A Martian meteorite that has been frozen in Antarctic ice hints that the surface of the Red Planet is riddled with chemicals related to those used in household bleach. That increases the likelihood that carbon-bearing compounds – strong indicators of life – may have been broken down by chemical reactions, suggesting that we need to dig deeper into Mars to search for traces of any past inhabitants.
"We're speculating that you perhaps cannot find organics on the surface of Mars," says Sam Kounaves of Tufts University in Medford, Massachusetts. "You have to be below the surface or inside sedimentary rocks."
Kounaves and colleagues studied a Martian meteorite called EETA 79001, collected in 1979 in Antartica where it fell 12,000 years ago. Its long stay means its outer layers were probably contaminated with earthly material, so the team cut it open to study the stuff inside.
They found a white substance nestled in the meteorite that turned out to contain a form of nitrate, a chemical that some earthly bacteria use as fuel. By comparing the ratio of isotopes found in it with those on Earth, the team determined it is not a contaminant.
"It's clear to us it's Martian," Kounaves told New Scientist at a meeting of the American Association for the Advancement of Science in Boston, Massachusetts, last week.
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