ID:277875
 Jun 12 2008, 4:24 pm
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What if you were in a car, going at light speed - no ... FASTER than lightspeed. Now, remember, I say "what if" so perhaps this IS possible in a few thousand years, (if humanity makes it that is). Now, anyway, what if you in a car going faster than lightspeed, and then you suddenly turned the headlights? Would the car just drive on faster than lightspeed with the headlights, or what about the lights from the headlights? Would the light be able to keep up with the car? Or would it leave a long long streak?
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Jun 12 2008, 4:34 pm
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GhostAnime
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If you traveled at the speed of light, chances are you'd wind up dead from crashing into something before you can see the result of that experiment :P Seriously, image all that blood and organ being pressed to one side of the body as well...
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GhostAnime wrote:
If you traveled at the speed of light, chances are you'd wind up dead from crashing into something before you can see the result of that experiment :P Seriously, image all that blood and organ being pressed to one side of the body as well... I guess that's true. That's why you should wonder about it now! | |
Firstly, the obvious answer is that the light couldn't keep up with you. The speed of light is constant. Of course, it's impossible for anything with a non-zero, real mass to travel at lightspeed, let alone faster than it, so the question itself is useless.
Also, if you travel faster than light, you travel backwards in time as well. Very odd things would happen. | |
Faster than light travel is impossible given current understandings of physics, to the point where attempting to discuss it is pointless, as we have no real point of reference. Like Popisfizzy said, current models would result in speeds >c to result in backwards time travel.
However, the question of "if you are moving near the speed of light, and turn on your headlights, what happens?" is one that has already been answered by relativity: light appears to move at the speed of light for all observers. So, somebody in the car would see the light moving away at the speed of light, and somebody outside the car would see the light moving at the speed of light and "slowly" advancing away from the car. | |
Popisfizzy wrote:
... it's impossible for anything with a non-zero, real mass to travel at lightspeed, let alone faster than it... not impossible, just currently technically impractical. Also, if you travel faster than light, you travel backwards in time as well. not sure what you are smoking, but i'd wish you would share it with the rest of us! as i understand it (as postulated by the likes of Carl Sagan, Einstein, and company), time doesn't go backwards, but your relative(?) perception of time differs. Something along the lines of if you travel faster than light for one year, when you get back home everyone is 30 years older. | |
digitalmouse wrote:
not impossible, just currently technically impractical. Please read up on physics. It is impossible to travel faster than the speed of light. It would require an infinite amount of energy to travel at c, and therefore it would require more than infinte to travel faster than c (if you have a non-zero, real mass). As we live in a finite universe, we can assume we have a finite amount of energy in the universe. If there were an infinite amount of energy, I believe one of two things would happen: the universe would be far too hot for matter to form, of the universe would be infinite dense at every point. Due to the law of conservation of mass-energy, we know no more energy will come into existence. not sure what you are smoking, but i'd wish you would share it with the rest of us! Einstein himself said that travelling faster than the speed of light the same exact thing as travelling bacwards in time. | |
Popisfizzy wrote:
Einstein himself said that travelling faster than the speed of light the same exact thing as travelling backwards in time. Yep impossible. | |
Yep, like how it was thought by people that it's impossible that the Earth revolved around the sun. <_<
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Are you seriously saying, "Religion was horribly wrong once, so general relativity could be horribly wrong as well!"
Because if you are, I'm so angry right now. | |
Also, if you travel faster than light, you travel backwards in time as well. Very odd things would happen. Hah, so IF the impossible DOES become possible then people will be mysteriously disappearing. I didn't know Einstien said that. | |
No, he didn't say "if the impossible becomes possible". Relatively, in some form or another, is here to stay. There is no variation of relativity that allows for faster-than-light travel, and nothing has ever been observed travelling faster than light. In all likelihood, faster-than-light travel is not possible.
