The Huygens probe photographed pale hills with dark 'rivers' running down to a dark plain. Current understanding is that the hills are composed of water ice. Dark organic compounds rain from Titan's atmosphere and flow down the hills to form the dark plains [14]. The images taken after the probe's landing show a flat plain covered in pebbles. The pebbles, which may be made of water ice, are somewhat rounded, which may indicate the action of fluids on them CICLOPS: Cassini Imaging. Retrieved March 28, 2005.
⇧NASA page: The Story of Saturn/The moons"On March 24, 1655, ... The next day, Christiaan Huygens ... discovered its largest moon, Titan." States the date of discovery. verified 22:00, 29 Mar 2005 (UTC)
⇧ *Bill Arnett (2005). Titan. Retrieved April 10, 2005. "Titan is nevertheless larger in diameter than Mercury"
⇧ ibid. "It was long thought that Titan was the largest satellite in the solar system but recent observations have shown that Titan's atmosphere is so thick that its solid surface is slightly smaller than Ganymede's."
⇧NASA Page: Cassini-Huygens: Operations"Oct. 26, 2004: Cassini makes its first close pass by Titan. Cruising by at a distance of only 1,200 kilometers (750 miles), the spacecrafts radar provides the first detailed glimpses of the moon's mysterious surface."
ibid.
⇧ ibid. "Jan. 14, 2005: The European Space Agency's Huygens probe descends through Titan's cloudy atmosphere, touching down on the surface about two and half hours later."
