Otherworldly water?

[Merkuri]

[From Space.com: (Click to see pictures) www.space.com/scienceastronomy/opportunity_evidence_040229.html ]

Mars: A Water World? Evidence Mounts, But Scientists Remain Tight-Lipped
By Leonard David
Senior Space Writer
29 February 2004


PASADENA, California -- Evidence that suggests Mars was once a water-rich world is mounting as scientists scrutinize data from the Mars Exploration rover, Opportunity, busily at work in a small crater at Meridiani Planum. That information may well be leading to a biological bombshell of a finding that the red planet has been, and could well be now, an extraterrestrial home for life.

There is a palpable buzz here at the Jet Propulsion Laboratory (JPL) in Pasadena, California that something wonderful is about to happen in the exploration of Mars.

There is no doubt that the Opportunity Mars rover is relaying a mother lode of geological data. Using an array of tools carried by the golf cart-sized robot -- from spectrometers, a rock grinder, cameras and powerful microscopic imager -- scientists are carefully piecing together a compelling historical portrait of a wet and wild world.

Where Opportunity now roves, some scientists here suggest, could have been underneath a huge ocean or lake. But what has truly been uncovered by the robot at Meridiani Planum is under judicious and tight-lipped review.

Those findings and their implications are headed for a major press conference, rumored to occur early next week -- but given unanimity among rover scientists and agreement on how and who should unveil the dramatic findings. Turns out, even on Mars, a political and ego outcrop hangs over science.


Scientific bulls-eye

It is clear that Opportunity's Earth-to-Mars hole in one -- bouncing into a small crater complete with rock outcrop -- has also proven to be a scientific bulls-eye. The robot is wheeling about the crater that is some 70 feet (22 meters) across and 10 feet (3 meters) deep.

It is also apparent that there is a backlog of scientific measurements that Mars rover scientists working Opportunity have pocketed and kept close to their lab coats.

For one, the rover found the site laden with hematite -- a mineral that typically, but not always -- forms in the presence of water. Then there are the puzzling spherules found in the soil and embedded in rock. They too might be water-related, but also could be produced by the actions of a meteor impact or a spewing volcano.

A few spheres have been sliced in half and their insides imaged. Patches of these spherules, or "berries" as some call them, have undergone spectrometer exam to discern their mineral and chemistry makeup. Close-up photos of soil and rock have also shown thread-like features and even an oddly shaped object that looks like Rotini pasta.


Brew of dissolved salts

There is speculation that the soil underneath the wheels of both Spirit and Opportunity rovers contains small amounts of water mixed with salt in a brine. That brew of dissolved salts keeps the mixture well below the freezing point of pure water, permitting it to exist in liquid form.

Opportunity has revisited select spots in the outcrop, drawn there, in part, to look for cross-beds -- sedimentary deposits that are formed in beach, river and sand-dune environments. Using its Rock Abrasion Tool (RAT), the rover has carried out several cleaning and grinding sessions on exposed rock outcrop.

Cross-beds are patterns of curving lines or traces found within the strata of sandstone and other sedimentary rocks. Cross-bedding indicates the general direction and force of the wind or water that originally laid down the sediments.


Right around the corner

Opportunity's research is a "work in progress", said Ray Arvidson, deputy principal investigator for the Mars Exploration Rover (MER) project from Washington University in St. Louis. Data is being gathered to present "a coherent story", he said during a press briefing last Thursday.

"That story is right around the corner," Arvidson told SPACE.com . "But we need to finish this work in progress, finish the set of experiments, get the data down from the spacecraft, processed and analyzed. Then I think that the story will be known," he said.

Arvidson said multiple working hypotheses are still at play. Water is involved, but only on some of the hypotheses. Until coordinated experiments on the outcrop are completed, what the right hypothesis is remains unknown, he added.


Severing the umbilical cord

Mars exploration using the rovers has allowed on-the-spot " discovery driven science", said MER Deputy Project Scientist Albert Haldeman. He likened the Mars robot work now underway to deep ocean research using remotely operated submersibles.

"It turns out that the best way to explore rocks [on Mars] is go look at craters. Mobility buys us the ability to do that. It was the right fit for looking at rocks," Haldeman told SPACE.com . "The discovery from the Microscopic Imager and seeing those spherules…and finding a larger population of spherules and seeing them in the rocks and the outcrop…that progression of discovery influences our thinking."

Haldeman said the next step will be severing the umbilical cord between Opportunity and the crater it's exploring. The robot would wheel itself out of that site and onto the expansive terrain of Meridiani Planum.

"That umbilical cord…that's hard to break. It's more than even just a tension within the science team," Haldeman said.


Tantalizing hints

Scientists are carefully analyzing the rock data gleaned by the Opportunity rover. "We really want to understand that we've got those figured out right," Haldeman said. Up to now they have offered some "tantalizing hints", he said, that speak to a possible relationship with water.

Piecing together the story of what Opportunity has found involves great care and deliberation, Haldeman said, based on a wide-range of viewpoints and levels of expertise. "We want to be cautious," he explained.

More to the point, the science output from Mars must withstand scrutiny by experts outside the rover investigation teams.

"There are lots of geologists out there who are looking at these pictures and they are starting to drool," Haldeman said. "The American taxpayer that spent $800 million on this deserves a thorough analysis," Haldeman said.


Slippery slope leading to life

One scientist eagerly awaiting the news from Mars, particularly from Opportunity, is Gilbert Levin. He is Chairman of the Board and Executive Officer for Science of Spherix Incorporated in Beltsville, Maryland.

Levin is a former Viking Mars lander investigator. He has long argued that his 1976 Viking Labeled Release (LR) life detection experiment found living microorganisms in the soil of Mars.

