NASA's Perseverance rover discovers underground ancient river delta on Mars

Researchers studying data collected by NASA's Perseverance rover have discovered underground remains of an ancient river delta on Mars that is almost as old as Earth.

This geological feature, which spans up to 115 feet (35 metres) in the Jezero crater, was revealed using the rover's Radar Imager for Mars' Subsurface Experiment or RIMFAX instrument designed to probe the underground world.

Perseverance rover has been investigating signs of ancient microbial life since February 2021 when it landed in the Jezero crater - which is believed to have been flooded with water and ‌home to an ancient lake basin long ​ago.

The Perseverance rover on Mars. 

According to researchers, who published their findings in the journal Science Advances, the underground delta may be about 3.7 to 4.2 billion years old. The estimated age of Earth is around 4.5 billion years. This makes for some of the oldest evidence of water on Mars.

The new findings are based on RIMFAX's deepest data collected to date, obtained from September 2023 to February 2024 over ⁠a span of 250 Martian ‌days.

This finding is significant because it gives crucial insight into Mars' wet past and when it may have begun losing its oceans. The red planet, scientists believe, was similar to Earth but its magnetosphere weakened and atmosphere eroded, causing the water to escape into space through a combination of different processes.

Scientists are interested in the red planet's watery past because the now-dry water bodies may have been the potential point of origin of bacterial and other life forms.

"From the features mapped by RIMFAX, we believe that Jezero Crater hosted an ancient ⁠water-rich environment, capable of biosignature preservation that existed prior to the formation of Jezero's Western Delta," Emily Cardarelli, UCLA planetary scientist on the Perseverance science team and lead author ‌of the study said per Reuters.

Cardarelli also said that Mars has numerous "channels ​where water may have flowed, crater lakes where water once ponded, and deltaic sediments deposited as rock outcrops and now as buried remnants."