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In the hit series Star Trek, the USS Enterprise made use of a "warp drive" that had the ability to contract space-time in front of the craft and expand the space behind it, making the space to travel between two points shorter. Are there any realistic aspects of a warp drive? Or is it even possible to build something capable of warping space-time?
Order of Kilopi
This is the only one I know of but I haven't a clue how the physics holds up as of 2010.
http://www.daviddarling.info/encyclo...lcubdrive.html
Order of Kilopi
The Alcubierre metric seems to be allowed in General Relativity. But how you would generate it, steer it, and turn it off when you got to your destination is a mystery.
Grant Hutchison
Order of Kilopi
But apart from those minor technical issues...Originally Posted by grant hutchison
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Don't forget about magnifying the nuclear gravity of Element 115 (aka Lazarium) and focusing it to bring a distant point in space to you. Then you fly over the compressed space and release the pull, rubbering-banding to your final destination.
It's how the aliens got to Area 51, after all.
C'MON PEOPLE THIS IS PROVEN FACT AND THE GOVERNMENT IS HIDING IT FROM US.
/sarcasm
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I agree with Garrison, those are technicalities for another day. As long as GR allows for a warp drive (such as in Alcubierre's model) we should figure out how to construct it first. It could be that the first Warp Drive will move along a preset "flight plan" if you will, or with pre-installed coordinates for a given destination.
Order of Kilopi
You asked for "realistic aspects". And I think Garrison may have been making a joke.
Grant Hutchison
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My mistake, although it seems to me that obstacles such as steering and turning the drive on/ off would be easy to overcome once the actual WD is built. As I mentioned earlier, would programed coordinates not be a realistic aspect? Just put the thing on auto-pilot and you'll be at Alpha Centauri in no timeYou asked for "realistic aspects". And I think Garrison may have been making a joke.
Grant Hutchison
Order of Kilopi
That would be a yes, I suspect the Alcubierre drive bears about as much relation to working drive as DaVinci's helicopter does to a Chinook.You asked for "realistic aspects". And I think Garrison may have been making a joke.
Grant Hutchison
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See, this is what I don't get. You compress the space in front of you and expand the space behind, but you still have not moved. How do you plan on traversing the compressed space in front of you without becoming compressed yourself? Until you accomplish that, turning off the engine and restoring the adjacent space back to its normal volume will only leave you at the place you started.My mistake, although it seems to me that obstacles such as steering and turning the drive on/ off would be easy to overcome once the actual WD is built. As I mentioned earlier, would programed coordinates not be a realistic aspect? Just put the thing on auto-pilot and you'll be at Alpha Centauri in no time
Order of Kilopi
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"Negative Energy Wormholes and Warp Drive by Lawrence H. Ford and Thomas A. Roman"
http://www.bibliotecapleyades.net/ci...tiveenergy.htm
"For example, in one model a throat radius of 1 meter requires the negative energy to be a band no thicker than 10-21 meter, a millionth the size of a proton. Visser has estimated that the negative energy required for this size of wormhole has a magnitude equivalent to the total energy generated by 10 billion stars in one year."
"In Alcubierre’s model, a warp bubble traveling at 10 times lightspeed (warp factor 2, in the parlance of Star Trek: The Next Generation) must have a wall thickness of no more than 10-32 meter. A bubble large enough to enclose a starship 200 meters across would require a total amount of negative energy equal to 10 billion times the mass of the observable universe."
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space-time is flat directly in front and in back of the spacecraft, theoretically. The actual spaceship would be inside of a "warp bubble" that protects it from time dilation and space-time warping
Order of Kilopi
Actually, it has a much, much, much smaller relationship than that. Because in fact, Leonardo's helicopter might have worked, in the sense that it actually follows a real physical principle.
And this is not responding to you, but to the OP. The Alcubierre drive is really just a flight of fancy, a sort of "what if." There is no way to actually do what it wants to do. So the fact that it doesn't violate GR in no way implies that it could actually work. It's just saying, "IF you could warp space, then you could get around relativity," but since we know of no way to warp space, then it's a fanciful concept and nothing more.
I could also say that GR does not forbid birds without spacesuits from flying in space, IF there were a way for their wings to propel them without the need for air, and IF they could figure out how to breathe without oxygen.
As above, so below
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The Alcubierra drive is old news guys
With the latest installment of the Star Trek franchise packing theaters, researchers are again speculating about the feasibility of building a faster-than-light "warp drive" similar to the one powering Star Trek's "Enterprise" star ship.
Researchers at Baylor University (Waco, Texas) claim that dark energy--the force causing the universe to expand--could power a warp drive by expanding the fabric of space behind the ship while simultaneously contracting space ahead of it. The scheme could theoretically enable a ship to traverse light years in distance without violating Einstein's prohibition on faster-than-light travel.
"In modern string theory, dark energy [also called the cosmological constant] is the energy stored in empty space, where pairs of matter and anti-matter particles are spontaneously created and annihilated," said Baylor researcher Gerald Cleaver.
