Ancient Mars Once Boasted 'Vacation-Style' Beaches

Scientists have discovered the perfect vacation spot: it's sun-soaked, has sandy beaches, sports gentle waves lapping rhythmically on the shore. But hold off on grabbing the sun lotion, because there's a catch—it's on ancient Mars.

Analyzing data collected by China's Zhurong Mars Rover, an international team of researchers have detected buried evidence of beaches beneath a plain on the Red Planet.

The discovery, they say, is the strongest evidence yet that Mars's northern lowlands once sported an ocean that covered a third of the planet's surface—and which could have provided a habitable environment for microbial life.

"We're finding places on Mars that used to look like ancient beaches and ancient river deltas," explained paper author and geologist professor Benjamin Cardenas of Pennsylvania State University in a statement.

"We found evidence for wind, waves, no shortage of sand—a proper, vacation-style beach."

Launched from Hainan, China, in July 2020, the Zhurong rover landed on Mars in May 2021 in an area known as Utopia Planitia, a plain which lies in the largest-known impact crater in the solar system.

The rover operated for a year, trundling some 1.2 miles alongside slopes that scientists suspect represent an ancient shoreline from 4 billion years ago, when Mars had a thicker atmosphere and a warmer climate.

Something that makes Zhurong special is that it is equipped with a ground-penetrating radar that allows it to probe the Martian subsurface and identify buried rock formations at depths of up to 260 feet.

"The capabilities of the Zhurong rover have allowed us to understand the geologic history of the planet in an entirely new way," said paper co-author and geoscientist Michael Manga of the University of California, Berkeley.

The radar scans, he added, "allows us to do geology that we could never have done before."

When Manga and his colleagues studied the data the rover beamed back, they found evidence of layered structures similar to those formed by beaches here on Earth.

Specifically, they identified rock formations known as "foreshore deposits" that slope down toward the ocean and are formed as sediment is deposited along the coast by waves.

Furthermore, the radar was even able to determine the size of the particles in these deposits—showing that they were sand-sized.

"This stood out to us immediately because it suggests there were waves—which means there was a dynamic interface of air and water," explained Cardenas.

According to the team, the consistent dipping of the formations allowed them to narrow the environment down to a coastal setting—and rule out other formation mechanisms like rivers, wind, or ancient volcanic activity.

"We're seeing that the shoreline of this body of water evolved over time," Cardenas said.

"We tend to think about Mars as just a static snapshot of a planet, but it was evolving. Rivers were flowing, sediment was moving and land was being built and eroded."

According to Cardenas, it is unclear how far Mars' ancient beaches might have stretched in total—but the present evidence suggests they grew out into the ocean basin for at least 0.8 miles.

The team believe that it would have taken tens of millions years to lay down foreshore deposits as thick as those Zhurong detected, suggesting that Mars' northern ocean must have been long-lived.

"What makes these deposits unique is that they are still buried, and thus have been protected from everything happening at the surface," he told Newsweek.

"Previous martian shoreline work has been done using satellite images of features exposed at the surface, where they are subject to a number of things that might make them challenging to interpret."

The findings of the study, Cardenas explained, could have implications for the search for evidence of potential ancient life on Mars.

"When we look back at where the earliest life on Earth developed, it was in the interaction between oceans and land, so this is painting a picture of ancient habitable environments, capable of harboring conditions friendly to microbial life," the geologist said.

The ancient beaches detected on Mars, he added, "can tell us what the landscape looked like, how [it] evolved and, importantly, help us identify where we would want to look for past life."

With their initial study complete, the researchers are now analyzing satellite data on another Martian location known as Aeolis Dorsa, which lies of few hundred miles southeast of the area studied by Zhurong.

"It's like the Gulf of Mexico on Mars," Cardenas said, "and very consistent with a martian ocean!"

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about Mars? Let us know via science@newsweek.com.

Update 02/03/25, 12:59 p.m. ET: This article was updated with additional information and comments from Benjamin Cardenas.

Reference

Lia, J., Liu, H., Meng, X., Duan, D., Lu, H., Zhang, J., Zhang, F., Elsworth, D., Cardenas, B. T., Manga, M., Zhou, B., & Fang, G. (2025). Ancient ocean coastal deposits imaged on Mars. PNAS, 122. https://doi.org/10.1073/pnas.2422213122