(ORDO NEWS) — Over the past two decades, scientists have discovered unusual ridge networks on Mars using images from spacecraft orbiting the Red Planet. How and why these ridges formed, and what clues they might provide about the history of Mars, remained unknown.
A team of scientists led by Aditya Haller of the School of Earth and Space Science at Arizona State University and Laura Kerber of NASA‘s Jet Propulsion Laboratory decided to learn more about these ridges by mapping a large area of Mars with the help of thousands of ordinary citizens.
Their results, which were recently published in the journal Icarus, show that ridges on Mars may contain fossilized records of ancient underground waters flowing through them.
How ridges formed on Mars has been a mystery ever since they were discovered from orbit. Scientists have established that there are three stages in the formation of ridges, including the formation of polygonal cracks, the filling of cracks, and finally erosion, which revealed the networks of ridges.
To learn more about these ridges, the team combined data from NASA’s Mars Odyssey THEMIS camera and the Mars Reconnaissance orbiter’s CTX and HiRISE instruments. They then rolled out their space lovers project using the Zooniverse platform.
Nearly 14,000 hobbyists from around the world have joined the search for ridge networks on Mars, focusing on the area around Lake Lake, where NASA’s Perseverance rover landed in February this year.
Ultimately, with the help of such amateurs, the team was able to map the distribution of 952 polygonal ridge networks over an area that makes up about a fifth of the total surface area of Mars.
“Space lovers have been integral to this study because these features are essentially patterns on the surface, so virtually anyone with a computer and the internet can help identify these patterns using images of Mars,” Haller said.
Most of the ridge networks (91%, or 864 out of 952) that have been analyzed are located on ancient, eroded terrain that is about 4 billion years old. It is believed that Mars was warmer and wetter during this time period, which may be related to how these ridges form.
Previous research in this area has shown that those ridges that have not been covered in layers of dust have spectral signatures of clay.
Since clays form as a result of weathering in the presence of water, this led the research team to believe that the ridges could have been formed by groundwater.
Although the abundance of surface dust in these regions makes it difficult to verify whether the new ridge networks mapped by the Haller and Kerber group contain clay, their similarity in shape and size suggests that they may have been formed by similar groundwater processes.
The discovery helps scientists “trace” the groundwater flowing across the ancient Martian surface and determine where, at that time, 4 billion years ago, there was a suitable place for liquid water to flow near the surface.
“We hope to eventually map the entire planet with the help of space lovers,” Haller said. “If we’re lucky, the Mars 2020 Perseverance rover will be able to confirm these findings, but the nearest set of ridges are several kilometers away, so they can only be visited as part of a potential extended mission.”
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