A cracked rock called Escher is helping NASA scientists reconstruct the history of water on Mars. They say that the crater currently being explored by the Opportunity rover may have been shaped by a second watery episode long after the wet period when the rocks first formed.
The flat rock carries a network of fissures that looks like cracked mud at the bottom of a dried up riverbed. "When we saw these crack patterns, right away we thought of a secondary water event significantly later than the episode that created the rock," says John Grotzinger, rover team geologist from the Massachusetts Institute of Technology, Cambridge, wrote Nature.
According to the CBC News, the cracks may have been caused by the impact that created Endurance Crater, or the rocks may have been drenched for a second time after the stadium-sized depression was formed, according to &to=http:// english.pravda.ru/science/19/94/378/12181_.html ' target=_blank>NASA.
On Earth, such cracks are associated with water that impregnates a rock, dries it out and pulls it in different directions, geologist John Grotzinger said Thursday.