If you're in a car traveling at the speed of light, what happens when you turn on the headlights?
82342
This is an impossibility.  Cars don't travel at the speed of light.
319610
Asking such questions shows that you are of an outstanding nature and an inquisical individual. This question has llong been the subject of discusion ever since albert einstein's theory of relativity in 1905, and later quantum in 1934. It has commonly been accepted that since you would never be able to lravle at the speed of light, it is pointless to speculate. However, it is possibly to say theoretically that switching the headlights on whilst travelling at the speed of light would cause you to see nothing but blackness, or no change from the surroundings, since the strings have the smae frequency and you cannot pass through them since they have already passed. Trusting this is of measurable help, yours brightly, jgdyrh
340667
Again, the speed of light is a constant!  It does not increase in speed of the flashlight is moving really fast.  Its' like sound, sound goes 700mph in air at sea level.  If the plane goes faster than that it catches the sound, the sound doesn't go faster in front of the plane.  Same with light. Same with the opposite direction.
506771
Actually by what Einstein explained, da light will still be in  front of da car, it won't go behind u no matter how fast u r going even if u r faster dan da speed of light. Weird? rit. I too thought so, It was explained in discovery channel. Well I'll try 2 explain it 2 u, But it wud hav been easier if I cud actually show it by som animations. When u r travellin at da speed of light, time stops. Ya it does. Time is somthin like per user setting, it is unique for u & each & every one. Think dat ur carrying an Einstein's clock, which is a simple devise with 2 mirrors facing each other with a photon bouncin of the mirror. Each time it bounces from a mirror u'll hear a tic sound, that will b 1 second for u. Say u travel at a speed little less dan light u r movin forward but da photon has 2 move a lot more distance than it initially had been, which was in a straight line, but now it's motion will b som what like a hypotenuse, so it has 2 travell more distance dependin on ur speed. So ur 1 sec will not be da same as 1 sec is for som 1 on earth. So actually ur headlight will be actually movin faster dan u no matter what
935501
Well theoretically you wouldnt be able to travel at the speed of light. At the speed of light yoru mass would become infinite and time would virtually stop for you. But at the speed of light the light would still be infront of you. Think of it this way if you are in a race and the runner directly infront of you is traveling at the same velocity as you you would neither fall behind nor would you catch up. So the light would be in front of you.
163148
Nothing happens, the car lights will travel at the speed of light in comparasion to the car. This doesn`t mean that the lights will travel twice as fast, you cannot add this velocities without taking into account Lorentz equations.\n\nIs it deja-vou or is it the third time this question has been asked?
1065439
The speed of light - it can't go any faster!\nThere will be a distortion however, called blue shift.\nThe perceived (by a stationary observer) frequency of the light would increase, and the wavelength would decrease, so that the velocity is constant v=fλ\nThe distortion would be infinitesimal 30 parts in 186000*60*60.\n\nSound would experience a similar distortion, so that if a vehicle sounds its horn as it drives past, there is a perceived frequency change in the sound.  This is called the Doppler Effect - there is a link at the bottom of the blue shift link... (see also red shift)
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!
1084318
Actually, the way modern physicists think of it, the question doesn’t quite make sense.  The problem is the “traveling at the speed of light” part, because one of the conclusions of Einstein’s Special Theory of Relativity is that nothing can travel that fast.\n\nInterestingly, though, its was consideration of a similar question that started Einstein down the path toward relativity… Light is best described by Maxwell’s Equations, which predict that any experiement will measure same speed for light in a vacuum.  When Einstein thought about traveling at the speed of light, he realized that there must be a problem.  In fact, Maxwell’s Equations don’t allow for a “standing wave” solution, which is what a light wave would look like if you were traveling at the speed of light. \n\nSo Einsten took things back to basics, which is what he was good at.  Let’s start with what he actually said… His Special Theory of Relativity started with two postulates (or assumptions): 1) that the laws of physics are observed to be the same in any non-accelerated “reference frame” and 2) that the speed of light (c) is observed to be the same for all observers.\n\nThe first assumption basically says that as long as you’re traveling at a constant speed, all your experiments will give the same results.  That seems reasonable.  But the thing about the speed of light always being the same sounds a little odd: the Michelson-Morley experiment (and others) had detected no change in the speed of light when measured from a moving frame of reference, however, and as I already mentioned, Maxwell’s Equations yield a specific value for the velocity of light.\n\nStarting from there, Einstein worked out how to add velocities together, and it comes out to be not simple addition, but a fraction that never gets larger than c. Basically, what happens is that the measurement of time and distance changes, so a physical object (e.g., a spaceship) can never achieve lightspeed.\n\nSo”  That’s a long-winded way of saying that your headlights themselves can’t travel at the speed of light.  If we want to think about them traveling very, very close to the speed of light, however, we realize that the light they emit still travels at lightspeed (as measured by the fast-moving headlights themselves), so they stil work the same way headlights would work on a car traveling much slower.\n\n\nRyan Wyatt\nRose Center for Earth & Space\nNew York, New York
45561
This is where The Theory Of Relativity starts to come in to play. Relative to your position in the car traveling at the speed of light, the headlights come on and illuminate your path. Relative to someone outside the car watching you travel the speed of light, nothing happens, no light travels outward past the headlamps.
89599
<You wouldn't see any light if you were traveling at the speed of light when you turned them on,but if you turned the lights on before you took off the light would stay in front of you.
