and Titan, Saturn's moon comes into focus today... round about noon...
Saturn's moon Titan, comes into focus today
Saturn's moon Titan comes into focus today
By Dan Vergano, USA TODAY
Saturn's mysterious moon Titan does a star turn today, getting a close-up from the international Cassini-Huygens space probe.
Larger than Mercury and Pluto, Titan is a full-fledged world in its own right, complete with a thick atmosphere and the largest expanse of unmapped surface geography in the solar system. At 12:44 p.m. ET, the probe will pass within 746 miles of the haze-shrouded moon's surface, snapping the closest-ever images of one side of Titan.
"I'm expecting to be pleasantly bewildered," says Torrence Johnson, an imaging scientist with NASA's Jet Propulsion Laboratory in Pasadena, Calif. Because today's flyby comes about 280 times closer to Titan than the probe did during a flyby in July, scientists hope for images that will answer questions, old and new, about the orange world.
NASA, which manages the $3.27 billion mission with the European Space Agency (ESA) and Italy's space agency (ASI), plans to release the first images from the flyby tonight.
"Titan is one of the most fascinating places in the whole solar system," says astronomer Antonin Bouchez of Hawaii's W.M. Keck Observatory, who is not a Cassini team member. "It is a completely alien place, but it may be the most Earth-like world we know, with beaches, lakes and oceans. That's what makes it interesting."
Researchers hope that with today's flyby they'll learn more about unexpected observations made during July's pass.
• White "ice" plains turned out to be mixtures of naturally occurring tar and ice, and dark "tar" plains turned out to be just ice.
• Jagged lines between plains suggest that clashing ridges, and even earthquakes, might plague Titan.
• A dearth of craters suggests that unexpected resurfacing takes place on the frozen moon.
"We'll probably see plains of tar with frozen continents of ice sticking out above them," Bouchez says. "But the truth is that nobody knows for sure."
The flyby should reveal whether a landscape of rugged, frozen features eroded by lakes and rivers of frozen oils and tar is hidden beneath Titan's orange methane clouds, says mission scientist Toby Owen of the University of Hawaii-Manoa. It's also possible that liquid hydrocarbons flowing over Titan's minus-290-degree surface might have smoothed the moon to resemble "a frozen chocolate sundae," Owen says. "We're going to find out what's down there over the next two days."
Like a time capsule from the earliest days of the solar system's 4.5-billion-year history, Titan's frozen state could give scientists insight into Earth's early surface if the moon's organic chemicals match those present on Earth before the development of life. Titan is "a flammable world," Owen says, covered in liquid and frozen hydrocarbons and sheathed in a natural-gas haze. Because whatever oxygen the moon possesses is frozen in ice, no spark can ignite the powder keg. "We're not expecting any life on Titan. It's much too cold," Owen says. "We are going back to the earliest days on Earth."
The flyby also will observe the region where the ESA's Huygens probe should make its parachute landing onto Titan in January. Radar and photo images from today's flyby should resolve features down to football-stadium size and help predict whether the 705-pound probe will survive its landing. Some of the probe's instruments, including a panoramic camera, can operate for 30 minutes after arriving on a solid surface.
Cassini is on a four-year mission to explore Saturn and its many moons (more than 30 and still counting) that started with its arrival at the planet in July. It will fly by Titan 44 more times, mapping the moon even as it uses the moon's gravity to adjust its orbit and explore the Saturnian system.
Measurements of Titan's atmospheric thickness taken during today's maneuver also will help navigators adjust subsequent flybys, some passing as low as 590 miles in altitude, and the landing trajectory of the Huygens probe next year.