I'm not sure what the big deal is all about. Considering that no one has actually traveled FTL, do we really know what happens? If it takes light about 8m20s to travel to the sun what would be the big deal if we found it could get there in 4m10s??
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I'm not sure what the big deal is all about. Considering that no one has actually traveled FTL, do we really know what happens? If it takes light about 8m20s to travel to the sun what would be the big deal if we found it could get there in 4m10s??
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The implication (assuming there was no mistake in figuring the neutrinos' speed) is that the laws of physics are incorrect, and therefore must be revised. That's the "big deal." Seems pretty significant. Now, it remains to be seen whether the particles were actually going that fast. I'd like to think they did, but I don't want to get my hopes up.
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Science is a very big and very complicated model which represents reality as closely as possible.
The planet Mercury is tidally locked so that one side always faces the sun. This is part of the model.
What's that you say? Scientists have discovered that Mercury is not tidally locked? Okay, so we change the model. That was easy - it was just a case of changing a detail.
But the idea that the speed of light is a cosmic speed limit is much more fundamental. Many significant parts of the model are based on that idea. If it turns out to be wrong, a very large part of the model will need remodelling.
Also, if faster than light travel is possible, then travel to the stars will be much more likely (or at least much less unlikely).
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The biggest problem is causality. If you have a way of FTL communication you can create specific setups in which you'll get causal paradoxes, effects happening before their causes. For example you sending out an FTL signal now that gets received by your parents earlier in time and stops them from getting to know eachother, meaning you'll never exist to send the signal, meaning they do get to know eachother, ... and enjoy the causal mess
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Does the math really PROVE that traveling FTL will result in traveling backwards in time? We know that time stops at the speed of light but is that not just relative to an observer not traveling FTL? Suppose there are no observers, it's just you and a crew on a spaceship going to Alpha Centuri, and you can move twice the speed of light, now you get there twice as fast....right?Originally Posted by caveman1917
The biggest problem is causality. If you have a way of FTL communication you can create specific setups in which you'll get causal paradoxes, effects happening before their causes. For example you sending out an FTL signal now that gets received by your parents earlier in time and stops them from getting to know eachother, meaning you'll never exist to send the signal, meaning they do get to know eachother, ... and enjoy the causal mess
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being able to travel faster than light means that it would take less time to get to other places in the universe. if we could get speeds that are many times the speed of light, it allows us to get to neighboring star systems within a reasonable timeframe- would you want to go to the Alpha Centauri system if you could get there as quickly as it takes to go on a cruise around the Caribbean?
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Just a thought, but what if the neutrinos really are traveling at the speed of light, *and* Einstein was right that it would take infinite energy for anything with mass to travel at or faster than the speed of light? Potentially we have discovered a force which can impart unlimited amounts of energy. If that force were somehow harnessed it would change literally every aspect of our civilization.
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AIUI the maths doesn't say explicitly that it will go back in time - it says that it will arrive at a location faster than any signal - including forces. Changes in gravity, EM and so on propagate at the speed of light. Being able to overtake them leads to problems with causality related to these forces. Like the old one about only being able to sink a ball in snooker if the ball collided with its future self!
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If we go back in time one nanosecond, there are two of us at that time; Both go back and we are four. Society would get complicated, if we could duplicate ourselves, and our gold ingots. But we don't know that is how time works. Neil
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This is a good description: http://www.sheol.org/throopw/tachyon-pistols.html
Get up, a get-get, get down.
Banned
We have not the mechanism to achieve this at this time.. Which is NOT to say that at some time we might not have..
That if we could make Alpha Cent., in 9 years if 0.5 of c. were available to us..
If we could do two times of c. then we could be whizzing buy Alpha Cent in about 2 years..
Just how these thing might become real and safe, is at this time unknown..and..interesting.
... and, That perspective is important. From the view of the traveller, from the view of a observer,
or from where you see these things changes the timing of what you see considerably..
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You have to keep in mind that the measurements show not that the neutrinos are traveling at the speed of light, but faster than it. So no, we haven't discovered such a force, even if it were logically possible for such a force to exist.
As above, so below
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Another thing that's important to remember: as you approach the speed of light, it requires more and more energy to get closer. We know this well, because we have particle accelerators that accelerate protons and electrons to very close to the speed of light, and as you probably know they require enormous energy to do so. And the closer you get, the more energy it takes. It would require infinite energy to reach the speed of light, so going beyond that is not possible. If there are particles that go faster than the speed of light, like postulated tachyons (or neutrinos
As above, so below
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And, most importantly, that they are undetectable. That's why nobody really cares much about hypothetical tachyons, if they are undetectable there are no causal violations, but we certainly did detect the neutrino's so that becomes a huge problem.
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According to Special Relativity, if a massive particle exceeds the speed of light, then elapsed time (and position) is no longer a real number (resp. real valued vector). It is a complex value (with a real part and an imaginary part). I'm not sure what it means for time to have a complex value. Do we exist in 8 dimensions ( 6 spatial and 2 temporal) instead of 4? Is there some connection to String Theory, which requires 10 dimensions? Perhaps someone will some day be able to explain it in a way that can be experimentally verified. Or perhaps Special relativiity needs some tweaking. Or perhaps we have to throw away the entire Special Theory of Relativity. SR works fine as long as you are going slower than light, but beyond that, it breaks down. Personally, I think that the real answer is that there is some extremely subtle error in the experiment. Time will tell.
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Well I do sometimes wonder if causality were to be violated this way, if instead it would become an experimental verification of the Many-Worlds Interpretation, on a macroscopic scale. In any universe that multiplies in the face of variant potential events, causality is arguably impossible to violate, all observers will see a consistent set of data... they just may all end up in different universes.
Banned
So can we yet say we have found that a sub atomic particle known as 'The Neutrino'
has been found to arrive at some moment prier to the light photon stream..
and NO, not yet. Work in progress still and ongoing... " Is it a BIG deal..?
You bet it is..
But, that it WILL be found to be wrong is my view at this time.. but yet wanting to be wrong..
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FTL is not a big deal to me.
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undidly. Yep, but FTL is a big deal in cosmology. The only way they can get the smoothness of the universe, seen in the CMB to match up with the present lumpiness of the universe (galaxy clusters) is to have the universe expand superluminally (inflation) at an early epoch for reasons unknown, and to stop at their assigned time frame, also for reasons unknown. This is zero experimental evidence to justify this from a particle physics lab. Nobody has ever seen a particle travel superluminally in vacuo until the recent neutrino anomaly....which has not been corroborated in other neutrino experiments....the acid test. pete
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Particle motion being FTL and superluminal expansion are very different things. One is an issue for GR, one is not. That is why it is significant, the effects it has on GR, it has nothing to do with superluminal expansion unless it is a pointer to new physics which turns out to be linked to that.
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