Martian Meteorite Contains Possible Traces Of Biological Matter

April Flowers for redOrbit.com – Your Universe Online

The debate has raged for a long time. Is there now, or has there ever been, life on Mars?

An international team of scientists, using data from a meteorite from Mars, reports that life on Mars is more likely than previously thought. The team, which included members from Ecole Polytechnique Federale De Lausanne (EPFL), published their findings in a recent issue of Meteorics and Planetary Sciences.

“So far, there is no other theory that we find more compelling,” said Philippe Gillet, director of EPFL’s Earth and Planetary Sciences Laboratory. The team conducted a detailed analysis of organic carbon traces found in a Martian meteorite. Their results indicate that these sources have a very probable biological origin. The researchers note that carbon could have been deposited into the rock’s fissures by infiltration of fluid rich in organic matter while it was still on Mars.

The meteorite, Tissint, was ejected from Mars after an asteroid struck the planet’s surface. Several eyewitnesses saw Tissint fall to the Moroccan desert on July 18, 2011. Scientists found fissures on the meteorite filled with carbon-containing matter, which have been shown by several previous studies to be organic in nature. Despite this, the scientists are still debating the origin of the carbon.

The team performed chemical, microscopic and isotopic analysis of the carbon material, which suggested several possible explanations for its origin. Characteristics were established that provided unequivocal proof that the material was not terrestrial in origin. They also revealed that the carbon content was deposited in Tissint’s fissures before it left Mars.

Previous studies suggested that the carbon traces originated through the high-temperature crystallization of magma. The new findings challenge this view, showing that 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.

The team says that their conclusions are supported by several intrinsic properties of the meteorite’s carbon, specifically its ratio of carbon-13 to carbon-12 — which was found to be significantly lower than the ratio of carbon-13 in the CO2 of Mars’s atmosphere as measured by the Phoenix and Curiosity rovers. The differences between these ratios perfectly matches observed levels of carbon on Earth between a piece of coal – which is biological in origin – and the atmosphere.

The team notes that the organic matter in the meteorite’s fissures could have been brought to Mars when very primitive meteorites – carbonated chondrites – fell on it. They feel that this scenario is unlikely, however, because carbonated chondrites 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.”

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