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Has time run out on Einstein's theory?

Atomic clocks on the space station might reveal truth

Has time run out on Einstein's theory?

By Eleni Berger

(CNN) -- Experiments with high-precision clocks in space could help shed light on whether Einstein's theory of relativity is ... well, relative.

"I don't think it's really possible to throw Einstein's theory out entirely, because it certainly holds to a fantastic degree of precision," says Dr. Alan Kostelecky, professor of physics at Indiana University in Bloomington. "The question is whether at very small scales you would need to adjust the theory to account for adjustments in space-time."

Atomic clocks that are scheduled to be placed on the international space station within the next few years could help researchers find out -- if station crews perform the tests Kostelecky and his colleagues are proposing.

Einstein's Special Theory of Relativity postulates that the laws of physics and the speed of light are always the same to an observer moving at a constant speed. That means a coin will always fall straight down, whether you drop it while standing still or while inside a moving vehicle.

Click here to see an animation of the proposed experiments 

Likewise, a clock on its side will tick at the same rate as a clock that is upright -- at least it will on earth.

But newer theories involving gravity and particle physics have led some scientists to speculate that Einstein's idea may not hold true in space.

Precision in time and space

"By comparing extremely precise clocks that can operate under zero gravity," Kostelecky says, "miniscule changes in the ticking rate might be found as the spacecraft moves around the earth."

The atomic clocks in question are so precise that measuring time with them is comparable to measuring the distance to the nearest star to within an inch, Kostelecky says.

And because the international space station spins faster and has a different rotational axis than the earth, experiments that aren't possible on terra firma can be conducted.

If variations in the ticking rate were discovered, Kostelecky says, it would be a "striking signal" that the laws of nature may be based on fundamental theories other than Special Relativity -- or perhaps in addition to it.

So are wormholes and time warps likely to move out of science fiction and into science fact?

"It's very difficult to say what would be within the realm of possibility," Kostelecky says, "but any small changes in clock ticking rates are not going to lead to 'Beam me up, Scotty.'"


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