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Popisfizzy wrote:
No, he didn't say "if the impossible becomes possible". Relatively, in some form or another, is here to stay. There is no variation of relativity that allows for faster-than-light travel, and nothing has ever been observed travelling faster than light. In all likelihood, faster-than-light travel is not possible. Sorry, meant the time travel thing. | |
GhostAnime wrote:
Wait, that was due to a religion? I take back that comment >_> Yeah, back then in Midieval Times Christians thought the Earth was the center of the universe and stayed still but it actually moved around the sun. It was against many laws - Galileo got house arrested for telling the public that the Earth actually revolved around the sun, beleive it or not. EDIT: Sorry, I meant the Renaissance in Italy. The Midieval times were done by then. But they still beleived the same thing in Midieval days until Galileo came up with his brilliant science. | |
Popisfizzy wrote:
digitalmouse wrote: it is impossible with our current understanding of physics. and since humanity has a penchant for achieving what was once thought impossible, it brings FTL travel into the "certianly not right now, but might be doable if x, y, and z happen" realm. there are quite a few examples where traveling faster than light may be possible once we gain better understanding of certain effects. Miguel Alcubierre's mathematical model of a warp drive is one such possibility (and a personal favorite). quoting from http://www.daviddarling.info/encyclopedia/A/Alcubdrive.html "Alcubierre concluded that a warp drive would be feasible if matter could be arranged so as to expand the spacetime behind a starship (thus pushing the departure point many light-years back) and contract the spacetime in front (bringing the destination closer), while leaving the starship itself in a locally flat region of spacetime bounded by a "warp bubble" that lay between the two distortions. The ship would then surf along in its bubble at an arbitrarily high velocity, pushed forward by the expansion of space at its rear and the contraction of space in front. It could travel faster than light without breaking any physical law because, with respect to the spacetime in its warp bubble, it would be at rest. Also, being locally stationary, the starship and its crew would be immune from any devastatingly high accelerations and decelerations (obviating the need for "inertial dampers"), and from relativistic effects such as time dilation (since the passage of time inside the warp bubble would be the same as that outside).  Could such a warp drive be built? It would require, as Alcubierre pointed out, the manipulation of matter with a negative energy density. Such matter, known as exotic matter, is the same kind of peculiar stuff apparently needed to maintain stable wormholes – another proposed means of circumventing the light barrier. Quantum mechanics allows the existence of regions of negative energy density under special circumstances, such as in the Casimir effect. Further analysis of Alubierre's warp drive concept by Chris Van Den Broeck of the Catholic University in Leuven, Belgium, has perhaps brought the construction of the starship Enterprise a little closer. Van Den Broeck's calculations put the amount of energy required much lower than that quoted in Alcubierre's paper. But this is not to say we are on the verge of warp capability. As Van Den Broeck concludes: 'The first warp drive is still a long way off but maybe it has now become slightly less improbable.'" Granted, "this method of travel does not actually involve moving faster than light in a local sense, since a light beam within the bubble would still always move faster than the ship; it is only "faster than light" in the sense that, thanks to the contraction of the space in front of it, the ship could reach its destination faster than a light beam restricted to travelling outside the warp bubble. Thus, the Alcubierre drive does not contradict the conventional claim that relativity forbids a slower-than-light object to accelerate to faster-than-light speeds." (Wikipedia) But as long as I can get to where I need to go faster than 'conventional' means, I don't care much how it works. It seems like the great minds of our time are split on the idea- some say impossible, some say improbable. I vote for the later. It's just a matter of time! :p | |
digitalmouse wrote:
it is impossible with our current understanding of physics. and since humanity has a penchant for achieving what was once thought impossible, it brings FTL travel into the "certianly not right now, but might be doable if x, y, and z happen" realm. Yes, but these "impossible" scenarios haven't shot down by one of the most successful, well-documnted scientific theories to ever exist, with a well-understood (for most things) mathematical basis. And Alcubierre not in violation of relativity. You're using space to push you along, but inside the bubble, a you don't travel locally faster than the speed of light, meaning that you still aren't travelling faster than the speed of light, really. That it's still within the bounds of relativity. Even theoretically, we have no methods for travelling at c, as it requires an infinite amount of energy. As anyone could tell, no one would even bother travelling faster than the speed of light. As well, there are a few problems with the Alcubierre drive. The bounds of bubble would be a singularity, meaning information can't cross it. There wouldn't be any known way to stop it, as it would have to be disabled outside the bubble, and since the bubble is travelling faster than light, there is no form of transmission we know of that can reach another point and let them know the bubble is coming and needs to stop there. Hell, we couldn't even detect the bubble coming, as it's travelling faster than photons we'd used to detect it. It also requires a large amount of negative energy to produce it for anything larger than a few atoms. All cases require it to have negative energy in some way. There is no source of negative energy that has ever been theorized or observed. | |
In all fairness, part of the reason why Galileo got screwed over was also because he was mocking the pope.
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The one thing people fail to take into account (people in this thread) is our amazing lack of knowledge about the universe and how it works. Sure, we've seemed to come up with something that generally works so far (relativity), but that's all based on things we know so far. We are not all-knowing, and things tend to change -- to say otherwise is being extremely short sighted. Something may come along in the future that will change science forever.
I side with the people who say it's not possible with our current understanding of physics. | |