Salt detected in Martian soil could attract water vapor from the red planet’s atmosphere at night, forming brine on the surface. Scientists have long suspected this possibility, given information they’ve had about the soil.
But a new study based on a year’s worth of data collected by the Mars rover Curiosity seems to corroborate the theory. And that hopeful data comes from Gale Crater, “one of the least likely places on Mars to have conditions for brines to form, compared to sites at higher altitudes,” according to Alfred McEwen at the University of Arizona, one of the new report’s authors. The brine hasn’t been confirmed, but the conditions for it seem likely given the new data. Its existence, even if confirmed, won’t support theories of life on Mars today. But brine would support theories that life has existed on Mars in the past.