Much like the “Mars Rat,” a Martian rock is causing quite the stir. Captured by NASA’s Opportunity Mars Rover, a rock appeared in an image that was not there previously. The Mars rock mystery quickly went viral and speculation ranges from Opportunity knocking the rock into the frame to, naturally, aliens.

Mars Rock Mystery The first image, Sol 3528, was taken 12 days ago. The new image, Sol 3540, features a rock that was not there previously and Opportunity had not driven over the area. Photo: NASA/JPL

The Mars Rock mystery was presented at the Mars Exploration Rover 10-Year-Anniversary event at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., on Thursday. According to a Mars Exploration Program blog post, Opportunity was working at “Solander Point,” located at the rim of the Endeavour Crater, and had completed observations of the area known as “Cape Darby” and was making its way to an area known as “Cape Elizabeth.” During this transition, researchers discovered the mystery rock.

According to the blog post, “While preparing to start robotic arm work on the target Cape Elizabeth on Sol 3541 (Jan. 8, 2014), Opportunity encountered a slight surprise -- a rock had appeared in the images that had not been there before. This target that has been named "Pinnacle Island" and its origin has been the target of much speculation.” Researchers hope to figure out how the rock appeared in these images in the coming days.

Steve Squyres, lead scientist for the NASA Mars Exploration Rover mission, discussed some of the biggest discoveries by the twin Mars rovers, Spirit and Opportunity, such as the “Berry Bowl” image. The Berry Bowl image was taken in 2004 and feathers spherical grains of hematite, a mineral form of iron oxide, which indicates ancient water deposits on Mars.

Mars Rock The raw image of Sol 3540. Photo: NASA/JPL

After a few older discoveries made by Opportunity, Squyres begins discussing some new observations made by the rover which have puzzled scientists. In 2012, Opportunity observed the Kirkwood outcrop and discovered spherical objects that were unlike the hematite “blueberries” previously discovered. Even after two years of study, Squyres said researchers are still unsure what these objects are.

Discussing Sol 3528 and Sol 3540, Squyres said these images were taken by Opportunity’s panoramic camera just 12 days apart. In the presentation, Squyres said, “We saw this rock, it’s sitting there, it’s white around the outside, in the middle there’s kind of a low spot that’s dark red. It looks like a jelly doughnut. And it appeared…it just plain appeared at that spot and we haven’t driven over that spot.”

Squyres suggests two possible theories about how the rock, dubbed “Pinnacle Island,” got there. It was either “flicked” there as the Opportunity rover made a turn a meter away, one of the rover’s tires could have hit the rock and it slid down into the area, or it was a piece of crater ejecta caused by a nearby impact.

Squyres believes the first scenario is the likelier of the two and the team is currently imaging the rock and learning more about the composition of the “jelly” and the “doughnut” part of the rock. Based on the preliminary findings of the “jelly,” the rock is “nothing like we’ve seen before” and it is high in magnesium and sulfur and double the amount of manganese seen in other Mars rocks. “We’re completely confused and having a wonderful time,” said Squyres.

Opportunity is currently in its tenth year on Mars, having launched with Spirit in 2003. The three month mission turned into 10 for Opportunity and just over six years for Spirit, the rover that got stuck in soft soil in 2009 and stopped communicating in 2010.

The video of the Mars Exploration Rover event can be viewed below. Squyres discussion of the “jelly doughnut” rock begins around the 25-minute mark.

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