Cratering in the Solar System

Cratering by impacts with asteroid-like bodies and meteorites has been experienced by the earth, moon, Mars and its two moons, Venus, and Mercury; cratering of the earth's moon and of Mars are described at length, and cratering of the earth (specifically the Canadian shield), Venus, Mercury, Deimos and Phobos is also discussed. Correlations between the spectrum of crater sizes and the spectrum of asteroids and meteorites, primary and secondary cratering, and the time and space variation of cratering are examined. Information on the space environment, on the surface environment (weathering and erosion, tectonic activity, volcanism) and on the age of the cratered bodies, formation of megaregoliths, possible cataclysm-derived asymmetries in planetary geological structure, and a conjectured period of cataclysmic activity dated 4.5 to 4 billion years ago are inferred from the cratering evidence.