ASTR 1101 : Astro Exam 3 Notes
Document Summary
10/25/2011 8:46:00 pm: iron and dense chemicals sink to center and less dense materials float up. As a result of differentiation, the earth has the layered structure that we see today. Continental drift: alfred wegener, 1915: continental drift jigsaw puzzle. Plate tectonics: heat pushes up form the core, separating the plates, earthquakes largely come from tectonic plates moving against each other. Convection within the earth: convection moves hot water form the bottom to the top; where it cools, moves laterally, sinks, and warms, and rises again. Radioactive decay: as earth"s radioactive elements decay, there is less heating of the interior, and plate tectonics starts slowing down. Plate tectonics on venus: we do see volcanoes on venus, but this does not imply plate tectonics. Gassy planets trap so much gas, that it increases the actual mass, causing a higher escape velocity, which causes a runaway process: the farther from the sun, the less the density.
