Martian Rocks Once Held Life, Scientists Report Fossils From Extraterrestrial Organisms Apparently Discovered; Could Interplanetary Meteors Have Been Seeds For Life On Earth?
In what some scientists say may be the most spectacular discovery since humans first gazed skyward at other worlds in our solar system, NASA and Stanford University researchers say they have found evidence that life may have existed on ancient Mars.
“This could be answering the question everyone’s been asking since they first saw the planet Mars,” said UCLA planetary scientist David Paige. “Could there be life there?”
NASA Tuesday confirmed that ancient Martian rocks found in Antarctica in 1984 contained fossils of one-celled organisms - similar to ancient life forms on Earth.
The 4.5-billion-year-old rock - dubbed ALH84001 - was chipped off the Martian surface some 16 million years ago, perhaps by a meteorite, and landed in Antarctica about 13,000 years ago, scientists believe.
“NASA has made a startling discovery,” said NASA chief Daniel Goldin, who emphasized that these were not “little green men.” Instead, he described them as “extremely small, single-celled structures that somewhat resemble bacteria on Earth.”
Stanford’s Richard Zare - one of the chief researchers on the finding - described the fossils as “egg shapes and tubular type things.” While it is conceivable that inorganic processes created the structures, he said, other independent lines of investigation concurred that the most plausible explanation was some primitive form of life.
For example, materials commonly associated with bacteria, like magnetite, iron sulfide and globs of carbonate material were found in the same place as the fossil-like structures.
“Everything we see has other possible explanations,” Zare said. “But it’s the fact that everything is spatially together” that makes the evidence for life so compelling.
Zare and colleagues from Stanford, NASA’s Johnson Space Center in Houston and Lockheed Martin subjected the rock to a series of tests to rule out the possibility it had become contaminated during its 13,000-year visit at the South Pole.
“We sliced it open,” said Zare, “then put it immediately into a high vacuum,” a process designed to keep the inside of the rock sterile.
The researchers were also able to show that the globs of carbonate came from deep inside the rock, and were not picked up on the surface.
Few scientists had actually seen the research paper, which is to be published in the journal Science Aug. 16. NASA was keeping the findings under wraps until a news conference planned today, and the authors from the Johnson Space Flight Center were not available for comment. However, the possibility of life on ancient Mars has become tantalizingly real of late, and many researchers were ready to take the findings seriously.
Still, scientific attitudes toward the possibility of life on Mars have undergone a “revolution,” in recent years, Leshin said.
In part, scientists have changed their views on the climate of early Mars: While the red planet is a parched desert today, researchers believe that it was wet and warm billions of years ago.
Some researchers believe that life could have originated on one planet and migrated to others, with comets and meteors acting like “seeds” to sprinkle DNA around the solar system.
“It’s not a disprovable concept,” said Paige, who said he remained skeptical about the new findings until he saw the evidence for himself.
Other researchers wondered whether it was reasonable to think that a rock could be blasted off the Martian surface, and still arrive intact and undisturbed on Earth. Andrew Ingersoll of California Institute of Technology, for example, pointed out that that would be “a pretty violent event,” although most researchers do agree the rock found at the South Pole was from Mars.
“The Mars gases have a real distinctive signature,” he said.
Because of its possible scientific and philosophical ramifications, Goldin briefed President Clinton and Vice President Al Gore last week.
White House officials said Clinton is likely to call for more study of the question of fossil life on Mars and may propose adding resources to ongoing NASA projects.