Not proof of life on Mars or even Elvis sending messages via doughnuts

On 8 January this year the Mars Exploration Rover Opportunity sent an image back to Earth that included a 4 cm wide, white-rimmed, red-centred rock that looked surprisingly like a jam doughnut. In itself this is not astonishing but the problem was that images from the same location four days earlier did not include the rock.

This magically appearing rock, dubbed ‘Pinnacle Island’, caused a flurry of theories around the world - from the logical to the ridiculous.

According to one report on Popular Science, one man has filed a lawsuit in a Californian court to force NASA to fulfil its “public, scientific, and statutory duty” and investigate the rock more closely. Apparently he believed the object was a living organism - “a fruiting body of a fungus which has just begun to germinate from spores”, to be precise - that proves life exists on Mars.

CNET suggested that it may have been from a  meteorite impact or, rather more tongue in cheek, that “Elvis is alive and well on Mars and placed the rock there as a message to Earth to send doughnuts”.

Sadly, the answer is more prosaic as researchers have determined that the rock is a piece of a larger rock broken and moved by the wheel of NASA’s Mars Exploration Rover Opportunity in early January.

“Once we moved Opportunity a short distance, after inspecting Pinnacle Island, we could see directly uphill an overturned rock that has the same unusual appearance,” said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St Louis. “We drove over it. We can see the track. That’s where Pinnacle Island came from.”

Examination of Pinnacle Island revealed high levels of elements such as manganese and sulfur, suggesting these water-soluble ingredients were concentrated in the rock by the action of water. “This may have happened just beneath the surface relatively recently," Arvidson said, ”or it may have happened deeper below ground longer ago and then, by serendipity, erosion stripped away material above it and made it accessible to our wheels.”

Now that the rover has finished inspecting this rock, the team plans to drive Opportunity south and uphill to investigate exposed rock layers on the slope.

Opportunity is approaching a boulder-studded ridge informally named the McClure-Beverlin Escarpment, in honour of engineers Jack Beverlin and Bill McClure. Beverlin and McClure were the first recipients of the NASA Medal of Exceptional Bravery for their actions on 14 February 1969 to save NASA’s second successful Mars mission, Mariner 6, when the launch vehicle began to crumple on the launch pad from loss of pressure.

“Our team working on Opportunity’s continuing mission of exploration and discovery realises how indebted we are to the work of people who made the early missions to Mars possible, and in particular to the heroics of Bill McClure and Jack Beverlin,” said rover team member James Rice of the Planetary Science Institute.

Opportunity’s work on the north-facing slope below the escarpment will give the vehicle an energy advantage by tilting its solar panels toward the winter sun. 14 February is the winter solstice in Mars’ southern hemisphere, which includes the region where Opportunity has been working since it landed in January 2004.

“We are now past the minimum solar-energy point of this Martian winter,” said Opportunity Project Manager John Callas of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We now can expect to have more energy available each week. What’s more, recent winds removed some dust from the rover’s solar array. So we have higher performance from the array than the previous two winters.”

During Opportunity’s decade on Mars, and the 2004-2010 career of its twin, Spirit, NASA’s Mars Exploration Rover Project has yielded a range of findings proving wet environmental conditions on ancient Mars - some very acidic, others milder and more conducive to supporting life.

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