2023-12-13 11:29:15
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The rover remained parked at Airey Hill for several weeks during the solar conjunction. – NASA/JPL-CALTECH/ASU/MSSS
MADRID, 13 Dic. (EUROPA PRESS) –
After 1,000 days on Mars, NASA’s Perseverance rover has crossed an ancient system of rivers and lakescollecting valuable samples along the way.
It is an ancient delta containing evidence of a lake that filled Jezero Crater billions of years ago. The six-wheeled scientist To date, a total of 23 samples have been collected.while revealing the geological history of this region of Mars.
One sample called “Lefroy Bay” contains a large amount of fine-grained silica, a material known to preserve ancient fossils on Earth. Another, “Otis Peak,” contains a significant amount of phosphate, which is often associated with life as we know it. Both samples are also rich in carbonate, which can preserve a record of environmental conditions since the rock formed.
The findings were presented at the fall meeting of the American Geophysical Union (AGU) in San Francisco.
“We chose Jezero Crater as the landing site because orbital images showed a delta, clear evidence that a large lake once filled the crater. A lake is a potentially habitable environment, and the rocks of the delta are an excellent environment for burial. signs of ancient life as fossils in the geological record,” he said it’s a statement Perseverance project scientist at Cakltech Ken Farley. “After exhaustive exploration, we have reconstructed the geological history of the crater, charting its lake and river phase from beginning to end.”
Jezero was formed from an asteroid impact almost 4 billion years ago. After Perseverance landed in February 2021, the mission team discovered that the crater floor is made of igneous rock formed from underground magma or volcanic activity on the surface. They have since found sandstone and shale, indicating the arrival of the first river to the crater hundreds of millions of years later. Above these rocks are salt-rich shales, indicating the presence of a shallow lake that is undergoing evaporation. The team believes the lake eventually grew to 35 kilometers in diameter and 30 meters deep.
Later, rapidly flowing water brought rocks from outside Jezero, distributing them over the top of the delta and other parts of the crater.
“We were able to see a broad summary of these chapters of Jezero’s history in orbital images, but it was necessary to get closer to Perseverance to really understand the timeline in detail“said Libby Ives, a postdoctoral fellow at NASA’s Jet Propulsion Laboratory, which manages the mission.
The samples Perseverance collects are about the size of a piece of school chalk and are stored in special metal tubes as part of the Mars Sample Return campaign, a joint effort by NASA and ESA. Bringing the tubes to Earth would allow scientists to study the samples with powerful laboratory equipment, too big to take to Mars.
To decide which samples to collect, Perseverance first uses an abrasion tool to abrade a patch of potential rock and then studies the rock’s chemistry using precision scientific instruments, including the Planetary Instrument for X-ray Lithochemistry, or PIXL, built by the JPL.
At a target the team calls “Bills Bay,” PIXL detected carbonates, minerals that form in aqueous environments with conditions that could be favorable for preserving organic molecules. (Organic molecules are formed through geological and biological processes). These rocks were also abundant in silica, a material that is excellent for preserving organic molecules, including those related to life..
“On Earth, this fine-grained silica is what you often find in a place that was once sandy,” said JPL’s Morgan Cable, deputy principal investigator for PIXL. “It’s the kind of environment where, on Earth, remains of ancient life could be preserved and found later.”
Perseverance’s instruments are capable of detecting both microscopic fossil-like structures and chemical changes that may have been left behind by ancient microbes, but they have yet to find evidence of either.
At another target examined by PIXL, called “Ouzel Falls,” the instrument detected the presence of iron associated with phosphate. Phosphate is a component of the DNA and cell membranes of all known terrestrial life and It is part of a molecule that helps cells transport energy.
After evaluating PIXL’s findings in each of these abrasion patches, the team sent orders to the rover to collect nearby rock cores: Lefroy Bay was collected next to Bills Bay and Otis Peak in Ouzel Falls.
“We have ideal conditions to find signs of ancient life where we find carbonates and phosphates, which point to a watery, habitable environment, as well as silica, which is excellent for preservation,” Cable said.
Of course, Perseverance’s work is far from done. The mission’s fourth ongoing science campaign will explore the margin of Jezero Craternear the canyon entrance where a river once flooded the carbon-rich bottom of the crater.
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