MajinVegeta Posted March 6, 2003 Posted March 6, 2003 Traveling faster than light, is it possible? here are 2 contradictory answers: First off, the tachyon paradox: tachyon paradoxThe argument demonstrating that tachyons (should they exist, of course) cannot carry an electric charge. For a (imaginary-massed) particle travelling faster than c, the less energy the tachyon has, the faster it travels, until at zero energy the tachyon is travelling with infinite velocity, or is transcendent. Now a charged tachyon at a given (non-infinite) speed will be travelling faster than light in its own medium, and should emit Cherenkov radiation. The loss of this energy will naturally reduce the energy of the tachyon, which will make it go faster, resulting in a runaway reaction where any charged tachyon will promptly race off to transcendence. Although the above argument results in a curious conclusion, the meat of the tachyon paradox is this: In relativity, the transcendence of a tachyon is frame-dependent. That is, while a tachyon might appear to be transcendent in one frame, it would appear to others to still have a nonzero energy. But in this case we have a situation where in one frame it would have come to zero energy and would stop emitting Cherenov radiation, but in another frame it would still have energy left and should be emitting Cherenkov radiation on its way to transcendence. Since they cannot both be true, by relativistic arguments, tachyons cannot be charged. This argument naturally does not make any account of quantum mechanical treatments of tachyons, which complicate the situation a great deal. and here is a contradictory article: http://scienceworld.wolfram.com/physics/Tachyon.html What do u think?
Deslaar Posted March 6, 2003 Posted March 6, 2003 If tachyons exist they will travel in negative time and they will never break the speed of light barrier because it takes an infinite amount of energy to slow them down to c.
MajinVegeta Posted March 6, 2003 Author Posted March 6, 2003 What's negative time? They themselves should already have infinite energy. they are classified by their ability to travel faster than light. Otherwise, they might as well be tardons.
Deslaar Posted March 6, 2003 Posted March 6, 2003 Originally posted by MajinVegeta What's negative time? They themselves should already have infinite energy. they are classified by their ability to travel faster than light. Otherwise, they might as well be tardons. The more energy a tachyon has the slower it goes. Tachyons cannot go slower than c for the same reason tardons cannot exceed c. You're saying that a tachyon should have infinite energy because it's going faster than c but that definition would make it a tardon. EDIT Negative time: -t in the equations that result in the mathematical prediction of tachyons.
MajinVegeta Posted March 6, 2003 Author Posted March 6, 2003 Yeah, but u (and Stephen Hawking) said that for ftl travel, you need infinite energy. Is it positive or negative energy?(i'm guessing negative energy?)
fafalone Posted March 6, 2003 Posted March 6, 2003 This is all assuming how we understand now is correct. In Newtonian mechanics accelerating past c would require infinite energy, but different laws apply in some situations. Also, none of the laws are broken if the velocity at the time of formation of the particle was already faster than light.
Deslaar Posted March 6, 2003 Posted March 6, 2003 Originally posted by MajinVegeta Yeah, but u (and Stephen Hawking) said that for ftl travel, you need infinite energy. Is it positive or negative energy?(i'm guessing negative energy?) According to special relativity it's impossible to travel faster than light if you start out slower than light. Equally it's impossible to travel slower than light if you start out travelling faster than light. Special relativity doen't rule out FTL travel it just rules out crossing the FTL barrier.
KHinfcube22 Posted April 17, 2003 Posted April 17, 2003 I have know clue what your all taking about. but here is something to think about, what happens when one excedes the speed of light? One man said, can't remember rightnow, that when the speed C is reached, time stops, son someone else thinks that means, going past C means you will go back in time. I contridict that earlier belief. I believe the closer one gets to C, time slows, but it does not stop. If you take a number and divide it by another number, does it ever reach a neegative one, not unless you start off with a negative number. The only way to reach a time stop statis is to go the speed of 0.
blike Posted April 17, 2003 Posted April 17, 2003 Originally posted by KHinfcube22 I have know clue what your all taking about. but here is something to think about, what happens when one excedes the speed of light? One man said, can't remember rightnow, that when the speed C is reached, time stops, son someone else thinks that means, going past C means you will go back in time. I contridict that earlier belief. I believe the closer one gets to C, time slows, but it does not stop. If you take a number and divide it by another number, does it ever reach a neegative one, not unless you start off with a negative number. The only way to reach a time stop statis is to go the speed of 0. Think of it as C as the limit. You can never reach C, and hence time can never stop. You can get infinitely close to C, and time will go infinitely slower, but it will never stop completely.
fafalone Posted April 17, 2003 Posted April 17, 2003 But light moves at C, and obviously moves through spacetime quite rapidly.
