Planetary Science Seminar

Earth and Titan are unique in the Solar System as the only planetary bodies with active hydrologic cycles that include reservoirs of stable, surface liquid. Titan's methane hydrologic cycle has been observed to include exchange between the surface and atmospheric reservoirs that is driven by seasonal variation in the distribution of solar energy. Recently, as the summer season approaches in the northern hemisphere, where greater than 99% of Titan's liquids are located, the Cassini orbiter has detected anomalously bright features in the seas. These features are unlikely to be SAR image artifacts or permanent geophysical structures and thus their appearance is the result of an ephemeral phenomenon on Titan. They are found to be more consistent with floating and/or suspended solids, bubbles, and waves than tides, sea level change, and seafloor change and based on the frequency of these phenomena in terrestrial settings, waves is considered to be the most probable hypothesis. These transient features are the first instance of active processes in Titan's lakes and seas to be confirmed by multiple detections and demonstrate that Titan's seas are not stagnant but rather dynamic environments.