The photo above shows Moqui Marbles in their native habitat of southern Utah. These curious rocks are actually concretions having iron (hematite) rinds. Very similar rocks, called blueberries, have been observed repeatedly on Mars by the rovers. Image © Bret Webster; Bret’s Web site; Bret’s Facebook page
Some scientific papers implicate the possibility of life on Mars playing a role in their formation while others do not. Discussions about the pros and cons of their formation have been quite lively at times. However, the consensus seems to be that both the marbles and the blueberries were created beneath the surface as naturally occurring substances, most likely minerals, precipitated from flowing groundwater. Pictured with the marbles is a Devil’s-Claw cactus (Sclerocactus parviflorus). Author © Bret Webster
Puzzling Little Martian Spheres That Don’t Taste Like ‘Blueberries’
Small spherical objects fill the field in this mosaic combining four images from the Microscopic Imager on NASA’s Mars Exploration Rover Opportunity. The view covers an area about 2.4 inches (6 centimeters) across, at an outcrop called “Kirkwood” in the Cape York segment of the western rim of Endeavour Crater. The individual spherules are up to about one-eighth inch (3 millimeters) in diameter. Image © NASA/JPL-Caltech/Cornell Univ./ USGS/Modesto Junior College
The Microscopic Imager took the component images during the 3,064th Martian day, or sol, of Opportunity’s work on Mars (Sept. 6, 2012). For a color view of the Kirkwood outcrop as Opportunity was approaching it two weeks earlier, see PIA16128 .
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