balance so that it neigther expands nor contracts. I sort of agree with Einstein in this respect, I find it hard to visualize "everything" being finite. If there is a so called boundary to the Universe, I will wonder what's beyond it. If there was a "beginning" I will wonder what came before.

Austin Stanley · 2007-09-07 08:44:22

That is the whole point of Warp drive, it does not allow for FTL travel locally, that is the space immediately around the ship. The ship does not in fact move at all, instead space outside a narrow bubble around the ship is manipulated to change the ship's position.

Again, the problem is not necessarily with the ship traveling FTL at all. If we hand wave and allow this, things work out quite fine for the ship. Time procedes in a normal manner for the ship. The problem is that FTL travel allows the ship to travel into the past of some other observers (who are just minding their own buisness about the universe). Thats the problem. If you go FTL, other observes see you as traveling into the past (their past). Again, the problem is that if another observer can measure you as traveling FTL, then you could be traveling into there past.

I have no problem with people saying that nothing can travel faster than the speed of light so long as its carried through the whole theory and that theory does not allow for the Universe to expand faster than the speed of light. The problem lies when scientists say, nothing can move faster than the speed of light but the Universe expands to millions of light years across in the first few seconds. But that FTL travel is not for you, you potential builders of warp drives, for you you can't go faster than the speed of light, but we leave this big exception for the universe. That is the inconsistency.

I see you ignored the several paragraphs of explanations I posted why that no, the initial expansion of the galaxy is not FTL travel. And in fact the theory was developed to deal with potential FTL violations we would have to have in other theories (such as how the universe could be homogenious if parts of it have never been in contact).

In a purely Einsteinian Universe, a universe that is only a few seconds old can only be a few light seconds across, the fact that modern theoriticians leave this big exception open for the entire universe makes me want to "drive a truck through it."

Or maybe again, you misunderstand this theory and its implications. And even if you did have it right (you don't), why should it be such a shock that the universe (as in the entirety of creation) is allowed to do some things that local regions of space are not? Certianly the implications of the two (one allows FTL communication, one does not) are not the same. And space != the universe, they are different cosomological concepts. And lastly, while the inflationary model of the universe does not allow for FTL travel, it is by no means the last word in cosmology, there are a number of flaws with it. Certianly it is held in less regard then Special Relativity.

but I don't like laws of the universe that apply to some but not to others. If there is a way to make FTL, then the Universe points to it in the way in which it began. If the physical laws changes and are different now than they were then, perhaps we could then locally change the laws of physics around a space ship, I not so quick to dismiss it as impossible as you. If there is a loophole that the universe uses to come quickly into existance, then I think it may be possible for us to exploit that loophole for FTL travel.

The Universe is entirely unconcurned about your feelings about its laws, as is science. If experimental evidence points to conclusions you are uncomforable with, guess who has the problem, you or science? And again far from dismissing FTL travel, I am mearly holding to the universe as we have observed to so far. Such observations are in conflict with your theories of FTL travel, its only natural to dismiss such theories then.

If this causes time travel, as you may well know, there are many possible resolutions to paradoxes besides you can't get there in the first place. If space and time are relative to one's point of view, why not also one's history. Causality might be only local as well with regards to travelling backwards in time.

Because this is nonsensical and in conflict with not just physics, but the fundementals of logic. Cause follows effect. This is the invariable law of nature. How can we have a universe that we can rationaly understand if it is not so? If events in the future were to influence events in the past, which then go on to again influence those future events again, which return to influence the past again... we are trapped in a loop with no end. Not only would it be possible to predict future events, it would be impossible to measure the outcome of events as these events would be continualy affected by their future results returning to the past.

In any case, an ordered causal universe is what we observe, thankfully.

There may be an infinity or worldlines splitting off from one another at all points in time with every decision we make or every random phenomina that occurs where more than one outcome occurs. If you go back and time and kill your grandfather, you do, you are not erased from existance because now you are on a different worldline that does not lead to yourself. This requires an infinity or infinities, so? Einstein was one who believed in an infinite and eternal Universe for one, he found the concept of an infinite universe the encompasses everything to be more philosophically "beautiful" to him than a finite Universe that was all there was, maybe he was wrong anout the "way" in which the Universe was infinite, and so proposed this repulsive force to keep the universe in balance so that it neigther expands nor contracts.

This is fine, but then again its interdimensional travel, not FTL travel. If to travel FTL you must leave our universe and enter into some alternate "worldline" never to return to the one I observe, I've got no problem with it (so long as concervation of energy is preserved). To my viewpoint you simple disapere and don't return, this is cool with me.

If there is a so called boundary to the Universe, I will wonder what's beyond it. If there was a "beginning" I will wonder what came before.

You are free to wonder the questions. I would point out though that from a scientific point of view, your questions are kind of meaningless. The Universe, by definition, encompases the entirety of observable creation. Asking what it expands into, or what lies beyond it is rather meaningless. Likewise the beginning of the universe marks the first point where observation was possible, so asking what came before this is also nonsensical. Remember that for science its only that which is observable that counts.

Oh, maybe you should check out this link on inflation, or this nice one about FTL travel, complete with pretty diagrams pointing out the problems.

