SATURN'S MOON Images of Titan thrill scientists

The Cassini craft flew just 745 miles above the mysterious moon.
LOS ANGELES TIMES
PASADENA, Calif. -- The closest images ever of Saturn's moon Titan began arriving from the Cassini spacecraft late Tuesday at the Jet Propulsion Laboratory here, presenting scientists with as many new questions as insights into the makeup of one of the solar system's strangest objects.
Despite concerns over rainy weather that threatened to disrupt the data signal, startling images of the second largest moon in the solar system -- and the only one with an atmosphere -- flashed up on video screens shortly before 7 p.m., just as planned.
Piercing Titan's thick atmosphere for the first time, the much-anticipated flyby revealed the brilliant white surface of a continent-sized land mass that scientists quickly named Xanadu. Next to it was an undefined dark mass that some scientists speculated could be a hydrocarbon slush, along with wispy clouds at the south polar region.
"This is utterly spectacular," said Cassini mission scientist Carolyn Porco. "This is the last, greatest expanse of unexplored terrain in the solar system. Once we figure it out, the solar system is going to become a very much smaller place."
Oohs and aahs
Scientists gathered at JPL oohed and aahed as the images came in from Cassini, which passed over the surface of the moon at an altitude of just 745 miles.
But as much as the pictures offered clues to the makeup of the moon, they raised new questions that scientists could be struggling to answer for years.
"We're awash in multiple hypotheses," said Cassini scientist Torrance Johnson. Referring to the strange dark area north of Xanadu, discovered by Cassini scientists only in the past few days, he wondered, "Is that liquid? Is it hard, like tar?"
Xanadu itself might be covered in ice, Johnson said.
One of the most intriguing early images focused on the dark mass, in the midst of which were several shining tendrils. Speculation was that they could be ice patches on a raised landform.
"It's pretty bizarre-looking; I'm not sure how to interpret it," said Robert H. Brown, the leader of Cassini's Visual and Infrared Mapping Spectrometer Science team. "Some of it looks like icy stuff," Brown said. "And the dark places look like something that has been filled in."
Mystery of Titan
Although much of the solar system had been revealed during the past five decades of space exploration, Titan, with its dense orange covering of methane gas, has remained a mystery. Cassini carried an array of instruments designed to part those clouds.
The imaging instruments, including several infrared cameras and radar, were expected to yield images with 100 times more precision than any previous spacecraft or Earth-based telescope. Features as small as a football field should appear, scientists said.
Titan has long interested scientists because they believe it to be a kind of time machine. In Titan, investigators think they could be looking at what Earth was like billions of years ago, before life developed.
The difference is that Titan is far too cold at minus 290 degrees Fahrenheit for any chemical interactions to produce life.
Essentially, Titan may represent young Earth if it had been placed in a deep freeze.
Assembling data
Some of the best data from Tuesday's flyby was expected to be assembled overnight for distribution today. One of the things scientists will continue to look for is evidence of possible volcanism on the moon, as well as any evidence that precipitation falls from the methane clouds. If so, it would not be water, but more likely a gasoline-type substance, scientists said.
The $3.2 billion mission is a collaboration among the National Aeronautics and Space Administration, the European Space Agency and the Italian Space Agency.