AST101H1 Lecture Notes - Lecture 14: Lunar Mare, Earth Radius, Impact Crater
23 Nov 2017
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Lecture 14 terrestrial worlds: moon, mercury, venus and earth. Small worlds: the moon and mercury: both are small, therefore, they are similar, cooled down long ago. No volcanism or tectonics: no outgassing, no atmosphere. No erosion: some ancient signs of geological activity, from before they cooled. Geological history of the moon: lots of craters, but also smooth dark lunar (cid:498)maria(cid:499, maria were made by floods of lava when the moon was geologically active. Formation of lunar maria: early surface is covered with craters, large impact crater weakens crust, heat build-up allows lava to well up to surface, cooled, lava is smooth, dark and has less craters. The maria formed after the heavy bombardment period, but before the moon cooled down. Tectonic features on the moon: wrinkles arise from cooling and contraction of a lava flood. The moon is geologically dead: geological processes have virtually stopped, the apollo astronauts" footprints will remain for millions of years.
