If you are traveling the speed of light and suddenly brake to a full stop... what happens to your tail lights?

Question

If you are traveling the speed of light on a car and suddenly brake to a full stop... what happens to your tail lights?

Answer 1

They will suddenly become VISIBLE --- at their usual rest wavelength!

Before that, while you were moving at essentially the speed of light, they would have been RED-SHIFTEd so strongly as viewed from the rear that they would not have been seen; the energy contained in each individual photon would have tended to zero, even though they were still moving towards an observer to the rear, at the unchanged speed of light.

Conversely, the light emitted "ahead" of you would not only be still very close to you, but it would be EXTREMELY BLUE-SHIFTED to any observer to the immediate front, and therefore have such a high x-ray intensity that it would be frying everything in its path that it DID reach, including that poor unfortunate observer.

(Note that I have considered the case of moving at "essentially light speed," asTHAT is in principle an attainable situation, albeit at the cost of huge amounts of accelerative energy. On the other hand, it is NOT possible
for any material entity with non-zero rest mass to actually travel "at the speed of light." With finite energy resources, we can really only imagine APPROACHING that ultimate condition, and that is what I have described above.)

Live long and prosper.

Answer 2

When any thing travels at the speed of light its mass becomes zero. You and your car becomes infinitismall. When suddenly you stop every thing will try to attain its mass and dimensions suddenly. Probably our body and the car materials can not sustain such force all of a sudden and fragmented.

If the question is only for tail light, hypothetically, then it could be answered like this. When car is travelling away from some one at the speed of light, the tail light will not be visible, since relative velocity of light coming towards you becomes zero, as both, light and car, are travelling at same speed but in opposite direction. And when car suddenly stops then the relative velocity of tail light travelling towards you gains back the speed of light. So it will reach to retina of your eye and you will see it again after the time it takes to reach to you. This time will depend how far your car had travelled (not on earth rather in space)

Answer 3

Sorry, but I can't resist....

They end up in your headlights! D

Let's say "suddenly" measn dt = 1 sec to stop from a v = c velocity. Therefore a = -dv/dt = 0 - 300,000,000 m/sec/1 sec = -300,000,000 m/sec^2 deceleration. Given the average car of 1,000 kg, we have F = ma = 1,000*300,000,000 = 300,000,000,000 kg-m/sec^2 = 3 X 10^11 Newtons of force on your car. At the very least, the tail lights would end up in where the headlights are.

I presume you understand v cannot = c light speed...impossible. It would take infinite force to accelerate to that speed; there isn't enough energy in the entire universe to do that.

Answer 4

You can't travel at the speed of light. There is no such thing as traveling at c, according to Relativity. It's not just *difficult* or *unlikely*, but *not physically sensical.* Massive bodies do not travel at c. Ever. If you were indeed to travel at c relative to some other nearby body, then you will have falsified Relativity and we will no longer have a theory of motion to answer your question.

Answer 5

Dr. Spock's answer is the best answer, but I did want to clarify one point. In Md. R's answer, it is mentioned that anything traveling at the speed of light would have a mass of zero. In fact, the opposite is true. As an object of non-zero rest mass approaches the speed of light, its mass increases and approaches infinity.

Answer 6

Nothing. Because you can't go at the speed of light.

Now, if you go ALMOST at the speed of light, and then brake to a full stop...

Again, nothing special will happen. The light from your taillights will continue to shoot out the back at the speed of light, relative to you, regardless of how fast YOU'RE going.

This according to the theory of relativity.

Answer 7

You should be more worried about your headlights - if you're going the speed of light, all that light going forward has collected inside them, and your car will send out a bright flash, which will alert the police, and you will likely get a speeding ticket.