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Images The Cassini spacecraft has used its visual and infrared mapping spectrometer to reveal Titan's exotic surface. These images show the moon's southern hemisphere surface to be covered with a variety of materials. This sequence of images illustrates the evolution of a field of clouds near Titan's south pole over a period of almost five hours. The images were acquired on July 2, 2004, by NASA's Cassini spacecraft at ranges of 364,000 to 339,000 kilometers (226,170 to 210,600 miles). These bright clouds, believed to be composed of methane, appear in generally the same area where Earth-based astronomers have previously detected clouds. Cassini also saw clouds in this region during its approach to Saturn. Image Credit: NASA/JPL/Space Science Institute    More Stories Cassini Surprises, Saturn Puzzles Scientists Ring Around the Planet: Cassini's First Images of Saturn from Orbit ARRIVAL! Cassini Enters Orbit Around Saturn Cassini Prepares To Put On The Brakes Cassini Participation a Boon for ESA

	Cassini Gets a Look at Saturn Moon Titan By John Antczak Associated Press Writer posted: 09:15 pm ET 3 July 2004

PASADENA, Calif. (AP) -- Scientists on Saturday released what they called the best pictures yet of the frozen surface of Saturn's enormous moon Titan but said they were puzzled that the Cassini spacecraft hadn't glimpsed any evidence of liquids.

The latest images of Titan revealed a single set of clouds about the size of Arizona and dark and light shapes across the moon that the imaging team continued to analyze.

The shots of the moon's surface features were taken during Cassini's first pass Friday at a distance of about 200,000 miles.

"It's different from anything we've ever seen before," imaging scientist Elizabeth Turtle said. "We're still trying to understand the surface of Titan."

One indistinct circular shape could be a huge crater, and a linear shape could be a hydrocarbon river or a fault line, scientists said.

Scientists believe the moon could have chemical compounds much like those that existed on Earth billions of years ago before life appeared.

Big enough to be a planet in its own right, Titan has an atmosphere 1 1/2 times as dense as Earth's, containing organic -- meaning carbon-based -- compounds. Scientists believe there could be hydrocarbon seas or lakes.

Turtle said initial data analysis suggested the moon is the site of some type of geologic activity that could include wind and erosion and development of the lakes or rivers.

Kevin Baines, a member of the visual and infrared spectrometer team, said scientists were disappointed that they hadn't seen evidence of liquids through reflections of sunlight on smooth surfaces of the moon.

We thought we'd see some flashes, and we haven't seen any. So we're a little perplexed,'' he said after a news conference at NASA's Jet Propulsion Laboratory in Pasadena.

Among the new pictures released were four images of a cluster of clouds near Titan's south pole that are believed to be composed of methane. They were the only brightly distinct spots on otherwise fuzzy images of Titan.

"Someone likened it to a melting ice cream sundae," Turtle said.

Near-infrared images of Titan prompted scientists to question previous theories about the moon's surface. They had thought brighter areas of the moon were thick layers of ice and darker areas were a mixture of substances including hydrocarbons, but they said it appears the opposite is true.

There will be many more chances to uncover the face of Titan during Cassini's planned four-year tour. The spacecraft will make 45 more flybys of the moon -- coming with 600 miles of Titan at times -- and then send a probe into its atmosphere in January.

The probe, named Huygens, will send pictures back to Cassini as it makes a 2 1/2-hour descent by parachute through the atmosphere.

Titan was Cassini's first encounter since the spacecraft began orbiting Saturn earlier this week.

The $3.3 billion mission, funded by NASA, the European Space Agency and the Italian Space Agency, was launched in 1997. The spacecraft flew 2.2 billion miles on a roundabout route to Saturn.

• Cassini Special Report