Astronomers at Keck Observatory in Hawaii have found a quartet of quasars, embedded in a giant nebula of cool, dense gas. The odds of four of them being so closely packed purely by chance is about 1 in 10 million.
A dark halo of gas that envelopes our neighboring Andromeda galaxy is 1,000 times more massive than previously measured and stretches halfway to the Milky Way.
Mysterious Spot 5 - most prominent of Ceres' bright spots - is shown to consist of many smaller spots in a new image from the orbiting Dawn spacecraft.