Astronomers examining 20 tidal-disruption events—stars torn apart by supermassive black holes—found radio evidence for two periods of outflow. Jets appeared while the black hole was feeding rapidly, then reappeared hundreds or thousands of days later as the feeding rate fell to roughly 2% of its maximum. The Guardian’s report on the Nature Astronomy study
That second threshold resembles a transition already observed around stellar-mass black holes. If it holds, the same accretion physics is operating across an enormous range of mass, with the clock simply running much more slowly around the larger object. It also gives observers a better idea of when to return to an apparently quiet event: the late radio signal is part of the process, not astronomical aftercare.