ASTRO-110 Lecture Notes - Lecture 9: Anaximander, Subduction, Society Of Jesus
9 Sep 2020
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Document Summary
Visible light passes through atmosphere and warms planet"s surface. Atmosphere absorbs infrared light from surface, trapping heat. X rays and uv light can ionize and dissociate molecules. Molecules tend to scatter blue light more than red. Venus would be 510 c colder without greenhouse effect. Earth would be 31 c colder (well below freezing) Runaway greenhouse effect would account for why venus has so little water. More intense sunlight higher temperature increase evaporation oceans evaporate and carbonate rocks decompose releasing co2. Minerals combine with carbon to make rocks on ocean floor. Rocks melt in mantle and outgas co2 back into atmosphere through volcanoes. Cooling allows co2 to build up in atmosphere. Heating causes rain to reduce co2 in atmosphere. Long-term climate change: role of earth"s axial tilt. Changes in earth"s axis tilt might lead to ice ages. Co2 from outgassing will build up if oceans are frozen, ultimately raising global temperatures again.
