warp drive - futuristic, but possible?

soph · 2002-12-03 18:00:19

i've seen articles here and there about warp drives. obviously this is something that isnt going to be done tomorrow, but is there any mathematical basis against warp systems?

i know einstein said that light speed travel is impossible-but what if it isnt? do we know this? also, how can we be sure that time dilates at the speed of light? what if it doesnt? when was the last time we traveled at light speed to know this?

im not trying to say that all these theories are wrong- in fact, im curious as to the concrete evidence theyre true.

but my whole point was, is warp drive possible? and could we in fact "break" the light barrier?

AltToWar · 2002-12-03 18:36:15

I can tell you one thing, we will never develop a 'warp drive' if we don't get a space program that leaves LEO.

Phobos · 2002-12-03 19:14:54

Relativity would make it mathematically impossible to exceed lightspeed, so according to current understanding it appears improbable that we could exceed that limit. However, I believe that warp drive just folds space, or basically compresses the distance, so it might be possible to traverse huge distances without actually needing to exceed the speed of light. I know one thing though something like that will never happen until we can generate so much energy that the sun looks like a 9 volt battery in comparison.

el scorcho · 2002-12-03 19:16:47

I have a Lego-level understanding of this, but I'll tell you what my understanding of some new theories are.

One theory that I have heard is that an antigravity "bubble" could be generated around the ship while an engine in the back of the ship created an explosion with more energy than all of that produced in the Sun's lifetime.

A pretty tall order, but the theory is that the space around the bubble is going faster than light while the ship inside the bubble is actually stationary. That's the best I can understand about it; when i first heard that theory, it confused me insanely.

Hope this helps

Austin Stanley · 2002-12-08 18:03:47

According to the laws of physics as we know them now, faster than light travel is not possible. A warp drive, as often proposed, would require generating a huge amount of negative energy. Which is difficult because negative energy probably does not exists (if not theoreticly forbidden outright).

Anyways, a good a sight about this can be found here in the realativity FAQ. Check out the section of the "Grandfather Paradox," I found it particulary helpfull in explaining this issue to me (that is, why FTL travel can create this paradox).

http://www.weburbia.com/physics/FTL.html

Echus_Chasma · 2002-12-15 19:48:02

I always thought that travelling by warp slipping into some sort of parallel universe where the laws of physics as we know them don't apply, well, at least thats what the sci-fi programmes I watch say.

RobertDyck · 2002-12-15 21:17:16

The only technique I know of that would permit faster than light travel is quantum tunnelling. Faster than light communication is possible using quantum wires and quantum entanglement. The quantum effects bypass the principles of relativity that cause time dilation, so this sort of thing does not involve time travel or the grandfather paradox.

Quantum wires require a wire so thin that 2 electrons cannot pass within the wire. This has already been built and faster than light communication confirmed. According to quantum mechanics the communication is instantaneous, but I believe it takes the time for one electron to pass from one atom to the next atom at 90% the speed of light. Since the valence electron of each atom move in perfect sync, the time does not increase with the length of wire. That means the time to transmit a signal over a 1 metre wire is still the time it takes for one electron to move from one atom to the next at 90% the speed of light. This does not move matter or energy faster than the speed of light, but the effect does move information faster than the speed of light. That is why time dilation does not apply.

Quantum tunnelling permits subatomic particles to travel a small distance instantaneously, without traveling through the intervening space. The distance is measured in diameters of an atom, but it is travel without time. If you could get all atoms of a spaceship to quantum tunnel forward the same distance, then keep doing so millions of times per second, that would permit faster than light travel. The problem is that quantum tunnelling tends to be random distances in random directions at random times. Electrons often quantum tunnel over a distance of 3 atoms, this is a problem microchip engineers have to deal with. Nuclei rarely quantum tunnel over a much shorter distance if at all. The question is how to get atomic nuclei to quantum tunnel over significant distance, in the same direction, and all at the same time. The only answer appears to be coherent matter, but that requires quantum entangling all atoms in the sample. The only known way to do that is a Bose-Einstein condensate. That requires freezing the sample to less than 0.1? above absolute zero. Freezing the sample that cold would also increase the wavelength if its quantum function, which limits the distance over which it can quantum tunnel.

I don't think the crew would want to be frozen solid. Beside, temperature that cold is colder than the cosmic background radiation so maintaining it would require active cooling. How do you do that when everything is frozen solid?

soph · 2002-12-15 21:28:15

if weve progressed this far with quantum tunneling by now, surely a century from now we'll be able to do some of what you suggested

Shaun Barrett · 2002-12-16 00:59:06

Robert Dyck writes:-

Faster than light communication is possible using quantum wires and quantum entanglement. ... Quantum wires require a wire so thin that 2 electrons cannot pass within the wire. This has already been built and faster than light communication confirmed.

This is very interesting news ... at least, it's news to me!
Up until now, I thought every attempt at circumventing the 'light barrier' (so to speak) had failed. The usual story is that no matter and no useful information can be transferred from A to B faster than light speed.

