Life on Red Planet
NASA scientists at Mars Curiosity found that Gale Crater had good physical and chemical life conditions of 700 million years – and part of that history housed a lake that could accommodate a wide variety of microbial life.
The results, published last week in the journal Science, documented a sustainable Martian environment that had the potential to house a wide variety of living things.
“This helps expand our understanding of what a habitable environment was on Mars, there are 3 1/2 billion years,” said author Joel Hurowitz, a geochemist at Stony Brook University.
Since its landing at Gale Crater in 2012, Curiosity has drilled X-rays and has launched a variety of rocks in the quest to understand if the red planet – a world that began as ours – could have been hospitable to life.
Using his instruments at the forefront of technology, the mission of curiosity led to Mount Sharp, the 3000 mound in the middle of the crater. There would rise its slopes, reading each layer of sedimentary rock as a chapter of the geological history of Mars.
In his journey, curiosity has discovered evidence of water in the past and the right chemical ingredients for life; Recent studies have revealed that Gale Crater was once filled with a series of lakes that may have come up and down over time.
But how does this ancient body of water?
In this new study, scientists have gathered evidence from several locations along the route to Mount Sharp, including six samples of perforated rocks from very different ancient environments.
The results revealed a wealth of life ingredients as we know it, including organic compounds of carbon, nitrogen and phosphate minerals, and iron and sulfur minerals in different redox states.
“Our analysis of these rocks indicates that gradients in the oxidation state of lake water were present in the primary lake environment,” the study authors wrote. “Overall, these results provide compelling evidence that the physical, chemical, and energy conditions necessary to establish a habitable environment were present on Mars between 3.8 and 3.1 (a billion years ago).”
Scientists also noticed a strange pattern in an extended rock layer. There were many areas where thick sediments were quickly dumped – marking the shallow water where the water empties into the lake from a stream or river that have left much of its heavy material.
There were also areas where both sediment had been gradually litter litter – closer to the center of the lake and near the mouth of the river.
Here’s the weird part: Chemically speaking, the minerals in the shallower parts of the lake appear to have been exposed to more oxygen, while the minerals in the deeper areas had none.
It seems that the waters of Lake Gale have, at least for part of their history, differentiated into an oxygen-rich layer of the surface layer and one that is poor in oxygen in its depths. It is very similar to lakes of the Earth, that also differ of the same way.
“It’s this relationship between mineralogy and the thickness of sediment layers that allows us to connect the dots,” said Ashwin Vasavada, co-author of the study, the project scientist for the mission at the Jet Propulsion Laboratory.
This complex lake could have lasted hundreds of thousands of years to 10 million years, Hurowitz said. Like lakes on the earth, which from Gale Crater could accommodate several microorganisms, including some preferred oxygenated waters near the surface, others prefer the deeper anoxic waters and those they loved exit at the interface between the two.
During this period, scientists also found that Mars appeared to move from a cooler, drier environment to warm and humid. In addition, their layered sedimentary records were changed to what appears to be salty liquid.
Studying these rocks could help scientists understand the final drying of Mars, while their water escaped from space, leaving the salts behind.