More on Mars "blueberries" -- Opportunity will head to big crater!

CAPTION This microscopic image, taken at the outcrop region dubbed "Berry Bowl" near the Mars Exploration Rover Opportunity's landing site, shows the sphere-like grains or "blueberries" that fill Berry Bowl. Of particular interest is the blueberry triplet, which indicates that these geologic features grew in pre-existing wet sediments. Other sphere-like grains that form in the air, such as impact spherules or ejected volcanic material called lapilli, are unlikely to fuse along a line and form triplets. This image was taken by the rover's microscopic imager on the 46th martian day, or sol, of its mission. Image Credit: NASA/JPLCornell/USGS

A major ingredient in small mineral spheres analyzed by NASA's Mars Exploration Rover Opportunity furthers understanding of past water at Opportunity's landing site and points to a way of determining whether the vast plains surrounding the site also have a wet history. The spherules, fancifully called blueberries although they are only the size of Bbs and more gray than blue, lie embedded in outcrop rocks and scattered over some areas of soil inside the small crater where Opportunity has been working since it landed nearly two months ago.

Individual spherules are too small to analyze with the composition-reading tools on the rover. In the past week, those tools were used to examine a group of berries that had accumulated close together in a slight depression atop a rock called "Berry Bowl." The rover's Moessbauer spectrometer, which identifies iron-bearing minerals, found a big difference between the batch of spherules and a "berry-free" area of the underlying rock.

"This is the fingerprint of hematite, so we conclude that the major iron-bearing mineral in the berries is hematite," said Daniel Rodionov, a rover science team collaborator from the University of Mainz, Germany. On Earth, hematite with the crystalline grain size indicated in the spherules usually forms in a wet environment.

Scientists had previously deduced that the martian spherules are concretions that grew inside water-soaked deposits. Evidence such as interlocking spherules and random distribution within rocks weighs against alternate possibilities for their origin.

Discovering hematite in the rocks strengthens this conclusion. It also adds information that the water in the rocks when the spherules were forming carried iron, said Dr. Andrew Knoll, a science team member from Harvard University, Cambridge, Mass.

"The question is whether this will be part of a still larger story," Knoll said at a press briefing today at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spherules below the outcrop in the crater apparently weathered out of the outcrop, but Opportunity has also observed plentiful spherules and concentrations of hematite above the outcrop, perhaps weathered out of a higher layer of once-wet deposits.

The surrounding plains bear exposed hematite identified from orbit in an area the size of Oklahoma -- the main reason this Meridiani Planum region of Mars was selected as Opportunity's landing site.

"Perhaps the whole floor of Meridiani Planum has a residual layer of blueberries," Knoll suggested. "If that's true, one might guess that a much larger volume of outcrop once existed and was stripped away by erosion through time."

Opportunity will spend a few more days in its small crater completing a survey of soil sites there, said Bethany Ehlmann, a science team collaborator from Washington University, St. Louis. One goal of the survey is to assess distribution of the spherules farther from the outcrop. After that, Opportunity will drive out of its crater and head for a much larger crater with a thicker outcrop about 750 meters (half a mile) away.

Halfway around Mars, NASA's other Mars Exploration Rover, Spirit, has been exploring the rim of the crater nicknamed "Bonneville," which it reached last week. A new color panorama shows "a spectacular view of drift materials on the floor" and other features, said Dr. John Grant, science team member from the National Air and Space Museum in Washington. Controllers used Spirit's wheels to scuff away the crusted surface of a wind drift on the rim for comparison with drift material inside the crater.

A faint feature at the horizon of the new panorama is the wall of Gusev Crater, about 80 kilometers (50 miles) away, said JPL's Dr. Albert Haldemann, deputy project scientist. The wall rises about 2.5 kilometers (1.6 miles) above Spirit's current location roughly in the middle of Gusev Crater. It had not been seen in earlier Spirit images because of dust, but the air has been clearing and visibility improving, Haldemann said.

Controllers have decided not to send Spirit into Bonneville crater. "We didn't see anything compelling enough to take the risk to go down in there," said JPL's Dr. Mark Adler, mission manager. Instead, after a few more days exploring the rim, Spirit will head toward hills to the east informally named "Columbia Hills," which might have exposures of layers from below or above the region's current surface.

The main task for both rovers is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life.

If you click the new image mosaic below, you'll get a medium-resolution image. You can see the big crater on the horizon in the medium-resolution image.

Like I said, I still want to see a pic of a wombat scratching his...

But a plain, regular ant would do.

There are pics from spirit showing anthill type arrangements. We'll see, I guess.

Alright, so lets say at one time Mars was covered in oceans of water. And lets also say maybe there were prolific bacterial life forms inhabiting these ancient seas. Would it not be unreasonable to expect deposits of methane hydrate would form through the decomposition of these primitive little hydrocarbon factories? Perhaps those ancient deposits of methane hydrate have now metamorphosed into vast fields of natural gas...

Top pic - is that Beagle's "landing spot" in upper right hand? The Crater?

I'm not sure what you're asking; Beagle didn't land anywhere near Opportunity or Spirit.

The mission will have to terminate at that point, unless the rovers can survive a 60-day or so loss of communications.

You're probably right. Supposedly the main constraints on the lander lifetime are the distance from the Sun (they get less power from the solar cells as the solar radiation decreases) and dust deposition on the cells. They probably know about when the distance-from-the-Sun parameter will curtail their power budget, and that's probably sooner than the communications interruption.

QUESTION
I have a question for you astronomy buffs. What is the large, bright planet (or star?) that is near the moon around 7-8 PM lately? I am on the East Coast, and this has been the brightest thing in the sky when the moon was unlit.

Thanks in advance. And please pardon my ignorance.

What is the large, bright planet (or star?) that is near the moon around 7-8 PM lately? I am on the East Coast, and this has been the brightest thing in the sky when the moon was unlit.

The brightest object in the sky after sunset right now is the planet Venus. Two nights ago the Moon was close to Venus; last night it was close to Mars. (Three nights ago I saw Mercury low on the horizon below the Moon; for at least another week, after sunset all five naked-eye planets are visible at the same time).

Thanks !!!
I told my 9 year old son that FReepers would know the answer. I'll betcha if I'd asked the question on FR they would have said it was Barbara Streisand.

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