Do Magnetospheres Matter?
When: November 27, 2012 3PM PST
A planet’s atmosphere is the net result of source and loss processes acting on it over time. One of the more poorly constrained processes in terms of its role in changing atmospheric abundance is 'escape to space’. This suite of mechanisms, where atmospheric particles are driven from the top of the atmosphere, is often thought to be more efficient at planets lacking global magnetic fields (such as Mars) than at planets with global dynamo magnetic fields (such as Earth) because the solar wind can directly encounter the atmospheres of unmagnetized planets. Thus, it is argued that escape to space could have resulted in the removal of significant amounts of an early Martian atmosphere. We will review the current understanding and outstanding questions about escape to space at Mars, and then discuss whether the presence of a global dynamo magnetic field should significantly influence a planet’s climate and habitability. Applications of these concepts to other planets in our solar system and beyond will be discussed.