Do you have a reference to this latest research, and/or do you know whether work is being done to extend the range of this near-instantaneous communication?
Even if warp-drive ultimately eludes us, some means of instant communication between, say, Mars and Earth would be very useful for future missions and colonisation. I appreciate that you can't physically run a wire from Mars to Earth, but if the principle of FTL information transfer is established, means may conceivably be found to conduct information through space without the wires.
This is starting to sound like Star-Trek-style "sub-space" communication, isn't it?

RobertDyck · 2002-12-16 03:12:58

Pardon me if I'm a bit vague. Quantum wires are one technique, quantum entanglement is another. I do have an idea how to communicate between Earth and Mars as easily as you pick up a telephone and talk to a friend across the street. The thing is that this could be the next cell phone: imagine a cell phone that has a range so great it does not require cell towers and has a band width so great it has the same quality as a land-line telephone. The telephone companies would love it because they wouldn't have the expense of cell towers and could compete nation-wide from just a few telephone exchanges. Since the telephone companies wouldn't even know how far you are from an exchange there would be no roaming charges. There are other applications, but pardon me for not posting details until it is patented. If you want a public domain document look up the paper published by Einstein, A.; Podolsky, B.; and Rosen, N. "Can Quantum-Mechanical Description of Physical Reality be Considered Complete?" Phys. Rev. 41, 777, 1935. For quantum wires, in 1982 I read a Scientific American article about molecular electronics published, I believe 1979. I tried searching the Scientific American web site and only found references from articles in 2001, so their web site may not include articles published before invention of the world-wide-web. Geeze this makes me sound old! I'm not old, I'm not old, I'm not old, I'm not old!

Shaun Barrett · 2002-12-16 03:55:31

Anyone who feels the need to say: "I'm not old" 4 times in quick succession ... is old!!! Believe Me!

Thank God I'm not old, I'm not old, I'm not old, I'm not old!

P.S. The very best of luck with your patent! I hope it works
and I hope you make a fortune from it!

mauk2 · 2002-12-16 11:12:04

Yes, the recent work on encoding up to several thousand bits into the spin state of an electron, combined with the ability of tangled pairs to apparently break the speed of light limitations, bodes well for schemes to have FTL communicators.

Granted, there is probably some conservation law that will make it impossible, but its fun to kick the ideas around.

Auqakah · 2002-12-18 16:06:00

Pardon me if I'm also a bit vague.

I've been working on a little formula for ten years now... and the applications are rather interesting. Unfortunatley, the field seems to be catching up on my little idea at the moment. I'm too lazy to find links (sorry ) but some phrases will give you an idea of what I'm on about. There are several groups I've heard of who are working on a drive which would warp space/time (although, thats rather an erroneous term :\), in order to allow for easier access to luminal velocity. Once proof is attained that an object can be accelerated to that velocity via the 'warp drive', a massive amount of thrust is applied (similar to the amount of energy expelled by our Sun in its in entire lifetime so far). This thrust then allows, via brute force (and the warping of space/time around you), to exceed luminal velocity.

/My/ approach is a little different. It involves a workaround to the whole you-can't-go-faster-than-light-except-in-a-transient-or-illusionary-manner problem. Imagine a fish that can change its shape, its mass, and its size at will. Now, that fish is put into a tank of water. This particular water has more D2O than is normal; and so the average mass of the water is higher. Therefore, the fish has to adapt - to attain a higher swimming speed.

So... what would our fish do?

Why, it would decrease its resistance.

And there lies the key.

But I'm not saying anything more, because I can't think of any damned way to explain it without giving it all away to you all. :angry:

Austin Stanley · 2002-12-19 12:09:18

All FTL methods of communicaton/travel can cause the grandfather paradox when the situation is right.

An exert describing how and why (find the whole thing http://sheol.org/throopw/tachyon-pistols.html]here)

"We can describe this effect by idealizing FTL to be "instantaneous", and describing how the more familar time dilation implies this effect. But remember, the same points apply to any FTL speed, you just have more messy arithmetic to grind through.

Consider a duel with tachyon pistols. Two duelists, A and B, are to stand back to back, then start out at 0.866 lightspeed for 8 seconds, turn, and fire. Tachyon pistol rounds move so fast, they are instantaneous for all practical purposes.

So, the duelists both set out --- at 0.866 lightspeed each relative to the other, so that the time dilation factor is 2 between them. Duelist A counts off 8 lightseconds, turns, and fires. Now, according to A (since in relativity all inertial frames are equally valid) B's the one who's moving, so B's clock is ticking at half-speed. Thus, the tachyon round hits B in the back as B's clock ticks 4 seconds.

Now B (according to relativity) has every right to consider A as moving, and thus, A is the one with the slowed clock. So, as B is hit in the back at tick 4, in outrage at A's firing before 8 seconds are up, B manages to turn and fire before being overcome by his fatal wound. And since in B's frame of reference it's A's clock that ticks slow, B's round hits A, striking A dead instantly, at A's second tick; a full six seconds before A fired the original round. A classic grandfather paradox.

