Methane clouds in the troposphere, the lowest part of the atmosphere, appear white here and can be seen moving east over several of Titan's large northern lakes. The darkest areas are lakes and seas of liquid methane, identifiable because they have a low albedo, meaning they do not reflect much light. (The difference in brightness and darkness on the surface here indicates a difference in composition.) The clouds seen near lakes and seas suggest that Titan (5,150 kilometers or 3,200 miles across) may have "lake-effect" clouds created by weather systems over large bodies of liquid. However, without earlier observations to show the clouds did not originate west of the large sea Kraken Mare, scientists can't determine conclusively if these clouds are "lake-effect" clouds.