NASA’s Perseverance rover has uncovered a massive ancient river system buried beneath Mars’ Jezero Crater. Using its RIMFAX ground-penetrating radar, the rover detected deep sediment layers arranged in sloping patterns consistent with water flow-evidence of a delta system active as early as 4.2 billion years ago.
The findings suggest Mars hosted flowing water for far longer than surface features alone indicate, significantly expanding the time window for potential microbial life. Layers up to 90 meters thick reveal multiple phases of deposition and erosion, pointing to repeated water activity during the Noachian period.
This subsurface discovery enhances the chances of finding preserved biosignatures, offering critical insight into Mars’ past habitability.