JPL atmospheric scientist Annmarie Eldering is Deputy Principal Investigator for the Tropospheric Emission Spectrometer (TES) on the Earth observing satellite called Aura. She'll tell us how it is helping us understand our planet's thin, life-preserving layer of air. Emily Lakdawalla's Q&A updates the Genesis solar wind mission. Mat Kaplan gets the night sky lowdown from Bruce Betts in a rather frigid edition of What's Up! All that and a new space trivia contest.