AST101H1 Lecture : AST101 Lecture - October 26.pdf
15 Mar 2014
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AST101H1 Full Course Notes
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Document Summary
Things orbit the sun and collide with each other at speeds of 10-30 kilometers per second. Fast enough to vaporize some rock and make an explosion. Larger impacts can produce shock waves which rebound off the planets" interior layers and thrust up the crater"s centre, making a central peak or terraces. Plate tectonics - movement of the continents - active geology. 1. accretion (hit it with stuff) - heat energy comes from motion and gravity - mainly happened in the early solar system. 2. differentiation (dense stuff sinks and less dense stuff rises) - heat energy comes from gravity - happened most when planets were young. 3. radioactivity (radioactive atoms decay) - heat energy comes from radioactive elements, made previously in exploding stars - strongest when young but can continue for billions of years. Convection: hot stuff rises, cool stuff sinks - heat is carried by hot material moving to a cooler area, e. g. boiling.
