Spiral galaxies might be a dime a dozen, but no two of them tend to be exactly the same. This oddball is a spiral oddball to beat all oddballs, called NGC 4275, it lurks around 41 million light-years from Earth in the constellation of Coma Berenices.
Most spiral galaxies, including our galaxy and Andromeda, are characterized by their two (or more) spiral arms. Strangely though, NGC 4275 only has one spiral arm, which can be seen in this color composite sweeping all the way around the galaxy. These structures are called spira mirabilis (or logarithmic spirals). This particular example is also noteworthy for its blue hue, which comes from a large number of high-mass, blue-white stars. The red and purple-tinged colors come from H II regions: regions where star formation activity is taking place.
Additionally, NGC 4275 has an impressive central bar structure, which is home to older populations of yellow-tinged stars, numerous dust-filled lanes, and a bright central core (believed to host a supermassive black hole millions of times heavier than the Sun). Overall, the galaxy spans around 100,000 light-years, across, making it approximately the same size as the Milky Way.
See a larger image here.