Thursday, March 27, 2008

We are Stardust

We truly live in amazing times.

Moons of Saturn spewing water vapor and organic compounds.

Somewher, the late Sir Arthur C. Clarke is smiling.

Through the plume
Cindy Tumiel: Express-News

A greatly enhanced and colorized image of the Saturn moon Enceladus shows the continuously erupting plume that Cassini flew through. The basic building blocks of living organisms abound on the mysterious and distant moon, scientists said.

If Old Faithful didn't impress you enough, picture this — pressurized water vapor spewing hundreds of miles into the air from deep cracks in the ground that are as long as the distance between San Antonio and Austin.

That is what a geyser is like on Enceladus, one of the 52 named moons circling Saturn. The space probe Cassini flew through the plume this month, two years after a geyser-like region was detected along the south pole of the exotic moon that is roughly the size of Arizona.

Cassini's scientists, including several from San Antonio's Southwest Research Institute, observed pristine water vapor and organic compounds erupting continuously from the interior of the moon and traveling into space at a speed of 1,000 mph. The findings excited and intrigued scientists, who said Enceladus' content more closely resembles a comet than a barren and rocky satellite.
"What something like a comet is doing orbiting Saturn is a very interesting question," said Hunter Waite, a space scientist from Southwest Research Institute who is part of the Cassini science team. "This is going to make us think a second time about the formation of the Saturn system."

Waite, who led the effort to analyze the chemistry of the plume, found it was composed of more than 90 percent water vapor and ice crystals, with small amounts of organic compounds like methane and propane. On Earth, these compounds result from decayed living material, something that isn't happening on frozen and distant Enceladus, he said.

But with water ice, organic compounds and energy from the geothermal eruptions, the basic building blocks of living organisms abound on the mysterious and distant moon, scientists said.

"Organics are clearly there in an abundance beyond what we expected," Waite said Wednesday at a news conference on the findings at NASA headquarters.

Cassini also detected heat in the geysers, which erupt from four parallel cracks, each about 80 miles long, covering the satellite's southern pole. Surface temperatures around the geyser spouts are about minus 135 degrees. That is plenty cold, but it still is 200 degrees warmer than other regions of the moon, said John Spencer, another Southwest Research Institute scientist. This suggests some powerful source of heat in the interior of the moon, he said.
"It means we have a great deal of energy being delivered to the surface in this region," Spencer said. "It is entirely possible that we have liquid water not too far below the surface of these fractures."
Cassini flew within 100 miles of the surface of Enceladus during the trip. Another fly-by is planned for later this year, when the probe will come within 30 miles of the surface and use its imaging instruments to map finer details about surface features on the moon.