Shannon McKenzie - Titan: what we know and why we need to go back

Speaker: Shannon McKenzie, Johns Hopkins University

Abstract: Life on Earth seems to require three key ingredients: carbon, water, and energy. In this talk, I will discuss the evidence from the Cassini-Huygens mission for each of these factors at Saturn's largest moon, Titan. Photochemistry in the atmosphere creates haze particles of complex hydrocarbons that obscure the surface in most of the visible and much of the near infrared. These haze particles can be up to the size of DNA and protein molecules found on Earth. Additionally, methane (CH4) plays the same role on Titan that water does on Earth, raining down out of the atmosphere to pool on the surface before evaporating back into the atmosphere. Titan has a subsurface ocean--like other icy satellites Encealdus, Europa, and Ganymede--hidden by a crust of water ice. In order to evaluate the habitability of Titan and explore the bounds of prebiotic chemistry, we need to go back and sample the diversity of materials on Titan's surface and understand how processes at the surface modify the photochemical products that fallout from the atmosphere. Dragonfly, a mission concept is currently in competition in NASA's New Frontier's program, is designed to do exactly that.