Astronomy 2021A/B Study Guide - Final Guide: Runaway Greenhouse Effect, Circumstellar Habitable Zone, Star System
13 Apr 2014
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Document Summary
Sun brightens with time so we expect a habitable zone to move outward with time. It is possible for life to exist outside of the habitable zones: these worlds could not have complex life (micro, subsurface oceans or in little pockets of water, liquids other than liquid water. Ethane (titan is the only planet that meets this criteria) Runaway greenhouse effect produced by atmospheric carbon dioxide. Has 200,00 times more of atmospheric co2 than earth: however they have the same total amount of co2 (just in locations, venus = all in atmosphere, earth = in carbonate rocks or dissolved in oceans. Venus lacks this cycle as it has no water in which carbon dioxide can dissolve. Has no magnetic field so solar wind strips away gas easily. This is proven through deuteurium atoms: rare deuteurium atoms are more common as they are twice as heavy and couldn"t escape to space. 100 times higher on venus than on earth.
