AST 2002 Lecture Notes - Lecture 21: Escape Velocity, Sedimentary Rock, Volcanism
Document Summary
Movement of rock by ice, liquid, or gas: valleys shaped by glaciers, canyons carved by rivers, sand blown by wind. Erosion not only wears down features, it also builds them: sand dunes, river deltas, sedimentary rock. Impact cratering: # of impacts same for all planets, larger planets eras more craters. Volcanism & tectonics: requires interior heat, retained longer by large planets. Erosion: requires an atmosphere, large size for volcanic outgassing, moderate distance from sun, fast rotation needed for wind. A layer of gas which surrounds a world is called an atmosphere: they are usually very thin compared to planet radius. Pressure is created by atomic & molecular collisions in an atmosphere: unit of measure: 1 bar= 14. 7 lbs. /inch2= earth"s atmospheric pressure at sea level. The more atmosphere above you, the greater the pressure. Greenhouse effect: makes the planetary surface warmer than it would be otherwise.
