·If you're in a vehicle going the speed of light, what happens when you turn on your headlights?

Answer 1

Some crazy answers on this one. Who says time travel will occur at the speed of light? It is an un-proven theory which, for the moment, cannot be proven. I could say one you reach the speed of light you would cease to exist... my theory cannot be proven or dis-proved until travel at the speed of light occurs. It will occur in space before too long. With the fantastic advances we are seeing since the dawn of the Century who knows what 2100 will bring. We, unfortunately wont be around then but our theories will. People said once you go over a certain speed, not sure if it was 25mph or 30mph or something like that we would suffocate... until it was proven wrong.
Anyhow, finally, to answer your question, if you were travelling at the speed of light and you switched your headlights on... from your position nothing would seem to happen as you are travelling as fast as the speed the light is. You would not be able to illuminate your path if it was dark no matter how bright your lights are. You cannot have light travelling at twice the speed of light...

Hope this helps..

Charlie boy

Answer 2

if you are in the vehicle, you still see the light going from the headlight at the speed of light as normal. If you are on the ground (stationary) you just see the light never comes out. It sounds contradictory. Does the light ever comes out form the headlight? it is because time in the vehicle stays stationary with respect to the people on the ground. So if time stays stationary, light doesn't move even if it moves a the speed of light.

Answer 3

The light wouldn't travel anywhere but stay. If you travel AT the speed of light.

Imagine running, if you run on a static surface you move forward, now imagine that surface starts to move against you, you won't get as far, now imagine the surface travelling at the exact speed you are running, you would stay static as if running on a treadmill.

Well thats like a partical of light running, but if the light source is travelling at the speed of light then the light partical would appear to stay static...

Theoretically if you then breached the speed of light, the light would appear behind the light source because you are going faster than it.

Imagine someone hits the high speed button on the treadmill and you can't go that fast, you would gradually head backwards, if the treadmill went on forever, and faster than you, you would travel backwards whilst running forwards.

I struggle to believe things will remain the same, but have an open mind if anyone has details... Lets talk theories.. Imagine that one photon of light come from the headlight, now lets make the headlight a gun, and the photon a bullet. Now lets say the speed of light (the speed of the bullet) is exactly 1mph, ok, so you run at exactly 1mph with the gun, and shoot, the bullet would travel at 1mph, you and the gun are going at the exact speed, therefore the bullet would stay in the barrel, travelling but remaining in the barrel...

Answer 4

Assume that you could actually do this and that the electons would flow from the battery to the light (which in realitythey couldn't, see below):

The General Theory of Relativity gives the speed of light in a vacuum as a Universal constant. Therefore the speed of the light from your headlamps would not be added to the speed of your vehicle. This means that the light waves would not be projected forward. If they could be generated at all (see below) they would remain 'stationary' at the point of generation.

Also, under E=Mc2, your vehicle would have infinate mass at the speed of light which means that the gravitational pull from the bodywork would also be infinate.
This would mean that light could not possibly escape from your car's Event Horizon anyway.

The result would be Nothing would happen because only Nothing could happen.

Don't try the experiment in a Ford or the light switch would drop off.

Answer 5

This is a very intriguing query indeed!. However, on closer scrutiny it will emerge as one relating to the properties of matter and energy; for the vehicle is solid matter and the speed of light is the measure of pure energy. If it were ever possible to travel at the speed of light, matter undergoes a metamorphosis as light.Then both the occupants and the vehicle will be transformed into subatomic particles and both will behave as particles{!} of light.
As for the headlights being on,the matter that generates light from will meet the same fate as the vehicle.From a mathematical point of view one will need to solve the equation; m= e/c2, using relativistic models. However that is an absurdity and so the answer to the wonderfully creative enquiry is that the situation cited is a TOTAL IMPOSSIBILITY. Sorry about that, but the question inself is challenging and mind-boggling. Many many thanks.

Answer 6

The light leaving your headlights would travel away from you at the speed of light, but because you are already travelling at the speed of light, the light from the lamps would be travelling at twice the speed of light relative to stationary objects). When it hit something stationary it would bounce backwards at twice the speed of light and with your forward speed still at the speed of light, it would hit your eyes at three times the speed of light.

So in effect, the wave lengths would be compressed meaning that you wouldn't be able to see any reds or possibly yellows. It could mean that all you'd see would be blues and violets.

That could make things very tricky to avoid.

So the best thing to do is either slow down a bit, or drive during the day!

Answer 7

It would be exactly the same as it would be if the car were not moving. That's the whole point of the theory of relativity, which says that all physical laws remain invariant with velocity - ie you can't tell how fast you are moving by observing differences in physical laws - only relative velocities matter. So the headlights would shine out in front of you in exactly the same way as they always do.

