The Mars rover Spirit has been stuck in sand for some 18 months, but that hasn't stopped JPL scientists from making new discoveries.
Analysis of soil layers that the rover exposed while trying to break free of a Martian sand trap has turned up new evidence that liquid water once existed on the Red Planet.
Just below the planet's dusty surface, water-soluble minerals were found layered below less-dissolvable minerals, leading the rover team to hypothesize that the water-soluble minerals were dissolved and then deposited by water percolating down from melting ice or snow.
"We see this kind of gradient of change in these trace elements as you go down into the soil over the few tens of centimeters we had to look at," said Bruce Banerdt, the JPL-based project scientist for the Mars Exploration Rover Project.
The evidence of liquid water that scientists have previously detected on Mars rocks could date back to as far as several billion years ago. These current findings, however, would place water on the planet much more recently — on the geologic timescale, at least.