Rhea was expected to be just another moon comprised of rock and ice - but that was until the Voyager and Cassini space probes arrived. The yin and yang moon also features an equatorial ridge, rising 13 km above the surface, like a walnut.Ī desolate landscape, with temperatures plummeting to -220 degrees Celsius in the shade, cratered and grey. The most likely responsible process was postulated after a Cassini probe flyby in 2007, thermal segregation, where the darker particles absorb more heat from the Sun, so any brighter volatiles within this region sublime out, and move to the cooler, brighter side, while the dark side becomes even darker. There are few explanations for the dark side of the moon, involving volcanic eruptions of hydrocarbons darkened by chemical reactions initiated by solar radiation, or that the moon is collecting particles from a nearby dark moon, Phoebe. In 1671, Cassini observed this difference and correctly predicted that the moon had two faces, one bright, and one impossibly dark. This made Iapetus difficult to spot, as it mysteriously became brighter and fainter as it completed its orbit of Saturn. Iapetus is tidally locked to Saturn (the same side is always facing the planet), despite the distance from its mother planet. Iapetus © NASA/JPL/Space Science Institute Oh, and if you haven’t worked it out by now, the moon looks like the Death Star from Star Wars. Mimas also disrupts the orbits of much smaller moons, and speeds up when passing the large moons Enceladus and Dione. Mimas is also tidally locked, with the same face towards Saturn throughout its 22.5 hour orbit of the planet. The moon is littered with craters, showing a lack of surface replenishment despite its close proximity to Saturn and elliptical orbit, which should provide enough heat through gravitational tidal activity. The body that struck the moon almost ripped it apart, as evidenced by the fractures on the opposite face of Mimas. The crater measures 130 km across with a 5 km surrounding walls is known as the Herschel Crater, after William Herschel who spotted the moon in 1789. The resemblance of Saturn’s moon Mimas to an iconic moon-shaped fictional space station is largely the fault of a giant impact crater that covers a third of its diameter.

So faraway pinc inc rarest