Two largest moons of Saturn, Titan (1st) and Rhea (2nd) appear to be stacked on top of each other in this true-color scene. This view was obtained on June 16, 2011 at a distance of approximately 1.1 million miles (1.8 million kilometers) from Rhea and 1.5 million miles (2.5 million kilometers) from Titan and looks toward the Saturn-facing side of Rhea.
Rhea is the second-largest moon of Saturn (949 miles or 1528 kilometers across) and the ninth-largest moon in the Solar System. It is also the second smallest body in the Solar System which precise measurements have confirmed a shape consistent with hydrostatic equilibriumNotes 3 (the smallest is the asteroid and dwarf planet Ceres, the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter, which has a diameter of approximately 587 miles / 945 kilometers).
Rhea was discovered by Giovanni Domenico Cassini on 23 December 1672. Image source: NASA