"I think we may have to accelerate some activities" with regard to collecting more samples from Mars, NASA chief Dan Goldin said at a packed news briefing to discuss scientists' contention that tiny fossils of Martian organisms are present in a meteorite that landed in Antarctica 13,000 years ago.
After talking with members of the world's space agencies, Goldin said, "I believe it will be a worldwide mission."
But he added that the mission would be driven by scientific concerns, "not a rush to go to Mars."
A golf-ball-sized chunk of the meteorite was on display at the news conference, cradled in midnight-blue velvet and contained in a clear plastic case labeled ALH84001, its scientific designation.
President Clinton said U.S. scientific prowess would be poured into followup investigation of possible life on Mars, include an agressive unmanned space-probe program and a bipartisan White House summit on future U.S. space policy. Goldin said the summit would occur in November.
"If this discovery is confirmed it will surely be one of the most stunning insights into our universe that science has ever uncovered," Clinton said. "Its implications are as far-reaching and awe-inspiring as can be imagined."
For the past two years, a team of scientists from the National Aeronautics and Space Administration and Stanford University has been examining the 4.2 pound, meteorite for traces of organic molecules and carbon compounds, the building blocks of life on Earth.
The scientists said the rock formed under the surface of Mars about 4.5 billion years ago. Between 3.6 billion and 4 billion years ago, water penetrated fractures in the rock and deposited carbonate materials.
The scientists said they believe living organisms may have been involved in the formation of the carbonate and some of the microscopic organisms may have fossilized in the rock.
Inside the microscopic globs of carbonate, the scientists said they found polycyclic aromatic hydrocarbons -- or PAHs -- which are mineral compounds associated with microscopic organisms and possible microscopic fossils.
Photographic images show the carbonate as orange-brown in color with black-and-white rims, which are composed of extremely fine-grained mineral compounds containing either iron and oxygen or iron and sulfur, Kathie Thomas-Keprta of Lockheed-Martin said at the briefing.
The compounds in these rims are very similar to those produced on Earth by bacteria, Keprta said.
"The simplest explanation is that these are products of micro-organisms on Mars," she said.
Even some of those on the investigative team were skeptical.
Stanford University's Richard Zare noted that PAHs are present on Earth in non-organic substances such as diesel exhaust, candle soot or even charred meat.
But David McKay of NASA's Johnson Space Center in Houston showed extremely high-resolution photographs of the alleged fossils, which looked like tiny worms on the rock surface.
He acknowledged that these worm-like structures could be dried-up mud, or microfossils from Antarctica, but his team's best interpretation was that they were microfossils from Mars.
McKay conceded more research was needed to confirm that these were remnants of living things.
Zare noted the possibility that life on Earth might have been "seeded" by a meteorite crashing in from Mars and added: "Who is to say that we are not all Martians?"
The meteorite was probably blasted off the surface of Mars 16 million years ago after a massive comet or asteroid struck the now-dead planet, the researchers said in a draft article of their findings to be published in Science magazine.
After floating in space for millions of years it plunged to Earth, where it was discovered in Antarctica in 1984. McKay's team got the rock in August 1994, and for the first six months of their study saw little of interest.
"About a year ago is when we started to get excited about the rock," McKay said.
The metorite's make-up matches the chemical composition of the surface of Mars measured by the Viking spacecraft that landed on the planet in 1976, the scientists said. Another unstaffed U.S. probe will head for Mars late this year.
Original file name: .CNI - Mars Spurs Exploration
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