Length Contraction

[Ishimura_]

Assuming a theoretical space ship traveling at 0.99c heading to Alpha Centauri C (4.3 light years away):

The length contraction formula places the perceived length of the distance traveled to Alpha C by the space ship as 0.606 light years allowing the craft to traverse this distance in 0.613 years (~ 7 months 10 days).

My question:

If length contracts for the people on a spaceship traveling at 0.99c, why does length not contract for a light beam traveling at 1.00c? If it did, wouldn't any light wave, from the perspective of the light wave itself, travel instantaneously from Alpha Centauri C to the Earth? What am I missing here?

 

[MeteorWayne]

Most simply, because a light beam is not matter, and light travels at the speed of light in our universe.

 

[Ishimura_]

So, the spaceship would reach Alpha C in ~ 7 months, but the light would still take 4.3 years? From your answer, I'm gathering that light does not experience relativistic effects?

 

[origin]

So, the spaceship would reach Alpha C in ~ 7 months, but the light would still take 4.3 years? From your answer, I'm gathering that light does not experience relativistic effects?

The part you are missing is it would not take you 7 months to reach Alpha C from the perspective of someone on earth or Alpha C - it would take you 4.3/.99 years and it would only take light 4.3 years. 7 months would pass for you but 4.3/.99 years would pass for the earth and anyone at Alpha C.

 

[darkmatter4brains]

Actually, you've sort of got it right on. If you plug c into the time dilation and length contraction formula, they basically say that any object traveling at C will experience zero time and zero space between any two points/events. When I was getting my physics degree back in the day I asked several teachers about this. I would get either blank looks or told that you can't interpret the equations that way without any real solid explanation as to why not. Admittedly, the equations do sort of break down, but you can also examine them "in the limit" and see that they still trend towards that answer.

But, it is generally regarded today that light does not sense the passage of time (i.e. experiences zero time between any two points, per the time dilation formula). This is, in fact, the logic that was used to explain why neutrinos do indeed have mass. They do experience oscillations and since oscillating is a time dependent phenomena, they must not travel at c.

I recently spoke again with one of my teachers, who now gives me a solid answer on this (at least the time part)

If the zero time part is right, perhaps the zero space part is too. In fact, it would seem it almost has to be so, to be logically consistent.

This all ties back to another idea that has been thrown around out there, but for now is really just a fanciful idea with no real theory or evidence to back it up. That is, that light is really a higher dimensional phenomena, of which, we only experience it's 4D aspect.