The evidence comes from data collected by China’s Zhurong Mars rover, which landed in the Utopia Planitia region of Mars in 2021. Unlike other rovers traversing the planet, Zhurong arrived with high- and low-frequency radar systems that allow it to conduct ground-penetrating scans of the Martian subsurface.

Data from China's Zhurong rover on Mars suggests an ancient ocean and strengthens evidence that the planet was once warm, wet, and habitable.

A Chinese rover found evidence of ancient beaches on Mars, suggesting the planet once had vast oceans 4 billion years ago. The discovery of sloping sand layers beneath the surface provides new insights into Mars' watery past.