A step closer to solving the mystery of methane on Mars

Scientists have taken an important step in discovering the mysterious source of methane on Mars, refining gas estimates in the global atmosphere.

The methane coming out of a huge crater on Mars could be a sign of life or some other non-biological activity beneath the surface of the planet. Some believe that the crater Gale, which measures 154 km in diameter and about 3.8 billion years, contains an old lake bed.

The team was able to improve the estimation of methane using data from a satellite, ExoMars Trace Gas Orbiter, and Curiosity Rover, which takes samples of rock, soil and water. air for onboard analysis.

Dr. John Moores, visiting researcher at ANU based at York University in Canada and responsible for the new study, said scientists have been speculating for more than a decade on the potential source of methane. on Mars.

"This new study redefines our understanding of how the concentration of methane in the Mars atmosphere is changing over time, which helps us to solve the biggest mystery of what the source could be," he said. Dr. Moores.

Professor Penny King, co-investigator at ANU, said there were several equally plausible explanations for methane detected on Mars.

"Some microbes on Earth can survive without oxygen, in the depths of the earth, and release methane into their waste," said Professor King of the ANU School of Earth Sciences Research. .

"The methane on Mars has other possible sources, such as water-rock reactions or decomposing materials containing methane."

Last year, scientists learned that methane levels changed over the seasons with a reproducible annual cycle.

"This latest work suggests that methane concentration is changing every day," said Dr. Moores.

"We were able – for the first time – to calculate a single number of methane infiltration rates in the Gale crater on Mars equivalent to an average of 2.8 kg per day in Martian."

Dr. Moores said the team was able to reconcile data from the ExoMars tracer gas orbiter and Curiosity mobile, which seemed to contradict each other with extremely different methane detections.

"We were able to resolve these differences by showing that methane concentrations were much lower in the atmosphere during the day and much higher near the planet's surface at night, while heat transfer was decreasing," he said. he declared.

The study, funded by the Mars Science Laboratory Mission of NASA and the Canadian Space Agency, is published in Geophysical Research Letters.