By Kalwinder Kaur
Opportunity, NASA's long-running rover, has delivered a mystifying picture of tiny Martian spheres that are differing in many ways from blueberries, an iron-rich spherule detected by the rover at its landing site in the beginning of 2004 and at several other Martian locations until today.
Puzzling Little Martian Spheres That differ from iron-rich spherules called 'Blueberries' (image credit: NASA/JPL-Caltech/Cornell Univ./ USGS/Modesto Junior College)
Opportunity found the puzzling objects with roughly 3-mm diameter during its exploration of an outcrop named Kirkwood in the Cape York segment situated in the western rim of Endeavour Crater. These spheres have lesser iron content when compared to Martian blueberries, which are concretions created by mineral-laden water within rocks, a proof indicating the presence of a wet environment on the earlier Martian surface.
Using the microscopic imager and Alpha Particle X-Ray Spectrometer mounted on its arm, Opportunity explored Kirkwood closely and analyzed the composition of the mysterious spheres. Opportunity's principal investigator, Steve Squyres from Cornell University has explained that the spheres are softer in the center but crunchy on the exterior and their concentration, structure, composition and distribution are different. The researchers have proposed multiple theories but none of them had an answer for the puzzle till now.
Opportunity's next site after Kirkwood is an area comprising pale-toned outcrop in the Cape York region where investigations from orbit have indicated the presence of clay minerals. Four years before, the rover exited Victoria Crater after two years of extensive exploration to get various sets of geological proofs at the rim of the Endeavour Crater.
John Callas, Mars Exploration Rover Project Manager at NASA's Jet Propulsion Laboratory, informed that Opportunity is still working well even after eight and a half years of hard work on the Martian surface and the researchers are expecting fruitful spring and summer seasons of investigations.