MARKET 1 Lecture Notes - Lecture 8: Radiography, Black-Body Radiation, Solar Wind
Document Summary
Consists of many different gases, e. g. oxygen, nitrogen, carbon dioxide, water, ozone . Most of the earth"s atmosphere lies within 10km of the surface (tiny fraction of the planet"s mass). You feel the weight of all the air above you! (like a diver in water) 15 lbs on every sq. inch of your body (but from all sides, so net zero) Planetary atmospheres exist in a state of hydrostatic equilibrium: Held up by thermal motion of molecules. Like the sun, the bottom has high pressure, high temperature, high density. The atmosphere is critical for like on earth for many reasons: water is liquid owing to atmospheric pressure and temperature. Mild greenhouse effect makes planet nicely habitable for us. Scatters blue light more, so sky looks blue. Ozone forms at low pressure, absorbs uv light. It protects us from cosmic rays & micro-meteorites: oxygen for us to breathe, co2 for plants.
