Astronomy 2021A/B Study Guide - Midterm Guide: Cambrian Explosion, Solar Wind, Tidal Locking
2 Oct 2015
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Lecture 5 chapter 6: when did life begin, stromatolitic, microfossil, and isotopic evidence point to life originating. Is the impact threat a real danger or media hype: dangerous impacts, albeit very rare, are a real danger, cratering evidence on earth and the moon show that they have occurred with regularity in the past. Impacts pose a threat, but the probability of a major impact during our lifetime is small. Jupiter and saturn: negative: uranus and neptune: unlikely, may have oceans of water and other liquids in deep interior of. In all cases robotic spacecraft, carry their own propulsion, power, and communication systems: can operate under preprogrammed control or with updated instructions from ground controllers. Differences in cratering across surface: regions densely cratered: old, fewer craters: younger. Rovers have found rocks that appear to have formed in water. Gullies in crater walls may indicate recent water flows. Orbital images of eroded craters, dry river channels, floodplains point to past water flows.
