After a tantalizing year-and-a-half wait since the Mars Perseverance Rover slammed into our nearest planetary neighbor, new data is coming — and it’s bringing a few surprises with it.
The rover, which is about the size of a car and carries seven science instruments, is exploring Mars’ 30-mile-wide Jezero Crater, once the site of a lake and an ideal spot to look for evidence of ancient life and information about its geological and climatic past planet.
In an article published today in the magazine Advances in Science, a research team led by UCLA and the University of Oslo reveals that the rock layers beneath the crater floor, observed by the rover’s ground-penetrating radar instrument, are unexpectedly tilted. The slopes, thicknesses, and shapes of the sloped sections suggest that they were either formed by slow cooling of lava or deposited as sediments in the former lake.
Perseverance is currently exploring a delta on the western edge of the crater where a river once fed the lake, leaving behind a large deposit of dirt and rock that it collected along its course. As the rover collects more data, researchers hope to unravel the complex history of this part of the Red Planet.
“We were surprised to find rocks stacked at an inclined angle,” said David Paige, professor of Earth, Planetary and Space Sciences at UCLA and one of the principal investigators on the Radar Imager for Mars Subsurface Experiment, or RIMFAX. “We expected to see horizontal rocks on the crater floor. The fact that they have such a slope requires a more complex geological history. They could have formed when molten rock rose to the surface or, alternatively, they could represent an older delta deposit buried in crater floor.”
Rendering of Perseverance, whose RIMFAX technology explores what lies beneath the surface of Mars. Credit: NASA/JPL/Caltech/FFI
Paige said most of the evidence gathered by the rover so far points to an igneous or molten origin, but based on the RIMFAX data, he and the team still can’t say for sure how the tilted layers formed. RIMFAX acquires a picture of subsurface features by sending bursts of radar waves below the surface, which are reflected by layers of rock and other obstacles. The shapes, densities, thicknesses, angles and compositions of underground objects affect the way the radar waves bounce, creating a visual image of what lies beneath.
During Perseverance’s initial 3-kilometer traverse, the instrument acquired a continuous radar image revealing the electromagnetic properties and rock stratigraphy—the arrangement of rock layers—of Jezero’s floor at depths of 15 meters, or about 49 feet. The image reveals the ubiquitous presence of layered rock layers, including those with slopes of up to 15 degrees. Adding to the mystery, within these sloping areas are some intricate highly reflective layers of rock that actually slope in multiple directions.
“RIMFAX gives us a view of Martian stratigraphy similar to what you can see on Earth in road sections, where tall stacks of rock layers are sometimes visible on a mountainside as you drive,” Paige explained. “Before Perseverance landed, there was much speculation about the exact nature and origin of the crater floor materials. We have now been able to narrow down the range of possibilities, but the data we have so far suggests that the history of the crater floor may it’s a lot more complicated than we expected.”
The data collected by RIMFAX will provide valuable context to rock samples collected by Perseverance, which will eventually be brought back to Earth.
“RIMFAX gives us the background of the samples we’re going to analyze. It’s exciting that the rover’s instruments are producing data and we’re starting to learn, but there’s a lot more to come,” Paige said. “We landed on the crater floor, but now we’re going up to the actual delta, which is the mission’s main goal. This is just the beginning of what we hope to soon learn about Mars.”
The paper, “Ground Penetrating Radar Observations of Subsurface Structures on the Floor of Jezero Crater, Mars,” is one of three papers published simultaneously discussing some of the first data from Perseverance.
New research sheds light on when Mars may have had water More information: Svein-Erik Hamran et al, Ground penetrating radar observations of subsurface structures in the bottom of Jezero crater, Mars, Advances in Science (2022). DOI: 10.1126/sciadv.abp8564 Provided by University of California, Los Angeles
Reference: First ground-level radar images from the Mars Perseverance Rover reveal some surprises (2022, August 25) Retrieved August 25, 2022 by
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