The astronomers studied the cloud at visible and ultraviolet wavelengths, which demonstrate that the Antlia object is indeed a supernova remnant. In particular, the visible light shows spectral signatures of shock waves, which result when high-speed gas from a supernova slams into gas around it. “The evidence for it being shocks in a supernova remnant seems to be very good,” says Roger Chevalier, an astronomer at the University of Virginia in Charlottesville not involved with the new work. He notes that the team detected red light from sulfur atoms that are missing one electron, a hallmark of ...