Astronomers find a dark matter galaxy far, far away
Galaxies such as our own Milky Way are believed to form over billions of years through the coming together of many smaller galaxies. As a result, it is expected that there should be many smaller dwarf galaxies scattered around the Milky Way. However, very few of these tiny relic galaxies have been observed, which has led astronomers to conclude that many of them must have very few stars or may be made almost exclusively of dark matter.In a discovery announced Jan. 18, a team of researchers including an MIT postdoc has found a dark dwarf galaxy about 10 billion light years from Earth. It is only the second such galaxy ever observed outside our local region of the universe, and is by far the most distant.The newly discovered dwarf galaxy is a satellite, meaning it clings to the edges of a larger galaxy. “For several reasons, it didn’t manage to...