01:750:109 Lecture Notes - Lecture 17: Gravitational Energy, Terrestrial Planet, Main Source
2 Nov 2018
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Document Summary
Venus is similar in size to earth. Mars diameter is half of earth (size of earth"s core) Geological activity depends primarily on planetary size. All planets were hot when they formed. Accretion and differentiation when planets were young. Radioactive decay is most important heat source today. Nuclear reactions release energy (extra source of energy in planets) Main source of internal energy of the earth. Unstable isotopes of heavier elements sunk to the core. Amount of internal energy proportional to the volume. Heat flows spontaneously from high temperature to low temperature regions (property of our universe) Gradient (difference) of temperatures within the planets (heat flows up to cooler areas) Temperatures increase from surface to center of planets. Convection transports heat as hot material rises and cool material falls. Loss of heat through surface of planet. The bigger an object, the more energy it has.
