Photos from NASA’s Curiosity rover suggest Mars had more water for longer than previously thought
Scientists say Mars may have had more water and stayed wet for longer than they had previously estimated based on photos from NASA’s Curiosity rover.
An international team of researchers led by Imperial College London recently found unusual formations in rock and sediment in unexpected places in the crater.
The rocks allow scientists to compare the evolving geology of Mars with Earth.
“What we found by looking at these rocks is that there was abundant water on the surface of Mars much later than we expected,” said Dr Steven Banham, a research fellow at Imperial College London and the lead author of the recently published study.
‘Must have been water more recently’
The Curiosity rover has been exploring Mars’ Gale Crater, south of the Martian equator, for more than a decade, analysing the minerals on its surface.
The area has mountains over five kilometres high and is built in layers first by lake and river sediments then by desert sediments blown in by Mars’ winds during a period when the planet dried out.
Specialist scientists at NASA examine photos sent back from Curiosity in detail, looking at the sediment and the chemistry of the rocks while astrobiologists look for organic molecules.
Previous studies of a sandstone structure show water must have existed on the red planet for much longer than expected, according to Banham.
“Within that sandstone, we find the structures which crosscut them, which are evidence of water,” said Banham.
“So they must be one of the youngest things to happen in the crater, which therefore means we have these structures which were formed by water. Therefore, there must have been water more recently, within the crater than we previously thought,” Banham added.
‘Similar conditions existed on Mars as on Earth’
“We understand that there was water sort of in Mars’ early history. But then as you go sort of from the start of the Hesperian, so, 3.7 billion years ago, towards 3 billion years ago, Mars dried out,” said Banham.
That’s around about the same time that life evolved on Earth.
But the very first signs of life might not show up in rock records because they need to become more abundant before a lasting impression is sustained.
“Similar conditions existed on Mars at the same time as that on Earth, and it would be reasonable to believe that life would potentially evolve on Mars, but then it would need more time to sort of evolve into a state where we could leave an impression in the rock record.
“And by identifying this water later in Gale Crater’s infinite history, it pushes back that window where the opportunity that life could evolve and be preserved in the rock record,” said Banham.
Researchers say the new insights could give a better indication of where to look for any life that might have existed on Mars.
The Curiosity rover has been operating on the red planet for more than a decade, long after the vehicle was expected to die out.
It’s expected to be able to continue for a few more years, revealing more of Mars’ secrets.
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Video editor • Roselyne Min
