If light is the ultimate speed, does time stop when we travel at the speed of light?

We think it does. If you accelerate a particle to the speed of light, it lasts longer.

As for why there are galaxies billions of light years away, that is because the galaxies are travelling through space. The light takes billions of our years to reach us.

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)

No mass can travel at the speed of light but time has stopped for photons that must travel at the speed of light and photons do not age. As a person in a spaceship approaches the speed of light time slows down and upon return to earth the traveler is younger than those who stayed behind (as proved by atomic clocks and calendars) but would not be physically aware of any differences in the passage of time other than perhaps needing a shave at noon? Both time and space are greatly distorted within black holes. Galaxies billions of light years away are racing away from us as the universe expands (like raisins in a rising loaf of bread!) and that stretches the wavelengths of light (red shift on the light spectrum due to the Doppler effect) but the photons arrive at the speed of light as young and fresh as when they started their long journey.

Technically no object can go at the speed of light since the object will have mass. It all gets into very complicated relativity theories once a mass approaches the speed of light, resulting in the object actually GAINING more mass. The only reason light can travel as fast as it does is that it is pure energy.

And as for light years, they represent the distance that a light wave can travel in one year (travelling at the speed of light).

Hope this helps!

a/ it is special relativity you are talking about, not general.

b/ this guy will seem to become almost (almost because he can't quite reach the velocity of light) eternal to the people he left back on earth. But in his spaceship, he will continue to age and feel time pass as usual. So he will be capable of attaining, say, the other side of the Milky Way and

come back in a few of his years, but he'll find a very much older earth without any of the people he left still living. But he will continue to age and die as usual. And he might die in his spaceship if he travelled for too long.

It is not really complicated. One must only get acquainted to the idea that time measurements are not absolute but do depend on relative motion.

Blue light produced in light water reactors is faster than natural light in the same medium. Time will not stop.

As far as a photon is concerned it is simultaneously at all places from beginning to end of its path. This only applies to massless particles, no massive particles can reach the speed of light

He'll be able to see the future. The stars don't look as they seem to us. Some of them exploded 10000000.. years ago. But now we can only see they're past.

And about the time: it doesn't stop even if we stop or make any move.

Really, Sister

if you wanna see which thing had travelled FASTER then LIGHT ???

do mail me i will reply you further if you are curious

it won't stop it will go along to run it...