NASA Vows All-Out Study of Mars Findings

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.

On close inspection, several of the structures appeared to be segmented, like worms. Magnetite grains found close by in the rock were similar in shape and size to those produced by bacteria on Earth. Moreover, organic compounds suggestive of life were found concentrated in the same “hot spots,” as the scientists called them.

Schopf gave high marks to the interpretation by the researchers of the dates and origins of the Mars rock, and the chemical composition of the samples. But he put less faith in the biological interpretation of their origin.

The structures were hundreds of times smaller than similar ancient bacteria found on Earth, he said, and the organic compounds found at the sites also are common in interstellar space, in diesel exhaust and in charred steak.

“More work needs to be done before you can say this is life on Mars,” said Schopf, who was not on the research team and was included by NASA specifically to offer an outside expert’s point of view.

As for a “smoking gun” that would clinch the diagnosis of fossil life, Schopf said that he would like to see a cell wall separating the structure’s inside from its outside, and population of structures that were clearly different from their environment. Most of all, he said, he would like to see signs of cell division--in other words, reproduction.

The next step for the researchers will be to analyze the rock in much greater detail, in particular to look for what McKay called “the inside machinery of the cell,” or evidence of walls. They will also look for more definitive biomolecules such as amino acids--which make up proteins. None of the tests will provide definitive results, Zare said. “Each time, you come up with a maybe, and when you put them all together, you still have a maybe, but it’s a much stronger maybe,” he said.

In addition, 11 other Mars meteorites will be examined more closely. While the others are much younger--perhaps far too young to carry traces of an ancient, warmer, wetter Mars--Sagan thought that some of them might prove plausible suspects.

Future missions to Mars include the Jet Propulsion Laboratory’s Mars Pathfinder, which will send a rover down to explore the Martian surface, and the Mars Global Surveyor, which will orbit Mars taking high-resolution pictures. Both will be launched later this year.

Neither mission, however, is expected to answer the question of whether there is, or ever was, life on Mars. The rover--which is being packed up for shipment to Cape Canaveral next week--carries far less sophisticated detectors than those necessary to spot the fossil-like structures. To properly analyze Mars samples requires laboratories on Earth, which means missions that will bring back samples.

To find current life on Mars--a possibility--would require digging deep inside the planet to find remnants of still watery worlds protected from the ultraviolet radiation of the sun. The only way to find out if such a world really exists, McKay said, “is to go there.”

And if such a mission requires sending astronauts to Mars, Goldin said, “We’ll do it.” However, he stressed that any such mission should be international in scope. “I believe it will be a worldwide mission,” he said. “There’s an unbelievable excitement throughout the world.”

* LOCAL REACTION: Southland residents react to possibility of life on Mars. B1

* CHEMICAL PUZZLE: Chemistry is key to Martian meteorite, scientists say. B2

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Signs of Life

Scientists continue to scrutinize a Martian meteorite found on an ice floe in the Antarctic in 1984. Fossils-like structures and chemicals in the meteorite provide the first strong evidence that primitive life may have once existed on Mars. Among the evidence is the presence of carbonate globules, the brownish areas in photo at left, in the rock.

THE EVIDENCE

* Carbonate globules--normally produced by living organisms--in the cracks of volcanic rock.

* Minerals, such as magnetite, that are normally formed by bacteria.

* Organic (carbon-containing) compounds.

* Microscopic structures that look like fossil bacteria.

* Each of these findings alone could have other explanations not involving the presence of life. But the fact that all occur in the same place strongly suggests that life was once present on Mars.

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THE TRAJECTORY

1) A comet or asteroid strikes the surface of Mars hard enough to eject a piece of 4.5-billion-year-old Martian rock into space.

2) The rock travels an elliptical orbid around the sun for the next 16 million years.

3) About 13,000 years ago, the orbits of the Earth and the rock intersect. The rock--now a meteor--lands on the Antarctic plateau.