Nasa's Opportunity rover has spotted a rock that seems to have appeared out of nowhere, leaving mission engineers scratching their heads.
The obstacle, which is about the size of a doughnut but has been given the rather grand title of "Pinnacle Island", popped up in front of the rover in early January 2014. A photo taken on sol 3528 of the mission shows bare bedrock, but on sol 3540, the rock had suddenly appeared. "It was a total surprise, we were like 'wait a second, that wasn't there before, it can't be right. Oh my god! It wasn't there before!'" Opportunity lead scientist Steve Squyres of Cornell University told Discovery News. "We were absolutely startled."
There are two possible explanations for the rock's sudden appearance. The first is that one of the rover's wheels may have pinged it forward by accident as it was manoeuvring. The second is that it landed there after being thrown from a meteorite impact nearby. The former is thought to be more likely.
Squyres said: ""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 ... we flung it."
The rock gives Opportunity the opportunity to do a bit of science. "It obligingly turned upside down, so we're seeing a side that hasn't seen the Martian atmosphere in billions of years and there it is for us to investigate," added Squyres. "It's just a stroke of luck."
This article was originally published by WIRED UK
