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There has been tremendous excitement in the space science community since NASA chose Jezero Crater as the landing site for its next Mars 2020 rover mission after a five-year search.
NASA’s Perseverance rover to Mars, expected to launch in July, will look for signs of past microbial life in river delta deposits formed over billions of years that could have improved the preservation of evidence of life.
The delta, speculated to have formed due to sediment deposits at the mouth of the Hypanis Valles, a river system on ancient Mars, separates the southern highlands from the northern lowlands.
Scientists believe that Mars once had an ancient ocean and a water cycle similar to that of Earth and the great seas, or an ocean that existed in the northern lowlands.
A new Stanford study, published online in AGU Advances on April 23, offers guidance for sample recovery to better understand the ancient Martian climate, the duration of this delta formation, and whether wet Mars was habitable.
“There was probably water for a significant duration on Mars and that environment was certainly habitable, even if it had been arid,” according to lead author Mathieu Lapotre, an assistant professor of geological science at the Stanford School of Earth, Energy and Environment. Sciences (Stanford Earth). “We showed that the sediments were deposited quickly and that if there were organic compounds, they would have been quickly buried, which means they probably would have been preserved and protected.”
The Jezero crater was selected for NASA’s next rover mission, in part because the site contains a river delta, which on Earth is known to effectively preserve the organic molecules associated with life. But without an understanding of the rates and durations of delta construction events, the analogy remained speculative.
The study incorporates a recent discovery that researchers made on Earth: winding single-stranded rivers that have no plants growing on their banks move sideways about ten times faster than those with vegetation. Based on the force of gravity from Mars, and assuming the Red Planet had no plants, scientists estimate that the delta in Jezero crater took at least 20 to 40 years to form, but that the formation was likely discontinuous and spread. for around 400,000 years.
The Jezero crater findings could help us understand how life evolved on Earth. If life ever existed there, it probably did not evolve beyond the single-celled stage, scientists say. This is because the Jezero crater was formed more than 3.5 billion years ago, long before organisms on Earth became multicellular. If life ever existed on the surface, its evolution was halted by some unknown event that sterilized the planet. That means the Martian crater could serve as a kind of time capsule to preserve signs of life, as it may have once existed on Earth.
“Being able to use another planet as a laboratory experiment on how life might have started elsewhere or where there is a better record of how life started in the first place, that could actually teach us a lot about what life is.” Lapotre said. “These will be the first samples we have seen as a rock on Mars and then we have brought them to Earth, so it is quite exciting.”
