Lakes and Seas on Titan, and an Ocean Within

Elizabeth Turtle and Ralph Lorenz, Space Department, JHU Applied Physics Lab

Abstract:

Titan was long speculated to have surface liquids, and the one-dimensional model that emerged in the 1980s, after Voyager, was of a deep, global ocean of ethane and methane. The reality, as revealed by Cassini, is much more interesting and complex. Lakes with morphologies suggesting different formation mechanisms (e.g. karst, flooded terrain) appear around both poles, but not at the dune-covered low latitudes. Titan's hydrological cycle is not yet understood - clouds appear at specific latitudes and seasons, but river channels are present at all latitudes. In addition to the surface observations, precision radar measurements of Titan's rotation state suggest that a water-ammonia liquid layer exists beneath an ice crust : it appears that seasonal changes in Titan's zonal winds torque the crust around easily enough to require that the crust is decoupled from the core. We will present Cassini observations of Titan’s lakes, seas and clouds, and discuss the implications of the radar observations for Titan’s interior structure.