DARMSTADT, Germany - European space officials displayed the first pictures of the surface of Saturn's moon Titan on Friday, black and white images of what appeared to be channels cut by a liquid - like river and streambeds running through hilly terrain.
The pictures were taken from about 10 miles above the surface as the European space probe Huygens descended by parachute to a safe landing, buoying hopes that the mission could shed light on the origins of life on Earth.
"I think all of us continue to be amazed as we watch our solar system unveil," NASA science administrator Alphonso Diaz said as the images were displayed on screens at mission control in Darmstadt, Germany.
"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," he added.
Huygens was spun off from the Cassini mother ship on Dec. 24 before its descent by parachute to the surface of Titan on Friday, capping a seven-year journey.
"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."
"This mission has been like a fantasy come true," she told CNN. "It's a great moment not only for science but for humankind."
David Southwood, the European Space Agency's science director, announced earlier that the probe had relayed scientific data - expected to include pictures and atmospheric measurements - to the mother ship and the information had been transmitted back to Earth.
Applause erupted at mission control in Darmstadt in western Germany at news of the data transmission. The data are expected to shed light on what Titan's atmosphere and surface are made of - and possibly on the origins of life on Earth.
"The scientific data we are collecting now shall unveil the secrets of this new world," said Jean-Jacques Dordain, ESA's general director. "This is a fantastic success for Europe."
Friday's landing makes Titan the only moon other than Earth's to be explored by spacecraft.
The heart of the mission was its 2 1/2-hour parachute descent, during which it was to take pictures and sample the atmosphere, believed to resemble that of the Earth when it was young.
Early signals confirmed it had powered up for entry and deployed the parachute, and officials were confident it had made a safe landing because Huygens was designed to go on transmitting from the surface for at least three minutes before its batteries died - a total transmission of less than three hours. But the signal had kept coming for more than five hours.
Mission officials - who have waited since 1997 for Huygens to reach its destination - had tears in their eyes as the first signal was picked up, indicating that the probe was transmitting to its mother ship, the international Cassini spacecraft.
Named after Titan's discoverer, the 17th century Dutch astronomer Christiaan Huygens, the probe carries instruments to explore Titan's atmosphere and find out whether it has the cold seas of liquid methane and ethane that have been theorized by scientists.
Timers inside the 705-pound probe awakened it just before it entered Titan's atmosphere. Huygens is shaped like a wok and covered with a heat shield to survive the intense heat of entry.
On the way down, it was to shed its shield and use a special camera and instruments to collect information on wind speeds and the makeup of Titan's atmosphere. The data is transmitted back to Cassini for relay to NASA's Deep Space Network in California and on to ESA controllers in Darmstadt.
Titan is the only moon in the solar system known to have a significant atmosphere. Rich in nitrogen and containing about 6 percent methane, its atmosphere is believed to be 1 1/2 times thicker than Earth's.
Alphonso Diaz, science administrator for NASA, said Titan may offer hints about the conditions under which life first arose on Earth.
"Titan is a time machine," Diaz said. "It will provide us the opportunity to look at conditions that may well have existed on Earth in the beginning. It may have preserved in a deep freeze many chemical compounds that set the stage for life on Earth."
Part of a $3.3 billion international mission to study the Saturn system, Huygens is also equipped with instruments to study Titan's surface upon landing.
The Cassini-Huygens mission, a project of NASA, ESA and the Italian space agency, was launched on Oct. 15, 1997, from Cape Canaveral, Fla., to study Saturn, its spectacular rings and many moons.