Traces of possible Martian biological activity inside a meteorite

December 2, 2014 by Emmanuel Barraud
Credit: Alain Herzog / EPFL

Did Mars ever have life? Does it still? A meteorite from Mars has reignited the old debate. An international team that includes scientists from EPFL has published a paper in the scientific journal Meteoritics and Planetary Sciences, showing that martian life is more probable than previously thought.

"So far, there is no other theory that we find more compelling," says Philippe Gillet, director of EPFL's Earth and Planetary Sciences Laboratory. He and his colleagues from China, Japan and Germany performed a detailed analysis of organic traces from a Martian meteorite, and have concluded that they have a very probable . The scientists argue that carbon could have been deposited into the fissures of the rock when it was still on Mars by the infiltration of fluid that was rich in .

Ejected from Mars after an asteroid crashed on its surface, the meteorite, named Tissint, fell on the Moroccan desert on July 18, 2011, in view of several eyewitnesses. Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature. But they are still debating where the carbon came from.

Maybe biological, but not from our planet

Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint's fissures before it left Mars.

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The researchers challenged previously described views (Steele et al., Science, 2012) proposing that the carbon traces originated through the high-temperature crystallization of magma. According to the new study, a more likely explanation is that liquids containing organic compounds of biological origin infiltrated Tissint's "mother" rock at low temperatures, near the Martian surface.

These conclusions are supported by several intrinsic properties of the meteorite's carbon, e.g. its ratio of carbon-13 to carbon-12. This was found to be significantly lower than the ratio of carbon-13 in the CO2 of Mars's atmosphere, previously measured by the Phoenix and Curiosity rovers. Moreover, the difference between these ratios corresponds perfectly with what is observed on Earth between a piece of coal – which is biological in origin – and the carbon in the atmosphere. The researchers note that this organic matter could also have been brought to Mars when very primitive meteorites – carbonated chondrites – fell on it. However, they consider this scenario unlikely because such meteorites contain very low concentrations of organic matter.

"Insisting on certainty is unwise, particularly on such a sensitive topic," warns Gillet. "I'm completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past."

Explore further: Organic carbon from Mars, but not biological

More information: "Nanosims Analysis Of Organic Carbon From The Tissint Martian Meteorite : Evidence For The Past Existence Of Subsurface Organic-Bearing Fluids On Mars," Meteoritics and Planetary Sciences, December 2014, DOI: 10.1111/maps.12389

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4.3 / 5 (6) Dec 02, 2014
Carbonated chondrites? Really?
3.4 / 5 (5) Dec 02, 2014
I'm sure they meant carbonaceous.

"a diverse class of chondrites (one of the two divisions of stony meteorites), important because of the insights they provide into the early history of the solar system. They comprise about 3 percent of all meteorites collected after being seen to fall to Earth. Carbonaceous chondrites are subdivided into six well-established groups..."

Spellcheck attack.
3.4 / 5 (5) Dec 02, 2014
That was my point. The editors here rely on ignorant people to hammer out error-ridden just-in-time rewrites, and then *they* rely on spell-checkers, not literate editors.

Pretty shitty for a supposed science site, eh?
1.8 / 5 (5) Dec 03, 2014
Traces of possible... Probably a biological activity of extraterrestrial Martian elements in a meteorite. Well all I got are conjectures and possible maybe's and more speculative assumptions base on ideas that life is cheaply mass produced by some basic single celled organisms or lightning heating up a pond into a soup of Alien microbes. Lunacy at its best people... And pretend we are intelligent creatures, more so Martians originated from Mars. Right! lol
Dec 03, 2014
This comment has been removed by a moderator.
5 / 5 (6) Dec 03, 2014
Nashingun---evolutionary "scientists" are full of that kind of vocabulary.
Really is paradoxical.

Perhaps you missed reading the final paragraph, which begins, "Insisting on certainty is unwise, particularly on such a sensitive topic," warns Gillet.

That's a much more sensible stance than a dogmatic insistence that an invisible sky being did it.
not rated yet Dec 03, 2014
It is good as far as a stand-alone hypothesis go, but we have to compare with similar Earth trace fossils. The use of kerogen with light isotopes encapsulated in metamorphosed minerals have not been in itself enough here, which implies that the martian constraints doesn't suffice.

As an example, there are 3.8 billion years old metamorphic Isua rock kerogen with light carbon that has been promoted as evidence. But they could add that the kerogens have the correct microtopography to be metamorphosed biotic residues. Still, it hasn't been a slam dunk acceptance but are likely placed among "putative fossils".

not rated yet Dec 03, 2014

Of course we have the added constraint that life has been long present here, which also shows up in that early zircons have been contaminated with light carbon diamonds when cut in diamond saws. But people have still been able to separate such abiotic diamonds, who get their light carbon content from volcanic and plate tectonic processes, from those that were produced out of kerogen (light carbon ecoglite diamonds, produced after oceanic plate subduction of fossil bearing sediments).

The paper is paywalled, but color me skeptic. (As opposed to the cockamamie-sure creationists that troll science with their ludicrous ideas of magic agencies.)
4 / 5 (4) Dec 03, 2014
That was my point. The editors here rely on ignorant people to hammer out error-ridden just-in-time rewrites, and then *they* rely on spell-checkers, not literate editors.

Pretty shitty for a supposed science site, eh?
If you google a phrase from the above article you see that it has been copied verbatim on a number of science news sites. You'll also note that the original was probably in French, and the error may have occurred in translation.

Physorg has neither the time nor the expertise to rewrite press releases, research the science behind the stories, or weed out every little mistake in them. If you don't like it why don't you stick to journals and scientific american instead of whining about it here? But you'll probably find typos in them as well so you'll probably never be satisfied.

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