The United States National Aeronautics and Space Administration (NASA) has identified a type of gas produced by living organisms on Earth on Mars. This could be evidence that life exists on the “Red Planet.”
According to the Daily Mail, NASA’s Curiosity rover has detected stable methane emissions from the Gale Crater, appearing at different times throughout the day and fluctuating seasonally, sometimes reaching levels 40 times higher than normal.
(Image source: Shutterstock).
Although no signs of life have yet been discovered on Mars, NASA scientists believe that this gas may originate from deep within the planet.
The research team suggests that methane could be trapped beneath a layer of frozen salt and only escapes when the temperature on Mars rises – or when the Curiosity rover rolls over the surface and cracks it.
On Earth, this simple molecule, consisting of one carbon atom and four hydrogen atoms, is often a sign of life. Methane is typically released by animals during digestion.
The Curiosity rover has been traversing the Martian surface since 2012. Throughout this time, the most perplexing finding has been the stable methane emissions from Gale Crater.
Gale Crater is the only location on the Red Planet where Curiosity has detected this gas. However, NASA’s rover has yet to find any signs of life on Mars.
The Curiosity rover may release methane as it cracks the rocky surface of Gale Crater. (Image: Getty Images).
Through experiments simulating Martian soil conditions, scientists seem to have answers to potential hypotheses.
Over time, salts will rise from deep beneath the dusty surface, covered by the hard rock of Mars. This type of salt is known as perchlorate, a toxic compound that is abundant in ice trapped beneath the Martian surface.
When there is too little air, this ice gradually evaporates. And when this salty vapor filters through the surface layer, it leaves behind traces.
As the salts accumulate sufficiently in the surface layer, they form a crust – similar to sand on a beach drying into a brittle layer, or like coffee grounds remaining after brewing.
The scientists behind the research published in the Journal of Geophysical Research: Planets state: “On Mars, this process occurs naturally over a long time in shallow permafrost regions and there may be enough salts accumulating in the uppermost layer. When salty vapor bubbles up, methane gas also escapes.”
However, the origin of this gas remains a mystery. Methane could be emitted from certain types of living organisms or could result from geological processes beneath the Martian surface that scientists have yet to explore.
Regardless of its source, ultimately methane remains trapped beneath this salt crust.
By pumping varying concentrations of perchlorate through a simulated Martian surface, scientists found that this impermeable crust formed within 3 to 13 days. Perchlorate concentrations of 5-10% can create a solid salt crust.
Scientists have injected neon gas beneath the crust to replace methane. They confirmed that this crust is strong enough to keep methane trapped below.
However, when temperatures on the planet rise at certain times of the day or during specific seasons, this crust breaks, allowing methane to escape. This may be when the Curiosity rover detects methane in the Martian atmosphere.
Nevertheless, temperature is not the only factor that can crack this crust.
The crust could be about 2 cm thick. The Curiosity rover is heavy enough to penetrate it as it moves across the surface.
“To test this hypothesis, methane measurements should be taken when the rover explores a location with high salt content. Another experiment is to try to extract Martian air when drilling into a salt-rich surface,” the scientists stated.
However, NASA has yet to conduct this experiment.
