ASTRO-110 Lecture Notes - Lecture 15: Runaway Greenhouse Effect
9 Sep 2020
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Document Summary
Chemical elements needed for life likely occur in all planetary systems. Consequence of how planets form from their parent proto- planetary nebulae. Amino acids and complex organic molecules require a liquid or gas to form and move about. Need either an atmosphere or an ocean. Sunlight is everywhere in solar system, although its intensity decreases with distance from the sun. Liquids are needed for: dissolution of chemicals, transport, metabolic reactions. Liquid has to be present in abundance - only water and molten rock on earth. At higher temperatures faster chemical reactions. Surface can not be seen from the earth. Without the atmospheric greenhouse effect, surface temperature would be ~35 c. Russian landers in 1970"s and 1980"s venera-1 and venera-2 revealed: thick atmosphere: Possibly only in the distant past. will never know - evidence erased by geological processes. One of the best candidates for life beyond the earth. Very high densities and pressures in interiors.
