Mars Climate Marker: Tiny Hematite Crystals Trace Long-Lived Warmth in Gale Crater
NASA's Curiosity rover, using the CheMin instrument on 20 Gale Crater samples, found hematite crystallites are smaller at higher elevations and larger lower down, with goethite present only higher up. The size pattern, explained by warmer, longer-lasting groundwater and Ostwald ripening, indicates extended warm, wet conditions in ancient Mars and potential habitability deep in Gale Crater.