Scientists find evidence of ancient ocean on Mars, boosting search for life
A hypothetical illustration of Mars 3.6 billion years ago shows the Deuteronilus ocean covering nearly half the planet, with blue areas representing ocean depth and stars marking the landing sites of the Zhurong and Perseverance rovers. (Courtesy of Robert Citron)
Mars may have once had sandy beaches and a vast ocean, according to new research based on data from China’s Zhurong rover.
Scientists have identified subsurface structures resembling coastal deposits, providing the clearest evidence yet that the planet was once home to a significant body of water.
The findings, published in the “Proceedings of the National Academy of Sciences”, suggest that Mars had a dynamic shoreline billions of years ago, possibly creating conditions favorable for life.
What radar scans revealed about Martian coastal formations
The Zhurong rover landed on Mars in 2021 and explored the Utopia Planitia region. It used ground-penetrating radar to scan beneath the surface. Unlike previous rovers, Zhurong could detect buried layers of rock and sediment, revealing structures similar to those found along Earth’s coastlines.
Key findings:
- Foreshore deposits: These formations, usually created by ocean waves, were detected beneath the surface.
- Dipping sediment layers: Similar to Earth’s coastal regions, these layers slope toward what was once an ancient Martian ocean.
- Evidence of erosion and land-building: Scientists observed patterns indicating that sediment was actively moved by waves and tides.
“We’re finding places on Mars that used to look like ancient beaches and ancient river deltas,” said Benjamin Cardenas, a geologist at Penn State and co-author of the study. “We found evidence for wind, waves, no shortage of sand—a proper, vacation-style beach.”
Scientists confirm evidence of ancient Martian ocean
The ocean, known as Deuteronilus, is believed to have existed more than 3 billion years ago. The new study adds to evidence that Mars once had a warm, wet climate that allowed liquid water to exist for long periods.
Why this matters:
- Extent of the ocean: Radar scans show coastal formations stretching over a kilometer, suggesting a large and stable body of water.
- Long-term presence of liquid water: The ocean was likely sustained for millions of years, rather than being a temporary melt event.
- Tidal activity: The thickness and angle of the sediments indicate waves and tides shaped the landscape, much like on Earth.
“This discovery supports the hypothesis that an ocean once covered a substantial portion of the northern pole of Mars,” the researchers wrote. “A body of water large enough to generate waves and tides also raises the chances of the planet supporting life.”
Search for life on Mars continues with new exploration targets
Scientists believe early life on Earth emerged where land and water met. If Mars had similar conditions, these ancient shorelines could be prime locations for discovering past microbial life.
Ongoing and future missions:
- NASA’s Perseverance rover: Currently exploring Jezero Crater, it has collected samples that may provide clues about past Martian life.
- Sample return mission delays: NASA’s plan to bring these samples back has been pushed to 2040 due to budget constraints.
- China’s Tianwen-3 mission: Set for the early 2030s, this mission aims to return Martian samples earlier than NASA.
Michael Manga, a professor at the University of California, Berkeley, emphasized the importance of this discovery. “The structures don’t look like sand dunes. They don’t look like an impact crater. They don’t look like lava flows. That’s when we started thinking about oceans,” he said.
These findings provide valuable clues about the planet’s geological history and suggest that Mars was once a world of vast oceans and shifting landscapes that may have supported life.
