The Huygens probe has captured an image of what may be the first drop of liquid ever observed on an extraterrestrial surface. The photo is evidence that liquids may exist on the surface of other planets and moons, not just frozen lakes. And liquid is more likely habitat for extraterrestrial life. Among the pictures snapped by the Huygens probe after landing on Saturn's moon Titan in 2005, one appears to show a dewdrop made of methane that briefly formed on the edge of the probe itself (indicated by arrow at bottom of image on right). Scientists think heat from the probe caused humid air to rise and condense on the cold edge of the craft.