The dry, dusty crater that NASA’s Mars rover Curiosity is exploring was once filled with a series of lakes that may together have lasted for millions of years, scientists at Jet Propulsion Laboratory say.
The findings, published by the journal Science, show that liquid water may have existed for long enough on the planet for life to (hypothetically) begin and thrive.
“Our results show that water pooled there, in surface and subsurface reservoirs, for a geologically and perhaps biologically relevant period of time,” the study authors wrote.
Since landing in Gale Crater in 2012, snapping pictures and drilling rocks, Curiosity has found plenty of evidence that liquid water was present in the rust-hued planet’s distant past. In Yellowknife Bay, the rover even discovered clear signs of a past habitable environment, filled with life-friendly chemicals.
“The geology of Mars still holds the tantalizing possibility that extraterrestrial life might exist or have been preserved, because the evidence of water is so plentiful,” Marjorie Chan of the University of Utah, who was not involved in the paper, wrote in a commentary.
But how long did this wet, life-friendly environment stick around? It would have to last long enough for life to emerge. Scientists don’t know how long that might take; it could be on the order of millions of years.
The new research takes into account observations from across Curiosity’s journey, from its landing site all the way to the base of Mount Sharp, the 3-mile-high mountain in the middle of Gale Crater. And it has found that the crater likely held a series of lakes over time that rose and fell before being filled again, perhaps by an underground reservoir.
“This intracrater lake system probably existed intermittently for thousands to millions of years, implying a relatively wet climate that supplied moisture to the crater rim and transported sediment via streams into the lake basin,” the study authors wrote.
Scientists have recently found evidence for extremely briny water sometimes flowing on the surface of Mars, but pure liquid water couldn’t really survive on the planet today; the atmosphere is so thin that the water would either immediately evaporate or freeze solid, depending on the temperature.
So if there is evidence for long-lived bodies of standing water, that means the atmosphere must have been much thicker, perhaps filled with puffy clouds. This world would have looked, in short, a lot more like our own planet.
“The more the geology looks like Earth, the more likely it seems that some life-form(s) could have developed in the martian waters,” Chan wrote.
By Amina Khan - Los Angeles Times (TNS)
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