The murmur of a monster
Monday, February 28, 2011 - 11:02
in Astronomy & Space
The Andromeda galaxy is the nearest large galaxy to our Milky Way. Like the Milky Way, it has a spiral-arm structure with a massive black hole at its nucleus. Unlike the Milky Way, however, its black hole is remarkable in size - about 30 times bigger than the one in our galaxy, or nearly one hundred million solar masses. It is also unusually passive: similar supermassive black holes in more distant galaxies are often surrounded by accretion disks that emit bright X-rays and generate powerful jets of charged particles. Andromeda lacks both.