02. Retaining an Atmosphere
The Atmosphere, the Ocean and Environmental Change (GG 140) There are other ways in which we can perceive the existence of the atmosphere, predominantly through our perceptions of pressure. Not all planets have atmospheres, and the existence of an atmosphere depends on the ability of gas molecules to remain trapped close to a planet by its gravitational force. The molecular velocity of each gas molecule depends upon its molecular weight, and must exceed the escape velocity of the planet to leave the atmosphere. 00:00 - Chapter 1. How Do We Sense Pressure? 02:42 - Chapter 2. Escape Velocity 08:31 - Chapter 3. Molecular Velocities 22:26 - Chapter 4. Which Planets have Atmospheres and Why? 29:30 - Chapter 5. Planetary characteristics in relation to their atmospheres 44:18 - Chapter 6. Vertical Profile of Temperature in the Atmosphere Complete course materials are available at the Open Yale Courses website: http://oyc.yale.edu This course was recorded in Fall 2011.