The Cartwheel Galaxy (ESO 350-40) in the constellation of Sculptor is 500 million light years distant and 150,000 light years across, and thus is slightly larger than our Milky Way Galaxy. This image is 15′ x 15′ (arcminutes) and the galaxy is about 1.4′ x 1.0′. It has a central yellow core surrounded by a bluish ring with what appears to be curved “spokes” in between, like spiral arms. The ring is knotted and contains may regions of new star formation. There are two smaller galaxies adjacent to the Cartwheel galaxy toward the upper left (northeast). It is thought that one of these two galaxies passed through the Cartwheel Galaxy when it had a more typical spiral shape. The collision distorted the shape of the Cartwheel galaxy into the ring shape that we see today, and, in the process, caused the new star formation in the ring.
The Hubble Space Telescope’s image is shown below (http://www.spacetelescope.org/images/potw1036a/):