NATS 1880 Lecture Notes - Lecture 10: Runaway Greenhouse Effect, Solar Wind, Carbon Cycle
25 Jun 2017
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Document Summary
Chapter 10: the nature & evolution of habitability. Habitable zone: range of distance around sun/star which a planet can have surface temperatures that allow for abundant liquid water (not frozen & not runway gg effect) Earth-like: only worlds similar to earth (aka: range where liquid water is possible) Not suf cient: habitable zone doesn"t = life (ex: our moon) Zone changes: as stars brighten with age, habitable zone moves further outward. Possible in subsurface water from geological, orbital resonance & radioactive heating. Orphan planet: earth-size planet with thick atmosphere, ejected from solar system & becomes free- oating with thick atmosphere - retain heat = surface water & life. Other liquid: possibly habitable if planet has thick atmosphere that will hold surface liquid (methane, etc. ) at far distances from habitable zone. Venus: why is it so hot? (470 c) Proximity to sun: not responsible for heat, if so, venus would only be < 30 c than earth.