Radical Edward Posted April 17, 2003 Posted April 17, 2003 Originally posted by KHinfcube22 One man said, can't remember rightnow, that when the speed C is reached, time stops, That would be Einstein, in his formulation of Special Relativity.
Dave Posted April 17, 2003 Posted April 17, 2003 Originally posted by fafalone This is all assuming how we understand now is correct. In Newtonian mechanics accelerating past c would require infinite energy, but different laws apply in some situations. Also, none of the laws are broken if the velocity at the time of formation of the particle was already faster than light. I think you mean relativistic mechanics I've pondered this question myself for a while, but lacking the physics behind it is kind-of useless. My own gut instinct is that we are missing something from the existing theories and postulates to explain this sort of behaviour should it ever occur. I also don't believe that we are constrained to travel up to the speed of light because it just doesn't feel right. Of course, I have nothing to back this up and I may indeed turn out to be completely wrong, but I certainly believe something is missing at the moment.
Radical Edward Posted April 17, 2003 Posted April 17, 2003 Originally posted by dave I've pondered this question myself for a while, but lacking the physics behind it is kind-of useless. My own gut instinct is that we are missing something from the existing theories and postulates to explain this sort of behaviour should it ever occur. I also don't believe that we are constrained to travel up to the speed of light because it just doesn't feel right. Of course, I have nothing to back this up and I may indeed turn out to be completely wrong, but I certainly believe something is missing at the moment. It occurs purely be the result that the speed of light is constant*... and the inclusion of this "fact" means that SR and GR are unavoidable. assuming that c in a vacuum is always the same, and doing a little bit of maths gets the SR result quite simply. THe Lorentz transforms themselves I have just put in the announcement at the top of the relativity section of the forums. *the velocity is obtained from the maxwell equations, and is equal to 1/sqrt(:mu:0 :epsilon:0)
M-CaTZ Posted April 17, 2003 Posted April 17, 2003 I know this isnt what is being discussed but i was just curious to know what your perspectives are on human traveling in terms of speed. Given the mass of humans and the components that would be neccissary to transport them, how close do you think humans could come to travelling at the speed of light. Im not sure if there is already a set limit theorized. Also what type of engery would have to be utilized, photon maybe?, or some other energy source.
Radical Edward Posted April 17, 2003 Posted April 17, 2003 well it depends on how much energy you are willing to dump into accelerating them. People aren't all that big, and energy is fairly freely available, so depending on the power source (fusion? antimatter?) you might be able to get up to significant fractions of c. of course there would be lots of problems associated with this, such as radiation and so on (since the stuff you are travlling towards would be massively blue shifted)
fafalone Posted April 17, 2003 Posted April 17, 2003 Studies suggest that the speed of light is NOT constant over time...
Radical Edward Posted April 17, 2003 Posted April 17, 2003 a drifting speed of light over time is different to the constrant speed of light referred to in relativity. I try not to confuse the two.
blike Posted April 17, 2003 Posted April 17, 2003 Originally posted by fafalone Studies suggest that the speed of light is NOT constant over time... He's talking about the speed of light being constant for all observers relative to their own motion.
blike Posted April 17, 2003 Posted April 17, 2003 Originally posted by fafalone But light moves at C, and obviously moves through spacetime quite rapidly. Photon that emerged from the big bang is the same age today as it was then. Time does not pass at C
fafalone Posted April 17, 2003 Posted April 17, 2003 Originally posted by blike Photon that emerged from the big bang is the same age today as it was then. Time does not pass at C Do you have any idea what you're talking about?
blike Posted April 17, 2003 Posted April 17, 2003 Originally posted by fafalone Do you have any idea what you're talking about? I bless you with another homemade graphic. We're always traveling through spacetime at C, though most of our motion is through time.
fafalone Posted April 17, 2003 Posted April 17, 2003 Wow, you really have no idea whatsoever what you're doing.
blike Posted April 17, 2003 Posted April 17, 2003 Originally posted by fafalone Wow, you really have no idea whatsoever what you're doing. How about posting something useful.. Faf|library> hey i heard that blike thinks time doesn't move and space is a scalar rather than a vector I don't think I need to comment. Its a simple rendition because you were having a hard time grasping it. <Faf|library> and for some reason thinks space-time has a velocity of 1/2c I know its a rough concept, but try reading first "We're always traveling through spacetime at C". The velocity on the graph is motion relative to the x axis (space).
fafalone Posted April 17, 2003 Posted April 17, 2003 Position in space-time is defined as s(t) = x(t)i+y(t)j+z(t)k, and velocity is ds/dt. How can this be constant if a <> 0, let alone be constant at c?
KHinfcube22 Posted April 17, 2003 Posted April 17, 2003 I heard once that if one travels at the speed C, the will expand and "become" the universe, in a manner of speaking. Is this true?
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