Of course there is the inconvenient detail that you can't actually move at the velocity of light anyway, but the above is true even if you could get up to 99.999% of the velocity of light.

Answer 8

The headlights would be visible normally relative to both observers - the one in the "car" and the one observing from a fixed point. This is called the theory of relativity.

According to Einstein's theory, the speed of light is a constant, which means it will always appear to be moving 186,000 miles per second in relation to the viewer. It will move away from you at that speed, and it will move toward the fixed observer at that speed, also. The only way to explain this is that it is not possible to achieve or surpass the speed of light. If that speed were to be approached, it would create a slowing effect for the passing of time relative to the person in the "car".

If it were possible to obtain a speed fast enough to pass a ray of light, then it would be possible to pass your own reflection and ultimately see yourself where you were a few minutes ago, meaning that you would have to travel through time first... much like looking at a star now (now being the future of what you are actually seeing) and seeing what happened hundreds of thousands of years ago.

The theory of relativity suggests that the question is not valid because it is not possible to approach the speed of light.

Answer 9

This must show up about 5 times a week. BUT, you can't go the speed of light. However let's say that you can get as close to it as you want. Now let's say you're in space with no stars around you and no McDonald's to measure your speed against. You have no idea what your speed is relative to anything else. You are at rest with respect to your vehicle. When you turn on the lights, the light goes away at the speed of light. Now I appear and you measure the speed difference between the two of us and it's close to the speed of light. Am I moving or you ? Who's at rest ? As far as your vehicle goes, it can't perceive that quantity. You turn on the lights and the light goes on away at the speed of light.

Answer 10

Your question contradicts Einstein's Special Theory of Relativity which states that no object with mass CAN travel at, or above, the speed of light (c). As your car approaches c, its resistance to acceleration (mass) increases so that it would take an impossibly infinite force to actually reach c. Your question, then, is based on an impossible premise. It's like asking 'What would happen if I reached the North Pole and kept going north?' As you approach the speed of light with your headlights on, however, you would still measure the light beam racing away from your car at 186,000 miles per second (c). A 'stationary' observer watching this happen, though, would not then measure the beam's speed at almost twice c. Relativity says that all observers always get the same measurement for c. While that may not sound logical or plausible, it happens because what we normally think of as fixed concepts--length and time--are both variable at high speeds. If you observed a car travelling past you at close to c, its length in the direction of travel would appear shortened and the passage of time on board would appear slowed down. Although these ideas sound strange to all of us not used to moving at relativistic speeds, they have all been confirmed experimentally. Answered by: Paul Walorski, B.A. Physics, Part-time Physics Instructor First of all, you need to realize that when you say you are traveling at the speed of light, that has to be with respect to, or relative to, something else. It is an underlying fundamental assumption of Einstein's special theory of relativity that uniform, non-accelerated motion has no meaning of and by itself. That is, there is, by assumption, no meaning to the idea of moving uniformly at the speed of light in an empty universe. That state is completely equivalent to being at rest in an empty universe.. I preface my answer with this comment because it leads immediately to the answer to the question. Imagine that you are in your car 'traveling at the speed of light' and that you turn on your headlights. That state of motion is utterly equivalent to being at rest in an empty universe. Since, when at rest, the light from your headlights would be launched forward from your car at the speed of light, relative to you, with a certain color spectrum, that is exactly what would happen if somehow you could be moving instead at the speed of light. In other words, the presence or absence of other objects or matter in the universe relative to which, if present, you could make a determination that you were moving at the speed of light makes absolutely no difference to your own experiences and experiments. The light that you launch behaves in exactly the same way whether the other referential matter exists or not. This leads into another interesting question, however. And that is whether the rest of the matter (mass) in the universe in some way affects your own local observations. So far this question has come up in relation to theories of gravity. If effect, the question is how does the universal gravitational constant, G, which determines how strongly gravitating masses attract each other, know what value to assume if there is no other mass in the universe. Mach proposed, essentially on philosophical grounds, that G must be determined by the sum total of all of the mass in the universe. Einstein assumed in his General Theory of Relativity that G is simply a universal constant, independent of the specific mass distribution of the universe. On the other hand, Brans and Dicke later proposed a so-called scalar-tensor theory of gravity in which the local value of G depends upon the rest of the mass in the universe through an additional scalar field that does not appear in Einstein's theory.

Answer 11

If Einstein couldn't answer that, I highly doubt anyone here will be able to

However, if you were travelling at the speed of light, you would not be able to switch your headlamps on because you would have ceased to exist - it is impossible for anything other than light to travel at that speed.

However, if you were travelling at 99.99% the speed of light, what would happen then. Would the light from your headlamps travel just a few inches in front of you?

Nope - no matter how fast you are travelling, light will always travel away from you at the same speed, so you would not notice any discernable difference.