If a source of light is travel faster than the speed of light what happens with or to the light?
547591
Since no physical object can travel that fast, the question makes no sense.
144613
light rays do not move faster or slower than the speed of light.  the speed of light is the speed of light, period.\n\nthat said, light often travels *slower* than c, which is a constant defined as the speed of light IN A VACUUM, approximately 3x10^8 m/s.  here is a way you can actually observe some honest-to-god light traveling slower than c:\n\nstep 1.  find a window.\nstep 2.  look at it.\n\ncongratulations, you have observed light traveling slower than c.  in ANY medium (air, glass, water - you name it) the speed of light is slower than the speed of light in a vacuum.  \n\nin fact, the so-called index of refraction (n, which equals 1.4 for glass) is defined as the ratio of c to the speed of light in that material.  generally, denser materials have a higher index of refraction, and people have been able to make light go REALLY slow by making some very dense materials.  all of this is perfectly consistent with general relativity.\n\nas for FASTER than c:  under certain conditions, it is possible to make photons with a "phase velocity" that is greater than c.  however, when people speak of the speed of light, they usually refer to the "group velocity".  the distinction between phase velocity and group velocity is kind of technical; but phase velocity refers to the speed at which the individual phase fronts propagate through space.  \n\nit is possible to make these phase fronts go faster than c; but because the energy or information or whatever carried by the light travels at the group velocity, the actual speed (as far as stuff like general relativity is concerned) is still less than c.\n\nanyway, all of these results are entirely consistent with general relativity.  in fact, i don't know of any published results of a scientific experiment which are not consistent with GR.  \n\nthe fact that einstein's theory, largely concocted out of the blue from basic principles and logical reasoning, has stood the test of time for so many years is a testament to the genius of the man's work.\n\nhere are some links to learn about phase velocity, group velocity and the speed of light:\nhttp://en.wikipedia.org/wiki/Group_velocity\nhttp://physicsweb.org/articles/news/4/7/8/1
13401
It's true that the speed of light is constant no matter what speed at which you or the source is moving.  This is a fundamental postulate of relativity, and there is no explination.  It's just accepted because our experiments indicate that it is true.  You used the formula "lights speed + X = actual speed"  this type of velocity addition is called "Galilean".  It turns out that speeds don't actually add that way.  Far out.\n\nWhere is the rest of the energy? Good question.  The frequency of the light you observe from the sun DOES depend on how fast you and it are moving.  The energy of each photon is given by E = hf, where f is the frequency of light.
281751
Nothing will happen. THere is no sense of time when travelling at the speed of light. No time - nothing happens.\nYour clock is stopped cold.
591715
No. First, matter can't get to the speed of light because it would be infinitly massive and would take an infinite amount of energy to do it so the question starts out with a bad premiss.\n\nHowever, if a plane were traveling at half the speed of light and turned on it's headlights, they would be going the speed of light to him and the speed of light for someone on the ground watching. You see the speed of light is constant for all observers in a non-Newtonian reference frame.
227315
Speed of light in vacuum is given, but light travels at constant speed in any medium, but the magnitude of the speed might be different than any other medium. There was a discussion about that here before. You might wanna check that.
966236
No matter how fast you go or think you are going, light always appears to be going the speed of light.\n\nEven if you are going 0.99999999999 c from the viewpoint of an outside observer, you would still see light traveling at the speed of light around you. Now, light sent by objects moving at 0.9999999999 c towards you (those "ahead" of you) would be severely blue-shifted and light from objects moving away from you at that speed (those "behind" you) would be severely red-shifted.\n\nBut light from any object moving the same speed as you would look perfectly normal. In fact if you covered the windows of your spaceship (it better be a spaceship, since you won't be in any atmosphere for very long), you wouldn't know you were moving at all!
644825
According to Special Relativity Theory, when you are transporting a mass at a speed near lightspeed, the energy needed to increase your speed rises to infinity. We can't provide the system with enough energy to reach the light of speed.\n\nEnergy, though, can travel at the speed of light because it has no mass. If we could transform a mass in energy (remember: E = m c^2) and re-create it at destination, travelling at lightspeed would be possible.\n\nBut, as Dark Helmet said, speed of light is too slow. We need ludicrous speed!
