Fifty years after it was conceived, a $760 million NASA spacecraft has confirmed Einstein’s theory of gravity, or general relativity, physicists announced today. Gravity Probe B achieved measurements that agreed with theoretical predictions for two effects of general relativity, which states that gravity arises when mass bends space and time. “Einstein survives!” said Francis Everitt, a physicist at Stanford University in Palo Alto, California, who reported the results at a press conference at NASA headquarters in Washington, D.C.
Other researchers, however, greeted the results with what amounted to polite applause. Gravity Probe B fell well short of the precision developers had hoped to achieve in making the key measurement. Moreover, the project got scooped 6 years ago, when two physicists made a similar measurement using data from much cheaper satellites. “I have to compliment the Gravity Probe B team for their result, because Gravity Probe B is a very difficult and very beautiful experiment,” says Ignazio Ciufolini, a physicist at the University of Salento in Lecce, Italy, who made the earlier measurement.