Astronomers from the Lawrence Livermore National Laboratory and the University of California captured the images using Hawaii's Keck Telescope, the world's largest telescope. The astronomers used a near-infrared technique to penetrate Titan's thick, smoggy atmosphere. The images have at least twice the resolution of any previous picture of Titan.

The pictures show a dark area that may be an ocean of methane, ethane or other hydrocarbons. If so, this would be the first uncovered ocean found on an extraterrestrial body. (Jupiter's moon Europa, by contrast, is believed to have subterranean oceans beneath layers of ice.)

The most likely explanation is that the dark area is "a big body of liquid," says Bruce Macintosh, an astrophysicist at Livermore. "If so, then you can stand on the beach of it -- and be very cold."

Titan's surface temperature is about -290 degrees F (-180 C).

An alternative explanation, says Macintosh, is that the dark material consists of solid organic matter -- similar to the building blocks of life on Earth. However, he says of Titan, "Obviously, there's not going to be any life, because there's no water and it's way too cold."