DARMSTADT, Germany - A European space probe Friday sent back the first detailed pictures of the frozen surface of Saturn's moon Titan, showing stunning black and white images of what appeared to be hilly terrain riddled with channels or riverbeds carved by a liquid.
One picture, taken about 10 miles above the surface as the Huygens spacecraft descended by parachute to a safe landing after a seven-year voyage from Earth, showed snaking, dark lines cut into the light-colored surface.
"Clearly there is liquid matter flowing on the surface of Titan," said scientist Marty Tomasko of the Lunar and Planetary Laboratory at the University of Arizona, in Tucson, which made the probe's camera.
He said the liquid appeared to be flowing into a dark area at the right side of the image.
"It almost looks like a river delta," he said. "It could be liquid methane, or hydrocarbons that settled out of the haze" that envelops Titan.
Titan is the first moon other than the Earth's to be explored. Scientists believe its atmosphere is similar to that of the young Earth, and studying it could provide clues to how life arose here.
"I think all of us continue to be amazed as we watch our solar system unveil," NASA science administrator Alphonso Diaz said as the extraordinary images were displayed on screens at mission control in Darmstadt.
"It challenges all our preconceptions that all these planets are static places. Seeing a planet emerge that has dynamics and complexity to it is just amazing."
Huygens was spun off from the Cassini mother ship on Dec. 24 before its descent to the surface of Titan. The mission is a joint effort among NASA, the European Space Agency and the Italian space agency.
Scientists say they received more than three hours of data from Huygens' descent, and more than 10 minutes of data from the surface itself.
"I'm shocked. It's remarkable," said Carolyn Porco of the Cassini Imaging Center. "There are river channels. There are channels cut by something ... a fluid of some sort is my best guess."
The probe was named after Titan's discoverer, the 17th century Dutch astronomer Christiaan Huygens.