Scientists on Tuesday revealed that NASA's Curiosity rover detected a tenfold spike in methane levels on the Red Planet last year. It was the first time Curiosity detected significant traces of the gas since the rover landed on Mars in 2012 and the discovery has reignited discussions about the possibility of life on the fourth planet from the sun.
What's the big deal about methane? It's an organic chemical, meaning it contains carbon, the building block of life. We know it mostly as a key ingredient in fossil fuels like natural gas. But numerous flatulent creatures emit it everyday, too.
"The biggest and most tantalizing part of this is that methane can be a byproduct of microbes," said Space.com managing editor Tariq Malik, speaking to VICE News. "On Earth, methane is the byproduct of many forms of life. Methane comes out of cows."
Malik cautioned that the methane could come from a geological-chemical reaction that forms rocks. But even that process would require liquid water and heat, the precursors of life. "It's obviously a major discovery," he said.
The discovery also poses a mystery, however: the methane appeared unexpectedly, but it also quickly dissipated. Some reaction, in other words, was rapidly producing and rapidly eliminating the methane. For now, the scientists have no explanations. "We will keep working on the puzzles these findings present," John Grotzinger, a California Institute of Technology professor working on the Curiosity project, said in a NASA statement.
The announcement came as a relief to NASA advocates. Curiosity, launched with the express purpose of looking for signs of extraterrestrial life, might finally have discovered a footprint in the search for Martians.
Around 10 years ago, scientists using telescopes on Earth believed they observed methane plumes on Mars, raising hopes of exotic life forms there. When the rover failed to confirm their findings, the scientists were crestfallen. Now it looks as if they might have stumbled across a mysterious pattern of methane eruptions.
"Curiosity has been looking for methane since it landed," said Malik. "Last year there were no traces for this stuff. It was a big blow. That story has completely changed."
On the same day, Grotzinger also announced another hopeful sign of life on Mars. Curiosity recently discovered carbon-based organic molecules in a chunk of rock it drilled out of the planet's rugged surface. The molecules don't necessarily mean life exists, but they are more potential building blocks for microbes and other aliens. The NASA geeks dubbed the chunk of rock Cumberland.
Luckily, NASA and other space agencies have been prepping for years for a major search for life on Mars. The US has four satellites orbiting Mars and collecting data. European space agencies, India, and others also have satellites.
The US additionally has two other rovers — Spirit and Opportunity — on Mars searching for liquid water, which appears to have been plentiful on the planet eons ago. NASA plans to land another rover on Mars in 2020. The agency hopes to put people there in the 2030s.
In the meantime, Curiosity is sleuthing for more clues in the case of the missing methane.
"That's a lot of assets to train on this problem," said Malik. "And Curiosity is not done yet. It has this weather station on top of it, and it can keep on tracking. It has a nuclear power source, too. They can keep this rover going for years to come."
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Photo via Flickr/European Space Agency