After having first sighted strange iron-rich Martian spheres – dubbed the Martian blueberries – eight years back, NASA’s Opportunity rover has now sent back some remarkable new pictures that take a much closer look at the sphere-shaped ‘blueberries.’

The pictures, which have been taken with the microscopic imager on the end of the robotic arm of Opportunity rover, show that the outlandish spherical shapes envelop the Kirkwood outcrop in the Cape York segment on the western edge of Endeavour Crater.

Noting that "Kirkwood is chock full of a dense accumulation of these small spherical objects," Cornell astronomer Steve Squyres – who is the chief investigator of the Opportunity mission – said in a recent press release: “We never have seen such a dense accumulation of spherules in a rock outcrop on Mars."

The newly-spotted blueberries – which have a diameter that measures approximately one-eighth of an inch – apparently comprise layers of a mineral called hematite; thereby indicating that these spherical shapes were formed by the action of mineral-loaded water that seeped in through rocks.

With scientists widely of the opinion that the blueberries could be of great significance in the search for signs of life on Mars, researchers from the University of Nebraska and the University of Western Australia asserted in an article - published in the August edition of the journal Geology – that the microbial activity which led to the formation of iron spherules on Earth could have played the same role on Mars as well!