Mars could have carried liquid water more recently than we thought

Ancient brine trapped within crystals dated to 757 million years ago suggests that liquid water remained present on the Martian surface long after the planet was believed to have become a dry, frozen desert. This shift in the timeline of Martian habitability challenges existing assumptions regarding the planet's atmospheric evolution and the longevity of its aqueous environments. Evidence for this revised history stems from diverse datasets, including new analysis of soil samples from the Gusev crater initially collected by the Spirit rover and contemporary observations from China’s Zhurong rover.

Scientists have identified primary evaporites that provide physical markers of recent liquid activity. Meanwhile, research centered on the landing site of the ExoMars Rosalind Franklin rover posits that a vast ocean once covered the region, further diversifying the evidence for a watery past across multiple landing zones. Researchers are now tasked with reconciling these fragmented findings to determine if these water sources were isolated occurrences or part of a global phenomenon.

Coverage does not yet specify how these discoveries will alter the trajectory of future landing site selections for upcoming exploration missions or whether these brine deposits might contain biosignatures.