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.
"We are just beginning to try and figure out quantitatively how all this might smooth a surface," Dr. Thomas said in the May 17, 2013 New Scientist.
Titan is certainly an exotic, fascinating, frigid oddball, that bears an eerie resemblance to the primordial Earth before life emerged and evolved on our planet (prebiotic). In fact, Titan is the only moon in our entire Solar System with a substantial atmosphere. It is also the only known world--other than Earth--where stable bodies of surface liquid exist.