It Took More Than 50 Years, But NASA Proves That Einstein Was Correct
NASA's six-year Gravity Probe B (GP-B) mission has confirmed two major predictions from Albert Einstein's general theory of relativity.
The four ultra-precise gyroscopes used by GP-B measured the hypothesized geodetic effect, or the warping of space and time around a gravitational body, and frame-dragging, which is the amount a spining object pulls space and time with it as it rotates.
To do this, GP-B was pointed at a single star, IM Pegasi, while in orbit around Earth. NASA said that if gravity had no effect on space and time, the gyroscopes on GP-B would point in the same direction indefinitely while in orbit. However, researchers found that the gyroscopes experienced very small changes in spin direction as Earth's gravity pulled at them, confirming Einstein's theories.
"The mission results will have a long-term impact on the work of theoretical physicists," said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. "Every future challenge to Einstein's theories of general relativity will have to seek more precise measurements than the remarkable work GP-B accomplished."
"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," Francis Everitt, GP-B principal investigator at Stanford University, said in a statement. "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."
The GP-B experiment launched in 2004 and completed its data collection by December 2010. But it is actually one of the longest running NASA projects ever, with the idea first suggested in 1959. Several years later, NASA received funding to develop a relativity gyroscope experiment, which eventually led to the development of technologies that allowed airplanes to land by themselves and help determine the universe's background radition, among other things. The measurement also helped NASA physicist John Mather develop the Big Bang Theory, for which he earned a Nobel Prize, NASA said.
GP-B also aided in the development of a drag-free satellite concept, which has helped develop the most precise satellite photos ever.
More than 350 college and four dozen high school students have worked on the GP-B project, including Sally Ride, who eventually became the first American woman in space.
GP-B was a joint effort between NASA's Marshall Space Flight Center in Huntsville, Alabama, Stanford University, and Lockheed Martin, which designed the space vehicle.
Thursday, meanwhile, also marks the 50th anniversary of Alan Shepard's historic flight, making him the first American in space.