In 1997, Levin reported that simple laws of physics require water to occur as a liquid on the surface of Mars. Subsequent experiments and research have bolstered this view, he said, and reaffirms his Viking LR data regarding microbial life on Mars.

Levin detailed his Mars views in a SPACE.com phone interview and via email.

"It's hard to image why such bullet-proof evidence was denied for such a long time, and why those so vigorously denying it never did so by meeting the science, but merely by brushing it away," Levin said.

"Of course, now that it must be acknowledged by all that there is liquid water on the surface of Mars," Levin added, "this starts those denying the validity of the Mars LR data down the slippery slope leading to life."


Mars mud

Levin points to Opportunity imagery that offers conclusive proof of standing liquid water and running water on a cold Mars.

Other images show the rover tracks clearly are being made in "mud", with water being pressed out of that material, Levin said. "That water promptly freezes and you can see reflecting ice. That's clearly ice. It could be nothing else," he said, "and the source is the water that came out of the mud."

As for the spherical objects found at the Opportunity site, Levin has a thought.

"I wonder on Mars if it can rain upwards," he said. The idea is that subsurface water comes up through the soils and then freezes when it gets to the surface.

"Maybe these little spherules form just like raindrops form up above," Levin explained.

Levin said that brine on Mars is a code word for liquid water. He senses that great care is being taken by rover scientists because the liquid water issue starts the road to life.

"That's the monument that they are afraid to erect without real due process," Levin concluded.

[Merkuri]

[From CNN.com: www.cnn.com/2004/TECH/space/03/02/mars.findings/index.html ]

NASA: Liquid water once on Mars
Red planet may have been hospitable to life
By Marsha Walton
Wednesday, March 3, 2004


(CNN) -- Mission accomplished: NASA scientists say the Mars rovers have found what they were looking for -- hard evidence that the red planet was once "soaking wet."

"We have concluded the rocks here were once soaked in liquid water," said Steve Squyres of Cornell University. He's the principal investigator for the science instruments on Opportunity and its twin rover, Spirit.

"The second question we've tried to answer: Were these rocks altered by liquid water? We believe definitively, yes," Squyres said.

Squyres and other NASA officials made the announcement at NASA headquarters in Washington, after several days of giving tantalizing hints that something significant had been discovered.

"Three and a half years ago, in July 2000, we were on stage here to talk about sending two rovers to get evidence of past water. NASA and its international partners have turned those dreams to reality," said Ed Weiler, NASA associate administrator for space science.

Scientists used instruments on board the golf cart-sized rovers to study the composition of the rocks and soil on the planet. The rocks' physical appearance, plus the detection of sulfates, make the case for a watery history, and more important, an environment that could have been hospitable to life.

While reporters pushed the scientists to come up with a "when" for the existence of water on Mars, Squyres said it was very difficult to infer an age simply by looking at pictures. He said a physical examination of samples would be the only way to to get close to a time frame.

Squyres did offer a couple of scenarios on what might have happened that led to the current discoveries:

One is that there was a volcanic eruption, possibly many eruptions, and volcanic ash settled out onto the Martian surface. Subsequently, water could have percolated through the ground, altering the ash to the chemical composition it has today.

Another possibility, said Squyres, is that there was a salty sea at the Meridiani Planum location, perhaps with currents, possibly even waves. As the water evaporated, the salt would settle out.

"Both are fundamentally possible," said Squyres. "But we may never know."

Spirit and Opportunity were sent to opposite sides of the planet with the possibility of investigating different types of terrain. Spirit, the first rover to arrive on January 3, landed near the Gusev Crater, which may once have held a lake.

But geologists and other researchers at NASA's Jet Propulsion Laboratory in Pasadena, California, were thrilled when they saw the possibilities surrounding Opportunity, which landed three weeks later. It landed inside a small crater in the Meridiani Planum, one of the flattest places on the planet. And its landing site was within driving distance for the spacecraft to reach an exposed slice of bedrock.

Since its landing January 25, Opportunity has used the same tools as a human field geologist would to determine the chemical contents of the rocks. Using an alpha particle X-ray spectrometer, a device that can identify chemical elements, scientists have identified a high concentration of sulfur in the bedrock.

Another instrument on board, a Moessbauer spectrometer, has detected an iron sulfate mineral known as jarosite. From their knowledge of rocks on earth, scientists say rocks with as much salt as this Mars rock either formed in water, or had a long exposure to water after they were formed. The scientists say these rocks could have formed in an acidic lake or even a hot springs.

Scientists say the case for a watery past is further strengthened by the pictures taken by the rovers' panoramic cameras and its microscopic imager. One target rock, named "El Capitan," is filled with random pockmarks. Geologists say a texture like that comes from sites where salt crystals have formed in rocks that have sat in salt water.

Scientists say they have gained other clues from the physical appearance of the rocks. They see a pattern called "crossbedding," which is often the result of wind or water moving across the rock's surface.

So what is ahead for the final few weeks of the rovers' operations on Mars?

"We need to take a close look at the outcropping, and broaden our view to get a better understanding of the geology of the region, which is about the size of Oklahoma," said Joy Crisp, project scientist at the Jet Propulsion Lab. She said there are also plans to drive about 740 meters east to a crater that has been nicknamed "Endurance."

And in the longer term?

"It's clear we have to do a sample return, both for the scientific side and in preparation for human landing," said Weiler. He said future Mars missions would also include miniaturizing equipment, and landing equipment that would help prepare for the eventual landings of humans. That might include tests for toxicity in the soil, and to determine if there are any materials that humans might find useful when they do arrive.

The cost of the two rover missions is about $820 million. With solar panels and lithium-ion battery systems aboard, each rover is expected to function and communicate with earth for about 90 Mars days, known as "sols." That's equivalent to 92 earth days.

[Iron Bonny Shades]

so when does mars become our home away from home