January 15, 2005

This image was returned Friday, January 14, 2005, by ESA's Huygens probe during its successful descent to land on Titan. This is the coloured view, following processing to add reflection spectra data, gives a better indication of the actual colour of the surface. Initially thought to be rocks or ice blocks, they are more pebble-sized. The two rock-like objects just below the middle of the image are about 15 centimetres (left) and 4 centimetres (centre) across respectively, at a distance of about 85 centimetres from Huygens. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of these objects, indicating possible fluvial activity.

Titan Probe Drops Into 'Creme Brulee'-Like Surface

LOS ANGELES (Reuters) - Data sent back by the Huygens space probe from the Saturnian moon Titan show a frozen, orange world shrouded in a methane-rich haze with dark ice rocks dotting a riverbed-like surface the consistency of wet sand, scientists said on Saturday.

The Huygens probe, part of a $3 billion joint mission involving NASA and the European and Italian space agencies, made its pioneering descent to Titan on Friday, sending back readings on the moon's atmosphere, composition and landscape.

Slowed by parachutes, Huygens took more than two hours to float to the icy surface, where it defied expectations of a quick death and continued to transmit for at least two hours.

Along with scientific instruments that measure the components of Titan's atmosphere, Huygens carried a sound recorder and lamp to look for signs of surface liquid.

One reading from an instrument protruding from the front of the saucer-shaped craft to gauge how deeply it penetrated upon impact suggested that the moon's surface was the consistency of wet sand or clay.

"We think this is a material which may have a thin crust, followed by a region of relatively uniform consistency," John Zarnecki, the scientist in charge of experiments on Titan's surface said at a televised news conference from the control center in Germany.

Zarnecki said one of his colleagues had suggested another analogy: creme brulee. "But I don't suppose that will be appearing in any of our papers," he said.

Titan, believed to be the only moon in the solar system with an atmosphere, is larger than the planet Mercury. Scientists believe a study of the icy moon could yield clues about how life developed on Earth.


One of the mysteries of Titan is the amount of methane that surrounds it, prompting speculation that there might be oceans of the element on its surface or below.

Some have also questioned whether the impact of a meteorite -- or some other event -- could have thrown off enough heat to liquefy water on Titan, where the surface is now an extreme cold measured at minus 292 F.

A panoramic picture sent back from Huygens shows what appears to be a coastal area with banks of fog-like clouds just above and a root-like system of rivulets just inland.

"It's almost impossible to resist the speculation that this is a drainage channel, that we're seeing a shoreline," said Martin Tomasko, a University of Arizona professor and the key researcher on images of the moon.

"You have the feeling that maybe this was wet not too far ago," he said.

Other rock-sized objects photographed in an apparent flow channel on the gold-orange surface of Titan measured appear to frozen blocks of water ice, Tomasko said, although he cautioned more study was needed.

"We just don't have the answers to many of the questions you can think to ask," he said. "Given a little bit of time we will mine (the data) for a new understanding of this mysterious world that has been veiled from our view for so long."

The mass spectrometer onboard Huygens, a complex instrument designed to analyze molecules in the atmosphere of Titan and on its surface, picked up evidence of a thick cloud of methane about 11-12 miles above the surface.

Once on the surface, a heated tube from the craft showed surface material evaporating and producing more methane.

European Space Agency officials said they would investigate why a second, back-up radio channel failed to transmit some data back from the Huygens probe.

The loss of that signal made it impossible to get immediate results from an experiment that had been intended to track wind direction and strength in Titan's atmosphere, scientists said.

But using data from radio telescopes in Australia, China, Japan, the United States and Europe, Huygens scientists said they expected to be able to piece together similar information over time.

The Cassini-Huygens mission to study Saturn's rings and moons was launched in 1997 and is named after two 17th-century European astronomers: Christiaan Huygens, who discovered Saturn's rings and Titan, and Jean-Dominique Cassini, who discovered the planet's other four major moons.

New Photos Show Titan Has Orange Surface

DARMSTADT, Germany - New, refined pictures from Saturn's moon Titan released Saturday show a pale orange surface covered by a thin haze of methane and what appears to be a methane sea complete with islands and a mist-shrouded coastline.

Space officials worked through the night to sharpen the new photos taken by the space probe Huygens, which snapped the images Friday as it plunged through Titan's atmosphere before landing by parachute on the surface.

Many scientists at the European Space Agency center in Darmstadt, Germany, looked tired from their overnight work but were still clearly elated about the successful arrival of data from Huygens the day before — a major triumph for the European space program.

"The instruments performed brilliantly," said John Zarnecki, in charge of the surface instruments. "We can't find a single missing data frame. The link and the quality of the data was absolutely superb."

Officials played back sound gathered from Huygens' microphone at the surface — a whooshing noise they did not identify. But the center of attention was the pictures.

One shot taken from an altitude of 10 miles showed dark lines that suggested stream beds carved by liquid flowing into a dark area suspected to be a sea of liquid methane — with light areas in the dark that could be islands.

"It is almost impossible to resist speculating that the flat dark material is some kind of drainage channel, that we are seeing some kind of a shoreline," said scientist Marty Tomasko from the University of Arizona, head of the camera team. "We still don't know if it has liquid in it."

Titan's notorious haze — which has kept astronomers from getting a better picture through telescopes — is obvious in the two refined images shown Saturday.

An image taken on the surface shows chunks of what scientists say looks like water ice scattered over an orange surface overcast by methane haze. On Friday, the chunks were described as boulder-sized, but overnight examination showed they are much smaller and simply look big because they are close to Huygens' camera.

Deep shadows and depressions around the chunks suggest they could have been surrounded by liquid at one time, scientists said.

Titan is the only moon in the solar system known to have a significant atmosphere. Rich in nitrogen and containing about 6 percent methane, its atmosphere is believed to be 1 1/2 times thicker than Earth's.

Shushiel Atreya, part of the group studying the atmosphere, said the instruments revealed "a dense cloud or thick haze approximately 11-12 miles from the surface."

"Presumably there is a reservoir of methane on the surface," Atreya said.

The surface itself appears to be "material which might have a thin crust followed by a region of relative uniform consistency," Zarnecki said. "The closest analogues are wet sand or clay."

The $3.3 billion Cassini-Huygens mission to explore Saturn and its moons was launched in 1997 from Cape Canaveral, Fla., in a joint effort by NASA, the ESA and the Italian space agency. Huygens was spun off from the Cassini mother ship Dec. 24.

Titan is the first moon other than the Earth's to be explored. Scientists believe its atmosphere is similar to that of early Earth's and studying it could provide clues to how life arose on our planet.

The heart of Huygens' mission was its 2 1/2-hour parachute descent, during which it also sampled the atmosphere and deployed a microphone to gather sounds.

Scientists want to know whether Titan has lightning and if it has the seas of liquid methane and ethane that have been theorized. Both ethane and methane are gases on Earth, but are believed to exist in liquid form on Titan because of high pressure and extreme temperatures of minus 292.

After entry into Titan's atmosphere, Huygens shed its wok-shaped heat shield and deployed a series of parachutes. The data were transmitted back to Cassini, which relayed them to Earth.

Titan's images came streaking across the cosmos Friday, and scientists grew increasingly ecstatic with the scenes from the probe, named after Titan's discoverer, the 17th-century Dutch astronomer Christiaan Huygens.

"I think all of us continue to be amazed as we watch our solar system unveil," NASA science administrator Alphonso Diaz said Friday 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."

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