A comparison of two raw Pancam photographs from sols 3528 and 3540 of Opportunity's mission (a sol is a Martian day). Notice the "jelly doughnut"-sized rock in the center of the photograph to the right. Minor adjustments for brightness and contrast.
January 20, 2014 11:30 AM EST

Scientists analyzing images from the Mars Opportunity Rover are flummoxed after a rock mysteriously appeared in the rover’s field of vision last week.

“It was a total surprise,” NASA scientist Steve Squyres told Discovery News. “We were like ‘wait a second, that wasn’t there before, it can’t be right. Oh my god! It wasn’t there before!’ We were absolutely startled.”

Some hypothesize the rock may have landed there after being flung skyward by a meteor that landed nearby, but the leading theory blames the rover itself for overturning a nearby rock with a quick, jittery wheel maneuver.

“You think of Mars as being a very static place and I don’t think there’s a smoking hole nearby so it’s not a bit of crater ejecta, I think it’s something that we did,” Squyres said. “We flung it.”

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