A Science Odyssey
People and Discoveries

Meteorite from Mars points to possibility of life on other planets

On August 6, 1996, NASA issued a news release.

"NASA has made a startling discovery that points to the possibility that a primitive form of microscopic life may have existed on Mars more than three billion years ago. The research is based on a sophisticated examination of an ancient Martian meteorite that landed on Earth some 13,000 years ago.

The evidence is exciting, even compelling, but not conclusive. It is a discovery that demands further scientific investigation. NASA is ready to assist the process of rigorous scientific investigation and lively scientific debate that will follow this discovery.

I want everyone to understand that we are not talking about 'little green men.' These are extremely small, single-cell structures that somewhat resemble bacteria on Earth. There is no evidence or suggestion that any higher life form ever existed on Mars.

The NASA scientists and researchers who made this discovery will be available at a news conference tomorrow to discuss their findings. They will outline the step-by-step 'detective story' that explains how the meteorite arrived here from Mars, and how they set about looking for evidence of long-ago life in this ancient rock. They will also release some fascinating images documenting their research."

A research group led by David S. McKay published its findings shortly after the NASA press release in Science, the official publication of the American Association for the Advancement of Science. The meteorite had been found in Antarctica in 1984, but had only recently been identified as having come from Mars. Researchers suggested that the meteorite was a chunk of Mars knocked into space by a comet or asteroid hitting Mars -- it would have traveled around the sun in an elliptical orbit until smashing into the Antarctic ice field.

The meteorite contained complex, carbon-based molecules that are key to life on Earth, similar in fact to simple bacteria living on Earth. Researchers felt confident ruling out contamination or other causes for the carbon. Although some of the features of the "fossil bacteria" (as it was often called in the press excitement that followed) could be explained by other theories, the weight of evidence seemed to suggest a primitive life form.

One of the repercussions of this discovery was to rekindle interest in space exploration, especially of the Red Planet. An experimental orbiting probe and surface rover were launched in late 1996. The director of the Lunar and Planetary Institute in Houston expressed hope that NASA would now get support for a new generation of space telescope, to explore the stars within 33 light-years of Earth.

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