"I'm glad we're here" is the start of this talk by Dave Brain. What does it take for a planet to be hospitable for life? On how many planets could we use a compass to find north (and what does that have to do with it)?

Dave Brain is an assistant professor in the Laboratory for Atmospheric and Space Physics and the Department of Astrophysical and Planetary Sciences at the University of Colorado. As a planetary scientist, he studies the interaction of unmagnetized planets such as Mars and Venus with their space environment. This topic is exciting to him because charged particles and magnetic fields from the Sun are believed to have fundamentally altered these bodies over the past 4+ billion years. By studying processes that occur there today we hope to unravel how these and other planets evolved, and why their atmospheres are so different from our own. He is a Co-Investigator for the MAVEN mission currently orbiting Mars.

This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at http://ted.com/tedx