Tom Kalbfus · 2007-09-07 17:29:51

So in otherwords whole galaxies didn't exist until we first saw them through the telescope. What we see through the telescope is a result of a collapse of a probability wave function, and nothing exists that hasn't been seen. That seems to solve the time travel paradox quite handily. Traveling back in time uncollapses the propability wave function of everything in the future you came from except yourself. Everything the time traveller remembers from his future is now only a probability and not a reality any more. From the point of view of the observer in the time machine the Universe runs backwards. An observer watching the spaceship move backwards in time will only see it for an instant before his reality is unmade, since he can't remember anything from the future, he never sees that FTL ship.

Probably backwards time travel would involve across time travel where the whole universe is an uncollapsing wave function until that ship resumes STL travel. The time travel only occurs from the point of view of those in the ship, they appear in a reality that appears to be the past, except this past has them in it.

... or alternately the FTL ship moves to a parallel universe that is younger than the one they left but entirely unrelated to their own history. Going back in time and traveling into your own past isn't necessarily the same thing. If the duration is negative from some observers who knows what that means.

Austin Stanley · 2007-09-07 22:18:37

So in otherwords whole galaxies didn't exist until we first saw them through the telescope. What we see through the telescope is a result of a collapse of a probability wave function, and nothing exists that hasn't been seen.

Now your just being pedantic. Of course galaxies existed before we observed them. I was speaking in a theoretical sense. The universe doesn't disappear when you close your eyes or anything of course. However, science is still only based on effects we have measured (like Time Dilation and SR), not those we only hypothesize (like FTL travel)

That seems to solve the time travel paradox quite handily. Traveling back in time uncollapses the propability wave function of everything in the future you came from except yourself. Everything the time traveller remembers from his future is now only a probability and not a reality any more. From the point of view of the observer in the time machine the Universe runs backwards. An observer watching the spaceship move backwards in time will only see it for an instant before his reality is unmade, since he can't remember anything from the future, he never sees that FTL ship.
Probably backwards time travel would involve across time travel where the whole universe is an uncollapsing wave function until that ship resumes STL travel. The time travel only occurs from the point of view of those in the ship, they appear in a reality that appears to be the past, except this past has them in it.
... or alternately the FTL ship moves to a parallel universe that is younger than the one they left but entirely unrelated to their own history. Going back in time and traveling into your own past isn't necessarily the same thing. If the duration is negative from some observers who knows what that means.

This is all simply nonsense. You can't simply wave you hand and unmake time, it doesn't work like that. It's not just the time travelers time you would have to unravel anyways, it would be the time of the entire universe, as your violation could lie with any part of it. And even if time did work like this you have not a single shred of proof that the universe works at all like this, besides your wishing that it would. We certainly observe time to be immutable. I guess your method has the advanatege of being apparently untestable (if other the observes can't detect it.. who can?). But untestable theorems are not science.

Tom Kalbfus · 2007-09-08 06:16:50

So in otherwords whole galaxies didn't exist until we first saw them through the telescope. What we see through the telescope is a result of a collapse of a probability wave function, and nothing exists that hasn't been seen.
Now your just being pedantic. Of course galaxies existed before we observed them. I was speaking in a theoretical sense. The universe doesn't disappear when you close your eyes or anything of course. However, science is still only based on effects we have measured (like Time Dilation and SR), not those we only hypothesize (like FTL travel)

So you admit then that there is a Universe that we don't see, then perhaps there are laws of physics and forces that we don't know about, and I was just speculating about what some of them may be.

That seems to solve the time travel paradox quite handily. Traveling back in time uncollapses the propability wave function of everything in the future you came from except yourself. Everything the time traveller remembers from his future is now only a probability and not a reality any more. From the point of view of the observer in the time machine the Universe runs backwards. An observer watching the spaceship move backwards in time will only see it for an instant before his reality is unmade, since he can't remember anything from the future, he never sees that FTL ship.
Probably backwards time travel would involve across time travel where the whole universe is an uncollapsing wave function until that ship resumes STL travel. The time travel only occurs from the point of view of those in the ship, they appear in a reality that appears to be the past, except this past has them in it.
... or alternately the FTL ship moves to a parallel universe that is younger than the one they left but entirely unrelated to their own history. Going back in time and traveling into your own past isn't necessarily the same thing. If the duration is negative from some observers who knows what that means.
This is all simply nonsense. You can't simply wave you hand and unmake time, it doesn't work like that.

How do you know that it doesn't work like that, you're speculating that FTL travel is impossible because the relativistic math doesn't work out, and you don't know that either. The twin paradox hasn't been tested under these conditions, the only thing we know about is how it works for slower than light conditions.

It's not just the time travelers time you would have to unravel anyways, it would be the time of the entire universe, as your violation could lie with any part of it. And even if time did work like this you have not a single shred of proof that the universe works at all like this, besides your wishing that it would. We certainly observe time to be immutable. I guess your method has the advanatege of being apparently untestable (if other the observes can't detect it.. who can?). But untestable theorems are not science.

You just sounded way too certain that FTL travel is impossible based on mathematics alone.

Ordinarily the twin paradox works this way:
You have 2 twins, one gets in a spaceship and accelerates away from Earth to reach a velocity 0.866 of the speed of light and he observes that his twin back on Earth only ages at half the rate that he does. The other twin who remained on Earth observes that his departing twin only aged half as much as he did, they can't both be right. Eventually the paradox gets resolved when the departing twin, turns his ship around and returns to Earth, by the time he returns to Earth he finds that his stay-at-home twin is older than he is. FTL travel short circuits this by eliminating the return of the departing twin at STL velocity and thus establishing that he has aged less.

