The discovery of methane on Mars has pleased scientists because, on Earth, gas is often produced by microbes – its very existence could indicate that similar life existed, or existed, on the red planet.
There are possible geological processes that could produce methane as well, but even before discovering a gas source on Mars, scientists have been trying to solve another mystery.
Methane discovery is inconsistent. Other instruments, such as NASA’s CASAosity Curivers, have repeatedly found gas above Gale Crater’s surface. One, an orbiter of ESA (European Space Agency), has yet to find a trace of methane up in the Martian atmosphere.
Inside the Curiosity rover is a metal device called the Tunable Laser Spectrometer (TLS) that has obtained various methane values ??- from less than half a billionth of “equivalent to a pinch of salt refined in an Olympic-sized swimming pool” to about 20 trillion each.
The problem is not design or inefficiency.
The TLS tool is precisely licensed to be used in industrial systems and aircraft to monitor gas levels.
ESA’s ExoMars Trace Gas Orbiter “is designed to be the gold standard for measuring methane and other gases worldwide”, explains NASA, and yet – contrary to all expectations – was not available at all methane.”When the Trace Gas Orbiter entered 2016, I was expecting the orbiter team to report that there was a small amount of meth everywhere in Mars,” said Chris Webster, who leads NASA’s TLS instrument.
“When the European team announced that it did not see methane, I was definitely shocked,” he added.
The TLS team checked to see if the rover emitted the gas itself in some way.
“We are looking at the merger by pointing to a robot, soil, stone crushing, wheel damage – you can tell.
Meanwhile, John Moores, a scientist at the University of York in Toronto proposed a solution.
“I have taken what some colleagues call the Canadian view of this, in the sense that I have asked the question: ‘What if Curiosity and Trace Gas Orbiter are right?'” Mores said.
Working with the Curiosity team, Moores assumed that the difference between the rates decreased during the day they were taken.
TLS, they found to be especially effective at night when other Curiosity instruments are asleep. As the Martian air is calm at night, any methane that explodes on the ground forms near the earth’s surface.
The orbiter however relies on sunlight to trace gases of about 5km from the planet’s surface. Since the atmosphere is very active during the day, any methane gift would be purified to levels not available.
Experiments quickly confirmed that it was, but another mystery remained beyond the origin of the methane: Why did it disappear?
Methane is a stable molecule. Although you do not have a protective atmosphere, you are expected to stay on Mars for 300 years before the sun’s rays break through.
If it stays out of every corner of the globe – something researchers believe, as there is nothing unique about the Gale Crater area – then there must be enough space for the orbiter to find it.
Researchers are now trying to determine if “the low-level emissions of dust from the Martian atmosphere could destroy methane, even if too much oxygen on the Martian surface quickly decomposes methane before it reaches the upper atmosphere”.
“We have to decide if there is a faster destruction method than usual to fully integrate data sets from rover and orbiter,” Webster said.
After that, the team can try to find out where the methane comes from.