Four superconducting ping-pong balls floating in space have just confirmed two key predictions of Einstein’s general relativity, physicists announced in a press conference May 4.
“We have completed this landmark experiment testing Einstein’s universe, and Einstein survives,” said physicist Francis Everitt of Stanford University, the principal investigator on NASA’s Gravity Probe B mission.
The probe, which launched in 2004, was designed to test the effect Earth’s gravity has on the space-time around it. According to Einstein, the Earth warps its local space-time like a bowling ball sitting on a trampoline, a phenomenon called the geodetic effect. This effect means that a circle of fabric with the Earth’s circumference, about 24,900 miles, would be pulled into a shallow cone with a circumference 1.1 inches shorter.
The Earth also swirls the nearby space-time around with it as it rotates, like water spiraling around a drain, in an effect called frame-dragging.