NASA Space Probe Backs Up Einstein’s General Theory of Relativity
Capping off a project 52 years in the making, NASA announced yesterday that its Gravity Probe B, launched into orbit in 2004 following decades of planning, development, and calculation, has gathered data which strongly supports two key predictions derived from Albert Einstein‘s general theory of relativity. One prediction, the geodetic effect, has it that time and space are warped around a gravitational body; the other, frame-dragging, concerns the effect of rotating objects on space-time. As both effects are relatively minute compared to other forces, it took some cleverness on NASA’s part to detect them.
GP-B 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, GP-B’s gyroscopes would point in the same direction forever while in orbit. But in confirmation of Einstein’s theories, the gyroscopes experienced measurable, minute changes in the direction of their spin, while Earth’s gravity pulled at them.
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“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 Francis Everitt, GP-B principal investigator at Stanford University. “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.”
According to NASA, more than 100 PhDs and 353 undergraduates worked on the project over the course of the ‘five decades it took for Gravity Probe B to be conceived, developed, launched, and its data analyzed.’ The results have been accepted for publication in the journal Physical Review Letters.
(via Universe Today, AFP, Nature, NASA)
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