Saturn's moon Titan reveals its atmosphere in this image taken by Cassini as the spacecraft passes 900,000 miles (1.4 million km) away. Titan is unique among the moons in our solar system; it is the only moon with a thick atmosphere composed mainly of nitrogen, small amounts of methane, and trace amounts of carbon-rich compounds that rain down on Titan's surface.
Titan is one of the most promising places to look for life in our solar system, suspected of having a vast ocean of liquid water hidden beneath its surface. But life on Titan would be very different from life on Earth, with rivers and lakes of liquid methane spread across its surface, an atmospheric pressure 60 times that of Earth, and a surface temperature of -290 degrees Fahrenheit or -179 degrees Celsius.
The Cassini spacecraft is imaging the night side of Saturn's largest moon and sees sunlight scattering through Titan's atmosphere to form purple and grey rings. Titan appears primarily black, with a hint of yellow highlighted against its atmosphere and the darkness of space.
Isn't that a great phone background?