Friday, December 9, 2011

Evidence of water on Mars

NASA Opportunity rover locates evidence of water on Mars

The State Column |  | 
Thursday, December 08, 2011
NASA’s Mars Exploration Rover Opportunity has discovered “bright veins of a mineral,” likely gypsum, dropped by water, according to a NASA press release. An examination of the vein will help scientists understand the history of damp environments on Mars. NASA’s announcement comes less than two weeks after its successful launch of the Curiosity rover.

“This tells a slam-dunk story that water flowed through underground fractures in the rock,” Steve Squyres of Cornell University, the principal investigator for Opportunity, said in a statement.

“This stuff is a fairly pure chemical deposit that formed in place right where we see it. That can’t be said for other gypsum seen on Mars or for other water-related minerals Opportunity has found. It’s not uncommon on Earth, but on Mars, it’s the kind of thing that makes geologists jump out of their chairs,” Mr. Squyres added.

Scientists presented the latest findings by Opportunity at the American Geophysical Union’s conference in San Francisco Wednesday.

“This is the single most powerful piece of evidence for liquid water at Mars that has been discovered by the Opportunity rover,” Mr. Squyres professed to reporters at the conference, according to MSNBC.

One of the veins inspected by Opportunity is about the width of a human thumb, 16 to 20 inches long, and sticks out a little bit higher than the rock layer on either side of it. Surveillance by the Opportunity Mars rover exposes that this vein and others like it within an apron surrounding a segment of the rim of Endeavour Crater.

This is the first time that NASA’s Opportunity Mars rover has seen a vein like this. Nothing similar was seen in the 20 miles of crater-pocked plains that Opportunity investigated for 90 months prior to reaching Endeavour.

In November, scientists deployed the Microscopic Imager and Alpha Particle X-ray Spectrometer on the NASA’s Opportunity Mars rover’s arm and several filters of the Panoramic Camera on the Opportunity’s mast to take a closer look at the vein, which is being unofficially named “Homestake.” The spectrometer recognized a lot of calcium and sulfur.

Calcium sulfate can survive in many different forms. The number of forms depends on how much water is bound into the minerals’ crystalline structure. The multi-filter data from Opportunity’s camera suggest gypsum, a hydrated calcium sulfate. Gypsum is typically used for making drywall and plaster of Paris.

This is not the first time that gypsum has been detected on Mars. According to the NASA press release, observations from orbit have discovered gypsum on Mars in the past. Apparently, one particular field of gypsum on Mars looks like the gypsum dunes in White Sands National Monument in New Mexico.

“It is a mystery where the gypsum sand on northern Mars comes from,” Opportunity science-team member Benton Clark of the Space Science Institute in Boulder, Colorado, said in a statement. “At Homestake, we see the mineral right where it formed. It will be important to see if there are deposits like this in other areas of Mars,” Mr. Clark added.

The “Homestake” deposit or vein is likely to have formed from water as it dissolved calcium out of volcanic rocks. The minerals combined with sulfur either trickled from the rocks or introduced as volcanic gas, and was deposited as calcium sulfate into an underground fracture that later was depicted at the surface.

During its travels across Mars’ Meridiani plain, Opportunity has driven over bedrock composed of magnesium, iron and calcium sulfate minerals that also suggest a wet environment existed billions of years ago on Mars. The highly concentrated calcium sulfate at “Homestake” may have been produced in conditions more neutral than the harshly acidic conditions suggested by the other sulfate deposits investigated by Opportunity.

“It could have formed in a different type of water environment, one more hospitable for a larger variety of living organisms,” Mr. Clark said.

“Homestake” and other veins with similar appearances show up in a zone where the sulfate-rich sedimentary bedrock of the plains greets older, volcanic bedrock exposed at the rim of Endeavour. Scientists believe that the location of “Homestake” at the intersection between old and new may help researchers learn more about origin of their new discovery.

“We want to understand why these veins are in the apron but not out on the plains,” the mission’s deputy principal investigator, Ray Arvidson, of Washington University in St. Louis, said in a statement.

“The answer may be that rising groundwater coming from the ancient crust moved through material adjacent to Cape York and deposited gypsum, because this material would be relatively insoluble compared with either magnesium or iron sulfates,” Mr. Arvidson said.

Opportunity and Spirit finished their three-month chief missions on Mars in April 2004, but both rovers have continued to conduct extended missions for years. Opportunity and Spirit have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life at one point in time.

Sadly, Spirit stopped communicating in 2010. Currently, Opportunity is on its way to a sun-facing slope on the northern end of the Endeavour rim fragment called “Cape York.” Opportunity will position its solar panels at a favorable angle during the mission’s fifth Martian winter.

“This is a very different situation than Spirit was experiencing,” Bruce Banerdt of NASA’s Jet Propulsion Laboratory said, according to National Geographic News. “We’re not talking about surviving. We’re talking about getting enough energy on the panels so we can stay active, Mr. Banerdt added.

On November 26th, NASA launched the next-generation Mars rover, Curiosity. However, it will not arrive at Mars’ Gale Crater until August 2012..

After launch on November 26th, NASA Administrator Charles Bolden expressed his excitement about the Curiosity’s future with NASA.

“We are very excited about sending the world’s most advanced scientific laboratory to Mars,” Mr. Bolden said.

“MSL will tell us critical things we need to know about Mars, and while it advances science, we’ll be working on the capabilities for a human mission to the Red Planet and to other destinations where we’ve never been,” Mr. Bolden added.


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