Q&A: Dark matter next door?

Astrophysicists Eric Charles and Mattia Di Mauro discuss the surprising glow of our neighbor galaxy. Astronomers recently discovered a stronger-than-expected glow of gamma rays at the center of the Andromeda galaxy, the nearest major galaxy to the Milky Way. The signal has fueled hopes that scientists are zeroing in on a sign of dark matter, which is five times more prevalent than normal matter but has never been detected directly. Researchers believe that gamma rays--a very energetic form of li...