A black hole in our galaxy
All the existing galaxies, and our Milky Way too, hide in their centres giant black holes, with masses estimated in 106 and 109 of the solar masses. In the centre of our galaxy, in a region hosting a radio source called Sagittarius A*, we can find a supermassive black hole. Its mass is 3,7 millions times superior than the Solar one. Scientists discovered its presence because of the gravitational effects on the surrounding stars. In fact, x rays coming from this region change drastically just in ten minutes. In such a short time, light and x rays can’t cover a distance of more than 150 millions km and, consequentially, the source could not be really larger than this distance.
During a recent observation, the American satellite Chandra noticed the largest black hole swarm, what remains of giant stars with masses ten times superior than the Solar one, orbiting around the central black hole.