Rutgers University astronomers have found a galaxy with no supermassive black hole at its center--or at least with a very small one. All the galaxies researchers have previously investigated have had a black hole at their centers with masses several million times that of the sun. But astronomer David Merritt and his colleagues reported in last week's Nature that galaxy M33--only 3 million light-years from us--contains a black hole that is no bigger than 3,000 solar masses and is potentially much smaller. A black hole is a region of space where the force of gravity is so powerful that nothing, not even light, can escape. Researchers are able to calculate the size of a black hole by measuring the speed at which stars in a galaxy are moving.
Compiled by Times medical writer Thomas H. Maugh II