A violent burst of flickering visible light created as matter falls into a black hole has been detected for the very first time, astronomers say. These flashes of light, which lasted between several minutes to a few hours, were seen coming from a black hole in the Cygnus constellation, located about 7,800 light-years away from Earth. Incredibly, some of the flashes were so bright, the team says amateur astronomers could see them with a modest 20-cm telescope.
Japanese researchers detected light waves from V404 Cygni - an active black hole in the constellation of Cygnus, the Swan - when it awoke from a 26-year-long slumber in June 2015.
Watch: Black Holes Explained – From Birth to Death
Black holes with nearby stars can burst into life every few decades. In the case of V404 Cygni, the gravitational pull exerted on its partner star was so strong that it stripped matter from the surface. This ultimately spiralled down into the black hole, releasing a burst of radiation. Until now, similar outbursts had only been observed as intense flashes of x-rays and gamma-rays.
At 18.31 GMT on 15 June 2015, a gamma ray detector on Nasa’s Swift space telescope picked up the first signs of an outburst from V404 Cygni. In the wake of the event, Japanese scientists launched a worldwide effort to turn optical telescopes towards the black hole.