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.

Scientists have used orbiters and rovers to find dried streams, lakes, and gullies on Mars that hint at its watery past, but their cavalry of robots has struggled to prove the Red Planet ever had an actual ocean.

Scientists have discovered that Mars once had beaches. While the past presence of water on the Red Planet is no longer in doubt, experts have now found layers of rock beneath Mars' surface, suggesting the likely existence of an ancient ocean.