Marina Cassini



Full moons make for a wonderful setting for criminal activity, as we find in detective novels. It's that night when the gruesome murderer commits the ghastly crime and is seen by a non-descript, aged neighbor. The neighbor's claim to credibility in the witness box is the fact that there was a full moon on the night in question and everything was there for all to see; it was only a matter of chance that he or she was the only one to spot it! Full moon nights also offer the perfect cover for the snooping detective to hide behind the bush with his dim-witted assistant in tow. 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. Tracing our Moon's changing porosity may ultimately help astronomers to track the trajectory of the invading army of a multitude of lunar impactors, that occurred during the Late Heavy Bombardment, 4 billion years ago.