New images from the Perseverance rover show where a mighty river might have existed on Mars

Pasadena, Calif. () — A mighty river could have flowed through Mars billions of years ago.

The Perseverance rover has captured new images that appear to show geological clues to a mighty river that fed Jezero crater, the site of an ancient Martian lake.

Perseverance began exploring the remnants of the environment inside the crater, which now resembles a dried-up lake bed, after landing on the red planet in February 2021.

About a year ago, the rover began studying a 250-meter-tall fan-shaped reservoir, likely the remains of an ancient river delta. First, Perseverance studied the eroded front edge of the fan. Now the rover has moved to the top of the fan to explore sedimentary rock that may preserve past evidence of water — and of life, if it ever existed.

“This fan really represents the main story of the water in the crater,” Katie Stack Morgan, deputy project scientist for Perseverance at NASA’s Jet Propulsion Laboratory (JPL), told . “With the rover, we’re actually moving through different environments that once had water associated with them. So here in Jezero, we have evidence of ancient lakes, deltas, and rivers.”

The fan’s curved layers suggest they got their shape from the flow of water, and the latest images taken by the rover point to a deeper, faster-moving river than scientists expected on Mars. It is the first time that scientists have observed environments like this on Mars.

Scientists have long been curious about the various types of waterways that existed on Mars more than 3 billion years ago, when the planet was warmer and wetter. Earlier observations from the Curiosity rover, which landed on Mars in 2012 and is exploring Gale Crater some 3,700 kilometers away, revealed evidence of shallow streams rather than powerful rivers.

The latest finds from Perseverance, collected in two mosaic images, show boulders and coarse sediment grains.

“This indicates that this is a high-energy river carrying a lot of debris. The more powerful the flow of water, the more easily it is able to move large pieces of material,” Libby Ives, a postdoctoral researcher at JPL, said in a release.

Rivers likely carried the large rocks and debris from other parts of Mars to Jezero crater, according to Morgan.

Clues in the new Mars mosaics

One of the mosaics shows a reservoir dubbed “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 seem to undulate the landscape are like the shifting banks of the Mississippi or the island-shaped shoals of the Platte River in Nebraska.

The rock layers were probably much higher in the past, but have been eroded by wind over time.

“The wind has acted like a scalpel that has cut through the tops of these reservoirs,” Michael Lamb, a river specialist and contributor to the Perseverance science team at Caltech, said in a statement. “We see deposits like this on Earth, but they are never as well exposed as here on Mars. Earth is covered in vegetation that hides these layers.”

Perseverance also observed “Pinestand,” an isolated mountain formation filled with layers of interspersed sedimentary rocks that curve skyward to a height of 20 meters.

“These layers are anomalously high for rivers on Earth,” said Ives. “But at the same time, the most common way to create these types of landforms would be a river.”

Perseverance and the pursuit of life

Scientists are using every tool at Perseverance to get to the bottom of the river mystery, including the rover’s Ground Penetrating Radar Imager for Mars’ Subsurface Experiment (RIMFAX) to search beneath the reservoir. The Perseverance team is also analyzing other images taken by the rover.

The rock and soil samples collected by the rover will eventually travel to Earth via the ambitious Mars Sample Return program, a series of successive missions scheduled over the next decade that will venture to the red planet, collect samples from the Perseverance stash, and bring them back. back for scientists to test in labs around the world.

“One of the reasons we chose Jezero as a landing site is because the more diverse rocks we have, the better chance we have of learning more about the processes that took place on Mars and formed Mars,” Morgan explained. “We have different types of potentially habitable environments recorded within these rocks.”

Rocks and Martian soil samples could reveal whether life ever existed on Mars.

“To answer that question, we have to bring these rocks back to Earth, where we have really sophisticated instruments and laboratories that can really probe that question,” Morgan said. “And it’s a hard question to answer. We have a hard time answering this question even with the rocks of the early Earth. But Perseverance’s job is to identify the rocks that are most likely to support life, and that’s what we’ve accomplished.” “.