Also consider that neigther twin can really observe the other in real time until the departing twin has returned home and the two get to compare their ages and clocks. No one really knows what instantaneous communication means. The time dialation is theoretical until the departing twin returns. The departing twin must wait for the radiation from his stay-at-home twin to catch up with him at his velocity of 0.866 the speed of light for him to determine what his stay-at-home twin was doing when his photons departed him. Those photons were stretched with the doppler shift of his departing relative velocity, with the stretching out of the photons, the clock on Earth will appear to tick slower. For the stay-at-home twin, the photons from his departing twin will be stretched and the clock will appear to tick slower on the spaceship than on Earth.

To sum it up from the point of view of the stay-at-home twin:

t0 > t1

Where t0 is the rate of time flow on Earth and t1 is the rate of time flow on the spaceship as seen from Earth.

For the departing twin

t0' < t1'

Where t0' is the rate of time flow on Earth and t1' is the rate of time flow on the spaceship as seen from the spaceship.

It could be that if instantaneous communication were suddenly established between the departing twin and the stay-at-home twin there would be no time dialation between them while the ship is departing. We have no way to test this as we have not established a means of instantaneous communication, it could be so, but we can't prove it. You could call this virtual time dialation, and it only becomes real when the departing twin returns and matches velocity with the Earth to meet his twin again, when that happens t0 > t1 overtakes t0'< t1' because the departing twin is the one who does all the accelerating, but the time dialation only becomes real when the two twins meet and compare clocks.

Tom Kalbfus · 2007-09-08 06:30:22

Also if the departing ship were to slow down and match velocities with Earth without returning to Earth, time will appear to move at the same rate on Earth as in the spaceship once more although there will be a delay in this observation due to the light carrying the signal. With this matched velocity it will be established that more time has ticked for Earth than for the spaceship as the spaceship changed its velocity relative to Earth from 0.000 of the speed of light to 0.866 of the speed of light and back down to 0.000 of the speed of light again and t0 > t1 will be established from both the spaceship and Earth as t0' becomes t0 and t1' becomes t1, that is after taking into account the time delay of the photons in delivering this message. presumably then an instantaneous communication will establish that t0 = 8 while t1 = 4 after taking into account the time delay for the photons to travel the distance between them. Then with the magic tachyon radio the spaceship at t1 = 4 can communicate with Earth at t0 = 8 and there is no paradox.

Tom Kalbfus · 2007-09-08 06:43:41

Now if the departing spaceship were to become the closing spaceship with t0 = 8 and t1 = 4, then at the closing spaceship's velocity of 0.866 of the speed of light:

t0 < t1 from Earth's point of view and t0' > t1' will be true from the spaceship's point of view. When the spaceship slows down and lands on Earth the twins can compare clocks and will find absolutely that t0 = 16 and t1 = 8, twice as much time has elapsed on Earth as on the spaceship due to the relative velocity of the spaceship to Earth. whereas before the Spaceship might have guessed that t0 = 8 and t1 = 4 because he factored in the time it took the photons to cross the distance between then, when he returns to Earth and the twins are standing right next to each other he notes that the t0 watch says "16" while his watch only says "8" and without the time delay calculation as they are standing right next to each other.

Who's to say what FTL travel might mean? We can plug in the relatavistic equations, but they were only meant to measure the time dialation between slower than light objects with no means to communicate at FTL velocities, perhaps other equations would do better once we introduce FTL, who can say? No one has seen FTL, so we don't know who is right and who is wrong. Without this knowledge we can't really say what is possible and what is impossible. The relativistic equations say that the light barrier cannot be breached through the normal means of accelerating the spaceship, but who's to say what happens should we gain the means to manipulate the fabric of space around objects as opposed to accelerating objects through space?

Austin Stanley · 2007-09-08 15:34:44

This is all simply nonsense. You can't simply wave you hand and unmake time, it doesn't work like that.
How do you know that it doesn't work like that, you're speculating that FTL travel is impossible because the relativistic math doesn't work out, and you don't know that either. The twin paradox hasn't been tested under these conditions, the only thing we know about is how it works for slower than light conditions.

Because all observations have shown time to be sequential and immutable. Its the very nature of time. There is no support for the concept that time can change on a whim. And obviously your FTL assumptions have not been tested because they are impossible, and thus impossible to test. You can't just claim that pigs are going to sprout wings and fly, and then when I say that no, this goes against our understanding of pigs, complain that I haven't tested it yet!

So you admit then that there is a Universe that we don't see, then perhaps there are laws of physics and forces that we don't know about, and I was just speculating about what some of them may be.

Fine, speculate all you want. But without any proof to back it up, thats all it is speculation. And I am right to object when your speculation buts heads with theories that DO have the force of proof behind them.

You just sounded way too certain that FTL travel is impossible based on mathematics alone. omitting long rambling on twins

Whats hard to understand about this?
A. There is 0 evidence of FTL travel. None, zip, zilch, nada.
B. Special Relativity (SR) is consistent with this as it holds that FTL to be impossible.
C. All other assumption of SR are also consistent with the universe.
D. Therefore we assume that FTL travel is impossible, its consistent with our observations, and fit our theories.

Your propositions that FTL be possible, despite total lack of proof and inconsistency with the natural laws as we understand them, is a bit like assuming that pigs will sprout wings and take flight tomorrow, despite the fact thats this to is inconsistent with all our observation of pigs (they have never sprouted wings and flown), and our understanding of how biology works (pigs don't just sprout wings and fly either). Both assumptions have the same about of observational and theoretical support, 0.

