Saturn’s fourth-largest moon, Dione (698 miles or 1,123 kilometers across), can be seen through the haze of the planet’s largest moon, Titan (3,200 miles or 5,150 kilometers across), in this view of the two posing before the planet and its rings.
Titan is the only moon known to have a dense atmosphere, and the only object in space other than Earth where clear evidence of stable bodies of surface liquid has been found. Many of the gases that make up Titan’s brown haze were hydrocarbons, theoretically formed via the recombination of radicals created by the Sun’s ultraviolet photolysis of methane.
In the photo, north is up on the moons. This view looks toward the northern, sunlit side of the rings from just above the ring plane.
Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft narrow-angle camera on May 21, 2011, at a distance of approximately 1.4 million miles (2.3 million kilometers) from Titan and 2 million miles (3.2 million kilometers) from Dione. Image source: NASA