NASA rover discovers evidence of water on the Red Planet
After spending 1,000 days on the surface of Mars, NASA's Perseverance rover has revealed new details about the history of an ancient lake and river delta on the red planet.
New data uncovered by the rover's detailed observations of the ground is helping scientists piece together the mystery of Mars' mysterious past, and they may ultimately be able to determine whether life ever existed there.
As CNN reports, Perseverance and its helicopter companion, Incognito, landed in Jezero Crater on February 18, 2021, to search for signs of ancient microbial life.
As part of the search, the robotic explorer has just completed an exploration of the river delta that once flowed into the lake , which filled the Jezero Crater billions of years ago. Along the way, Perseverance also collected 23 rock samples from various locations throughout the crater and delta.
Each sample is about the size of chalk and packaged in metal tubes and could be returned to Earth in the future as part of a joint campaign between NASA and the European Space Agency to return samples from Mars. Studying the samples on Earth would allow for more detailed analysis using laboratory equipment that is too bulky to send to Mars on board a rover.
Scientists shared some of the insights they've gleaned from Perseverance's journey to Mars on Tuesday at the American Geophysical Union's fall meeting in San Francisco.
The rover collects samples using an abrasive tool on its arm to scrape away the surface of Martian rock. , and then analyzes the composition of the rock using its planetary X-ray lithochemistry instrument, known as PIXL.
Some of Perseverance's recent rock samples include silica, a fine-grained mineral that helps preserve ancient fossils and organic molecules on Earth. Organic molecules can be formed through geological and biological processes.
“On Earth, this fine-grained silica is what you often find in places that were once sandy,” said Morgan Cable, deputy principal investigator. PIXL at NASA's Jet Propulsion Laboratory in Pasadena. “This is the environment in which the remains of ancient life could have been preserved on Earth and found later.”
Some rocks also contained iron bound to phosphate, a natural source of the element phosphorus, which acts as a component of DNA and cell membranes.
Carbonate was also found in the samples. These minerals point to water-rich environments in the past, acting as time capsules to describe environmental conditions on Mars since the rocks were originally formed.
“We chose Jezero Crater as the landing site because orbital images showed a delta—clear evidence that the crater was once filled by a large lake. A lake is a potentially habitable environment, and delta rocks are an excellent environment for preserving signs of ancient life as fossils in the geological record, explains Ken Farley, Perseverance project scientist and professor of geochemistry at Caltech. “After extensive research, we have pieced together the geological history of the crater, mapping its lacustrine and fluvial phases from beginning to end.”
Scientists believe that Jezero Crater was formed when an asteroid crashed into Mars 4 billion years ago, notes CNN.
The Perseverance mission began by studying the floor of the crater shortly after landing. The rover's detective work helped scientists determine that the crater floor is composed of volcanic rock, which was formed either by magma rising to the surface or by volcanic activity on the surface of Mars.
As Perseverance progressed, the rover encountered samples of sandstone and mudstone, suggesting that a river flowed into the crater millions of years after its formation. A top layer of salt-rich mudstone is all that remains, indicating that the crater was filled by a shallow lake that was 35 kilometers wide and 30 meters deep before some climate change caused the lake to evaporate.
The rover also found evidence of boulders that originated from other places on Mars and were deposited in the river delta and crater by fast-flowing rivers.
“We were able to see the broad outlines of these chapters in Jezero's history in orbital images, but it took have to be persistent to really understand the chronology in detail,” says Libby Ives, a research scientist at NASA's Jet Propulsion Laboratory.
Perseverance's suite of instruments is capable of detecting microscopic fossil structures and chemical signatures left behind by microbial life, but the rover did not detect neither one nor the other. However, the geological data collected by the rover so far paints a tantalizing picture.
“We have ideal conditions for searching for signs of ancient life, where we find carbonates and phosphates that indicate a watery, habitable environment, and also silica, which is perfectly preserved,” emphasizes Morgan Cable.
And the mission is not over yet. The rover will then examine an area near the crater's entrance where a river has spilled across the crater floor, leaving behind carbonate deposits that resemble a bathtub ring.
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