Tom Kalbfus · 2007-09-08 18:16:46

Millions of years in the future if evolutionary conditions are just right, then the descendents of pigs might very well sprout wings and take to the skies, there is nothing to suggest that this could happen. Insects have flown, birds and bats have flown, and if bats can fly, why not the evolutionary descendents of pigs. Evolution has granted ample precident for this. Pigs would probably follow the rough evolutionary path of the dinosaurs. First pig would develop larger hind legs and develop bipedalism, while their front legs get smaller and move to the sides of their bodies, and following the path of bats, the pigs would grow hair and develop large flaps of skin for flying membranes and hollow bones to make them lighter. Pigs would also likely have to get smaller too, and thus millions of years hence pigs will fly. I don't know that this will happen, but it certainly could, evolution has shown stranger things to occur over this time scale.

Also Not Proven is not the same thing as Impossible. Current theories do not support FTL travel. Also does time even exist, maybe atoms and molecules simply slow down as things approach the speed of light. Does the past exist as a place we could travel to.

Your "proof of impossibility" seems to be the following, your mathematically show that some thing will cause Time Travel, in fact must cause time travel, and then reason since it must cause time travel, that thing must be impossible. Basically a two step process, one step backwards and one step forwards, but math has been wrong before. Just because you can add, subtract, and multiply, does not mean you are using the right equation. You can have a number of different equations, each one is slightly different and each one models the same thing faily well. So whos to say that some mathematician won't develop a new formula that models both special relativity and also FTL travel without time travel.

If the math gives an impossible result, isn't it also a possibility that the math may be suspect even if it model's some things right under certain conditions?

Austin Stanley · 2007-09-12 08:50:24

Millions of years in the future if evolutionary conditions are just right, then the descendents of pigs might very well sprout wings and take to the skies, there is nothing to suggest that this could happen. Insects have flown, birds and bats have flown, and if bats can fly, why not the evolutionary descendents of pigs. Evolution has granted ample precident for this. Pigs would probably follow the rough evolutionary path of the dinosaurs. First pig would develop larger hind legs and develop bipedalism, while their front legs get smaller and move to the sides of their bodies, and following the path of bats, the pigs would grow hair and develop large flaps of skin for flying membranes and hollow bones to make them lighter. Pigs would also likely have to get smaller too, and thus millions of years hence pigs will fly. I don't know that this will happen, but it certainly could, evolution has shown stranger things to occur over this time scale.

Oh I'm not talking about pigs 'evolving' wings, that might certianly be possible, and there is proof to support this. Your ideas have absolutly no proof, so it is more like pigs having wings just suddendly pop out of their back like magic, or the Earth gravity just suddenedly repulsing us all instead of attracting us, or all the colors blue turning red, or any other equaly implausible thing. There is, of course, no proof that none of these things will not occur, except that it contradicts all our current and past observations on the nature of the universe and our theories that explain it, much like FTL travel. This is also know as the logical fallacy "negative proof."

Also Not Proven is not the same thing as Impossible. Current theories do not support FTL travel.

I agree, not proven is not the same thing as impossible. But it IS the same thing as meaningless. Things that are not proven (or at least have no proof to support them) are meaningless. See my above example. All of the things I pointed out before are not strictly impossible in the scientific sence, as we have no proof that they might not occur some time in the future. However, while this absence of proof may not be proof of absence, it does not absolve your theories of the 'burden of proof'. Its not simply enough to say that I can't disprove it, you have to provide evidence to support its truth.

Also does time even exist, maybe atoms and molecules simply slow down as things approach the speed of light. Does the past exist as a place we could travel to.

Time, as a sequential measure of events certianly exists. Or at least the functionaly identical perception of it exists. I would probably argue that the past does not exist in any sense that we could travel to, but this simply agrees with my argument that FTL, and thus time travel, is impossible.

Your "proof of impossibility" seems to be the following, your mathematically show that some thing will cause Time Travel, in fact must cause time travel, and then reason since it must cause time travel, that thing must be impossible. Basically a two step process, one step backwards and one step forwards, but math has been wrong before. Just because you can add, subtract, and multiply, does not mean you are using the right equation. You can have a number of different equations, each one is slightly different and each one models the same thing faily well. So whos to say that some mathematician won't develop a new formula that models both special relativity and also FTL travel without time travel.

There is no predicting the future. But without some evidence to indicate that FTL travel might be possible, and SR might be overturned, your speculations are pointless. Pigs MIGHT start to fly, I haven't observed the future, it MIGHT be possible, but clearly such suppositions are meaingless.

If the math gives an impossible result, isn't it also a possibility that the math may be suspect even if it model's some things right under certain conditions?

The rocket equation also gives impossible results under certian conditions. For example it makes it clear that it impossible for me to jump from the Earth to the Moon. Does this mean all aplications of it is incorrect? Of course not. Your problem is that you are starting with an UNPROVEN result (FTL) and then try and reason backward that SR must then be incorrect. Only when you have a valid example of something that violates theory should the theory be overturned. The mere fact that a theory deams some things impossible is not enough.

Tom Kalbfus · 2007-09-12 16:06:21

Isn't there a Department in NASA called the Breakthrough Science Division that investigates things like antigravity and FTL travel?

I hear they've instructed some physicists to first assume FTL travel was possible and then devise a theory which would explain how FTL travel would work while also remaining consistent with all known properties of the Universe, and once the theory is devised, then it is tested if possible.

