Warp Drive: Is it Possible to Travel Faster Than the Speed of Light?

[Whitestar]

The warp drive concept is a fascinating idea as a means to get from point A to point B in a much shorter time as opposed to traveling through normal space, which would undoubtedly take many years to centuries. Still, there is something fishy about warp drive. While many difficult issues have been addressed, such as the negative energy requirement, some rather simplistic problems have been ignored (or rather left to be assumed by the reader). Such as obtaining the mass necessary to curve spacetime in order to induce the warp drive. From the stand point of General Relativity, this is not an initial concern, however it is for body which obeys conservation laws.


An object of several tons can not generate a mass several times its own magnitude through any known scientific process. And even if it were possible, one runs into the very severe risk of generating a singularity in spacetime, i.e. a black hole. Again, even under the best of circumstances, it appears that negative energy densities are required for the warp drive Thereby from a physical point of view this makes the warp drive look even more unrealistic. A more plausible means of intestellar travel are the jump gates depicted in Bablyon 5.


In the fascinating book entitled, "Indistinguishable From Magic" by the late Robert L. Forward, renown physicist and science fiction writer, he discusses the possibility of time machines, reactionless drives, faster than light drives and building real starships. In one section of the book, Mr. Forward talks about two methods of traveling faster than light.


Here are the two possibilities:


1) Find some future technology that allows movement through space between "here" and "there" faster than light.


2) The other way is to obey the cosmic speed law limit, but find some method of getting from "here" to "there" without having to go through all that empty space in between. In other words, the space warp.


Unfortunately, the author does not give any details on how method number one could work in theory. However, for method number two, he states that space warps are “bridges” or “tunnels” that shortcut through higher dimensions from one point in space to another. This particular space warp concept that is an exact solution to the equations of the Einstein Theory of Gravity, and yet does not involve singularities, or even stellar masses. This is known as the Morris-Thorne Field-Supported Space Tunnel.


These are tunnels through space that are kept from collapsing to a singularity by threading the throat of the tunnel with special fields. The fields holding up the Space Tunnel have to be exotic fields that have a tension greater than their energy density. Such fields are known to exist in high energy density matter such as is found in neutron stars. Other versions of these fields have been made in the laboratory at low energy densities. These exotic fields holds the Morris-Thorne Space Tunnel open, thereby allowing a starship to pass through.


Thought anyone?

 

[Bunting]

Uhmmm, I was going to start a new thread for this, and then saw this thread and thought I may as well ask it in here as its basically along the same lines :) And you would problalbly know the answer ;)

What exactly is the theory of warp drive? How does it supposedly work! And what is the light speed equivalent of Warp 1 (assuming warp 2 is (Warp 1 x 2).

Thanks :)

 

[Locutus]

Originally posted by Whitestar
Mr. Forward talks about two methods of traveling faster than light.

Here are the two possibilities:

1) Find some future technology that allows movement through space between "here" and "there" faster than light.


2) The other way is to obey the cosmic speed law limit, but find some method of getting from "here" to "there" without having to go through all that empty space in between. In other words, the space warp.

Well, warp drive fits both those criteria. It is a future technology that allows FTL travel, and the way it does this is by warping space in front of the ship. At every integerial warp value, a corresponding warp field is emitted that directs a high concentration of energy (from matter/antimatter reactions) into bending the space in order to traverse the distance faster. The vessel is not traveling through space faster than light, it is just traveling through less space...

Albeit, this concept IS quite sketchy and, of course, only just sci-fi. However, it will remain intriguing as long as nobody can DISprove it.

By the way, the formula for determining how many factors of c a given warp speed propels a ship is as follows:

xc = cw^(10/3), where xc is the velocity in terms of c, and w is the warp speed. Thus, warp 1 is 1c, warp 2 is 10c...

Star Trek imposes a maximum of warp 10, meaning a ship traveling at warp 10 is traveling at an infinite rate. I have derived a formula for determining xc for values of w between 9 and 10:

xc = c(w^(10/3) + 31(tan(90w - 810))).

 

[Hurkyl]

IIRC, the star trek universe has a well defined mathematical calculation for warp speeds in terms of c. I don't have my encyclopedia anymore, so I can't look it up.

Hurkyl

 

[russ_watters]

Since magnetic and gravitational fields propagate at c, nothing inside the field can move faster than c (to an outside observer) - otherwise it would leave the field.

 

[CJames]

The idea behind warp drive in Star Trek isn't seriously considered by physicists. The story essentially goes that the Enterprise moves from normal space to a subspace bubble that somehow lowers the weight of the starship and can propel it faster than light through an asymetrical interaction of "warp fields." Subspace is never really defined in Star Trek, though most assume it to have something to do with warped spacetime. In reality, there is no theory behind this.

A theory was devised a while back proposing how a "warp drive" could work by compressing the space in front of a ship and expanding the space behind. While the expansion and contraction would get the ship there "faster than the speed of light", it still requires the propogation of gravitational fields, which move at the speed of light. Therefore, once you decided to go to Alpha Centari, it would still take four years to get there.

