All terrestrial (rocky) planets within the Solar System bear the scars of past celestial impacts. Craters of all sizes pinpoint locations where meteorite and asteroid debris impacted with unimaginable force. None of the planets or moons escaped the era of the 'Great Bombardment'. Falling material originates from the remains of the galactic cloud which condensed to form the planetary bodies of the Solar System. Impacts were generally larger and more frequent in the past, an indication of the gradual diminishing of potential impact material left in spaceA crater consists of two primary regions, the excavation zone and the deposition zone.
The excavation zone is geologically concave. It is the region carved out by the force of the impact. Here, original surface material has been thrown out in all directions.
The deposition zone is convex. It surrounds the impact excavation. In this region, ejected material has been deposited creating familiar crater walls. Often, lines of debris extend for distances across the planet's surface radiating from the impact site.
Craters exist in sizes from those no bigger than a human hand right up to massive impacts thousands of kilometres across. The size of a crater governs its format. By analysing this size relationship it is possible to determine the planetary structure beneath.
This is where some amazing facts come to light....
