Life on Mars may have developed billions of years ago when the planet was still hot, humid and home to vast seas and oceans. Today, the Red Planet is a barren and desolate landscape devoid of any immediate evidence it could still be home to alien organisms. There are, however, scientists who have dedicated their lives to answering the ultimate question of are we alone in the universe. A key clue to determine whether Mars could be hiding alien life right under our noses is the irregular appearance of methane in the planet’s carbon dioxide-heavy atmosphere.
Since 2004, different space probes sent to the Red Planet have been detecting trace amounts of methane on Mars.
The initial discovery was exciting because here on Earth, different types of microbes living deep beneath the surface produce methane.
Professor Penny King from the Australian National University said: “Some microbes on Earth can survive without oxygen, deep underground, and release methane as part of their waste.”
Even larger organisms like cows are another major contributor to atmospheric levels of methane on Earth.
Life on Mars: Trace amounts of methane on Mars could be produced by alien microbes
Life on Mars: NASA’s Curiosity rover is currently exploring the Red Planet
On Mars, however, there are no obvious signs of life that could be producing these methane spikes.
Microbes on Earth can survive without oxygen, deep underground, and release methane
Another problem faced by scientists is the levels of atmospheric methane detected on Mars never quite matched the various records collected by missions like ExoMars or NASA’s Curiosity rover mission.
Scientists at the Australian National University addressed this issue in a new study published on August 20 in the journal Geophysical Research Letters.
The study claims to have figured out why the data on methane concentrations does not match between missions.
The study should help scientists track down the origin of the gas, whether it is biological or geological.
Dr John Moores, from York University in Canada who led the study, said: “This new study redefines our understanding of how the concentration of methane in the atmosphere of Mars changes over time, and this helps us to solve the bigger mystery of what the source might be.”
Last year, scientists have discovered methane concentrations on Mars are seasonal and differ at different times of the year.
Now, researchers have found methane concentrations can wildly differ thought the course of a single day.
Dr Moores said: “This most recent work suggests that the methane concentration changes over the course of each day.
“We were able – for the first time – to calculate a single number for the rate of sewage of methane at Gale crater on Mars that is equivalent to an average 2.8kg per Martian day.”
The discovery can explain why the ExoMars Trace Gas Orbiter and the Curiosity Rover both detected different concentrations of methane.
Dr Moores said: “We were able to resolve these differences by showing how concentrations of methane were much lower in the atmosphere during the day and significantly higher near the planet’s surface at night, as heat transfer lessens.”
Life on Mars: The methane can also be produced through geological processes
Life on Mars: Different Mars explorers have detected different concentrations of methane
But what does this mean for the possibility of life on Mars?
Hopes are high after scientists recently discounted the effect of wind erosion in releasing methane into the atmosphere.
However, according to Professor King, there are still non-biological processes that can explain the Martian mystery.
The Mars expert said: “The methane on Mars has other possible sources, such as water-rock reactions or decomposing materials containing methane.”
The Mars study was supported by NASA’s Mars Science Laboratory mission and the Canadian Space Agency.