Yes I know its unscientific to assume something is true if not proven, but here the scientist goes two steps forward. Assume what is known then assume some desirable result, devise a theory that allows for both to happen and then see if that theory is true. Do you have a problem with this approach? It may be a waste of time, but who knows, we may get lucky, consider it the equivalent of buying a lottery ticket.

Austin Stanley · 2007-09-16 00:52:15

Isn't there a Department in NASA called the Breakthrough Science Division that investigates things like antigravity and FTL travel?
I hear they've instructed some physicists to first assume FTL travel was possible and then devise a theory which would explain how FTL travel would work while also remaining consistent with all known properties of the Universe, and once the theory is devised, then it is tested if possible.
Yes I know its unscientific to assume something is true if not proven, but here the scientist goes two steps forward. Assume what is known then assume some desirable result, devise a theory that allows for both to happen and then see if that theory is true. Do you have a problem with this approach? It may be a waste of time, but who knows, we may get lucky, consider it the equivalent of buying a lottery ticket.

Yes, I've heard of this so called "breakthrough science devision," and I would say that it is a colossal waste, and patently unscientific. I would point out that if there WAS anything to FTL theories NASA would hardly have to pay scientists to pursue it as overturning SR would certainly net someone a Nobel Prize, at the very least.

I think that describing it as "buying a lottery ticket," is an excellent analogy for this line of research. Lottery's are a tax on stupid people who do not understand statistics. The odds of winning the lottery are not in proportion to the price you pay for a ticket, hence why a lottery (and similar games like Keno) is profitable for institutions that run them. Similarly the odds of this "Breakthrough Science Division," actually returning any results are likely to be insanely low, and the pay-off not worth the amount invested into it. That money could be better spent on virtually any other scientific endeavor instead of wasting it investigating FTL and Anti-gravity in an unscientific manner.

Tom Kalbfus · 2007-09-16 08:15:30

But the theories they come up with will be of some use to science fiction writers at least, and people pay money for science fiction novels.

I think the main difference between the kind of science you like and what's going on in the Breakthrough Science Division, is that they used deductive reasoning. Instead of saying there is no evidence for FTL or anti-gravity, they ask the question, "what if antigravity and FTL did exist in our universe? In what way would they manifest themselves in our universe so we can test them?" The purpose is to counter the kind of self-censorship among scientists that stear clear of such subjects for fear of damagining their reputation. What your talking about is conventional wisdom among the scientific crowd, there is a bit of social pressure that dissuades scientists from pursuing certain lines of inquiry. Social pressure is not scientific, and there may be phenomina in the universe that goes unstudied because the scientific community has already decided that it does not exist, and thus won't expend any effort to pursue it. I'm sure even you realize that the crowd is not always right, sometimes there are certain individuals that see things that others can't. Certian lines of investigation have been hampered because of social pressure, and certain advances have been delayed because of that.

NASA deems the benefit of a Breakthrough in FTL or antigravity to be worth the small price they are paying for this investigation, even if presently unsupported by the present day conventional wisdom scientific crowd. There is a gap between what is know to be true and what is known to be untrue, there is what is not known at all, and that is the realm of theories. There are many different theories, some theories command greater scientific support than others even if they remain unproven. NASA is simply selecting those unproven/undisproven theories that are most useful to space exploration if they prove to be true, and spending some money to investigate them deductively, that is all. If nothing else it is good fare for the science fiction writer.

Austin Stanley · 2007-09-17 14:18:27

But the theories they come up with will be of some use to science fiction writers at least, and people pay money for science fiction novels.

So you argument for FTL and anti-gravity research is that is provides science fiction writers with material? And this is the sort of things NASA and the US goverment should be subsidising via the Breakthough Science Division? Well... ::shrug:: guess I can't argue with that...

I think the main difference between the kind of science you like and what's going on in the Breakthrough Science Division, is that they used deductive reasoning. Instead of saying there is no evidence for FTL or anti-gravity, they ask the question, "what if antigravity and FTL did exist in our universe? In what way would they manifest themselves in our universe so we can test them?"

This is not Deductive Reasoning. Deductive reasoning is the process of developing a conclussion based upon previously established premises. If anything it is closest to Abductive reasoning but in reality this form of thinking doesn't realy fall under normal logical reasoning. Which flows forward from observations to hypothesis to conclusions, not in the reverse order as your line of reasoning seems to.

The purpose is to counter the kind of self-censorship among scientists that stear clear of such subjects for fear of damagining their reputation. What your talking about is conventional wisdom among the scientific crowd, there is a bit of social pressure that dissuades scientists from pursuing certain lines of inquiry. Social pressure is not scientific, and there may be phenomina in the universe that goes unstudied because the scientific community has already decided that it does not exist, and thus won't expend any effort to pursue it. I'm sure even you realize that the crowd is not always right, sometimes there are certain individuals that see things that others can't. Certian lines of investigation have been hampered because of social pressure, and certain advances have been delayed because of that.

See the great thing about science is that it is results focused. I can guarntee you that if someone came out with some conclusive evidence that SR was incorrect and that FTL travel was possible, that person would not be persecuted, in fact they would most likely win a nobel prize for there discoveries. The problem of course is that propoents of FTL travel do NOT have conclusive evidence that could overturn SR. Or realy any sort of evidence what so ever. Remeber a theory without proof to support it pretty worthless. And so far FTL proponents are big on theory but light on proof.