671137
Actually....according to Einstein...if you could survive traveling at that speed the answer would be yes. Einsteins theory states the light from your headlights would be traveling at the speed of light! Let me make this simple...if the auto you were driving was travelling at the speed of light the light from the headlights at any given point in your travel would still be traveling forward again at the speed of light. His theory also states that at the speed of light the only variable that changes is time. Personally, I dont believe in the theory, in particle physics it has been proven that paired particles "know" when their particle twin has had a change of state regardless of how far away from each other they are...this being said...some form of communication between the two must travel faster than the speed of light!
44895
Interesting quatum phenomenon question.  The lights would come on, but they might appear strange to an observer due to the Doppler effect.  You, inside the car, would continue to see a headlight 'beam' because light's speed is a universal constant and not dependent on the speed of the source.  However, traveling beyond the speed of light in conventional space is not possible, to our knowledge.  For one, it would require infinate energy.  It would also cause macro-scale collapses in casaulity (effects happening before the cause).  To date, these bizzare effects have only been seen on quantum scales.
109643
No you can not.\nNothing can travel faster than light. Not even light itself.\n\nIf you think that light is a wave (like a wave on the ocean) Imagine that you were riding one wave and were trying to make a new wave from your position (with equal frequenzy ofcours). The new wave would not have twize the speed as the one you were riding, it would have the same speed as the one you ride (try in the bathroom and you will see).\n\nMy point with this explanation is that the light from the back of your car will never reatch the mirror. I think your mirror would seem black, because no light would reatch it. The lightwave from the back of your car would be "flying" towards the mirror in the same speed that the mirror would fly from it. :)
56541
You would be in a different universe than you are now, because the laws of our universe say that a massive object can't go faster than the speed of light (or even as fast).\n\nAlso, if you changed the question to "...1 mile per hour less than the speed of light", you would have to specify "relative to ..." (what?)  And then you would have to say, what would happen as observed by (whom?).  In this question, relative to you, the headlights would turn on and you would be able to see things 186,000 miles ahead of you (as you measure miles) within 1 second (as you measured seconds) .  Relative to the observer that thought you were moving 1 mile per hour less than the speed of light - assuming you were moving toward the observer - you would get to him or her just a tiny fraction of a second after he/she saw the headlights turned on.  Your measurement of the speed of light would be consistent, but your measurments of time and distance would be very different.
70554
First of your car can't go faster than the speed of light.  If your car were going faster than the speed of light, the laws of physics would not apply (since the car is breaking them), so there is no way to accurately predict what would happen.\n\nThat said, if you were going really close to the speed of light relative to some observer (keep in mind that velocity is relative, so it could just as easily be you standing still and the observer moving at near the speed of light), you would see the headlights behave perfectly normally, but he would see you almost catching up to them.  So if we imagine that you could go faster than the speed of light it would follow that everything would seem normal to you, but the observer would see you pass the front of the beam of light emitted by the headlights (actually he would see you in front of the light because he can only see the light when it reaches his eyes, and basically you would get there first, but it's the same idea).\n\n***Response to Cecil***\nAnyone with the audacity to assert that they *know* what would happen based on the laws of physics is mistaken.  Because the car CANNOT travel faster than the speed of light, and therefore the laws of physics DO NOT APPLY!  Any attempts to address this question are purely speculative, and an explaination based on science is no more likely to be correct than one based on Gene Roddenberry's imagination.  Anyone who attempts to apply Einstein's theory of relatively or any other scientific law or theory to this senario and present it as the absolute truth clearly has no understanding of the theories they are attempting to apply, and is, so to speak, the one "without a clue."\n\n***Response to Boomer***\nApparently I need to defend my answers yet again.  Nothing can travel faster than the speed of light.  There are no exceptions, and that's not a "belief," it's a fact.  Thus the car defies the laws of physics, and consequently its interactions with the physical world are unpredictable.  Meaning we cannot predict them, and thus cannot know what would happen.  And anyone who thinks that light and urine behave in the same manner is in no position to be calling others "ignorant morons."\n\n***Response to Cecil's Response***\nFirstly, if you're going to assert that your answer is correct based on the extend of your education, I strongly recommend the use of proper grammar.  As for the car and the light, if you had actually read my answer you may have noticed it is based on the assumption that the speed of light is constant.  For the person in the car, everything is perfectly normal.  He would see the light moving in front of him at 3 x 10^8 m/s and the observer (relative to whom we are measuring the speed of the car) would appear to be moving away from him faster than 3 x 10^8 m/s second, lets say 4 x 10^8 m/s.  The observer would also see the light moving 3 x 10^8 m/s, but he would see the car moving in the same direction at 4 x 10^8 m/s, so to the observer it would appear that the car reaches any given point before any of the light it had previously emmitted.  Also, I'm not sure what the doppler effect has to do with any of this, but it occurs because the wavelength of the sound waves decreases because the object creating the wave moves either closer to or farther away from the previous peak before creating the next one, not because the speed of the sound waves change.  This occurs with light as well, and can been observed as red shift and blue shift.  When this occurs, the speed of the light does not change but the wavelenght of the light is altered by the motion of its source.\n\n***Comment on Tjtindal's Response to Cecil***\nStar Trek is science fiction, but the entire concept of faster-than-light travel is pure fiction.  Nothing can move faster than the speed of light because mass increases with velocity and becomes infinite at 3 x 10^8 m/s.  Because F=ma the force need to i
25198
You can't be in a vehicle going the speed of light, because as objects accelerate they gain mass and a car going the speed of light would be insanely massive.