Astronomers see many periodic emissions from space, typically caused by rotation of stars and often very regular. Astrophysicists noticed a unique periodicity in the soft gamma ray emissions from a magnetar located in our galaxy. The soft gamma repeater SGR1935+2154 appears to emit bursts only within regularly spaced windows, and is inactive in between. Based on their analysis, they predicted a resumption of bursts last month; so far, a dozen have been detected.