When massive stars explode they create large radioactive blast clouds which expand into interstellar space. As the radioactive elements decay, they produce gamma-rays. Possible locations of these stellar explosions known as supernovae, are indicated by the bright clumps in this map of the central regions of our Milky Way Galaxy. The map was made by a telescope onboard NASA's orbiting Compton Gamma Ray Observatory using detectors sensitive to gamma rays from the decay of radioactive aluminum.