Researchers from NASA’s Curiosity rover mission have found evidence that there was once an ancient lake on Mars that may have been able to support life.
Possible extent of an ancient lake inside Gale Crater, Mars, estimated by mapping lake and stream deposits and recognizing that water flowed from the crater rim into the basin, shown by arrows. The water would have pooled in the linear depression created between the crater rim and Mt Sharp. The base map combines image data from Mars Reconnaissance Orbiter and color information from Viking Orbiter imagery. Image credit: NASA / JPL-Caltech / MSSS.
The scientists have analyzed a set of sedimentary rock outcrops at a site named Yellowknife Bay in Gale Crater – a 150 km wide impact basin with a mountain at its center – near the Martian equator.
Their results, reported in a series of papers published in the journal Science, show that Gale Crater sustained at least one lake around 3.6 billion years ago. The scientists believe that the lake may have lasted for tens if not hundreds of thousands of years.
The lake was calm and likely had fresh water, containing key biological elements such as carbon, hydrogen, oxygen, nitrogen and sulfur.
Such a lake would provide perfect conditions for simple microbial life such as chemolithoautotrophs to thrive in. On Earth, chemolithoautotrophs are commonly found in caves and around hydrothermal vents. The microbes break down rocks and minerals for energy.
Mudstones generally form in calm conditions. They are created by very fine sediment grains settling layer-by-layer on each other, in still water.
“It is important to note that we have not found signs of ancient life on Mars. What we have found is that Gale Crater was able to sustain a lake on its surface at least once in its ancient past that may have been favorable for microbial life, billions of years ago. This is a huge positive step for the exploration of Mars,” said team member Prof Sanjeev Gupta from Imperial College London, UK.
“It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake’s calm waters, converting a rich array of elements into energy. The next phase of the mission, where we will be exploring more rocky outcrops on the crater’s surface, could hold the key whether life did exist on the Red planet.”
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