FLORIDA:
Using ground-penetrating radar, NASA’s Perseverance rover has uncovered underground remnants of an ancient river delta on Mars, providing some of the oldest evidence yet of how water once flowed on the Red Planet.
Researchers reported that the six-wheeled rover detected geological features up to 115 feet (35 meters) below the surface while traversing 3.8 miles (6.1 km) across Jezero Crater, a region in Mars’ northern hemisphere believed to have once hosted a lake basin.
Perseverance identified layered sediments and eroded surfaces characteristic of a delta—a fan-shaped deposit formed where a river meets a larger body of water, such as a lake. Scientists estimate that the buried delta formed between 3.7 and 4.2 billion years ago. Given that Mars formed about 4.5 billion years ago, this delta appeared relatively early in the planet’s history.
The newly discovered delta predates a nearby surface feature called the Western Delta, which formed roughly 3.5 to 3.7 billion years ago.
The rover’s RIMFAX instrument sends radar pulses into the ground and measures the reflections to create a three-dimensional map of underground structures. These findings are based on the deepest RIMFAX data collected to date, gathered from September 2023 to February 2024 over 250 Martian days.
Because water is essential for the possibility of past life, this evidence of Mars’ watery history is particularly significant. Once warmer and with a thicker atmosphere, Mars could sustain liquid water on its surface.
“From the features mapped by RIMFAX, we believe Jezero Crater hosted an ancient water-rich environment capable of preserving biosignatures, existing prior to the formation of Jezero’s Western Delta,” said Emily Cardarelli, a member of the Perseverance science team and lead author of the study published Wednesday in Science Advances.
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