M83 spiral galaxy. Artist's illustration of M83 (NGC 5236), a spiral galaxy in the constellation of Hydra. The M83 galaxy is about 27 million light-years away from Earth and is receding from us at a little over 500 kilometers per second. It has a diameter of around 30 thousand light years, and a mass similar to the Milky Way. A large proportion of the stars in M83 are young hot stars lying in the galaxy's spiral arms. The brighter stars amongst them are short-lived and die as supernova. In our own galaxy such an explosion is expected to occur about once every 30 to 50 years, but in M83 supernova occur every 10 to 15 years, more frequently than in any other galaxy.