esocid writes "Using NASA, Japanese, and European X-ray satellites, a team of Japanese astronomers has discovered that our galaxy's central black hole let loose a powerful flare three centuries ago. The finding helps resolve a long-standing mystery: why is the Milky Way's black hole so quiescent? The black hole, known as Sagittarius A*, is a certified monster, containing about 4 million times the mass of our Sun. Yet the energy radiated from its surroundings is billions of times weaker than the radiation emitted from central black holes in other galaxies. X-ray pulses emanating from just outside the black hole take 300 years to traverse the distance between the central black hole and a large cloud known as Sagittarius B2, so the cloud responds to events that occurred 300 years earlier. "By observing how this cloud lit up and faded over 10 years, we could trace back the black hole's activity 300 years ago," says team member Katsuji Koyama of Kyoto University. "The black hole was a million times brighter three centuries ago. It must have unleashed an incredibly powerful flare."
Why the Milky Way's black hole is so quiescent 0 Comments More Login /
Get More Comments