This illustration shows the location of the 43 quasars scientists used to probe Andromeda’s gaseous halo. Quasars are extremely distant, brilliant cores of galaxies powered by star-eating black holes.

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. This illustration shows a stage in the predicted merger ...

The Andromeda Galaxy, shown here with two of its satellite or companion galaxies, is one of few objects in the night sky visible with the unaided eye that's outside our own Milky Way Galaxy. And I do ...

Both the Milky Way and the Andromeda galaxy (M31) are giant spiral galaxies in our local universe. And in about 4 billion years, the Milky Way and Andromeda will collide in a gravitational sumo match ...

In the next several billion years, our Milky Way Galaxy will merge with the neighboring Andromeda Galaxy, which is now some 2.5 million light-years away. Currently, Andromeda’s disk of stars is a few ...