NASA scientists believe they are days away from concluding whether or not Mars once had water using data from the Mars rover Opportunity, they revealed on Thursday.
Opportunity, which has been roaming inside a 20-metre crater on a plateau called Meridiani Planum for nearly five weeks, has been focusing its attention for the past three on a 30-metre outcrop of bedrock and its immediate environs. It has taken microscopic images and spectroscope data and ground portions of the rock surface to peer beneath its coating of dust.
The site was chosen for its rich deposits of haematite, suggestive of a watery formation, and for its location within a region that some scientists say shows signs of once having been an ocean basin.
The craft is now in the midst of grinding and examining several spots on the outcrop, to gather information about the details of the finely layered structure of the rock, says deputy principal investigator Ray Arvidson.
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Together with the chemical and mineralogical data already collected, this should provide the information needed to decide between the various theories – volcanic or sedimentary – about how the rock and soil in this region were formed, Arvidson says.
Curly macaroni
It should take a few “sols,” or Martian days, to finish this grinding and data taking, perhaps a few more to finish sending all the data to Earth, and a few more to complete the analysis, he said at a news conference on Thursday.
Already colour images of the rock and soil there – taken through 14 different colour filters – are showing a rich variety of colours and textures. These include some signs of bends and curves in the layers that could be indicative of formation in a water environment. And close-up images reveal intriguing shapes, including spheres, threadlike features, and one shape resembling a piece of curly macaroni. The variety of colours suggests several different rock types.
One small patch that was photographed this week shows “more variety than we’ve ever seen in any other data set on Mars,” says science team member Jim Bell of Cornell University. Some of the pebbles in that image – “dark, angular particles” -show colour characteristics suggesting they may be carrying the long-sought hematite, he says.
Firm conclusions about the origin of these rocks and soil may be “right around the corner,” Arvidson says. The team feels as though it were Christmas Eve, with exciting gifts just on the verge of having their contents revealed, he adds.
