Stacking Dolls in Space: Concentric Bubbles Seen Around Star Cluster

The concentric bubbles, which comprise what researchers call a triple-bubble, are actually three supernova remnants, shells of gas and dust that form following the explosion of a star. This is the first known case of three supernova remnants nesting one inside the other, said the researchers from the Institute of Astrophysics of the Canary Islands (IAC), who made the discovery. The shells provide a unique opportunity to study the remains of these stellar explosions, as well as the the interstell