Rover finds evidence of 'holiday-style' beaches on Mars

A recent study suggests that Mars may have once possessed sunny, sandy, and shimmering coastlines. This discovery offers a new perspective on understanding Mars' past and further sparks contemplation about the possibility of past life on the planet.

An international team of scientists analyzed data transmitted by China's Zhurong rover, identifying rock layers hidden beneath the Martian surface. The structure of these rock layers strongly suggests the existence of an ancient northern ocean. The study, published this week in the Proceedings of the National Academy of Sciences, provides the clearest evidence to date that Mars once had a substantial body of water and a more habitable environment.

Benjamin Cardenas, an assistant professor of geology at Pennsylvania State University and a collaborator on the study, stated, "We're finding evidence of places on Mars that would have looked like ancient beaches and ancient river deltas. We found evidence for wind, waves, and copious amounts of sand—a veritable resort-style beach."

The Zhurong rover landed in Utopia Planitia on Mars in 2021 and transmitted data about the surrounding geological environment in search of signs of ancient water or ice. Unlike other rovers, Zhurong is equipped with ground-penetrating radar, enabling it to probe beneath the Martian surface. Using low-frequency and high-frequency radar, Zhurong was able to penetrate the Martian soil and identify buried rock layers.

While reviewing the radar data, the research team discovered that the rock layer structure on Mars is similar to beaches on Earth, exhibiting structures called "foreshore deposits," which slope downwards towards the ocean and are formed when tides and waves carry sediment into a large body of water. Cardenas stated, "That was immediately what caught our eye because it showed the existence of waves, which meant there was a dynamic interface between air and water." By comparing the Martian data with radar images of coastal sediments on Earth, the research team found striking similarities. The observed inclination of the Martian surface to the ocean is completely consistent with the range of inclination observed in coastal sediments on Earth. This finding suggests that Mars was once wetter than it is now, further supporting the hypothesis that Mars once had an ocean covering most of the planet's northern hemisphere. The study also provides new information about the evolution of the Martian environment, indicating that a warm, humid period suitable for life may have lasted for tens of millions of years.