Search for Alien Life Set to Take Giant Leap Forward

Scientists haven't found E.T. just yet, but they may bepinning down the best places and ways to look for alien life during futurespace missions, NASA researchers said Wednesday.

Experts on the search for extraterrestrial life spoke toreporters from the Astrobiology Science Conference near Houston to celebrate 50years of astrobiology research.

Scientists there said they are still eager to find life elsewherein the universe despite the firestorm this week kicked off by famed cosmologistStephen Hawking, who suggested that perhaps humans shouldn't be so eagerto find aliens since there's a chance they would want to colonize Earth orstrip it for resources.

"We're interested and prepared to discover any form oflife," said Mary Voytek, astrobiology senior scientist at NASAHeadquarters, during the teleconference.

The lure of new missions

Cornell University planetary scientist Steve Squyres, principalinvestigator of the MarsExploration Rover project, said NASA scientists were currently consideringa list of 28 future science missions that could help discover signs ofextraterrestrial life.

"Astrobiology and the search for life is really centralto what we should be doing next in the exploration of the solar system," Squyressaid.

He mentioned a host of possible robotic missions, includingvisits to Mercury, Mars, the moons of Jupiter and Saturn, and even distantouter solar system flybys. In particular, the Saturnianmoons Titan ? with its lakes of methane and ethane ? and Enceladus, withits plumes of water vapor, seem like possibly habitable sites.

Squyres also said NASA is considering an ambitiousthree-part mission to Mars that would return samples of rock back to Earth forscientists here to study in person.

This mission "might reveal a great deal about whetherMars once harbored life," he said.

Mars samples

Other scientists on the panel agreed that a Mars samplereturn mission would be invaluable.

"I personally think if we're ever going to be able toshow that there was past life on Mars ? if there was past life on Mars ? Ithink we're going to need to study the samples here on Earth rather thanrobotically," said Bill Schopf, a researcher at the University ofCalifornia, Los Angeles. "I think if we had the rocks back tomorrow and Ihad them in my lab, I think we could solve this problem."

Schopf and another researcher, Jack Farmer of Arizona StateUniversity, announced the results of a recent study in which they found that atype of mineral deposit called sulfate can harbor fossils of ancient organisms.

Although the scientists studied samples of sulfate fromEarth, this material is also present in large quantities on Mars. The fact thatthey found fossilized life in Earth's sulfate means that Mars' sulfate would becapable of storing a record of life, too, if that life existed. Thus,collecting samples of sulfate on Mars would be a good place to look for Martianlife, they said.

Another possible place to look for life in the solar systemis asteroids. Researchers announced for the first time Wednesday that they'dfound direct proof of frozenwater and organic compounds ? which could include the ingredients for life? on a space rock in the main asteroid belt between Mars and Jupiter. Bothwater and organic materials are considered necessary to make a place habitable.

"Any time you have materials like that present you havea candidate that is worthy of study," Squyres said. "We should gowhere the data lead us."

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