A crater about 100 miles wide was once a freshwater lake and may have been an ancient incubator of life on Mars, a Long Island scientist has found in a new analysis of information gleaned from the Red Planet.
Joel Hurowitz of Stony Brook University, who has been studying data beamed to Earth from a NASA rover craft dubbed Curiosity, has found that a Martian region called Gale Crater was once a freshwater lake of varying depths and each may have hosted unique forms of life. Hurowitz and a team of NASA researchers have been able to re-imagine the Red Planet’s ancient past through an extensive study of its 3 billion-year-old geological remnants.
Sediments and rocks that have remained intact at the site hold some of the Martian landscape’s deepest secrets, and only now have scientists been able to determine what is inside some of them, Hurowitz said.
The intrepid spacecraft has onboard instruments that pulverize the rocks to unmask their basic elements.
“Looking down into the crater we see land forms that look very much like what we see here on Earth,” said Hurowitz, a geoscientist.
With the sophisticated equipment aboard Curiosity, Hurowitz said that he and a team of NASA scientists have been able to go well beyond simple observation of the Martian landscape, to divining the precise mineral composition of the rocks and sediments arrayed throughout the crater. The rover, like a robot on wheels and equipped like a Swiss Army knife, has also drilled into the sediment on the crater’s walls, to grab samples for study.
Images and data are relayed back to Earth, Hurowitz said.
Curiosity, about the size of a sport utility vehicle, has been exploring Gale Crater since 2012. It landed in August of that year in an area of frigid plains between the crater and foothills of a Martian region called Aeolis Mons.
“There’s no question that it was freshwater, water like you would find here on Earth so it is like looking at an ancient Earthlike area, something that is much more familiar to us rather than the alien landscapes of other planets,” Hurowitz said.
Because the water was fresh, he and his colleagues think it could have supported microbial life, the first to spring from the primordial soup on Earth.
Hurowitz’s research is to be reported in Friday’s journal Science.
Mars, fourth rock from the sun, is a rusty red orb as seen through Earth-based telescopes. The planet got its color through the oxidation of iron, and is also a dark, subzero mystery whose countless craters were created by meteors that struck it over millions of years. Hurowitz additionally theorizes, based on the new research, that Mars was once shrouded with an atmosphere that made it warmer and more Earthlike.
Earlier studies, based on data from other rovers, and even orbiters that flew by, have likewise suggested the Red Planet was endowed with water. But those projects, including some involving Stony Brook, suggested Mars’ ancient water was too briny — salty — to support life.
In 2015, NASA scientists suggested that Mars has evidence of existing water — seasonal trickles apparent in the Martian summer. But that water, experts said, is also briny and unlikely to incubate life.
The ancient freshwater lake is a new way of understanding a primordial Mars, Hurowitz said.
One NASA scientist estimated the one-time lake was probably larger than California’s Lake Tahoe, but smaller than Lake Michigan and the other Great Lakes.
The saga of ancient Martian water, told through its rocks and sediments, suggest that their basic chemical composition is nearly identical to the minerals trapped in rocks found in dry lake beds on Earth, said Curiosity’s mission specialist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Pasadena, California.
Vasavada, one of the team members who worked with Hurowitz, said the nuclear-powered Curiosity takes instructions once a day, uses its embedded artificial intelligence to carry out tasks and reports back to Earth when its job is done. Curiosity is now climbing a 600-foot-high hill on one side of the crater, Vasavada said.
“We have instruments [onboard Curiosity] that we use for analysis,” he added.“They emit alpha particles and those alpha particles interact with the rocks and produce X-rays. That allows us to look at the elemental composition of the rocks.
“We also have an instrument that shoots a laser at rocks, which causes little sparks, and we can look at those sparks to determine what the rocks are made of.”
Vasavada said Curiosity’s power source will allow it to continue working at the Gale Crater site for years to come.
“There is still a lot about Mars that we would like to learn,” he said. “We know how things degrade over billions of years, based on research here on Earth. But we also know that rocks maintain their secrets very well over that same length of time.
“What we want to determine is what went on in the ancient environment that is recorded in those rocks.”