Epimetheus is the fifth satellite of Saturn and was discovered R. Walker in 1980. The surface presents many valleys and ridges in combination with different crustal deformations. Its heavily cratered surface shows that its surface is billions of years old.
Epimetheus has an orbit of 151,472 kilometers from Saturn's center, the same as Saturn's other moon Janus, and not more than 50 kilometers away from it. A very interesting fact is that Epimetheus and Janus swap orbits due to their close approach to each other once every four years. The momentum that is exchanged flings one inward and the other outward. The two moons may have once had once large parent.
|PHYSICAL DATA FOR EPIMETHEUS|
|Mass (kg)||5.6e + 17|
|Mass (Earth = 1)||9.3708e - 08|
|Radius (km)||72 x 54 x 49|
|Radius (Earth = 1)||1.1289e - 02|
|Mean Density (g/cm3)||0.7|
|Mean Distance from Saturn (km)||151,422|
|ORBITAL DATA FOR EPIMETHEUS|
|Rotational period (days)||0.6942|
|Orbital period (days)||0.6942|
|Mean orbital velocity (km/s)||15.87|
|Orbital inclination (degrees)||0.34|