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Meteorite study 'shows that life may have existed on Mars'

Paul Sutherland, Feature writer
Dec 4, 2014, 0:41 UTC

Sen—An international team of scientists have made the latest controversial claim that they have found evidence pointing to life having existed on Mars.

The researchers have studied a meteorite that originally came from the Red Planet and say it contains traces that “have a very probable biological origin”.

Their findings are anounced in the learned journal Meteoritics and Planetary Sciences. And in a video produced to mark the announcement, the team say: “Until somone comes up with another more convincing scenario, we can take for granted that life on Mars has existed.”

The organic material was found within a rock that fell from the sky over southern Morocco’s desert in July, 2011. When examined in the laboratory, it was found to contain small fissures, or cracks, filled with carbon-containing matter.

The scientists, from China, Japan, Germany, and Switzerland, say their analysis rules out the possibility that the rock, known as the Tissint meteorite after where it fell, was contaminated by organic material after it landed on Earth.

And they challenged previously published views that suggest the carbon traces originated through the high-temperature crystallisation of magma. 

A cartoon explains the origin of the material in the Tissint meteorite. Credit: EPFL

Instead they believe the biological matter got into the Mars rock when an organic-rich fluid infiltrated it on the martian surface. Later the rock was blasted out of Mars by an asteroid impact and spent billions of years circling the Sun before running into the Earth.

“So far, there is no other theory that we find more compelling,” said Philippe Gillet, director of the Ecole Polytechnique de Lausanne’s Earth and Planetary Sciences Laboratory in Switzerland. “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.”

The team say their conclusions are supported by several intrinsic properties of the meteorite’s carbon, for example its ratio of carbon-13 to carbon-12 isotopes. This was found to be significantly lower than the ratio of carbon-13 in the carbon dioxide of the martian atmosphere, as measured by NASA’s Phoenix lander and Curiosity rover.

Previous claims that martian fossils have been found in meteorites have caused controversy. Most notable was a rock found in the deep freeze of Antarctica and called Allan Hills 84001. It provoked “Life on Mars” headlines in newspapers and prompted US President Bill Clinton to make a televised address to the nation.

Scientist Philippe Gillet describes why his team came to the conclusion they did over Tissint. Image credit: EPFL