Earlier this month scientists detected gravitational waves, but it wasn't easy. Because of the tiny forces involved, it took us nearly 100 years to confirm Einstein's original prediction that ultra-massive objects like black holes could send ripples across space-time. A team of astronomers from a group called NANOGrav thinks it can use stable pulsar signals to track tiny movements in the Earth when it's jostled by gravitational waves. "Detecting this signal is possible if we are able to monitor a sufficiently large number of pulsars spread across the sky," says Stephen Taylor from NASA's Jet Propulsion Laboratory. "The smoking gun will be seeing the same pattern of deviations in all of them."