NASA deems the benefit of a Breakthrough in FTL or antigravity to be worth the small price they are paying for this investigation, even if presently unsupported by the present day conventional wisdom scientific crowd. There is a gap between what is know to be true and what is known to be untrue, there is what is not known at all, and that is the realm of theories. There are many different theories, some theories command greater scientific support than others even if they remain unproven. NASA is simply selecting those unproven/undisproven theories that are most useful to space exploration if they prove to be true, and spending some money to investigate them deductively, that is all. If nothing else it is good fare for the science fiction writer.

Though I don't necessarily disagree with this premiss, that there are things we know, things we know to be untrue, and things unknown. However I would arguee that FTL travel falls pretty cleanly in the relm of things we know to be untrue, or at least have fairly convincing evidence that it is so.

cIclops · 2007-09-17 23:56:24

And this is the sort of things NASA and the US goverment should be subsidising via the Breakthough Science Division?

Is this "Breakthough Science Division" the same as NASA Institute for Advanced Concepts? They funded studies into FTL communications and several other extreme "ideas". Recently they lost their funding when NASA had its budget frozen.

Tom Kalbfus · 2007-09-18 08:55:23

But the theories they come up with will be of some use to science fiction writers at least, and people pay money for science fiction novels.
So you argument for FTL and anti-gravity research is that is provides science fiction writers with material? And this is the sort of things NASA and the US goverment should be subsidising via the Breakthough Science Division? Well... ::shrug:: guess I can't argue with that...
I think the main difference between the kind of science you like and what's going on in the Breakthrough Science Division, is that they used deductive reasoning. Instead of saying there is no evidence for FTL or anti-gravity, they ask the question, "what if antigravity and FTL did exist in our universe? In what way would they manifest themselves in our universe so we can test them?"
This is not Deductive Reasoning. Deductive reasoning is the process of developing a conclussion based upon previously established premises. If anything it is closest to Abductive reasoning but in reality this form of thinking doesn't realy fall under normal logical reasoning. Which flows forward from observations to hypothesis to conclusions, not in the reverse order as your line of reasoning seems to.

Logic is a form of mathematics, you can make logical arguments with any premises whether true or not and come to a conclusion whether true or not. The validity of the conclusion depends upon the validity of the premises. The deductive reasoning comes in, when you first relax the requirement that the premise be proven, you can prove or disprove it later after you've made your logical argument with them. You can start with premises such as that FTL travel is possible or that antigravity exists, even though no proof exists for these premises, and then you can make logical arguments using them as axioms, if the conclusions don't match reality, then you go back and modify the premises, you do this until you reach a good model that's compatible with both the Universe as we know it and the premise that supposes the existance of FTL travel, then you find a way to test it out, in other words find out something new about the Universe through observation and experiment. If the theorist is luck, he may discover antigravity. Theorising is cheap, what NASA basically does is through some chump change to some theorists to devise some theories for some useful premises for space travel, should they prove to be true they could be of great benefit. That is not to say there is exactly no evidence for antigravity, the universe is accelerating as it expands after all, the reason could be a manifestation of antigravity for example. One might for example create a model of the universe where negative mass/energy exists and see if the resultant model matches what we observe of the universe. It may be false too, but paying those scientists to make theories is cheap, funding experiments to test them can get expensive though, but you never know. Government wastes so much monsy anyway, and this is but a drop in the bucket, but on occasion a breakthrough has happened upon happenstance, wasn't that how those high temperature superconductors were discovered, no theory at the time supposed their existance, but their discovery was made accidentially. NASA here is simple allowing for the possibility of further fortuitous accidents by encouraging some professionals to inquire further.

The purpose is to counter the kind of self-censorship among scientists that stear clear of such subjects for fear of damagining their reputation. What your talking about is conventional wisdom among the scientific crowd, there is a bit of social pressure that dissuades scientists from pursuing certain lines of inquiry. Social pressure is not scientific, and there may be phenomina in the universe that goes unstudied because the scientific community has already decided that it does not exist, and thus won't expend any effort to pursue it. I'm sure even you realize that the crowd is not always right, sometimes there are certain individuals that see things that others can't. Certian lines of investigation have been hampered because of social pressure, and certain advances have been delayed because of that.
See the great thing about science is that it is results focused. I can guarntee you that if someone came out with some conclusive evidence that SR was incorrect and that FTL travel was possible, that person would not be persecuted, in fact they would most likely win a nobel prize for there discoveries. The problem of course is that propoents of FTL travel do NOT have conclusive evidence that could overturn SR. Or realy any sort of evidence what so ever. Remeber a theory without proof to support it pretty worthless. And so far FTL proponents are big on theory but light on proof.

Thus NASA is throwing some of its money around to give some theorists a further change to prove their strange theories. Proving something can get expensive sometimes, and purveyors of these theories have difficulty finding funding from the usual sources as their theories aren't taken seriously and people don't want to waste their money. The reasoning goes that the scientific community may have come to some premature conclusion, and the institutions might not fund lines of investigation that they have already established or think they've established were not true, and if someone comes up with a slightly different theory, they may be unwilling to give it a second look. Cold Fusion is one such example, after the fiasco with cold fusion, somebody with a difference theory about how to achieve cold fusion might not be listened to, it could have nothing to do with past frauds in the field, but since the proffessionals have been previously burned on the subject they will turn their backs on further legitimate investigations into the subject and money might not be forcoming on further experiments. The world might be missing out on an opportunity to benefit from a cheap power source because to the low esteem such investigations are held in, and I think that would be a shame.

