In 1996, a team led by NASA announced that the organic compounds in the rock looked as if they had been left by living organisms. Other scientists have been skeptical and researchers have dismissed this hypothesis for decades, most recently a team led by Andrew Steele of the Carnegie Institution for Science.
Steele said small samples of the meteorite show that the carbon-rich compounds are actually the result of water — salty or likely salty water — that flowed over the rock for a long time.
During the Martian wet period and early past, at least two impacts occurred near the rocks, warming the planet’s surrounding surface, before a third impact bounced off the Red Planet into space millions of years ago. The 4 pound (2 kilogram) rock was found in Antarctica in 1984.
According to the researchers, the groundwater moving through cracks in the rock, while it was still on Mars, formed the tiny balls of carbon present. They said the same could happen on Earth and could help explain the presence of methane in Mars’ atmosphere.
But two of the scientists who took part in the original study disputed these latest findings, calling them “disappointing”.
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