AST101H1 Chapter Notes - Chapter 10.1-10.6: Thermostat, Cool Air, Escape Velocity

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Bryan Gaensler

Document Summary

Mixture of gases that may consist of atoms or molecules. Collisions of individual atoms and molecules = pressure in all directions. Pressure holds up atmosphere and keeps from collapsing under weight. Higher altitude = less weight of gas above. Some of visible light is absorbed or reflected. Without greenhouse effect, only distance from the sun and reflectivity would determine temperature. Can ionize any atom or molecule - absorbed by all atmospheric gases. Scattering = bright daytime sky, otherwise light would travel in straight lines (black sky and black shadows) Gas molecules scatter blue molecules more effectively --> colour of sky. Stratosphere has heat from absorption of solar ultraviolet light by ozone. Stratified: layers of warm over cooler - no weather or rain. Earth is the only planet with stratosphere - must have an atmosphere that can absorb ultraviolet photons (ozone) Increase heat, but lower density and pressure = can"t feel. Ionize gas in thermosphere: ionosphere --> radio communications.