http://www.theage.com.au/articles/2004/04/04/1081017035962.html NASA puts new spin on old Einstein
By Richard Macey
April 5, 2004
Almost 90 years after Albert Einstein published his theory that space and time are "curved", it is about to be put to a $US850 million ($A1.1 billion) test.
Next Sunday week, if all goes well, a NASA satellite fitted with four tiny gyroscopes will be fired from Vandenberg Air Force Base, California, into a 640-kilometre- high orbit.
The size of ping-pong balls, the gyroscopes will be set rotating, aligned to a star tracked by the satellite's on-board telescope.
If Einstein's theory of relativity is right, the angle at which they spin should gradually drift over the next two years as the satellite orbits.
According to the theory, gravity does not only distort space up and down, left and right, forward and backward but can also make time run slower, so that the tick of a second on a clock may not always take exactly one second.
But Einstein's theory has only been partially verified.
"Until a theory is thoroughly tested," said Stanford University scientists, who helped develop the mission, "we cannot accept it as fact."
NASA said the satellite "will measure how space and time are warped by the presence of the Earth, and, more profoundly, how the Earth's rotation drags space-time around with it".
These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the universe," the agency said.
First proposed in the 1950s, the satellite, Gravity Probe B, has been funded by NASA since 1964, its design extensively changed to ensure success.
It is arguably "among the most thoroughly researched programs" that NASA has undertaken.
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