May 5, 2011
Probe Confirms Key Elements Of Einstein Theory
NASA's Gravity Probe B (GP-B) has produced astonishing new confirmation of two key predictions derived from Albert Einstein's general theory of relativity, which the spacecraft was designed to assess.
The satellite's observations show the Earth is very slightly warping time and space, and even pulling them around with it. The findings validate Einstein's prediction, devised nearly a century ago, that large objects in the universe distort space and time with the force of their gravity, scientists said.The experiment was launched in 2004 and was 40 years in the making. Scientists used four ultra-precise gyroscopes to measure the hypothesized geodetic effect, the warping of space and time around a gravitational body, and frame-dragging, the amount a spinning object pulls space and time with it as it rotates.
"Einstein survives," said Francis Everitt, Stanford University physicist and principal GP-B investigator.
"GP-B confirmed two of the most profound predictions of Einstein's universe, having far-reaching implications across astrophysics research. Likewise, the decades of technological innovation behind the mission will have a lasting legacy on Earth and in space."
"In Einstein's universe, space and time are warped by gravity. The Earth distorts the space around it very slightly by its gravity," he explained.
Had Einstein's theory been disproven, the "gyroscopes would point in the same direction forever while in orbit," said NASA in a statement.
However, the probe's measurements instead came amazingly close to Einstein's projections.
"In confirmation of Einstein's general theory of relativity, the gyroscopes experienced measurable, minute changes in the direction of their spin as they were pulled by Earth's gravity," NASA said in a statement.
"Imagine the Earth as if it were immersed in honey. As the planet rotates, the honey around it would swirl, and it's the same with space and time," Everitt explained.
"That measurement is the underpinning of the 'big bang theory' and led to the Nobel Prize for NASA's John Mather," the space agency said.
The technologies created in the development of the gravity probe have been used in making precise global position systems (GPS) and in evaluating the background radiation of the universe.
The NASA satellite concluded its data mission last year.
The findings were published in the journal Physical Review Letters.
Image 1: One of the most perfect spheres ever created by humans. A fused quartz gyroscope for the Gravity Probe B experiment which differs from a perfect sphere by no more than a mere 40 atoms of thickness as it refracts the image of Albert Einstein in the background. Credit: NASA/Standford University
Image 2: Artist illustration of the Gravity Probe B. Credit: NASA/Standford University
On the Net: