A few years ago, a large controversy was set in motion in the international scientific community about the possible existence of fossilized life forms in a Martian meteorite that crash-landed in Antarctica. The piece of rock, known as ALH 84001, was then believed by some to contain certain proof that life existed on the Red Planet sometime in the past. Skeptics were naturally less than willing to accept that, and proposed that cross-contamination may have been responsible for the discovery. Just recently, results of a new set of analysis have demonstrated that a non-biological explanation for how the structures formed is unfeasible and impossible.

This of course means that only a biological explanation for the formation of the worm-like structures can be possible. The meteorite arrived on our planet more than 13,000 years ago, after floating through space for more than 16 million years. When it was originally studied, in 1996, the meteorite hinted that it may contain biological samples, but critics dismissed this claim, saying that a non-biological explanation could be found to explain them. In the recent investigation, a team of experts at the NASA Johnson Space Center, led by Chief Scientist for Astrobiology David S. McKay, looked at the rock again, using technology that was not available to science 13 years ago, Times Online reports.

McKay was the author of the 1996 paper postulating the existence of life on Mars. The paper appeared in the August 16, 1996 issue of the top journal Science. “This is very strong evidence of life on Mars. We feel vindicated. We’ve shown the alternate explanation is absolutely incorrect, leading us back to our original position that these structures are formed by bacteria on Mars,” McKay says. The team used a technique known as high-resolution electron microscopy in order to study the physical and chemical make-up of the rock sample. They discovered no plausible geological scenario to pinpoint at a different kind of origin for the small fossils. The biological theory is therefore back on the table.

“Until now I was on the fence but this paper has really thrown out the non-biological explanation,” says University of Nevada astrobiologist Dennis Bazylinski, who was a member of the peer panel that reviewed the Johnson team's new work. He believes, however, that a single find is not enough to prove for certain that bacterial-like life existed, or still exists, on the Red Planet. “One meteorite is never going to answer such a complex question,” argues Bazylinski. Details of McKay's work will be published in the November issue of the scientific journal Geochimica et Cosmochimica Act.

Nakhla and Yamato 593 are two other Martian rocks, which are also under investigation by the Johnson team. The complete analysis results will be published shortly, but the team says that these rocks contain signs of microbial life too, which must have come from the Red Planet. If the find is confirmed, then we may be at the dawn of a new age. In 1997, when the original work was published, even then-President Bill Clinton made a public announcement.

The find “speaks of the possibility of life. 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,” he said at the time.