Xkcd Rover Spirit

Earth's Moon Reveals An Ancient Secret. Many astronomers think that during an ancient era, termed the Late Heavy Bombardment, our young Moon was violently battered by a marauding multitude of invading asteroids that crashed onto its newly formed surface. This attack of pelting objects from space occurred about 4 billion years ago, and the shower of crashing asteroids excavated impact craters, and also slashed open deep fissures, in the lunar crust. This sustained shower of merciless impacts increased lunar porosity, and opened up an intertwining network of large seams under the Moon's surface. An Icy Nest Of Space Eggs. Methone is actually only one member of an icy nest of Space eggs, which also includes the very strange and smooth moons of Saturn, Pallene and Aegaeon. Aegaeon is a very, very small moonlet that also twirls around between Mimas and Enceladus. Like Methone, Aegaeon displays a mysteriously unblemished surface. The three little moons (Methone, Pallene, and Anthe) orbit at very similar distances from Saturn, and they have a dynamical relationship. Mimas disturbs the trio of little moons, and causes the orbit of Methone to vary by as much as 20 kilometers (12.4 miles). Mimas causes the orbit of Pallene to vary by a slightly smaller amount--but it has the greatest influence on the orbit of the moon Anthe.