Hanny's Voorwerp (Hanny's Object in Dutch), shot here by NASA's Hubble Space Telescope, appears to be a strange green blob floating in space near a normal-looking galaxy. Hanny's is actually the only visible part -- the size of our own Milky Way Galaxy -- of a stream of gas that stretches around the galaxy for 300,000-light-years. "The greenish Voorwerp is visible because a searchlight beam of light from the galaxy's core illuminated it," NASA explained. "This beam came from a quasar, a bright, energetic object that is powered by a black hole. The quasar may have turned off about 200,000 years ago."
The yellowish-orange area seen at the top of the Voorwerp is a pocket of star clusters; the youngest are a few million years old.
Image: NASA, ESA, W. Keel (University of Alabama), and the Galaxy Zoo Team.
View more Pictures of the Day.
We want to hear what you think about this article. Submit a letter to the editor or write to email@example.com.