122048
Peple I know you want the points, but can you please not just make up answers out of whole cloth like that?\n\n>>>>>Massive objects cannot go the speed of light.\n\nYeah, they can. They can't accellarate to the speed of light but they can be created at lightspeed and continue on.\n\n>>>>>> However if they could, no you could not see, becuase the light could not go furthur then the builbs at the front of your car\n\nNonsense. The speed of light is constant for all frames of reference. From the FOR of the bulbs the light would be seen travelling away from it at lightspeed. \n\n>>>> You'd be seeing the light go by your side.\n\nNo, you would not be seeing the light by your side. You would still be seeing all light in the universe travelling away form you or towards you at the speed of light, just as you do at your current velocity\n>>>>>The light would not shine out in front of you because you are going the same speed.\n\nIncorrect. Light always sines out in front at lightspeed in the observers FOR. It makes no difference if that FOR is stationary or lightspeed itself.\n\nYou quite obviously made that answer up.\n\nws, this question seems to get asked here every couple of days. You can go back and have a look and see it answered quite well several times.\n\nIn brief,\n\nLight is funny stuff. Light always travels at the same speed relative to you, it doens't matter how fast you travel. \n\nIf you are sitting still and a person is going past you at light speed you can both look at exactly the same light beam, and it will be travelling at lightspeed compared to both of you.\n\nIf you are going at lightspeed and turn on the headlights the light will move away fomr you at lightspeed. If it strikes something it will be refelected back at lightspeed. If someone is sitting completely still beside you he will also see that light move away form him at lightspeed, and get reflected back at lightspeed.\n\nIt's weird stuff light, it doesn't behave like anything else. The answer to any question that asks how fast light is moving towards you or away from you is always "lightspeed". It doesn’t matter what else we add to the question, the answer is always 'lightspeed".\n\nSo if the light leaves the bulbs at lightspeed and gets reflected back at lightspeed does that mean you could see?\n\nProbably not. \n\nAlthough light doesn't change speed relative to the observer it does change wavelength. The faster you travel towards a light source the bluer it will look. \n\nAny object that your headlights strike will reflect the light back to you at lightspeed, that's OK. But because you are travelling towards the object at lightspeed the light will be shifted way, way towards the blue end of the spectrum. It would all be ultraviolet an X-rays. The human eye simply can't see those wavelengths. So plenty of light would be reflected back, but it wouldn't be visible to you. As a result it would all look dark.\n\n\n>>>>> if the interior light inside your car was on at\n>>>>> the time would you see that?\n\nYes. Because both you and it are travelling at the same speed it woulnd't be red shifted at all. Similarly because you and the interior of the car are travelling at the same speed you would be able to see the light reflected off that just fine as well.\n\nEverything in the universe that is travelling as fast as you will look normal.Everything outside will appear black.
15559
Light travels roughly 186,000 miles per second. Einstein once said that nothing can move faster than light, and this previously was an accepted truth because visible light was considered to be just a wave of energy. However, when studying how light reacts to strong gravitational pulls, such as one from a black hole, we can see that it bends under gravity. This indicates that it shares some characteristics with matter. It could even have a minute amount of mass. If light shares characterisitcs with matter, then we can harness it and use it the same way we do air in a jet engine. Can we not go faster than the wind naturally blows with a jet engine? Yes. Then I do not see why we can't go faster than light when harnessing light itself as energy.  There have been several questions like this, and I really feel that traveling faster than lightspeed is only decades away.
555954
Updated 1997 by PEG.\nOriginal by Philip Gibbs 1997.\n\n\nI am driving my car at the speed of light and I turn on my headlights.  What do I see?\n\nSadly this question and all others about experiences at the speed of light do not have a definitive answer.  You cannot go at the speed of light so the question is hypothetical.  Hypothetical questions do not have definitive answers.  Only massless particles such as photons can go at the speed of light.  As a massive object approaches the speed of light the amount of energy needed to accelerate it further increases so that an infinite amount would be needed to reach the speed of light.\n\nSometimes people persist: What would the world look like in the reference frame of a photon?  What does a photon experience?  Does space contract to two dimensions at the speed of light?  Does time stop for a photon?. . .  It is really not possible to make sense of such questions and any attempt to do so is bound to lead to paradoxes.  There are no inertial reference frames in which the photon is at rest so it is hopeless to try to imagine what it would be like in one.  Photons do not have experiences.  There is no sense in saying that time stops when you go at the speed of light.  This is not a failing of the theory of relativity.  There are no inconsistencies revealed by these questions.  They just don't make sense.\n\nDespite these empty answers, nobody should feel too put down for asking such questions.  They are exactly the kind of question that Einstein often asked himself from the age of 16 until he discovered special relativity ten years later.  Einstein reported that in 1896 he thought,\n\n``If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as a spatially oscillatory electromagnetic field at rest.  