Order of Kilopi
This article by John Cramer describes a modification of the Alcubierre 'metric' by Chris Van Den Broeck which gets round some of the problems, but by no means all of them.
http://web.archive.org/web/200701031...v/altvw99.html
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Yes, but it still has not moved.
If it moves forward, it will necessarily move through compressed space. How does the ship do this without becoming compressed itself.
Please note that I am assuming some kind of spatial integrity. In other words, that space will "bounce back" to its normal volume once the compression/expanding forces have stopped.
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What about using Inflationary theory as a concept to design some sort of a drive to manipulate space-time?
Banned
You assume that "warping" space only "compresses" space. What if it moves the space ahead elsewhere? To the side so to speak. Notwithstanding popular graphic reprsentations of "compressed ahead expanded behind", think more of the representation of the folded membrane where the ship passes through a "hole" or "contact" through the membrane from the origin to the destination. The membrane between has been folded to the side. Of course that's a lot of membrane if you're talking about folding all the membrane between stars. But what if you're talking about folding a short amount of membrane between the origin and destination but you make numerous folds until you get there?
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well, the spaceship really isn't moving at all. That is the beauty of ever constructing a warp drive, it can travel faster than light (in a sense) without using any fuel to move (fuel to power the actual drive is another issue). The spaceship would theoretically be pulled by the contracted space in front of it, and pushed by the expanded space behind it, while the actual craft it stationary inside of a "warp bubble" that, as i mentioned earlier, protects it from such problems as time dilation, space contraction, and high velocity accelerations.
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how so?
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I like my own theory.
It is predicated on a certain attribute of space-time that I call "elasticity". I have even devised experiments to show that "elasticity" exists (or doesn't exist). These experiments would be an adjunct to underground nuclear tests.
Imagine a sufficiently dense mass with a measureable gravity field. Now, imagine that mass being instantaneously converted to energy (the delta-time of "instantaneous" to be determined, but I would imagine it has to be in the femtosecond regime). What happens to the gravitational field surrounding the mass? A wave will be created and radiate away from the place where the mass existed.
If space is "elastic" and critically damped or overdamped, the wave will propagate away and what could be detected at a distance is the prior existance of the original mass.
But if space is elastic and underdamped, a temporary, low amplitude, negative gravity field would be created. This negative gravity "overshoot" from the destruction of the original mass would tend to push mass away, rather than attract mass toward it. Imagine the step response to a linear time invariant system that is underdamped. The step response shows "ringing", and overshoot. It is this overshoot that is representative of negative gravity.
If the amplitude of the overshoot is equal to the amplitude of a starship's gravity field, the two would cancel out and the starship would have an effective zero mass. Any force applied to zero mass produces infinite acceleration.
I have devised a couple of experiments that could be added on to a nuclear test to show whether space-time exhibits "elasticity" and "overshoot".
As for the sufficiently large mass being destroyed to create the negative gravity overshoot... if you feed a sufficient quantity of highly accelerated matter and antimatter into a chamber and let them annihilate each other, this might create the necessary negative gravity overshoot. The reaction chamber would have to be placed at the center of gravity of the starship. The problem I see with the steady state matter-antimatter reaction is, that it *is* steady state and I need a transient event to produce an overshoot of negative gravity.
Critique? anyone?
Some of the math is beyond me, so I have no math to back this up (other than the experiments -- because those reduce to one-dimensional representations of the three-dimensional fields).
Even if it all doesn't work out, it still makes for a good technical sci-fi explanation.
.
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Understood, but that's more of a wormhole analogy. The Alcubierre drive discussed in this thread specifically uses a "compressed ahead expanded behind" mechanic to move.
Maybe I am just over-thinking this particular work of fiction.
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This is where the ship and its crew go splat?
Order of Kilopi
That's just ludicrous, it happens on deceleration.
Order of Kilopi
Sorry but that's little unfair, the Alcubierre concept is not a work of fiction. It may not be feasible in practice but it's a serious effort to explore the possibilities.
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Fiction (Latin: fictum, "created") is any form of narrative which deals, in part or in whole, with events that are not factual, but rather, imaginary and invented by its author(s).
A propulsion system that requires the consuming of entire galaxies as a power source is of course a work of fiction. This, however, does not make it uninteresting or unworthy of discussion!
Order of Kilopi
To be honest I'd settle for a drive that could get us to Mars in six weeks instead of six months, interstellar travel can wait a while.
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agreed :d
Order of Kilopi
You don't traverse the compressed space-- you'd be spaghettified, just like the tidal force of a black hole. You sit still in the middle and let space move around you. If, as the others note, it were somehow possible to create such a warp bubble in the first place. The last thing I read said it would take more energy than exists in the known universe to do so.
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary
Order of Kilopi
Also, stopping isn't a matter of turning off the engine. IIRC, the bubble has event horizons causally separating the interior and the exterior...nothing inside can affect the outside, and vice versa. If such a bubble were formed, it would just evaporate via Hawking radiation until it collapsed into a black hole or converted itself and its contents entirely to such radiation and vanished.
The structure itself is physically plausible (and a theoretical construct, not a fictional one...there is a difference), but formation and orderly deconstruction appear physically impossible.
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