Study uncovers source of Mars' redness — a key indicator the planet (maybe) once had life

The first thing most people think of when they consider Mars is its deep red color. Using state-of-the-art equipment, as well as firsthand analyses of Martian dust from the red planet’s surface, the researchers found that “ferrihydrite remains stable under present-day Martian conditions, preserving its poorly crystalline structure.” This in turn suggests that the ferrihydrite “formed during a cold, wet period on early Mars under oxidative conditions, followed by a transition to the current hyper-arid environment.” In contrast to the conventional wisdom that Mars was continuously dry while its surface oxidized, the new study suggests “ancient Mars experienced aqueous alteration before transitioning to its current desert state.” Want more health and science stories in your inbox? “The finding is relevant to inferring the conditions of early Mars as the composition of minerals on the Mars surface tell us about the past climate,” Dr. Geronimo Villanueva, the associate director for Strategic Science of the Solar System Exploration Division at NASA’s Goddard Space Flight Center, and co-author of this study, told Salon. “Importantly, the new findings suggest a wetter and potentially more habitable past for Mars because ferrihydrite forms in the presence of cool water, and at lower temperatures than other previously considered minerals, like hematite.” Villanueva added that scientists already knew Martian dust contains a number of minerals, including iron oxides; this study narrows down the number of potential iron oxides that could cause the distinctive red color to just one, ferrihydrite. He added that scientists “still don't know the original source location of the ferrihydrite before it was distributed globally through dust storms, the exact chemical composition of Mars' atmosphere when the ferrihydrite formed, or the precise timing of Mars' oxidation.” In addition to encouraging professional scholars to do research, Valantinas urged ordinary citizens to take a crack at looking at the Martian surface.