Sun, sand, and…sedimentary rock?!
This is Sandra Tsing Loh with the Loh Down on Science.
Imagine going to the beach and… dude where’s my ocean?! That’s what Jianhui Li and an international team just discovered on Mars!
We’ve long suspected parts of Mars were once underwater, but lacked evidence. Enter the Zhurong Rover, which scanned the Martian surface using radar, like an X-ray.
Coastal waves on Earth leave behind sediment deposits, up to tens of meters deep. Mars has similar layers, between ten to thirty five meters deep, hinting at a long-lost ocean.
If Mars had an ocean, it once had a stable climate. Maybe even life!
But where did all that water go? Scientists are still searching.
For now, this beach remains closed—by a few billion years.
Reference: Li, J., Liu, H., Meng, X., Duan, D., Lu, H., Zhang, J., Zhang, F., Elsworth, D., Cardenas, B. T., Manga, M., Zhou, B., & Fang, G. (2025). Ancient ocean coastal deposits imaged on Mars. Proceedings of the National Academy of Sciences of the United States of America, 122(9), e2422213122. https://doi.org/10.1073/pnas.2422213122