H₂O

The brown splotchy areas in this shot of Mars’ Hale Crater are salt deposits formed by flowing liquid water, NASA scientists recently announced. That Day-Go blue stuff is pyroxene, a common mineral on Mars. Photo: Mars Reconnaissance orbiter/University of Arizona/JPL/NASA.

• NASA Discovers Evidence for Liquid Water on Mars, WIRED, September 28, 2015
• NASA Confirms Evidence That Liquid Water Flows on Today’s Mars, nasa.gov, September 28, 2015