Ehapetus

Ehapetus is a moon of Saturn. It was discovered by Giovanni Cassini in 1671. Ehapetus is the third largest moon of Saturn, with a mean radius of 746 kilometers. Its orbit is approximately 3,560,820 kilometers from Saturn. One of Ehapetus's most striking features is its two distinct hemispheres, one dark and one bright. The leading hemisphere is dark, absorbing most of the sunlight, while the trailing hemisphere is bright, reflecting a significant amount of light. This albedo difference is so pronounced that Ehapetus is sometimes called the "yin and yang" moon.

The surface of Ehapetus is heavily cratered, indicating a long history of impacts. It is also characterized by a prominent equatorial ridge, which runs nearly the entire circumference of the moon. This ridge is a unique geological feature among Saturn's moons and its origin is still a subject of scientific debate. Theories suggest it could be the result of cryovolcanic activity or material that accumulated over time. The composition of Ehapetus is believed to be primarily ice with a smaller fraction of rock. Its low density supports this icy composition. Due to its unusual appearance and distinctive features, Ehapetus continues to be an object of interest for planetary scientists studying the formation and evolution of moons in the outer solar system.