## Negative Energy and a SciFi ftl

I know crazy unsupported theories aren't supposed to be posted, but I have been working on some fiction which requires faster than light travel. I have read many other guides to ftl in SciFi, and I had origionally fitted in a form of hyperdrive, which would simply avoid the issue by ignoring the relevent dimensions of space. But, I don't like it either. Anyway, if it's ok here is what I made up so far. Admin I don't mind to delete if it really shouldn't be here:

 The speed of light is the relative propagation of disturbances to the background “medium”. All energy propagates at the speed of light, either in the form of a photon or a fermion. Negative energy can be used to oppose this. When normal energy propagates it warps space and time and causes the phenomenon known as gravity. Everything in the immediate vicinity is effected by this and everything slows down, like it got stuck in a muddy space-time rut. The negative energy acts in the opposite way, altering space and time so that everything speeds up. A single notohp (get it, negative photon), or small number of notohps, will still traverse at the speed of light. But as these particles build the cumulative effect of the negative energy causes the relative propagation to exceed the speed of light. The amount of negative energy needed to complete a hyperspace jump depends on the mass of the ship, how far the destination is, and how quickly the arrival is desired. The mass of the ship and the distance traveled both increase the demand in a linear fashion; in other words twice the distance means twice the demand. This may be larger or smaller depending on how much in-jump navigation is required. The amount of negative energy used through the time dimension has a minimum at the speed of light which is considered the optimal. Going too slow actually increases the demand in a linear fashion. However, as the traversal time goes to zero, the needed negative energy approaches infinity.
Of course, causality is a concern, but I think I can say that if you change reference frames such that causality would be violated that the negative energy wouldn't necessarily look as negative, lessening the exceedence of the speed of light and allowing causality to be restored. I'm wondering if that even makes sense in the concepts of the paradox, even though negative energy can't exist in the equations.

Also it seems that the ship would have to be isolated from the effects of negative energy for the ftl to be usefull for a number of reasons; the ship falling apart and the crew aging and dieing from the opposite of the twin paradox.

So, I guess my question now is does this make any more sense than the other SciFi forms of ftl, or is it just as "magical"? What really would happen if you had negative energy, assuming of course it could exist appart from normal energy.
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 Fermions (i.e. half-spin particles: electrons and the like) don't propogate at c. Photons are actually bosons, they're spin 1, although not all bosons propogate at c either. One thing that's always bothered me about FTL in Sci-Fi is that there's an implicit assumption that you can define simultaneaty across large distances in a curved space, which I do not think is true.

 Quote by dicerandom One thing that's always bothered me about FTL in Sci-Fi is that there's an implicit assumption that you can define simultaneaty across large distances in a curved space, which I do not think is true.

In general, its not. Simultaneity is not universal, not even in flat minkowksi space.

## Negative Energy and a SciFi ftl

Your approach is of course "magical" because it is not currently believed anything can go faster than light. But when some way is found to circumvent that all ideas about FTL will come under new scrutiny.
 I don't know why I'm so concerned over the details. I think that even if ftl was plausable theoretically it wouldn't be very practical. After I posted I though, you know, I wish I didn't post that since there really isn't any way to qualify anything. I have read in other forum about Heim theory, and of course there was an article proposing that alternate geometries would allow alternate speeds of light; using dark energy particles I think, which is similar to the concept of negative energy.

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But be really aware of what dicerandom said:
 One thing that's always bothered me about FTL in Sci-Fi is that there's an implicit assumption that you can define simultaneaty across large distances in a curved space, which I do not think is true.
SF authors from the golden age onward have used this or that bafflegab to achieve FTL in their stories but how many have indicated they understood the consequences? FTL means time-travel, at least to some observers, simultaneity is gone from the galaxy, and negative energy matter would enable constant costless acceleration.

When I read that Honor Harrington zips hither and yon and when she gets back her elapsed time exactly adds up to that of the people who stayed home, I can only smile, and concentrate on the adventures and personalities.
 Here is a question. Say there is a cylinder planet where the diameter is << than the length. Bob and Alice live millions of miles apart. There are also satelites in orbit as in the picture I attached. If they send a laser beam direclty from one house to the other, and also a beam that is relayed through the salelites, which signal arives at the other house first? Edit: I guess the question should be, can the laser relayed through the satelites ever get there before the direct one. Attached Thumbnails

