• Did Mars once have an ocean? Evidence has increased over the past few decades that the vast plains of the northern hemisphere are a basin of a now-dried ocean.
• Zhuhrong rover data: Data from the Zhuhrong rover over the past two years has provided further evidence. It has found subsurface layers that resemble coastlines on Earth.
• New findings: Recent results from the Zhuhrong mission, by a new team of international researchers, support the possibility that an ocean once existed. Its shores had sun-drenched sandy beaches, just like on Earth! 🏖️

New evidence of a lost ocean on Mars

Imagine Mars billions of years ago, with a vast ocean and sun-drenched sandy beaches! In 2023 and 2024, Chinese scientists announced evidence of an ancient ocean on Mars, thanks to the Zhuhrong rover. And on February 24, 2025, another international group of researchers, including those at the University of Pennsylvania, announced the existence of a massive ocean that may have existed in the northern hemisphere of Mars. This ocean was remarkably similar to Earth's environment, with sandy beaches perfect for holidays and gentle waves! 🌊

The research team's findings were published in the Proceedings of the National Academy of Sciences (PNAS) on February 24, 2025. Read the full research paper.

Are there vacation-style beaches on Mars?

Scientists on China's Zhuhrong mission first reported evidence of a possible ocean in 2023. The rover used its built-in ground-penetrating radar to study subsurface deposits. It found what appeared to be ancient coastal sediments, remarkably similar to those found on Earth. The rover is located in a region of the Utopia Plateau, where scientists have previously theorized the existence of a former ocean in the Northern Hemisphere.

Now, new findings from the international research team reinforce previous work. They support the existence of the ocean, as well as holiday-style beaches! 🏝️

See more details

Old Coast deposits

Data from the Zhuhrong rover revealed buried stratified structures resembling beaches on Earth. More specifically, their shape resembled tidal beach deposits, or the face of a beach. These deposits—the beaches—plumb downwards from the landscape into the ocean. Waves and tides are essential for their formation. This is exciting for scientists, as Cárdenas explained:

This immediately caught our attention because it suggests the presence of waves, implying a dynamic interface between air and water. When we consider where the earliest life forms on Earth evolved, it was in the interaction between the oceans and the land, so this paints a picture of past habitable environments, capable of supporting conditions conducive to microbial life.

Even the angles of the slopes were in the same range as their ground counterparts.