

Did the rover produce this odd shape in the soil or was it something else ? Image Credit: NASA

A strange cross-shaped pattern with a circle around it has been spotted on the surface of Mars.

There have been a lot of reports lately of anomalous objects turning up in pictures of Mars, but while most of these are almost certainly little more than unusually shaped rocks there remains one recent image that shows something a little bit different.The anomaly, which was spotted in a photograph returned by NASA's Opportunity rover, consists of what looks like a perfect circle with a cross design in the center.Having been captured by the rover's microscopic imager camera however the unusual shape is also extremely small and is likely to measure only a few millimeters across.While some Internet users have been promoting the discovery as evidence of extraterrestrial life, others have pointed out that the circular cross shape happens to bear an uncanny resemblance to the type of screw-heads found in the rover's Alpha particle X-ray Spectrometer tool.The most likely explanation therefore is that the rover left an unintentional imprint of one of the spectrometer's screw-heads in the soil just before the photograph was taken.