METHANE LAKES ON TITAN

Abstract

IT'S OFFICIAL: The northern hemisphere of Saturn's giant moon Titan is dotted with liquid hydrocarbon lakes. The finding vindicates a long-standing prediction that Titan, shrouded in dense nitrogen and methane clouds, should also have reservoirs of liquid—likely methane—on its surface. Images showing the taken by NASA's Cassini spacecraft as it scanned the northern area of Titan with its cloud-piercing radar, were initially released last July. Now, after detailed scrutiny, scientists are confident that they're seeing about 75 some enclosed by craterlike rims and some intersected with riverlike channels ( Nature 2007 , 44s, 61). They have so many characteristics expected of lakes, says Ellen R. Stofan, a planetary scientist at Proxemy Research in Laytonsville, Md., who is on the Cassini radar team. The discovery also adds weight to the idea that cold, dense methane on Titan participates in a cycle of evaporation and precipitation as does water here on Earth. This ...