- Did Mars ever have an ocean? Some studies have suggested it did, in the northern hemisphere lowlands, billions of years ago.
- A new analysis of data from China’s Zhurong rover adds to previous evidence for the ocean.
- The ocean covered much of the Utopia Planitia region in the northern hemisphere, the new study suggests. It was at least 1,900 feet deep in the deepest parts. It later froze and then disappeared altogether.
More evidence for an ancient ocean on Mars
Last year, EarthSky reported that China’s Zhurong rover found evidence for an ancient ocean on Mars. Now, another team of scientists in China said they’ve found even more evidence for that ocean. The ocean would have covered a vast region of the lowlands in the Utopia Planitia region in the northern hemisphere.
James Woodford wrote about the newest results in New Scientist on November 7, 2024.
Researcher Bo Wu at Hong Kong Polytechnic University and his team published their peer-reviewed findings in Scientific Reports on November 7, 2024.
A possible ancient shoreline has been found in the region of Mars being explored by the Chinese rover Zhurong, hinting that an ocean may once have covered a vast area of the lowlands in the planet’s northern hemisphere. https://t.co/khxEsUtv96
— New Scientist (@newscientist) November 16, 2024
Shoreline of ancient ocean in Utopia Planitia
Previous evidence suggested there was a possible ancient ocean shoreline in Utopia Planitia. And that’s where Zhurong landed in May 2021. Now, a new comprehensive study of topographic features in the region further supports that interpretation. This includes old trenches and riverbeds containing sediments. Surface deposits also point to an ancient shoreline.
As the paper stated:
The Chinese Mars rover Zhurong successfully landed in southern Utopia Planitia on Mars in May 2021. Previous research suggested a Hesperian ocean might have existed in the northern lowland on Mars. Recent research observed water-related features at the Zhurong landing site from in situ data.
In this study, we conducted a comprehensive geomorphological analysis of the landing area using remote sensing data, supplemented by in situ observations, and unveiled features consistent with the existence of a nearshore zone in southern Utopia.
The new evidence not only supports the existence of the ocean, but also sheds light on how it evolved over time. Wu said in New Scientist:
The findings not only provide further evidence to support the theory of a Martian ocean but also present, for the first time, a discussion on its probable evolutionary scenario.
Ocean froze, then disappeared
The researchers think the ocean later froze over and then eventually just disappeared altogether. But clues can still be found in the rocks and terrain that Zhurong was studying. The researchers estimated the ocean existed about 3.68 billion years ago and ultimately vanished 260 million years later.
The ocean was shallower in the south and deeper in the north. The evidence suggests it was at least 1,900 feet (580 meters) deep.
Life in the ocean?
Right now, we have no way of knowing if any life – most likely microbial – existed in the ocean. But it’s certainly possible, as Wu noted:
Water is a key ingredient for life, and the past presence of an ocean on Mars raises the prospect that Mars once might have been capable of harboring microbial life at its early stage.
Bottom line: A new analysis of data from China’s Zhurong rover supports the existence of an ancient ocean on Mars billions of years ago in the northern hemisphere.
Read more: Ancient ocean on Mars? Chinese rover finds marine sediments
Read more: Oceans of water on Mars deep underground?