However, there seems to be no such thing, whether on the basis of experience or according to Maxwell's equations.  From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest.  For how, otherwise, should the first observer know, i.e., be able to determine, that he is in a state of fast uniform motion?  One sees that in this paradox the germ of the special relativity theory is already contained.  Today everyone knows, of course, that all attempts to clarify this paradox satisfactorily were condemned to failure as long as the axiom of the absolute character of time, viz., of a simultaneous, unrecognizedly was anchored in the unconscious.  Clearly to recognize this axiom and its arbitrary character really implies already the solution to the problem.''\n\nIn 1905 he realised how it could be that light always goes at the same speed no matter how fast you go.  Events that are simultaneous in one reference frame will happen at different times in another that has a velocity relative to the first.  Space and time cannot be taken as absolute.  On this basis Einstein constructed the theory of special relativity, which has since been well confirmed by experiment.\n\nQuestions of relative velocity in relativity can be answered using the velocity subtraction formula v = (w - u)/(1 - wu/c2) (see relativity FAQ: velocity addition).  If you are driving at a speed u relative to me and you measure the speed of light in the same direction (w = c in my frame), the formula gives v the speed of light in your reference frame as, v = (c-u)/(1 - u/c).  For any speed u less than c this gives v = c so the speed of light is the same for you.  But if u = c the formula degenerates to zero divided by zero; a meaningless answer.\n\nIf you want to know what happens when you are driving at very nearly the speed of light, an answer can be given.  Within your car you observe no unusual effects.  You can look at yourself in your mirror which is moving with the car and you will lo
442563
There's a number of ways to answer this.  Einstein's theory of Relativity says that all things are moving at the speed of light through spacetime, with stationary objects moving wholely in the time dimension.  As you start moving, some of your velocity is directed away from time and in a physical dimension.  When you approach the speed of light, you are traveling very little in the time dimension and mostly in the physical dimesions.  If you actually reached the speed of light you would experience no time whatsoever; your entire trip across the universe would be one instantaneous flash.  However, the faster you travel, the more difficult it is to travel even faster.  When you are traveling relativistically, Newton's second law of F=ma no longer applies.  You continue adding force, but rather than creating acceleration, you'll begin gaining mass.
174384
when light moves from 1 medium to another..say air to water..it changes in its speed...this change in speed leads to a change in the direction of the light.
368030
The speed of light in matter is always less than the speed of light in a vacuum. It is the speed of light in a vacuum that cannot be exceeded. If a particle goes faster than the speed of light in whatever matter is around, Cerenkov radiation is given off. The radiation itself is a form of light, but it is made when something else goes through matter at a speed faster than light in that matter. \n\nFor example, the speed of light in water is only 75% of the speed of light in a vacuum. If a particle goes through water at 85% of the speed of light in a vacuum, Cerenkov radiation will be emitted.
53622
Well, its absolutely impossible to travel at or faster then the speed of light, but lets pretend you can so i can actually give you an answer to the question. The speed of light is actually the ultimate speed limit to the universe, nothing can travel faster than light, so although you would expect the light to be going at twice the speed of light (you plus the speed of light)it can't because it is physically impossible for even light to travel faster than the speed of light so it would be going slower than you and not reach any path in front of you. Of course, if you turned on your headlights before you started moving, the light would be one step ahead of you.\n\nOf course, still, nothing can go faster then the speed of light because in the formula for time dialation(time slows down for an object moving close to the speed of light) t'=t/sqrt(1-v^2/c^2) where t' is the time passing for an outside observer, t is the time that passes for the object going at the high velocity, v is velocity, speed is the speed of light and ^2 is squared. (note: this formula is definately correct, it's part of einstein's theory of relativity and I've had to derive it myself for class in the past) so if v was bigger than c, you would have a number greater than one and therefore a negative number under a square root, which is impossible.
447950
1.  According to the Special Theory of Relativity you can't travel as fast as the speed of light.\n\n2.  The General Theory of Relativity has to do with gravity, not what happens when you approach the speed of light.\n\n3.  If you could travel at the speed of light, the light from the sun could not catch up with you, no more than a pulse of light can catch up with another pulse of light.  So, you couldn't see the sun again.
349427
no, anything that travels close to the speed of light becomes more massive as it goes faster, and would actually become infinitely massive at the speed of light. this means it would take an increasing amount of energy just to get close, and an infinite amount to reach that speed. the only reason light can reach that speed is because it is made of photons which have no mass. even a tiny particle like an electron can never actually reach the speed of light.\n\nHowever, faster than light travel may be possible by warping space-time itself, using phenomena like wormholes or even black holes.