Saturn's Largest Moon Titan: A World Much Like Earth

Since its discovery in 1655 by the Dutch astronomer Christiaan Huygens, the surface of Titan has remained largely a mystery. A thick, cloudy atmosphere, largely impenetrable by telescopes and cameras, envelops Saturn's largest moon.

In December 2004, the robotic Huygens probe detached from the Cassini spacecraft and descended into Titan's thick, hazy atmosphere in January of 2005. Lasting a mere 3 hours in the cold atmosphere and on the surface of Titan (about minus 178 degrees Celsius, or minus 289 degrees Fahrenheit), the probe revealed a thick atmosphere, land masses with signs of erosion, and seas of methane on the surface. The Huygens probe came to rest on what appeared to be a floodplain, surrounded by rounded cobbles of water ice.

About 100 kilometers smaller in diameter than Jupiter's moon Ganymede, Titan is the second largest moon in our solar system. With an equatorial radius of 2,575 kilometers (1,600 miles), Titan is larger than both the Earth's moon and the planet Mercury.

Titan orbits Saturn at a distance of about 1.2 million kilometers (745,000 miles), taking almost 16 days to complete a full orbit. Titan is of great interest to scientists because it is the only moon in the solar system known to have clouds, a mysterious, thick, planet-like atmosphere and surface lakes.

•* Source:  http://sse.jpl.nasa.gov/