Astronomers at MIT and universities across Canada and the United States have detected a strange and persistent radio signal from a far-off galaxy that appears to be flashing with surprising regularity. The signal is classified as a fast radio burst, or FRB — an intensely strong burst of radio waves of unknown astrophysical origin, that typically lasts for a few milliseconds at most. However, this new signal persists for up to three seconds, about 1,000 times longer than the average FRB. Within this window, the team detected bursts of radio…