Humankind stretched its legs farther into the solar system early Friday, and in a historic first kicked up some dirt on another planet’s moon. The result: Eerily Earthlike photos of Saturn’s moon Titan.
The European space probe Huygens landed human technology on a cosmic surface farther from Earth than ever, revealing a moon with recognizable features such as river channels, hills and shorelines.
Huygens, a 700-pound wok-shaped lander, lived hours longer than engineers expected, and is beginning to provide a peek at what Earth could have looked like in its infancy.
More discoveries are likely as scientists sort through the 350 images that started streaming late Friday to mission control in Darmstadt, Germany. The best images are expected to debut today.
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, 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.
‘‘I am just delighted,’’ said David Southwood, science chief of the European Space Agency. ‘‘I wanted to know that this (mission) was going to produce unprecedented science, and it has. It’s the end of a wonderful day.’’
Huygens’ arrival at Titan, 900 million miles away, marked the longest distance from Earth that a humanmade spacecraft has ever traveled to make a landing, and the near-perfect journey put a new exclamation point on the four-year, $3.3 billion mission to explore Saturn, its rings and seven of its 31 known moons.
Titan holds a particular fascination for scientists. Not only is it the only moon in the solar system known to have a significant atmosphere — about 1 1/2 times as dense as Earth’s — but it is also regarded as ‘‘pre-biotic,’’ with characteristics that Earth probably possessed before life evolved.
These include an atmosphere composed mostly of nitrogen and the presence of water ice and hydrocarbons — building blocks of life.
Another image, taken about five miles above the surface, showed light and dark masses, which Tomasko said seemed to be shadows, indicating a varied terrain. The dark areas appeared to be flooded or to have been so at an earlier time.
A third image taken at the surface showed several large white chunks — boulders or blocks of water ice — in the foreground and a stretch of gray surface behind them.
‘‘There aren’t too many planets with liquid,’’ Tomasko said. ‘‘There’s Earth, and now there’s Titan.’’
‘‘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 NASA’s 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.
The surface picture presented a forbidding, Mars-like landscape, and Tomasko said the large rocks ‘‘may well be ice boulders,’’ hard as stone in Titan’s frozen wilderness and eroded by the wind.
‘‘We have a scientific success,’’ announced Jean-Jacques Dordain, director general of the European Space Agency, when the Huygens data reached Earth, triggering prolonged cheers and applause from a packed meeting room. ‘‘We are the first visitors to Titan.’’
‘‘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.’’
Applause erupted at mission control in Darmstadt at news of the data transmission from the probe.
‘‘The scientific data we are collecting now shall unveil the secrets of this new world,’’ Dordain said. ‘‘This is a fantastic success for Europe.’’
The heart of the mission was the probe’s 2 1 /2-hour parachute descent, taking pictures and sampling the atmosphere before landing on Titan, where temperatures are estimated at 292 degrees below zero.
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 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 the probe was transmitting to the Cassini mother ship.
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 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.
The probe was designed to shed its heat shield during descent and use a special camera and instruments to collect information on wind speeds and the makeup of Titan’s atmosphere for transmission back to Cassini and relay to NASA’s Deep Space Network in California and to ESA controllers in Darmstadt.
Titan is the only moon in the solar system known to have a significant atmosphere. It is rich in nitrogen and contains about 6 percent methane.
Diaz said Titan may offer hints about the conditions under which life first arose on Earth.
‘‘Titan is a time machine,’’ he 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.’’
The Cassini-Huygens mission was launched on Oct. 15, 1997, from Cape Canaveral, Fla., to study Saturn, its rings and many moons.
Distance from Saturn: 759,200 miles. Titan is one of 33 moons that orbit Saturn.
Distance from Earth: About 750 million miles.
Atmosphere: Orange and opaque, 10 times thicker than Earth’s, reaching 375 miles high off the surface. It’s 95 percent nitrogen with methane and cyanide. Titan is the only moon in the solar system with clouds and a planetlike atmosphere.
Diameter: 3,200 miles, larger than Mercury or Pluto. Second-largest moon — Jupiter’s Ganymede is the biggest — in the solar system.
Orbit around Saturn: Every 15.95
Surface temperature: 288 degrees below zero.
Surface: Until Huygens landed, scientists weren’t certain whether Titan’s surface was solid or liquid. The successful landing indicated that it has a solid surface.
Discovered: In 1655 by Dutch astronomer Christiaan Huygens.