Mars is the Red Planet, but turns out the moon has the makings of a reddish cast, too. Yes, scientists have found rust on the moon. The question is: why?

Iron, a key material in steel and other applications, is most often found in hematite and magnetite ores, though goethite, limonite and siderite ores are also common sources of iron ore.

Previous analyses of iron oxide on Mars, based only on observations by spacecraft, didn’t detect any evidence of water, which led researchers to believe that the iron oxide must be hematite.