Cape Town - A mystery rock that suddenly appeared in front of the Mars Opportunity rover has baffled astronomers, a report says.
According to a report on the Independent as well as other media, the rock appeared without explanation in an area that had been empty just days before.
While it is conceivable that the rock could be from a meteor impact because the area was photographed days apart, the rock seems anomalous on first inspection.
What puzzles scientists is that the rock appears to look like a jam doughnut and there are ongoing discussions as experts investigate by what mechanism that rock could have landed in its present position.
The rock has been named Pinnacle Island as scientists prepare to conduct a more detailed investigation into how it appeared in front of the rover.
It is also possible that the rock may have been rolled into place but that theory would require an external agent to move the object.
Nasa's Opportunity rover landed on Mars in 2004 and has been broadcasting imagery and scientific data back to Earth. Its twin rover, Spirit, was officially declared "dead" due to freezing on the hostile Martian surface.