NASA has featured an image of Enceladus, a moon of Saturn, in its Astronomy Picture of the Day. The image, taken by the Cassini spacecraft on November 1, 2009, shows Enceladus in silhouette, backlit by the Sun. This dramatic illumination reveals the plumes of ice that continuously spew into space from the south pole of the moon.
The icy plumes, discovered by Cassini in 2005, are believed to be connected to an ocean beneath the ice shell of Enceladus. These plumes supply material to Saturn's outer E ring and make the surface of Enceladus highly reflective. In the image, Saturn's icy rings can also be seen scattering sunlight towards the Cassini spacecraft's cameras.
In the lower right corner of the image, the night side of Pandora, another moon of Saturn, can be faintly seen lit by Saturn's light. The image was captured by the Cassini Imaging Team and is a collaboration of several space agencies and institutions, including NASA, the European Space Agency, and the Jet Propulsion Laboratory.
The Astronomy Picture of the Day is a service provided by NASA and Michigan Tech University.