Origin of radioactive space material finally identified

Two small stars that collided thousands of years ago are at least partly responsible for a strange signature astronomers are seeking to understand.

Over 2,500 years ago, two small stars collided. The collision produced an outburst called a red nova, which then slowly cooled, producing molecular gas and dust. By the time the light from the nova reached Earth in 1670, astronomers were already keenly observing heavens with telescopes. They noted the event and kept records as the outburst faded over nearly two years. Recently, astronomers took a closer look at the remnant and saw a something never seen in space before — an object producing radioactive elements. Read more.