Methane drizzle on Titan

Saturn's moon Titan and the Earth are the only Solar System worlds where rain reaches the surface. Titan's rain may not be much like ours, as it's methane rain, and the atmospheric cycles of water and methane are very different. Two papers this week offer clues as to what a rainy day on Titan might be like. Hueso and Sánchez-Lavega use a numerical model to show that severe methane convective storms accompanied by intense precipitation may occur in certain conditions. These storms would be comparable to flash flood events on Earth. Tokano et al. present methane distribution and temperature data from instruments on board the Huygens probe. Huygens recently took images of landscapes suggestive of rivers or lake-beds, but the camera did not show any liquid. The new data point to the presence of weak drizzle-like rain. In contrast to clouds observed by telescopes or the Cassini spacecraft, the barely visible clouds encountered by Huygens are widespread, suggesting that rainfall occurs globally and may affect Titan's surface structures.