A billion years ago, our Moon was closer to Earth than it is now. As a result, it appeared to be a much larger object in the sky. During that ancient era, if human beings had been around to witness such a sight, it would have been possible to see the entire Moon--not merely the one near side face that we see now. A billion years ago, it took our Moon only twenty days to orbit our planet, and Earth's own day was considerably shorter--only eighteen hours long. Stupendous, almost unimaginably enormous tides, that were more than a kilometer in height, would ebb and flow every few hours. However, things changed, as the lunar orbit around our primordial planet grew ever wider and wider. Annually, Earth's Moon moves about 1.6 inches farther out into space. Currently, the lunar rate of rotation, as well as the time it takes to circle our planet, are the same.
Other than the sun, no other celestial body significantly affects the earth as the moon does. It is well know that the moon affects the rise and fall of the ocean tide. Such is the effect of the gravitational pull between the earth and the moon. Jupiter is easily the largest planet in our solar system. To put its size in context, Jupiter is more than 300 times the mass of Earth. Here is the interesting part; Jupiter has 63 moons that orbit it and yet it is not the planet in the Solar System with the most moons. That honor belongs to the ringed-planet Saturn, which has 66 moons identified so far. Pluto, the farthest flung among the nine planets, has been the subject of heated debate on whether it really qualifies to be considered a planet. Nowadays, it is classified as a dwarf planet. Its orbit around the Sun is somewhat heavily elliptical. In fact, there are instances where Pluto is actually closer to the Sun than Neptune, the planet that precedes it.
"Impact simulations indicate that impacts into a hot, thin crust representative of the early Moon's near-side hemisphere would have produced basins with as much as twice the diameter as similar impacts into cooler crust, which is indicative of early conditions on the Moon's far-side hemisphere," noted lead study author Dr. Katarina Milijkovic in the November 7, 2013 JPL Press Release. Dr. Milijkovic is of the Institut de Physique du Globe de Paris.