In this view of two of Saturn’s 60-plus moons, icy Rhea passes in front of Saturn’s largest moon, the enormous Titan. This image was taken by NASA’s Cassini spacecraft on November 19, 2009, at a distance of approximately 713,300 miles (1,148,000 kilometers) from Rhea.
Some of the differences between the two moons are apparent in this image. While Rhea is a heavily-cratered, airless world, Titan’s nitrogen-rich atmosphere is even thicker than Earth’s.
The moons of Saturn are numerous and diverse, ranging from tiny moonlets about half a mile (less than 1 km) across to huge Titan, which is larger than the planet Mercury. You can read about Cassini’s encounters with Saturn’s moons here.
The Cassini spacecraft ended its mission on September 15, 2017.
Bottom line: Cassini spacecraft photo of Saturn’s icy moon Rhea and large moon Titan.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.