Dining on Diamonds
|Principal investigator, Dr. Steve Squyres, Cornell University, describes Mars surface operations Credit: NASA-TV|
As Opportunity creeps down the slopes of Endurance Crater, it stops to do a grind. When the rover took on a rock called ‘Diamond Jenness’, it found more of what has fascinated scientists since January: the mystery of martian blueberries.
On February 11, principal investigator Steve Squyres revealed his surprise in his mission journal: "… we saw some very strange things… we see these strange round objects we’re calling ‘spherules’ embedded in the outcrop, like blueberries in a muffin. The outcrop erodes away as it gets sandblasted, and the spherules (which seem to resist erosion better than the rest of the outcrop does) fall out and roll down the hill. Weird."
Two weeks later, the team concluded that the rocks near Opportunity’s landing site had at one time been soaked in water. Squyres wrote on March 4, "we now think it’s pretty likely that the little round things in the outcrop (the ‘blueberries’) are what geologists call ‘concretions’. They seem to be different in composition from the stuff in which they’re embedded, they don’t deform the layers around them, they’re not concentrated along layers, and we sometimes see layers running through them… all of which are consistent with the idea that they’re concretions. And if that’s what they are, then they point to water, since concretions form when minerals are precipitated from groundwater."
Squyres went on to speculate about what once was this strange world that seemed so different from the dry desert barely able to keep an atmosphere, "So water once flowed through these rocks. It changed their texture and their chemistry, and it left behind the clues that we’ve been able to read. It’s a nice conclusion, and we feel pretty confident about it. The really cool thing here, of course, is that a groundwater environment like this would have been suitable for some simple forms of microbial life. That doesn’t mean life was there, of course! But we flew this mission because we wanted to find out if Mars ever had habitable environments. And the answer, we now believe, is that it did. "
To continue this line of investigation, a crucial excursion was to see if this finding was widespread or local. The rover team pointed Opportunity to the nearest large crater, Endurance, and what they have found is more evidence of the strange blueberries. As they have driven the rover down the crater walls, Mars has yielded up new examples of concretions or ‘blueberries’. Even after many months of seeing these spherules, the latest microscopic images have the same startling effect first experienced in mid-February when Squyres wrote "Weird".
|This microscopic imager mosaic of the rock called "Diamond Jenness" was snapped on sol 177 before NASA’s Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool, or "Rat." Opportunity has bored nearly a dozen holes into the inner walls of "Endurance Crater." On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover’s alpha particle X-ray spectrometer. On Sol 178, Opportunity’s "robotic rodent" dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.02 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.
|This microscopic imager mosaic taken by NASA’s Mars Exploration Rover Opportunity shows the rock dubbed "Diamond Jenness." It was taken on sol 177 (July 23, 2004) after the rover first ground into the rock with its rock abrasion tool, or "Rat." The rover later ground into the rock a second time. A sliced spherule, or "blueberry," is visible in the upper left corner of the hole. The image mosaic is about 6 centimeters (2.4 inches) across. Credit: NASA/JPL|
|This microscopic imager mosaic of the target area called "Diamond Jenness" was taken after NASA’s Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.
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Alpha Proton X-ray Spectrometer