Fast Radio bursts

Scientists have recently discovered repeating radio signals coming from a mysterious source well beyond the Milky Way. While one-off fast radio bursts (FRBs) have been detected in the past, this is the first time multiple signals have been detected coming from the same place in space. They were theorized to be exploding stars but a recent observation of a sequence of these pulses from the same location essentially rules that out. One particular interesting FRB has been named FRB 121102. It is too bright to be radio-wave burps of evaporating supermassive black holes at galactic centers, and they are far too frequent to be easily explained as the echoes from energetic mergers of neutron star pairs. Similarly, gamma-ray bursts occur only about once a day, not often enough to be obviously associated with FRBs. The sources are thought to be a few hundred kilometers or less in size, as the bursts last for only a few milliseconds, and if the bursts come from cosmological distances, their sources must be very energetic, generating as much energy in a millisecond burst as the Sun does in 80 years. Some have speculated that these signals might be artificial in origin, that they may be signs of extraterrestrial intelligence.