Note, this is NOT a matter of when light gets to an observer, it is NOT an optical illusion. It is due to the fact that, in SR, the question of what occurs at the "same time as" something else is observer dependent.

As A fired that first show at tick 8, the bullet effectively teleported from A's gun to B's back instantly --- instantly according to A. But for B, who was moving at 0.866 lightspeed WRT A, B was hit in the back by the bullet 4 seconds BEFORE the bullet was fired. And again note, this is NOT due to the optical illusion of lightspeed delay in viewing A's turn-and-shoot; the light form that event wouldn't reach B until MUCH later, not tick 4."

As you can see the problems with causality and simultaneity at a distance don't specificly lie with the FTL travel, but the rest of the universe. Any FTL situation could cause a grandfather paradox similar to the one above.

Two theories have been proposed to get around this. First is the multiple universe theory. Unforchenetly, short of causing a grandfather paradox, this theory seems impossible to prove and some of it's consiquenses (such as there exists universes where no consicous observer has ever lost conciousness?) are hard to swallow.

The other theory, Novikov self-consistency principle, is little better. To me it amounts to little more than arm waving in saying that time-travel cannot effect future events, because it can't. And it sacrifices free will to boot.

But I try and perserve and open mind, and I'm eager to here why other means of FTL travel might be able to get around these problems.

Auqakah · 2002-12-20 16:31:35

Perhaps the whole 'grandfather paradox' is in fact a weak signal that somewhere, somehow, there is a very deep hole in our understanding of physics :0 - something that we take as concrete, and obvious, is perhaps wholly incorrect and inaccurate. If the results yielded do not make sense in a real-world sense - take the example in the post above - then is it not the scientific method to assume that the original data/assumptions were incorrect?

Austin Stanley · 2002-12-20 17:21:44

Well that's one possibility. However, do not forget that the vast, VAST majority of evidence is on special realitivites side. So more likely that the Grandfather paradox being an example of a fundamental misunderstanding of physics, is that events which can cause such a paradox (ie, FTL travel) are simply not possible. Rememeber we still lack clear and concreat evidence of FTL travel or communication, it's all mainly theoretical with very little (or very skimpy) proof to back it up.

Auqakah · 2002-12-22 11:39:52

Cough, tachyons, cough.

Austin Stanley · 2002-12-22 16:10:19

??

As far as I know the existance of tachyons is still hypothetical. I haven't heard of any successfull detection of Cerenkov radiation or any other indicator of there existance. If you've got some reports on there discovery please forward them to me.

But you know, why you think about it, not finding evidence for there existance isn't supprising. I mean consider:

m = m0 / SQR(1 - v^2/c^2)

m = relativistic mass
m0 = rest mass
v = velocity
c = speed of light

So, if you're velocity is greater than c, v^2/c^2 is greater than one and becomes negative. Giving you an imaginary mass. Which of doesn't make a heck of a lot of sense. The example I gave below was just hypothetical, you could replacy tachyons with hyperdrive, quantum tunneling, warp driver, or whatever you want, the concept remains the same.

Auqakah · 2002-12-22 16:36:40

I was reasonably sure that they had been observed acting upon other particles? I might be mistaken...

And quite how you could 'see' tachyons is beyond me, too. If they have negative mass, then they are smaller than photons. And if they're smaller than photons... then they would pass through photons, maybe? So perhaps a way to see them would be to find a way to observe a single photon, and look for some kind of drift that shouldn't be there. Like watching a star wobble to find a planet?

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#1 2002-12-03 18:00:19

Re: warp drive - futuristic, but possible?

#2 2002-12-03 18:36:15

Re: warp drive - futuristic, but possible?

#3 2002-12-03 19:14:54

Re: warp drive - futuristic, but possible?

#4 2002-12-03 19:16:47

Re: warp drive - futuristic, but possible?

#5 2002-12-08 18:03:47

Re: warp drive - futuristic, but possible?

#6 2002-12-15 19:48:02

Re: warp drive - futuristic, but possible?

#7 2002-12-15 21:17:16

Re: warp drive - futuristic, but possible?

#8 2002-12-15 21:28:15

Re: warp drive - futuristic, but possible?

#9 2002-12-16 00:59:06

Re: warp drive - futuristic, but possible?

#10 2002-12-16 03:12:58

Re: warp drive - futuristic, but possible?

#11 2002-12-16 03:55:31

Re: warp drive - futuristic, but possible?

#12 2002-12-16 11:12:04

Re: warp drive - futuristic, but possible?

#13 2002-12-18 16:06:00

Re: warp drive - futuristic, but possible?

#14 2002-12-19 12:09:18

Re: warp drive - futuristic, but possible?

#15 2002-12-20 16:31:35

Re: warp drive - futuristic, but possible?

#16 2002-12-20 17:21:44

Re: warp drive - futuristic, but possible?

#17 2002-12-22 11:39:52

Re: warp drive - futuristic, but possible?

#18 2002-12-22 16:10:19

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#19 2002-12-22 16:36:40

Re: warp drive - futuristic, but possible?

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