If there ever was Life on Mars,verified before Rover Perseverance From the ancient lake in Jezero crater It enhances hope that traces can be found in that environment.
Thus, in a new research published in the journal “Advancement of science“, a team led by University of California (UCLA) and the University of Oslo showed that at some point, the crater filled with water, depositing layers of sediment on the crater floor.
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According to this work, the lake then shrank and sediments carried by the river that fed it formed an enormous delta. As the lake dissipated over time, the crater sediments eroded away, forming the geological features visible today on the surface.
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The radar indicates that periods of sedimentation and erosion occurred over eras of environmental change, confirming the accuracy of inferences about the geological history of Jezero Crater based on satellite images of Mars.
“From orbit we can see a lot of different deposits, but we cannot say with certainty whether what we see is their original state or whether we are witnessing the end of a long geological history,” says Professor David Page. Earth, Planetary, and Space Sciences at UCLA and first author of the article. “To figure out how these things form, we have to look beneath the surface,” he adds in a statement.
The vehicle, which is approximately the size of a car and carries seven scientific instruments, has been exploring the 45-kilometre-wide crater, studying its geology and atmosphere and collecting samples since 2021.
Perseverance's soil and rock samples will be returned to Earth by a future expedition It is studied for evidence of past lives. This new study reinforces the hope that it contains traces of life.
We should remember that between May and December 2022, Perseverance headed from the bottom of the crater toward the delta, a vast expanse of 3-billion-year-old sediment that, from orbit, resembles river deltas on Earth. As the vehicle moved toward the delta, the instrument appeared Perseverance radar imaging of the Mars subsurface experiment The satellite, or RIMFAX, fired radar waves downward at 10-centimeter intervals and measured reflected pulses from depths of about 20 meters below the surface. Using radar, scientists can see the base of the sediment to reveal the upper surface of the floor of the buried pit.
Years of research using ground-penetrating radar and testing RIMFAX on Earth have taught scientists how to read the structure and composition of subsurface layers from their radar reflections. The resulting subsurface image shows rock layers that could be interpreted as road cuts. “Some geologists say that radar's ability to see beneath the surface is like cheating,” Page says.
the pictures remfax It revealed two distinct periods of sediment deposition sandwiched between two periods of erosion. The floor of the crater beneath the delta is not uniformly flat, suggesting a period of erosion occurred before lake sediments were deposited, UCLA and the University of Oslo reported. Radar images show that the sediments are regular and horizontal, just like sediments deposited in lakes on Earth.
The presence of lake sediments was suspected in previous studies, but was confirmed by this research.
A second period of deposition occurred when fluctuations in lake level allowed the river to deposit a broad delta that had previously extended into the lake, but had now been eroded near the river mouth.
“The changes we see preserved in the rocky record are driven by large-scale changes in the Martian environment,” Page concludes. “It is great that we can see so much evidence of change in such a small geographical area, allowing us to extend our results to the size of the entire crater,” the work concludes.
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