April 2 (UPI) – About 15 years ago, a European probe measured traces of methane in the Martian atmosphere. Now, the Curiosity rover from NASA and the Mars Express from the European Space Agency have confirmed the presence of gas in the air over Gale crater.
"The presence of methane could improve habitability and could even be a signature of life," the researchers wrote in a new article published in the journal Nature Geoscience.
On June 15, 2013, the NASA Curiosity rover collected a methane peak measuring 6 parts per billion in air samples collected and badyzed within Gale crater. The next day, the ESA Mars Express probe captured air samples with a methane concentration of 15.5 parts per billion as it pbaded through the atmosphere over Gale crater.
The independent confirmation by two spacecraft was a coincidence.
"We were very lucky, as this is not the result of coordinated observations," Marco Giuranna, lead author of the new Nature Geoscience article and planetary scientist at the National Institute of Astrophysics in Rome, told Space.com. "Just by chance!"
To find the possible source of methane, the scientists used computer models to closely badyze the surface structures found in the Gale crater, as well as in the surrounding region. The algorithms compared the various characteristics of the surface with the environments on Earth that are known to produce methane emissions.
On Earth, methane is typically a sign of life. But the new badysis suggests that a frozen slab of ice or permafrost containing methane, located beneath tectonic faults outside of the Gale crater, is the most logical explanation for the seasonal methane peaks of the Red Planet. Scientists estimate that periodic fusion causes ice to release the compound as a gas.
At first, scientists thought that methane originated inside the Gale crater.
"Our new Mars Express data, taken a day after the Curiosity recording, changes the interpretation of where methane originated, especially when considering global atmospheric circulation patterns along with local geology," Giuranna said in a statement. ESA press. "Based on the geological evidence and the amount of methane we measure, we think it is unlikely that the source will be located inside the crater."
The conclusions of computer simulations are not definitive, and there is still much to be learned about methane from Mars. Scientists are still unsure how methane is removed from the atmosphere and trapped in permafrost.
But the latest findings suggest that scientists are getting closer to explaining the methane that Mars Express first measured 15 years ago.
"Our results support the idea that the release of methane on Mars could be characterized by small transient geological events rather than a global presence that is constantly replenished," said Frank Daerden, a researcher at the Royal Belgian Institute of Space Astronomy in Brussels.
Scientists hope to gain new insights into the nature of methane from Mars and other trace gases from data collected by ESA's ExoMars Trace Gas Orbiter, a probe with a set of instruments designed to study the atmospheric composition of Mars.