The joint mission to Saturn by the Cassini and Huygens spacecraft is a result of international collaboration between NASA, ESA (European Space Agency), and ASI (Italian Space Agency). The Cassini spacecraft orbiting Saturn, its rings, and moons released the Huygens spacecraft that landed on Saturn’s clouded moon Titan on January 14, 2005. The data that is still being sent back by both spacecraft is revealing the amazing world of Titan.

Titan is the only moon in our solar system with a thick atmosphere. The atmosphere is composed of nitrogen, methane, and ethane, with a trace of 2 argon isotopes.

The methane and ethane provide humidity, like water does in Earth’s atmosphere. The average humidity level at Titan’s surface is 45%. Methane on Titan acts as water does on Earth. It rains methane either in a steady drizzle or an occasional deluge. Titan’s lakes are composed of liquid methane. Methane evaporates at the surface, returning into the atmosphere.

One argon isotope indicates an active interior of Titan. Plate tectonics, the movement of large masses of the crust like on Earth, occurs on Titan. As the plates move apart, materials from under the surface emerge and fill the gaps, forming mountain chains like the mid-Atlantic Ridge on Earth. Plate tectonics probably created the mountain ridges on Titan too. There may be an insulating layer of water ice and methane buried inside the moon close to the surface, trapping heat inside it. The heat could cause cryo-volcanoes, or ice volcanoes, that erupt at the surface and spew icy lavas. Cryo-volcanoes have been seen on Titan from the Cassini spacecraft. They are circular features from which icy flows appear to emanate. The second argon isotope indicates that Titan was formed after Saturn was formed.