NASA Mission Confirms Two Of Einstein's Theories

Originally published on May 4, 2011 8:47 pm

It took more than 50 years for technology to catch up to brain of physicist Albert Einstein.

"We've tested Einstein's universe, and Einstein survives," said Stanford University physicist and principal investigator Francis Everitt, as he presented the results from Gravity Probe B. What the experiment proved was that, indeed, huge objects, like the Earth, distort the space around them very slightly.

"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," said Everitt.

"GP-B confirmed two of the most profound predictions of Einstein's universe, having far-reaching implications across astrophysics research," he said.

Time's Techland reminds us that those two elements are the geodetic effect and frame dragging:

The first, the geodetic effect, concerns the warping of space and time around a gravitational body such as the Earth, while the second, frame-dragging, asserts that a spinning object pulls space and time with it as it rotates.

Here's how physorg describes how the experiment proved Einstein right:

After 52 years of conceiving, building, testing and waiting, the science satellite has determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth. If gravity did not affect space and time, Gravity Probe B's gyroscopes would point in the same direction forever while in orbit. But 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.

Back in 1997, NASA confirmed frame dragging by observing black holes. But Gravity Probe B is a controlled experiment.

If you want a more detailed explanation, including how scientists used the "most spherical man-made object," we recommend you head to Wired, which does a great job at explaining this in simple terms.

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