The brightest flash in the universe measured so far – known as ASASSN-15lh – was thought to be caused by an extremely bright supernova, but it was actually a supermassive black hole ripping apart a nearby star, scientists say. This is a very rare event as the star has to be at just the right distance from the black hole to be torn apart by it but not vanish inside the event horizon, or the destruction would be invisible.
