sulfur can take many forms (or oxidation states)—elemental sulfur ions, mineral sulfate and sulfide gas. It does that by changing its valence, or the number of negative charges, during the ...

These minerals are commonly associated with microbial life on Earth. In places like deep-sea vents and acidic hot springs, sulfur compounds support entire ecosystems. While that doesn’t confirm ...

On Earth, sulfur compounds sustain ecosystems in extreme places like deep-sea vents. That same chemistry on Mars sparks questions of habitability. Gale Crater’s mineral layers point to repeated ...