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NASA Vows All-Out Study of Mars Findings

Science: Chief sums up world reaction to possible signs of life as 'Wow!' He invites other researchers to join probe.

August 08, 1996|K.C. COLE | TIMES SCIENCE WRITER

Declaring Wednesday "the day we opened the door" to other worlds, NASA chief Dan Goldin promised to do whatever is necessary to confirm whether the microscopic worm-like structures found on a meteorite from Mars are really signs of life beyond Earth.

That might include, he said, more missions to Antarctica to pick up stray pieces of the red planet, sending astronauts to dig deep into the Mars surface, or developing better microscopes to probe the samples already on hand.

After speaking to the leaders of space programs from Europe to Brazil, the U.S. space chief was clearly giddy after years of seeing his agency suffer budgetary and public relations problems. He offered an open invitation to scientists around the globe to study the evidence.

The overwhelming international reaction, he said, could be summed up in a single word: "Wow!"

"We're now on the doorstep to the heavens," said Goldin, sighing. "What a time to be alive!"

President Clinton joined in the accolades Wednesday, saying, "If this discovery is confirmed, it will surely be one of the most stunning insights into our universe that science has ever uncovered. Its implications are as far-reaching and awe-inspiring as can be imagined."

The planetary scientists from Stanford University, Johnson Space Center and other institutions who analyzed the Martian sample presented their findings at NASA headquarters in Washington on Wednesday to an international listening audience.

Meticulously reconstructing the trail of evidence that leads them to believe fossil-like structures represent ancient forms of life, the researchers stressed that results would have to be confirmed by further study. "We think they are micro-fossils from Mars," said Stanford's Richard Zare. "But this is an interpretation. It could be a dried-up mud crack."

UCLA's William Schopf, an authority on the evolution of life who has found some of the oldest fossil bacteria on Earth, gave several reasons to be skeptical of the interpretation--foremost among them, he said, that there is as yet no evidence of internal structure. To know for sure, he said: "We've got to look inside these things." That will be no easy task because the largest of the structures are one-hundredth of the diameter of a human hair, the smallest, one-thousandth.

Johnson Space Center's David McKay, principal author of the research, stressed several times that the findings are tentative.

Still, the researchers believe that the structures have a biological origin, because that is the simplest idea that fits all the evidence.

"I've spent many nights in the lab until midnight looking at the rock, too excited to go home," said McKay, who first became intrigued by the potential life locked inside the rock about a year ago.

The structures from Mars--looking more like one-celled bacteria than relatives of E.T.-- came to Earth locked in a meteorite that had drifted in space for about 16 million years. It crash-landed on the blue ice fields of Antarctica about 13,000 years ago, where it was discovered in 1984.

Scientists think the potato-sized, 4 1/2-pound hunk got chipped off Mars when an asteroid slammed into the surface, tossing bits of Mars into space.

If the structures do turn out to be fossil life forms, the impact on humanity's place in the cosmos could be profound. For example, it is possible that ancient life forms on Earth somehow made their way to Mars, as well as vice versa, Zare said.

"Who is to say that we are not all Martians?" he asked, pointing out that ancient Mars may well have been even more hospitable to life than ancient Earth.

Cornell astronomer Carl Sagan said the discovery "raises the possibility of a universe burgeoning with life."

The fossil-like forms were discovered lurking in the cracks of a rock that crystallized out of the molten ancient Mars landscape soon after the solar system formed, when planets were too hot to have solid surfaces. Researchers believe that in ancient times, water flowed freely on Mars and carbon dioxide from its atmosphere might have formed reactions in the water that created the ingredients for life.

As the Martian landscape dried up and its atmosphere blew off into space, any life forms would have been destroyed by intense ultraviolet radiation. (Mars has no ozone layer.) The micro-fossils would have survived because they were sealed inside the rock.

When the researchers sliced open the rock in the sterile conditions of the laboratory, they found what looked like orangish blobs enclosed in a black-and-white striped covering, which they called "Oreo cookie" rims.

As they zoomed in with higher and higher magnification, they began to see textured surfaces and tube-like structures with an uncanny resemblance to bacteria on Earth. The detection of the structures depended on new techniques in microscopy--in particular, the transmission electron microscope--a sophisticated way of using electron beams instead of larger, cruder light waves to see deep inside matter and analyze its contents.

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