Gravity Probe B finally pays off

Orbiting experiment confirms general relativity

The longest-running project in NASA’s history has completed its mission. Gravity Probe B has finally confirmed that the Earth drags spacetime around as it rotates like a spoon twisting in a jar of honey, mission scientist announced at a May 4 NASA press briefing.

PERSEVERANCE PAYS After years of setbacks, Gravity Probe B has finally measured the twisting of spacetime by rotating objects, a phenomenon predicted by Einstein’s theory of general relativity.