ASTR 101 Lecture 29: The Dynamic Earth, Plate Tectonics
20 Nov 2016
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Lecture 29 - the dynamic earth, plate tectonics. Plate tectonics is key for discovering life on other planets. There are small and global scales of earth activity. Energy that drives this is convection motion; like boiling water; churning motion. Went on expeditions and make well made maps. Fossil records are found on different continents but are very similar. Plate tectonics happened in <5% of the earth"s age. Wegener had a problem; didn"t know how it happened. Died before he was able to modify his theory. 6 evidences: undersea ridges; with upwelling materials. Undersea black smokers" are signi cant to astronomy; active life around them but proves life is possible in extreme environments. Europa (jupiter"s moon) has icey surface; nasa sent satellites and they found that there"s possible a body of water (like lake or ocean) that has similar convection motion: rift valleys. Movements of plates and land; move 1cm/year, so 10 km/million year.
