On today's Cool Science Radio, Lynn Ware Peek and John Well's guests include:(01:13) Dr. James Garvin, NASA Goddard Chief Scientist and Principal Investigator for the upcoming DAVINCI mission. DAVINCI will explore the evolutionary histories of Venus versus Earth by measuring the detailed chemistry of the atmosphere and local surface using both spacecraft flybys and a descent probe.Then (27:41), NASA’s Dr. Compton Tucker joins the show. Dr. Tucker specializes in studying the earth with satellite data. Among other things Dr. Tucker studies global photosynthesis on land, determining land cover, monitoring droughts, providing famine early warning, and predicting ecologically-coupled disease outbreaks.