Why does time dialation occure?

[Stellar]

Why is it that as we approach the speed of light, time slows down? Ive never understood why.

[antares]

Time dilation has to do with the Lorentz transformation of velocities in the fixed and moving frames. For instance, a clock in a moving frame will be seen to be running slow, or "dilated" according to the Lorentz transformation. In everyday life velocities of the objects are so small that Lorentz factor is practically 1. As soon as you have an object moving with a relativistic speed the the Lorentz factor gama=SQRT (1-v^2/c^2) rapidly changes.

[Stellar]

Yes but is time actually slowing down or does it just seem to be slowing down cuz you're approaching the speed of light? I thought that time actually does slow down, and what truely does link speed to time. I dont understand that.

[antares]

Time is slowing down for the person in the moving frame, but not for the person in the fixed frame - this is the so called "twins paradox". The time will not slow down if you are not moving with a relativistic speed. Imagine you are riding a bus and your friend is waiting for you at the bus stop. The time is the same for both of you, since the bus is moving with a speed much lower than the speed of light. If you ride a hypotetic bus with 300 000 km/s your time will slow down compared to the time of your friend waiting for you at the bus stop.

So the time is relative and depends on the frame where it is measured...

[Stellar]

I know that, but why is it slowed down for you?

[Virulence]

Also other people in the bus at your rate of speed? do they act as if they're in the normal frame because they're travelling with you? or is everything you see slower?

[Universal Absurdity]

There are a couple reasons that i can think of.

Time is relative, so because you are moving faster time therefore goes faster, (to an outside observer), the time you experience is still normal from your perception.

Another reason, (i may be wrong) is the effect that mass (gravity) has on time, it slows time down.

if you travel at very high speeds, your density (mass) will increase which could explain the slowing of time, compared to an outside observer. As you approach light speed, your mass would become infinite (one good reason light speed travel may not be possible), which could theoreticly stop time alltogether

Edited August 10, 2004 by UniversalAbsurdity

[antares]

Time is relative, so because you are moving faster time therefore goes faster, (to an outside observer), the time you experience is still normal from your perception.

Yes, I think this is a good point.

Stellar, you don't know that your time has slowed down until you compare it with another observer.

Virulence, all other passengers in the bus will be experiencing the same effects as you do, because you all move with the same speed.

[Stellar]

I know that.