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CNN
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A raging river may have crossed Mars billions of years ago.
The Perseverance rover has captured new images that appear to show geologic evidence of a fast-flowing river flowing through Jezero Crater, the site of an ancient Martian lake.
The probe began exploring the remnants of the atmosphere inside the crater, which now resembles a dry lake bed, after landing on the red planet in February 2021.
The rover began studying a fan-shaped deposit in the area at an elevation of 820 feet (250 meters), likely the remains of an ancient river delta, about a year ago. First, Perseverance studied the eroded front edge of the fan. Now, the rover has climbed to the surface of the fan to explore sedimentary rock that may preserve evidence of past water — and life, if it exists.
“This fan really represents the primary history of water in the crater,” Katie Stack Morgan, the Perseverance project scientist deputy at NASA’s Jet Propulsion Laboratory, told CNN. “With the rover, we’re actually moving into different environments that once had water associated with them. So here in Jezero, we have evidence of lakes, deltas and ancient rivers.”
The fan’s curved layers suggest flowing water shaped them, and the latest images taken by the rover point to a deeper and faster-moving river than scientists on Mars expected. This is the first time scientists have seen environments like this on Mars.
Scientists have long been interested in the different types of waterways that once existed on Mars more than 3 billion years ago, when the planet was warmer and wetter. Earlier observations by the Curiosity rover, which landed on Mars in 2012 and explored Gale Crater about 2,300 miles (3,700 kilometers) away, revealed evidence of shallow streams rather than powerful rivers.
The latest findings of persistence, collected in two mosaic images, show cobbles and coarse grains of sediment.
“That indicates a high-energy river that’s truckin’ and carrying a lot of debris. The stronger the water flow, the easier it is to move larger pieces of material,” said Libby Ives, a postdoctoral researcher at JPL, in a statement.
Rivers likely brought boulders and debris from other places on Mars to Jezero Crater, Morgan said.
One of the mosaics shows a deposit called “Skrinkle Haven,” where flowing water carved layers of rock that remain billions of years later. Scientists aren’t sure if the rows of rocks that appear to flow across the landscape are like the shifting banks of the Mississippi River or the island-like sandbars of the Platte River in Nebraska.
NASA/JPL-Caltech
The bands of rocks in this image of “Skrinkle Haven” taken by the Perseverance rover may have been formed by a fast-flowing river. The rover took 203 images between February 28 and March 9 to create this mosaic.
The rocky layers were probably higher in the past but were eroded by the wind over time.
“The wind acted like a scalpel cutting off the tops of these deposits,” said Michael Lamb, river expert and collaborator of the Perseverance science team at Caltech, in a statement. “We see deposits like this on Earth, but they’re not as exposed as they are on Mars. The ground is covered with vegetation that hides these layers.”
The pursuit also observed the “Pinestand,” an isolated hill filled with layers of sandwiched sedimentary rock that curves skyward as high as 66 feet (20 meters).
NASA/JPL-Caltech/ASU/MSSS
The rover also captured a mosaic of “Pinestands,” where layers of sedimentary rock may have been formed by a deep and fast-flowing river.
“These layers are not that high for rivers on Earth,” Ives said. “But at the same time, the most common way to create these types of landforms is a river.”
Perseverance and finding life
Scientists are using all the tools in Perseverance’s kit to get to the bottom of the river’s mystery, including the rover’s ground-penetrating Radar Imager for Mars’ Subsurface Experiment, or RIMFAX, to search below the site. The Perseverance team is also analyzing other images taken by the rover.
NASA/JPL-Caltech
The Ingenuity helicopter, which serves as an aerial scout for the rover, took a picture of Perseverance on its 51st flight on April 22. The rover can be seen at the top left of the image.
Samples of rocks and dirt collected by the rover will travel to Earth through the ambitious Mars Sample Return programa series of successive missions set for the next decade that will venture to the red planet, retrieve samples from the Perseverance cache and bring them back for analysis by scientists in labs around the world.
“One of the reasons why we chose Jezero as the landing site is because the more diverse rocks we have, the more opportunities we have to learn more about the processes that took place on Mars and formed Mars,” said Morgan. “We have a wide variety of potentially habitable environments recorded within these rocks.”
Martian rocks and soil samples may reveal whether life exists on Mars.
“To answer that question, we need to bring these rocks back to Earth, where we have really sophisticated instruments and laboratories that can probe that question in depth,” Morgan said. “And it is difficult to answer the question. We struggle even with early Earth rocks to answer this question. But Perseverance’s job is to identify those rocks that have the best chance of having life in them, and we’ve done that.”
