This graphic gives a summary of our best current understanding of the evolution of stars, showing their birth, middle age and eventual demise. The lowest mass stars are shown at the bottom and the highest mass stars at the top. The very top line is a new addition, compelled by the detection of SN 2006gy, that describes the evolution of the most massive stars in the universe. Observational evidence for the special type of explosion shown here - which is incredibly bright and obliterates the star rather than producing a black hole - was lacking until SN 2006gy was found. Credit: NASA/CXC/M.Weiss
