View from the Cassini spacecraft of the trailing hemisphere of Rhea. Image Credit:​ NASA/JPL/Space Science Institute (Click to Enlarge)

Rhea is Saturn‘s second largest moon, with a mean radius of 764 km (475 miles) – about 0.4 times the size of the Earth’s Moon and about 0.3 times the size of Saturn’s largest moon, Titan.

Through a small telescope Rhea can be seen as a small point of light orbiting Saturn alongside its other large moons, Titan, Iapetus, Dione and Tethys.

Rhea has a grey, rocky, cratered surface and an extremely tenuous atmosphere of oxygen (70%) and carbon dioxide (30%).

Astronomy, Cosmology, Space and Astrophysics