Originally posted by justsomeaussie
I think some people are getting their physics confused. Time is directly linked to speed. The faster you go, the slower your time is compared to
everything else that is going slower than you. So according to modern physics if an object were to travel at the speed of light its time would stop.
However the problem arises is that the faster you go the more energy it takes to get you to that speed.
So for any object other than fundamental particle current theories say nothing can go at the speed of light.
Bingo. You have it in one. It's what's known as Time Dilation.
Effectively, the faster an object travels, the slower time is for said object. As an example - Say you are on a "space shuttle" that can travel at
the speed of light. Now, you are on your way to a planet that is 20 Light Years away. Now, since you are travelling at the speed of light, the trip
will only take you 20 years (I know, I know, it's twenty years, but let me continue). Now, for you, the trip has taken only 20 years (I SAID HANG
ON!!!!!

), because of Time Dilation, 10,000 years have really passed. It's a funny little thing Time Dilation.
And that about sums it up. Theoretically, Time Travel IS possible, but physically, at the moment, we can't do it. Well not that I'm aware of.
Basically, the faster you travel, the slower time gets for you.
Oh and as for the two clocks on the planes experiment, that was because of Time Dilation as well. One plane was flying at 10,000 feet, the other at
100,000 feet. The one at 10,000 feet was flying at a slower speed than the one at 100,000 feet, and that is why the clock came back a couple of
hundred thousandths of a second slower, because of said Time Dilation.
I hope that makes sense to everyone.