National Post (Latest Edition)

Life on Mars possible — billions of years ago

- Sarah Knapton

Freezing, arid and lifeless, the dusty Jezero crater on Mars is currently an inhospitab­le desert. Yet 3.7 billion years ago, it was full of water and could have harboured life, scientists believe.

The first analysis of images from NASA’S Perseveran­ce rover show that the crater was once a 34-kilometre wide lake, which was fed by a river, and which suffered flash flooding.

Huge boulders now lie in the lake bed after being swept tens of kilometres downstream by the raging currents, the pictures show. But researcher­s are most excited by the discovery of layers of fine-grained clay and mudstones at the site, because they could preserve traces of ancient life.

Sanjeev Gupta, a professor at Imperial College London and one of the researcher­s who analyzed the images, said: “The finest grained material at the bottom of the delta probably contains our best bet for finding evidence of organics and biosignatu­res. We’re not expecting to find fossils, but we could find evidence of microbial life.

“We’ve already drilled two samples and put them into the rover and we will be driving to the region in the next few years to take 38 samples and then there will be a joint European Space Agency and NASA mission that will retrieve the samples so we can analyze the rocks on Earth.

“I think finding life is entirely likely. It would seem surprising that life only formed on Earth and these are definitely the right rocks to look for it.”

Perseveran­ce landed on Feb. 18 in the Isidis Planitia region, just north of the equator in the eastern hemisphere of Mars, around one mile from the delta.

The region was chosen because images taken by orbiting spacecraft showed the area resembled river deltas on Earth, where layers of sediment are deposited in the shape of a fan. But without being on the ground it was impossible to know if the patterns were formed by the wind or other processes.

Zoomed images taken by Perseveran­ce of the cliffs surroundin­g the crater show sloping rock beds sandwiched between horizontal layers that indicate rocky deposits from an ancient river.

The team says it suggests that there was steady water flow, consistent with a warm and humid Martian climate 3.7 billion years ago.

“If you look at these images, you’re basically staring at this epic desert landscape. It’s the most forlorn place you could ever visit,”

“There’s not a drop of water anywhere, and yet, here we have evidence of a very different past. Something very profound happened in the planet’s history. Without driving anywhere, the rover was able to solve one of the big unknowns, which was that this crater was once a lake,” says Benjamin Weiss of MIT and a member of the analysis team.

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