New evidence from China’s Zhurong rover suggests Mars once had an ocean
With the help of China’s Zhurong rover, scientists have uncovered fresh evidence suggesting that Mars was once home to a vast ocean billions of years ago. This new discovery provides further insight into the planet’s ancient past, which contrasts sharply with its dry and barren present.
On Thursday, researchers revealed that data collected by Zhurong, which landed in Mars’ northern lowlands in 2021, alongside information from the Tianwen-1 Orbiter, NASA’s Mars Reconnaissance Orbiter, and other robotic missions, indicate the existence of an ancient Martian coastline. The findings were published in *Scientific Reports* and shed light on Mars’ earlier, potentially habitable conditions.
The evidence was gathered from the Utopia Planitia region, a large plain in Mars’ northern hemisphere. The Zhurong rover analyzed rock formations on the Martian surface, identifying geological features that suggest the presence of a coastline from a time when Mars was significantly wetter and warmer.
“Surface features like troughs, sediment channels, and mud volcanoes indicate that an ocean once existed in this area,” said Bo Wu, a planetary scientist at Hong Kong Polytechnic University and lead author of the study. These formations suggest a dynamic environment with both shallow and deeper marine areas, providing key evidence of an ancient Martian ocean.
Researchers estimate that this flooding event in the Utopia Planitia occurred around 3.68 billion years ago. However, the ocean likely froze over in a relatively short geological period, with its disappearance happening roughly 3.42 billion years ago. The sedimentary deposits left behind by the ancient ocean show signs of heavy silting, creating distinct layering structures that support the idea of a former, stable water body.
While Mars’ history has long suggested the possibility of water, this new evidence significantly strengthens the case for an ocean that existed at a time when the planet was likely transitioning from a warm, wet environment to the cold, dry world we know today.
“The presence of an ancient ocean on Mars has been debated for decades,” said Wu. “Our findings not only bolster this theory but also provide insights into its evolution and eventual disappearance.”
Water, a key ingredient for life as we know it, has been a focal point for researchers studying Mars’ potential to support microbial life. “During Mars’ early history, when the atmosphere was thicker and warmer, microbial life could have been much more likely,” added Sergey Krasilnikov, a co-author of the study.
The Zhurong rover, named after the Chinese god of fire, has played a crucial role in this discovery. Launched in May 2021, the rover spent nearly a year conducting scientific research before going into hibernation in May 2022, likely due to an accumulation of dust and sand on its solar panels. Despite its relatively short mission duration, Zhurong exceeded its original three-month lifespan, contributing valuable data to our understanding of Mars.
This new study adds to ongoing research into the fate of Mars’ water. In August, a separate study based on seismic data from NASA’s InSight lander suggested the existence of a vast reservoir of liquid water deep beneath the Martian surface, possibly trapped in fractured igneous rocks.
The discovery of an ancient ocean on Mars could have significant implications for the search for past life on the Red Planet, as scientists continue to explore the mysteries of our neighboring world.