Wormholes still seem to be the most plausible solution, and they're an unlikely step that will take place, if ever, in the very distant future. If it were possible to create the right kind of wormhole, a huge trick in and of itself, you would have two ends next to each other in the same universe. It get somewhere, you would have to move one end of the wormhole somehow. If you wished to go somewhere in your lifetime, you will still need to accelerate this wormhole to near lightspeed, sustaining yourself until you reached your destination via time dilation. (I'm speaking from the reference frame of Earth.) To return home, then, you would simply hop into the distant end of the wormhole and find yourself in the past, which is right here. The wormhole would not only shortcut a distanc, but shortcut time.

Just be careful not to bring the distant edge too close to the other to generate a time paradox, or the wormhole vaporizes.

 

[Zefram]

Therefore, once you decided to go to Alpha Centari, it would still take four years to get there.

Are you sure about that? If you're talking about Alcubierre's idea, I always thought it would take "an arbitrarily small time to complete the round trip" (if you could really construct that kind of "warp drive"). He actually uses those words in his paper.

 

[CJames]

The way I understand it, which could indeed be far off, the trip would in fact take less than 4 years. But it would take over 4 years to manipulate the gravitational field appropriately to make the jump. Perhaps space stations could be set up between stars that expand and contract at regular intervals, so that a spaceship caught in the right place at the right time would make the jump. It wouldn't be effective onboard, as it is in startrek

 

[selfAdjoint]

Don't think so. People worked out that it really would go faster than light, and that all the usual relativity problems with that (time travel into the past) would arise.

There are two problems with making it.

1) It's just a solution of Einstein's metric equations. No suggestion for a mechanism at all.

2) It requires negative energy. Some people think you can get negative energy by Casimir type reactions with the quantum vacuum. This too has been calculated and to get any significant amount would add megatons to the payload. OTOH, new derivations of Alcubiere's result have greatly reduced the amount of negative energy required. So "metric engineering" forges on.

 

[wimms]

Can someone say in few words what is physical sense of "negative energy"? Capacity of undoing work? Must be timetravel..

 

[russ_watters]

Originally posted by Zefram
Are you sure about that? If you're talking about Alcubierre's idea, I always thought it would take "an arbitrarily small time to complete the round trip" (if you could really construct that kind of "warp drive"). He actually uses those words in his paper.

I only skimmed the paper, but I didn't see anywhere where he addressed the issue of the field propagating faster than the speed of light.

 

[Whitestar]

Warp Drive Travel

Many people are familiar with Star Trek in which a fictional warp drive is used to propel a ship many times faster then the speed of light. Of course, this drive is fictional. However, after many years of thinking about how this could be accomplished and finding out that NASA is working on a type of warp drive for intersellar travel, I have come to the conclusion that it is possible to use warp drive, maybe even to travel faster then the speed of light. In order to travel incredibally fast velocities, we must look at some of Einstein theories. Einstein says that as a vessel approaches light speed the mass of the vessel approaches infinity. Thus, the energy needed to propel such a craft would also approach infinity. In order for this to all work, the speed of light must remain constant and as a consequence, time become variable. That is the key element that makes Einsien's equations work.


So, the key to making warp drive possible is by making time a constant factor and the speed of light variable. In space, the speed of light is indeed variable. What causes it to vary is gravimetric fields, or gravity. In a gravimetric field, light accelerates and when light leave the gravimetric field, it slows down again to the universal constant. This works because gravity itself is nothing more then a warp in the scace-time continuum. According to Einstien, the space-time continuum is structured, like liquid water at rest. Gravity is created by mass. Mass pushes space out of the way. The effect might best be described as space being several rubber bands tight and in a grid. When a marble is put on the rubber bands, the bands warp or change from their original static apperance to allow for the marble.


If a ship could create a warp field large enough, it could indeed travel at rapid velocities. The problem comes with the above diagram in that a gravity field like that would accomplish nothing. If a ship were to generate a large field of that shape, it would just sit there. So, a field must be produced that is assymetric with respect to the ship itself.


It is very difficult to generate large amounts of gravity. Mass the size of the Earth generates enough gravity to leave us anchored to earth. The moon is 1/6 the size of Earth but only generates 1/10 of the gravity. However, two metal plates a hair's width apart does generate a small amount of anti-gravity (the opposite of gravity). I believe this affect can be amplfied by charging the plates with electricity or plasma. The two plates can also be turned into one large plate and then coiling that plate in on itself. The final spacing of the coil would the nessescary width generate anti-gravity. Of course, the placement of the coils and the design of the ship still determines whether or not the ship will move. I would like to suggest that the design put for in Star Trek Enterprise of the starship Enterprise is actually a very good design to create the needed assymetric field.


The naccelles (the large cylinders) would generate the antigravity field which would in turn generate a symmetric gravimetric field around the ship. This is because an inversion of gravity forces the surrounding space to form gravity. Once the gravity is very close to the gravity and is then sucked toward the gravity. This would cause speed and therefore warp drive. The affect would look something like this.


I don't really know what kind of speeds can be accomplished with this kind of setup, but I would at least think that percentages of light speed should be able to be attained. This would make travel within our solar system much easier. If speeds above light speed were to be achieved, then this setup would work very well for interstellar travel. Perhaps this is where theoretical quantum drive comes in? What does everybody else thinks?