NASA deems the benefit of a Breakthrough in FTL or antigravity to be worth the small price they are paying for this investigation, even if presently unsupported by the present day conventional wisdom scientific crowd. There is a gap between what is know to be true and what is known to be untrue, there is what is not known at all, and that is the realm of theories. There are many different theories, some theories command greater scientific support than others even if they remain unproven. NASA is simply selecting those unproven/undisproven theories that are most useful to space exploration if they prove to be true, and spending some money to investigate them deductively, that is all. If nothing else it is good fare for the science fiction writer.
Though I don't necessarily disagree with this premiss, that there are things we know, things we know to be untrue, and things unknown. However I would arguee that FTL travel falls pretty cleanly in the relm of things we know to be untrue, or at least have fairly convincing evidence that it is so.

Wasn't it not too long ago that a scientist with a theory about the Universe expanding ever faster and faster as time goes on would have been laughed at as a crackpot - as everyone "knew" back then that gravity would gradually slow the universe's expansion as time passed, they had no reason to suppose that the Universe would do otherwise until certain observations were made. Also not many people were looking for high temperature superconductors until they were accidentally discovered.

Now imagine what would have happened if high temperature superconductors were discovered in the 1930s. There was absolutely no reason why they could not have been. The technology for making high temperature superconductors existed in the 1930s, if only the people at that time knew what to do with it. They could have made liquid nitrogen back then, they could have mixed the right compounds together and made those high temperature superconductors in the 1930s instead of the 1980s, it was only chance that determined when they would be discovered. Imagine scientists and inventors experimenting with these high temperature superconductors through the 1930s, 40s, 50s, 60s, 70s, 80s, and 90s. Now imagine where we might be today in the field of superconductors had that discovery been made in the 1930s instead of the 1980s. I'm sure we'd know alot more about these materials now after 70 years of investigation instead of only 20 years. We might now be riding on inexpensive maglev trains for instance.

Austin Stanley · 2007-09-18 21:19:50

I think the main difference between the kind of science you like and what's going on in the Breakthrough Science Division, is that they used deductive reasoning. Instead of saying there is no evidence for FTL or anti-gravity, they ask the question, "what if antigravity and FTL did exist in our universe? In what way would they manifest themselves in our universe so we can test them?"
This is not Deductive Reasoning. Deductive reasoning is the process of developing a conclussion based upon previously established premises. If anything it is closest to Abductive reasoning but in reality this form of thinking doesn't realy fall under normal logical reasoning. Which flows forward from observations to hypothesis to conclusions, not in the reverse order as your line of reasoning seems to.
Logic is a form of mathematics, you can make logical arguments with any premises whether true or not and come to a conclusion whether true or not. The validity of the conclusion depends upon the validity of the premises. The deductive reasoning comes in, when you first relax the requirement that the premise be proven, you can prove or disprove it later after you've made your logical argument with them. You can start with premises such as that FTL travel is possible or that antigravity exists, even though no proof exists for these premises, and then you can make logical arguments using them as axioms, if the conclusions don't match reality, then you go back and modify the premises, you do this until you reach a good model that's compatible with both the Universe as we know it and the premise that supposes the existance of FTL travel, then you find a way to test it out, in other words find out something new about the Universe through observation and experiment. If the theorist is luck, he may discover antigravity.

I don't disagree that theoritcal reasoning along these lines is possible, only that it is counter productive, and still not technically logical reasoning. What you are proposing is something like the universe + some-mechanisms = FTL. However since you are unsure what the mechanism is, and how FTL travel takes place, you cannot really solve this equation for either value. Except, as you point out, for luck. However since both variables are unknown and total unobserved there could be an infinite number of possibilities for them, making guessing them out of luck unlikely. And this still does not answer the question of how do you TEST such hypothesis...

Theorising is cheap, what NASA basically does is through some chump change to some theorists to devise some theories for some useful premises for space travel, should they prove to be true they could be of great benefit. That is not to say there is exactly no evidence for antigravity, the universe is accelerating as it expands after all, the reason could be a manifestation of antigravity for example. One might for example create a model of the universe where negative mass/energy exists and see if the resultant model matches what we observe of the universe. It may be false too, but paying those scientists to make theories is cheap, funding experiments to test them can get expensive though, but you never know.

The problem with this (and this method of theorizing in general) is that it does not tend to produce testable theories. If you are basing your theories that on things other than the the observable universe (ie just supposition) than this is to be expected. And again, without testable results, theorizing is useless.

Government wastes so much monsy anyway, and this is but a drop in the bucket, but on occasion a breakthrough has happened upon happenstance, wasn't that how those high temperature superconductors were discovered, no theory at the time supposed their existance, but their discovery was made accidentially. NASA here is simple allowing for the possibility of further fortuitous accidents by encouraging some professionals to inquire further.

I would argue that we should strive to eradicate government waste as much as possible. Especially in departments such as NASA where money is already tight and there are lots of better things to spend it on.

However, you specific example (high temperature superconductors) is a perfect example of why your line of reasoning is not likely to be effective. Despite actually having high temperature superconductors on hand now, the theory behind how and why they work is still not understood. Thus it is highly unlikely that we would have been able to work out the theory behind high temperature superconductors (which again we still don't have) before such things were even discovered and from this theory to practical examples. Similarly it is unlikely that we will be able to theorize backward to a theory of FTL travel and then actual practical applications.