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 Quote by Longstreet Here is a question. Say there is a cylinder planet where the diameter is << than the length. Bob and Alice live millions of miles apart. There are also satelites in orbit as in the picture I attached. If they send a laser beam direclty from one house to the other, and also a beam that is relayed through the salelites, which signal arives at the other house first?
In SR, the fastest way for a light signal to get between two points should always be a straight line through space('straight' in an inertial coordinate system), so a one-to-one signal should be the fastest. If you ask the question in GR figuring out the answer would be more complicated, but if the gravity is less than or equal to earth-gravity I doubt the answer would change.
 Yes. Clues are planet, millions of miles, and the general construct is a question reguarding general relativity. You don't even need SR to answer the question in flat space.
 Note: this is very much off the cuff, basically I'm assuming that the metric for your cylinder world will have roughly the same characteristics as the Kerr metric for a spherical rotating mass. With the spinning cylinder you're going to end up with two major curvature effects (I'm thinking of Christoffel symbols here): 1) There's the standard radial 'pull' $\Gamma^r_{tt}$ due to the mass of the cylinder. 2) There's also a contribution like $\Gamma^\phi_{tt}$ due to the rotation of the cylinder. Now your light from the laser will follow a geodesic, so you should be looking at the geodesic equation: $$\frac{d^2 x^\alpha}{d\tau^2} + \Gamma^\alpha_{\mu \nu} \frac{d x^\mu}{d\tau} \frac{d x^\nu}{d\tau} = 0$$ So initially your photon will have velocities in t and z, the t component of the velocity will result in "accelerations" in the r and $\phi$ directions, so basically your laser will end up dropping towards the surface of the cylinder and picking up rotation along with the cylinder as well. Now, unless the cylinder is rotating extremely quickly I can't imagine this effect (namely the spin) being nearly large enough to justify taking the light beam out to a larger radius. I think that the magnitude of the rotation will also be limited like it is with the case of the Kerr black hole, so you'll have a definite upper limit imposed on how quickly you can spin this thing.
 I'm more interested in time and distance differences between the two houses, and between the "satelites". Will the light beam traveling from one house to the other take any longer than from one satellite to the other.
 Recognitions: Science Advisor Staff Emeritus While you could work out the geodesic equation in the curved coordinates, the easiest solution is to use Minkowski coordinates (i.e. non-rotating coordinates), and then you know that light follows a straight-line path. Your diagram does not show the curvature of the cylinder. the ideal path will be tilted slightly "up" because the cylinder is curved.
 Maybe I need to be more explicit. Time passes more slowly in the houses than in the satelites, right? This is my only assumption so far from what I have gathered from other websites, sense I don't know the math to find out myself. Say you have a light clock manufactured by AB corp. One clock is in Alice's house on the surface and one is in the satellite orbiting above her house several thousand miles away (this is a really big planet btw.). If alice looks up at the satelite will she see the clock running faster than her own? I'm guess the answer is yes, but that the clock also looks smaller so the speed of light is not violated here? Now, the two houses (Alice's and Bob's) can act like one giant light clock, and the two satellites act like a giant light clock, and lets say that AB corp. built them too (ie they are idential in their reference frame). If my previous assumptions are true, then Alice and Bob will, from the surface of the planet, see the satellite light clock run faster than their house light clock. But that the satellites are somehow closer together than the houses preserving speed of light. But now how can Alice and Bob still independently verify that they see their satellite orbiting directly above their house? Ok, I'll eagerly await replies. :)

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 Quote by Longstreet Maybe I need to be more explicit. Time passes more slowly in the houses than in the satelites, right? This is my only assumption so far from what I have gathered from other websites, sense I don't know the math to find out myself.
Yes, this is correct, and time will pass the fastest at the center of the cylinder.

 Say you have a light clock manufactured by AB corp. One clock is in Alice's house on the surface and one is in the satellite orbiting above her house several thousand miles away (this is a really big planet btw.). If alice looks up at the satelite will she see the clock running faster than her own? I'm guess the answer is yes, but that the clock also looks smaller so the speed of light is not violated here?
Alice will see the clock running faster than her own. Assuming that by speed you mean the rate of change of the distance coordinate with respect to the time coordinate, Alice will not see a constant speed of light from her location. However, if Alice visited the light clock, she would measure the speed of light as 'c'.

 Now, the two houses (Alice's and Bob's) can act like one giant light clock, and the two satellites act like a giant light clock, and lets say that AB corp. built them too (ie they are idential in their reference frame). If my previous assumptions are true, then Alice and Bob will, from the surface of the planet, see the satellite light clock run faster than their house light clock. But that the satellites are somehow closer together than the houses preserving speed of light.
OK, this is the tricky point you are missing.

The "speed" of light, as definied by the rate of change of the distance coordinate with respect to the time coordinate, is not constant.

What is constant is the speed of light as measured by a local observer, using local clocks and rulers.

An example might help. Let us suppose you are in a spaceship accelerating at 1g, using acceleration to create "artificial gravity" rather than rotation as in your example. Using standard coordinates, clocks "above" you will tend to tick faster. The metric of space will, however, not change at all. You can find the "speed" of light to be as fast as you like by looking at a light beam sufficiently far "above" you.

At 1g of acceleration, roughly 1 light year above you light will be travelling twice as fast (in coordinate terms) than it will be at your location.

It's not directly relevant, perhaps, but it's interesting to note that a person 1 light year above you will accelerate at only 1/2 g to "hold station" a constant distance above you (while you accelerate at 1g). This is related to the "Bell spaceship pardox".
 It may be a minor point, but the planet is solid, and Alice and Bob live on the surface like on earth. But the matter has been stretched into a cylinder (instead of a sphere). The cylinder isn't necessarily rotating. Ok, so what I am hearing is that Alice can indeed observe what looks like faster than light travel between the two satellites, as long as she doesn't try to measure it herself. By that I mean that Alice knows Bob's house is 3 million km away by surface travel. Ignoring the fact that you can't have a prefectly straight laser beam over that distance because of gravity (ie they have some kind of relay system that make practically a straight path operating at c), they should be able to send emails directly between the houses in 10 seconds (3x10^9m/3x10^8m.s = 10s). The two satellites are directly above each house, and they can fire a signal directly up to hit the satellite. The satellite can then send a signal to the other and then back down to the other house. I don't know how to calculate the time difference (so I leave out exact satellite distances), but lets just say for argument sake it takes 9 seconds to relay the emails. pt1: From the point of view of Alice and Bob is this not a form of ftl communication? In other words, the fastest they can signal each other on the surface is in 10 seconds with a beam traveling at c. But an alternate path, shorter I guess, only takes 9 seconds. Is this causing any "time travel" problems? pt2: If it is possible to have negative energy, would the argument not be reversed that a cylinder planet made of negative energy could relay a signal faster than the satellites, instead of slower? pt3: Is this a form of ftl communication, and do "time travel" problems occur? variations: Since the length of the cylinder planet is still undefined, it could stretch from here to alpha centari. Also, it needen't really be a planet, but simply a small path of energy/negative energy. The planet analogy is simply to relate to what we already know from GR.

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