Scientists have finally looked behind the veil of gas that has shrouded Titan, Saturn's largest moon, from human eyes for all of known history.

And they are overwhelmed with both what they've seen and how well they were able to see it.

"This will undoubtedly go down in history as one of, if not the, biggest single step that mankind has taken," Bob Mitchell of the NASA Jet Propulsion Laboratory said.

Amateur astronomer Denis Legault echoed that wow factor Saturday, saying: "We're looking at this object as a tiny dot in our telescopes and now we're actually landing on it. It's very exciting."

Space officials worked overnight to sharpen photos taken by the space probe Huygens -- part of the Cassini-Huygens mission -- as it landed on Titan Friday, cause for huge celebration at the European Space Agency.

The pictures showed a pale orange surface blanketed by a dense fog of methane and what appeared to be a methane sea with islands and a coastline.

They were taken from about 16 kilometres above the surface as the probe made a soft parachute landing.

The surface itself appears to be "material which might have a thin crust followed by a region of relative uniform consistency," John Zarnecki of the European Space Agency said.

"The closest analogues are wet sand or clay."

Officials were unable to identify the whooshing sound gathered at the surface by Huygen's microphones.

Pictures tell a story

But it was the pictures that garnered the most attention.

One snapshot showed what appeared to be liquid flowing into a dark area, which officials suspected to be a sea of liquid methane.

Ivan Semeniuk, the Discovery Channel's space commentator, said the most important result "are the pictures that show the clear sign of fluids altering the surface of Titan."

Another image captured chunks of what seemed to be ice on a flat surface. Initially, they were thought to be large boulders but scientists retracted the notion after further inspection.

"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.

The $3.3 billion Cassini-Huygens mission to explore Saturn -- most famous for its rings -- and its moons was launched in 1997 from Cape Canaveral, Fla., in a joint effort by NASA, the ESA and the Italian space agency.

The probe, named after the Dutch scientist Christiaan Huygens who discovered Titan in 1655, was spun off from the Cassini mother ship on Dec. 24 when it began its three-week trip to the moon.

Titan is the first moon -- other than that of planet Earth's -- ever to be explored.
The probe captured measurements, images, and sounds and sent them back to Earth where scientists have been ecstatically poring over them ever since.

"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."

Scientists believe Titan's atmosphere is similar to that of a young Earth's and that its study could help provide clues as to how life began on Earth.

"It challenges all our preconceptions that all these planets are static places," Diaz said.

"Seeing a planet emerge that has dynamics and complexity to it is just amazing."

Semeniuk said this mission "truly pushes the envelope" of space exploration, noting this is the furthest out that scientists have been able to land a spacecraft. Saturn is 1.2 billion km from earth, on average.

NASA's website said the probe sent back enough information to fill 400 CD-ROMs. Semeniuk said it will take years to comprehensively analyze it.

With a report from CTV's Paula Newton, Discovery Channel's Ivan Semeniuk and files from The Associated Press