Mon, Oct 14, 2024 HOW TO SEE A BLACK HOLE
In the autumn evening sky, there are three bright stars high overhead which are called the Summer Triangle. In the middle of this triangle there is a great mystery - something which is invisible to the eye - that enigmatic phenomenon known as a black hole. It is called Cygnus X-1, and we can't see it directly because its gravity field is so intense that light can't escape it. But we know that it is there, because we've discovered an incredible amount of x-rays pouring out of this part of the sky. Cygnus X-1 is part of a binary star system. Gas from its companion, a massive blue giant, is being pulled from it to feed the accretion disc surrounding the hole; it’s here that the x-rays are being made, just outside the black hole's event horizon - its point of no return; it’s about 2500 parsecs, or a little less than 48 quadrillion miles from Earth.