http://www.planetary.org/news/2006/0724_Cassini_RADAR_Reveals_Lakes_on_Titan_At.html The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's north pole. Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder polar regions. In the images, a variety of dark patches, some with channels leading in or out of them, appear. These two radar images were acquired by the Cassini radar instrument in synthetic aperture mode on July 21, 2006. The top image centered near 80 degrees north, 92 degrees west measures about 420 kilometers by 150 kilometers (260 miles by 93 miles). The lower image centered near 78 degrees north, 18 degrees west measures about 475 kilometers by 150 kilometers (295 miles by 93 miles). Smallest details in this image are about 500 meters (1,640 feet) across.