Astronomers have found evidence of a big black hole

Tech Explorist: The peculiar movement of gas at the galactic centre could be the smoking gun that finally leads astronomers to the most elusive type of black hole – the middleweight.Black holes are pretty hard to find unless they’re actively feeding (or colliding), since they don’t emit any electromagnetic radiation (except perhaps for Hawking radiation, which, if it exists, we can’t detect). That’s because electromagnetic radiation can’t achieve escape velocity from beyond the event horizon; thus black holes are invisible to our detection methods when they’re not doing something noticeable.