AST101H1 Chapter Notes - Chapter 10: Solar Wind, Planetary Science, Thermosphere

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Michael Reid

Document Summary

Collisions of individual atoms or molecules in an atmosphere create pressure that pushes in all directions. In planetary science, we usually measure atmospheric pressure in a unit called the bar (as in barometer). An atmosphere is a layer of gas that surrounds a world. It can create pressure, absorb and scatter sunlight, create wind and weather, interact with the solar wind to create a magnetosphere, and cause a greenhouse effect that can make a planet"s surface warmer than it would be otherwise. Gases that are particularly good at absorbing infrared light are called greenhouse gases, and they include water vapor, carbon dioxide, and methane. Greenhouse effect a greenhouse gas molecule that absorbs an infrared photon does not retain this energy for long; instead, it quickly reemits it as another infrared photon, which may head off in any random direction. These photons can then be absorbed by another greenhouse molecule, which does the same thing.