About six months ago, Opportunity established that its exploration area was wet a long time ago. The area was wet before it dried and eroded into a wide plain. The team's new findings suggest some rocks there may have gotten wet a second time, after an impact excavated a stadium-sized crater.
Evidence of this exciting possibility has been identified in a flat rock dubbed “Escher” and in some neighboring rocks near the bottom of the crater. These plate-like rocks bear networks of cracks dividing the surface into patterns of polygons, somewhat similar in appearance to cracked mud after the water has dried up here on Earth.