aging while traveling at light speed?

Question

If one ages slower while traveling at the speed of light in relation to someone stationary then is that person in essence traveling faster than the speed of light? Take for example: if a light beam was directed at a mirror 1 light year away we would expect to see the return of the light in 2 years (stationary time for us). If a person were to be travelling alongside that lightbeam also at the speed of light then we would expect them to return in 2 years as well (stationary time for us). But according to Einstein the person travelling would not age as much as the stationary person (ie: something less than 2 years) and if that is true then didn't the person travel faster than the speed of light? (he covered 2 light years physical distance in less than 2 years of his life)

OK thanks, but I'm still playing devils advocate and want to see if someone can give me an answer that even one NOT versed in physics could understand.

Let's say the mirror was 5,865,696,000,000 miles (1 Lt yr) from earth (a fixed distance) An observer on earth would see the beam return in exactly 2 years. lf a traveller went alongside the beam and travelled at .99999... the speed of light then he would return in just over 2 years. According to his clock, he would have been gone for some fraction of 2 years. Even taken into acct. that due to Lorentz contraction, a 2nd observer (half way to the mirror) would view the traveler and his ship as being smaller than it is as it passed by him, that still doesn't change the fact that the traveller covered 11,731,392,000,000 (2 LT yrs - fixed distance) in a fraction of 2 years of his life. Faster than light travel?

Even more interesting is the paradox that if the beam of light could have on a watch then it would not have moved at all (0 seconds) during it's 2 Lt. year trek.
Thus light travels faster than the speed of light or instantaneously.

Answer 1

The Fitzgerald contraction shrink the relativistic distance (in the direction of travel) exactly corresponding to the change in the passage of time. According to the theory, the person traveling at the speed of light would not age at all, would not percieve any passage of time, and would travel anywhere immediately: no passage of time, no distance covered.

This is by definition: Einstein began with the assumption that the speed of light is constant in any reference frame under constant acceleration. The rest of specific relativity devolved from that. General relativity came from the spatial assumptions necessary to support specific relativity on a cosmic scale. I know this is over-simplification, but it seems to work for explaining these things to my mother -- they may help you, too.

Still, you're asking for trouble when you apply the theory to areas that simply cannot be experimentally verified. Relativity breaks down in many respects where it meets quantum mechanics. It may also break down very near the speed of light (although it's held up admirably, even in the extremely high-energy physics labs of CERN, Argonne, etc.). When you try to break the barrier between "nearly the speed of light" and the speed of light itself, you're crossing several "you can't do that" barriers ... in theory. In other words, the theory doesn't cover that possibility, because it's theoretically impossible.

As a parallel, take your basic math operations. We're taught at an early age that you can't divide by zero -- it's undefined. Parts of your question are equivalent to asking "If you *could* divide by zero, what would one divided by zero be?"

Answer 2

No. From the observer's point of view it would still take 2 years for the traveler to return hence the traveler is not traveling faster than the speed of light regardless of the fact that the traveler is aging at a slower rate. The traveler might think it took less than two years because of time dilation, but the fact remains is that it still took two years to make the round trip.

Answer 3

The fist part of this you clearly get - that someone travelling at speed (you cannot go at the speed of light) compared to someone else will not agree on the rate of passage of time.

However, you then assume that they will agree on distance. In fact, they will not.. In the frame of the moving observer, the distance to the mirror is not and never was 1 light year. Its called the Lorentz contraction.

Answer 4

I think the flaw in your reasoning is the assumption of 2 years to get to the mirror. If you are traveling at near the speed of light, you will get there very quickly if it is only 2 light years away because time is not the same for you.

Answer 5

You can't travel at the speed of light, but if you were traveling close to the speed of light, you could say, because of time dilation, that it only took you maybe a month to travel two light years, so it would seem so. But it is just time slowing down, not you going faster than light.

Answer 6

- If matter reaches the speed of light, then it gains infinite mass and time stops for that object alone. However, it is still traveling at the speed of light to the someone outside and can travel farther becuase it gains more time than what was experienced by the stationary observer.

I'm not sure what your question is? Is this an example? There are two equations by Newton and Einstein that can calculate how much time SLOWS DOWN therefore allowing light to travel at speed c to TRAVEL LONGER than compared to the someone that's stationary.

From my high school physics class, I learned that the speed of light is not necessarily a constant between reference frames. It depends on which system you are taking your measurement from, If someone is traveling in the same direction as light, than it only matters what their speed is relavant to the reference system of the light beam. To the stationary observer, the traveler may be appearing to go twice the speed of light. It is still going at the same speed but becuase time slows down, it had more time to overtake those going at a lesser speed.

The speed of light is only constant if the person observing it is stationary or there is constant acceleration. In reality, it is always the same but it changes depending on the different rates of acceleration between systems. When you are traveling at the speed of light, everything appears to be standing still - including another beam of light!!

Answer 7

Somebody who is travelling at the speed of light will see light move away from them at the speed of light. Time is altered to account for the speed of light being relative to every observer.

Answer 8

according to the special theory of relativity I THINK when you
travel fast there is a shrinkage in distance too so there is no
physical distance in your case, so near speed of light the distance travelled according to the traveller is smaller.
That distance / that time is still less than velocity of light.
you cant take one quantity relative to observer (distance).
and the other relative to the traveller.

thanx!

Answer 9

good point but i do believe einstein also proved that people couldn't go faster than the speed of light because it requires an infinite amount of energy to get an atom of something to go faster than the speed of light.

Answer 10

gravity affects the speed