Astronomy Picture of the Day

Explanation: The long winding arms of this nearby spiral galaxy define it as the "Southern Pinwheel." But M83 is quite a typical spiral - much like our own Milky Way Galaxy. Spiral galaxies contains many billions of stars, the youngest of which inhabit the spiral arms and glow strongly in blue light. Dark dust lanes are mixed in with the stars and help define M83's marked spiral structure. The space between the spiral arms is also filled with stars - but stars that are typically more dim and red. M83 has shown an unusual amount of stellar supernovae explosions - six since the turn of the century - more than any other Messier galaxy.