The closer you reach to being the speed of light, time slows. It's been showed in accelerators, correct?

Answer 1

This is called time contraction, and is a consequence of Einstein's special theory of relativity. Here's the cool part:
The speed of light measures the same, regardless of how fast you are moving away from the light source. Say you use an instrument to measure the speed of light emitted from the sun while sitting on the earth, and you get 100,000 miles per second. Now, you jump onto a spaceship with your instrument and travel away from the sun at 90,000 miles per second. The speed of light will still measure 100,000 miles per second, not 10,000 as you would expect.
Now, if you standardize the distance that you are measuring by, say to 1 light second (the distance light travels in one second), if a length of T time passes on earth, the length of time encountered by the person on the spaceship is only Tsqrt(1-90,000^2).

Answer 2

Correct. They use muons, an exotic "heavy" cosmic particle. A muon, at rest, lives for about 1/100000 of a second before it degrades into other particles. No matter what, after 1/100000 of a second, it's doom time for the muon. Accelerate that muon to near light speed in an accelerator, the muon now lives for a whopping 1/10000 of a second, ten times longer!

Here's the weird part. As far as the muon is concerned, it's standing still and those nice men in their lab coats are the ones moving near light speed and therefore live 10 times as long, from the muon's perspective. This is no mere play of words, it is very real, but involves a much longer discussion of relativity and the logical puzzles it represents. There is, however, no violation of the laws of relativity for this to be real. An explanation of this is quite interesting but much too long to go into here.

Answer 3

Yes, it has been shown in accelerators as well as other places. For example, at the Tevatron at Fermilab, protons are accelerated to within a fraction of a percent of the speed of light. After the collisions, the particles produces are also going at these vast speeds. It is found that the time it takes for the unstable particles to decay (and hence how far they travel) is directly affected by how fast they are going in the way that special reltivity predicts.

Answer 4

Scientists put an atomic clock on 2 airplanes. They had a 3rd at the airport. The 2 planes left when all three read the same time. 1 circled the earth one way, one went the other way. When the 2 planes landed, all 3 clocks were different.

Answer 5

Yes...it's also been tested using synchronized atomic clocks...one on the ground and stationary, the other aboard a supersonic jet.
The clock on the jet will show it arrived a few nanoseconds earlier than the reading on the stationary clock. Meaning, the jet LITERALLY moved a few nanoseconds into the future relative to the stationary clock.

Answer 6

Correct.

Answer 7

It's been shown in atomic clocks aboard airplanes (Einstein's Universe by Nigel Calder (good book)).

The mass of particles in accelerators have been shown to increase at high speeds, but I don't know about time.

Answer 8

depends on your position. according to EINSTEIN time is relative to the observer. So, time in not necessarily a constant. being that you can not stand on a particle in an accelerator, there is no DEFINATE way of knowing. your position as an observer destroys the accuracy of any result in an experiment.
accuracy is critical in any experiment to give validity !
otherwise, it is theory, not law.

Answer 9

Yes.

And here is a link to some further background to the brilliant responses before mine:

http://en.wikipedia.org/wiki/Time_dilation#Experimental_confirmation

Answer 10

Also cosmic particles in the atmosphere last longer due to relativistic effects than they normally would.