Sublime Ground

Image source with more information
Credit: NASA/JPL-Caltech/University of Arizona
/Texas A&M University

Any doubts that Phoenix might have landed on the wrong spot have been dispelled, as the white layer dug up by the robot's arm has been seen to be subliming* away over time - confirming, according to NASA scientists, the existence of ice.

*The low temperature and pressure on Mars conspire to make liquid water impossible to exist, so when ice heats up it will instead sublime straight to water vapour.

Oh, and a Sol is a Martian day, but you knew that. ;-)