The Perseverance rover discovered an ancient river delta beneath the Martian surface.

Brief news summary

NASA rover Perseverance used the RIMFAX ground‑penetrating radar to investigate the delta of an ancient river that flowed into a lake in the Yezero crater. By combining data collected over several months, scientists discovered another, deeper delta hidden beneath Mars’ surface at depths up to 35 m. This finding increases the likelihood of ancient microbial life and suggests a longer presence of water in this area.

What Perseverance did?
- Instrument – RIMFAX radar (Radar Imager for Mars' Subsurface Experiment), capable of “seeing” down to 35 m below the surface.
- Terrain – delta of an ancient river that flowed into a lake at the site of Yezero crater.
- Data collection – 78 passes along a track totaling 6.1 km (September 2023 – February 2024).

What the results looked like
1. Combined map
After merging images taken over months, scientists saw not only surface traces but also the deep structure of the delta.

2. Depth and thickness
- The radar scanned down to 35 m depth.
- Accounting for elevation changes along the rover’s path, the estimated total thickness of the sedimentary deposits of the ancient delta is about 90 m.

3. Structural features
On the radar map typical water‑process formations are visible: layered deposits, boulder inclusions transported by strong flows.

Why this matters
- New evidence for prolonged water presence
The deeper structures indicate that the delta operated much longer than previously thought, raising the chances of past microbial life on Mars.

- Radiation‑protected layers
Deep sedimentary rocks lie beneath an insulating layer and could preserve traces of biological processes if they ever existed there.

Conclusion
What was detected by orbital missions and further studied in situ by Perseverance shows a deeper river delta. This discovery reshapes our understanding of Mars’ hydrologic history and raises the question of ancient life hidden within the planet’s protective layers.