NASA's Curiosity rover finds new evidence Mars might not be a dead planet
We now know alien life might have another piece of what it needs to survive on the red planet.
- Finalist for the Nesta Tipping Point prize and a degree in broadcast journalism from the University of Missouri-Columbia.
No, it's still not news of aliens on Mars. Instead, NASA has revealed that Curiosity, its youngest rover on the red planet, has found methane and other organic compounds that are the basic building blocks of life as we know it.
In two studies published Thursday in the journal Science, researchers from the US space agency, and from other institutions around the world, present data from Curiosity's instruments, which picked up seasonally fluctuating levels of methane in the Martian atmosphere, along with organic molecules in drilling samples.
Observers have presumed for decades that organic compounds must be present on Mars, but gathering conclusive evidence has proved difficult.
"These discoveries are the two most compelling discoveries about the possibility of Martian life that Curiosity has found," Rice University Martian geologist Kirsten Siebach, who wasn't involved in the research, tells me.
The drill samples come from mud stones in Mars' Gale Crater that could be 2 billion to 3 billion years old. This means the organic compounds found in the samples could be ancient, originating from a time period when it's thought Mars was likely more friendly to life than it is now.
"Curiosity has shown that Gale crater was habitable around 3.5 billion years ago, with conditions comparable to those on the early Earth, where life evolved around that time," Inge Loes ten Kate, a professor of Earth sciences at Utrecht University in the Netherlands, writes in a separate column in Science.
It's thought that the wide crater where Curiosity has been roaming around was once a Martian lake. Siebach says the discovery of small carbon-based molecules preserved in the sediments of that ancient lake means it was home to larger molecules that came from meteorites, volcanoes or perhaps a biological source.
"That means that more than 3 billion years ago, there was a lake on Mars with organic matter floating in it that could have built or provided energy to microorganisms, and, importantly, the evidence has been preserved for the billions of years since then."
Perhaps even more exciting is the data suggesting that methane is currently being released seasonally on Mars through a cycle that isn't yet understood.
"There are active processes happening in the Martian subsurface today, which could include heated reactions between water and rocks, possible biological activity, or some other mechanism," Siebach explains. "That means Mars today is not a 'dead planet,' but somewhere underground there are reactions occurring today that release and absorb an atmospheric gas that is almost always related to warm water or life on Earth."
It's not quite evidence that Martian life does exist or has existed, but it's evidence that life could be, or could have been, possible on Mars.
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