Thus NASA is throwing some of its money around to give some theorists a further change to prove their strange theories. Proving something can get expensive sometimes, and purveyors of these theories have difficulty finding funding from the usual sources as their theories aren't taken seriously and people don't want to waste their money. The reasoning goes that the scientific community may have come to some premature conclusion, and the institutions might not fund lines of investigation that they have already established or think they've established were not true, and if someone comes up with a slightly different theory, they may be unwilling to give it a second look. Cold Fusion is one such example, after the fiasco with cold fusion, somebody with a difference theory about how to achieve cold fusion might not be listened to, it could have nothing to do with past frauds in the field, but since the proffessionals have been previously burned on the subject they will turn their backs on further legitimate investigations into the subject and money might not be forcoming on further experiments. The world might be missing out on an opportunity to benefit from a cheap power source because to the low esteem such investigations are held in, and I think that would be a shame.

Cold fusion in fact is a perfect example of how science DOES work correctly. Some people came forward with some surprising and controversial results which looked to overturn conventional theory. Far from dismissing it out of hand, other labs were eager to test and confirm these results. Unfortunately it turned out that they had no merit to them. Even today however research in these fields still progresses, though at a slower rate. The reason for this is simple. Science is results focused. Cold Fusion has not had very good experimental returns, so science has focused instead on veins with more promising experimental like traditional containment fusion. I can guarantee you that if a cold fusion research starts to get some interesting results it will start to gather increased interest and funding.

Though I don't necessarily disagree with this premiss, that there are things we know, things we know to be untrue, and things unknown. However I would arguee that FTL travel falls pretty cleanly in the relm of things we know to be untrue, or at least have fairly convincing evidence that it is so.
Wasn't it not too long ago that a scientist with a theory about the Universe expanding ever faster and faster as time goes on would have been laughed at as a crackpot - as everyone "knew" back then that gravity would gradually slow the universe's expansion as time passed, they had no reason to suppose that the Universe would do otherwise until certain observations were made. Also not many people were looking for high temperature superconductors until they were accidentally discovered.

This is an unfair characterization. While it is true that for a time a contracting model of the universe was supported, investigations into the truth of this did not stop. When more powerful telescopes and more accurate instruments became available, they were quickly turned to confirming outstanding theories. When these observations turned out to be other than what the theories predicted, the theories where then scraped and new ones developed.

The problem of course with FTL travel theories is that they do not have any evidence to support them. Therefore unlike our theories on the expansion of the universe there is no reason to overturn SR which DOES have experimental support. Research and experimentation continues to advance and surely as new ways to test SR become available it will be tested again. But until one of these tests find SR invalid, it continues to hold weight over untested FTL.

-- edit --
I checked out the page you linked cIclops and I don't have any problem with most of the research they did. Most of it (I didn't look through all of it) appeared to be focused on more far out but still plausible concepts such as Space Elevators, scramjets and the like. Though I am pretty certain at one point NASA did cough up some money to some of this FTL/anti-gravity bunk. Though really I don't have any problem with that, so long as it is confined to testing or reproducing test on their theories.

Tom Kalbfus · 2007-09-18 22:28:32

Antigravity itself might lead to FTL travel. If antigravity existed, what would Einstein's theory say about it? Basically that antigravity would pucker the space/time manifold instead of depress it. A person standing in the middle of an antigravity field would be at a higher gravitational potential than the rest of the Universe, it would be like the rest of the Universe was sitting in a gravitational well and the observer was not. Clocks would tick slower everywhere else outside of the antigravity field, and light itself would have to fight the antigravity field to travel upward, being redshifted just as light escaping from a massive gravitational body would to escape it. If the observer was in an intense enough antigravity well, time would seem to slow to a crawl for the rest of the universe while flowing normally within the antigravity field. For an observer beyond the antigravity field, time would seem accelerated for those inside it. Everything moves faster within the antigravity field relative to the outside, including light, though nothing exceeds the speed of light locally within the antigravity field.

Though I think we'd be lucky to produce enough antigravity to get us off Earth's surface, much less cause reverse time dialation for those within. Since the only known method of generating a gravity field is with mass, antigravity would require anti-mass, and the energy-mass equivelence formula being what it is: E = mc^2, if mass is negative then so must the energy it is equivalent to. The Casimir effect might be employed to produce negative energy, though getting enough negative energy to produce anti-mass particles would be a formidable challenge and getting enough anti-mass particles together to generate an antigravity field would be orders of magnitude harder still. getting enough matter together and achieving sufficient density to produce significant gravity without a planet's worth of material is currently beyond us at the moment.

This is all very theoretical stuff, I think at this point, it makes very little difference whether something is very very hard to achieve or impossible. I'd rather throw in a few coins to keep a few theorists thinking about these matters, because who knows what they may come up with. I think as far as government waste is concerned, it certainly is cheaper to pay a few scientists salaries than to build a "bridge to nowhere" in Alaska.

When someone flatly says something is impossible, I tend to keep an open mind about it and suppose it might just be very very difficult instead. Most of the so-called "time machines" usually require feats of engineering and mass manipulation achievable only by a supercivilization orders of magitude more advanced than ourselves, so it really is only of academic interest to me, as I don't think there is a chance that someone will invent an "antigravity" drive in the near future, but I don't discount the possibility entirely, so throw a few "crackpots" some chump change, so long as their theories are sufficiently plausible so as not to be obviously flat out wrong. Make the "crackpots" work hard to produce plausible theories though, not just any "crackpot" will do.

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