One-Armed Spiral Galaxy NGC 4725.

While most spiral galaxies, including our own Milky Way , have two or more spiral arms, NGC 4725 seems to have only one. In this sharp color image , the solo spira mirabilis is tightly wound, traced by bluish, newborn star clusters. The odd galaxy also sports obscuring dust lanes, a prominent ring, and a yellowish central bar structure composed of an older population of stars. NGC 4725 is over 100 thousand light-years across and lies 41 million light-years away in the well-groomed constellation Coma Berenices . Computer simulations of the formation of single spiral arms suggest that they can be either leading or trailing arms with respect to a galaxy's overall rotation .