'Mystery' rock's appearance in front of Mars Rover puzzles scientists

A rock that mysteriously appeared in front of the Mars Rover a few days back, has left scientists baffled.

NASA Mars Exploration Rover (MER) lead scientist Steve Squyres of Cornell University reported appearance of a suspected gypsum near Endeavour Crater's rim - a region of Meridiani Planum that Opportunity has been researching since 2011 - and the discovery of clays, which likely formed in a pH-neutral wet environment in early Mars, Discovery News reported.

In a comparison of newly clicked pictures on sol 3528 of the mission, only bare bedrock can be seen. However, on sol 3540, a fist-sized rock had appeared. MER researchers have nicknamed the object "Pinnacle Island."

Squyres told Discovery News that the rock was the size of a jelly doughnut.

Only two options have so far been identified for this, one is that the rover either "flipped" the object as it maneuvered or it may have landed there after a nearby meteorite impact event. However, Squyres said that that he thinks that the rock may have come after the rover did a turn in place a meter or two from where the rock now lies.