Friday, August 26, 2011

What does a more than three billion year old sandstone formation in Western Australia have in common with Mars?

The Aussie stones contain the oldest living microbial record of life on Earth – and it might be the basis of fossil discovery on Mars. The early Archaean rocks are providing geologists with microfossil evidence that early life might have been utilizing sulpher – instead of oxygen – for their ecosystems.

“At last we have good solid evidence for life over 3.4 billion years ago. It confirms there were bacteria at this time, living without oxygen,” said co-researcher Professor Martin Brasier at Oxford University, UK. “Such bacteria are still common today. Sulphur bacteria are found in smelly ditches, soil, hot springs, hydrothermal vents – anywhere where there’s little free oxygen and they can live off organic matter,” he explained.

But providing morphological evidence for these sulphur-metabolizing bacteria hasn’t been as easy as just digging up some stones. The first detection came in 2007 at Strelley Pool, a now arid area which may have once been an estuary or shallow water region. Associated with micrometre-sized pyrite crystals, these microstructures show all the right ingredients for early life properties, such as hollow cell lumens and carbonaceous cell walls enriched in nitrogen. Spheroidal and ellipsoidal forms are good indicators of bacterial formations and tubular sheaths point to multiple cell growth. They also display pyrite content, but there’s no “fool’s gold” here in these light isotopes… it’s a metabolic by-products of the cells.

“Life likes lighter isotopes, so if you have a light signature in these minerals then it looks biological,” said lead author Dr David Wacey from the University of Western Australia. “There are ways to get the same signature without biology, but that generally requires very high temperatures. So when you put together the light isotope signature with the fact the pyrite is right next to the microfossils – just a couple of microns away – then it really does look like there was a whole sulphur ecosystem there,” he reported to BBC News.

So what does this discovery have to do with Mars? In its northern hemisphere is a region called Nili Fossae which photographically bears a strong resemblance to Australia’s Pilbara region – home to Strelley Pool. With a huge amount of clay minerals documented, Nili Fossae just might be the ideal place for US space agency’s Curiosity-Mars Science Laboratory rover mission to begin a search for early Martian life forms. But don’t get too excited just yet… The study on a remote planet is going to prove even more difficult than here on Earth.

“Some of the instruments we used can fill a whole room, but some of them can be miniaturised,” said Dr Wacey. “A rover could narrow down the targets but then you’d really have to bring samples back to Earth to study them in detail.”

Thursday, August 18, 2011

Microbial life on Mars: Could saltwater make it possible?

Globules of liquid saltwater were pictured on the leg of the Phoenix Mars Lander. NASA/JPL-Caltech/University of Arizona/Max Planck Institute

This project begins three years after beads of liquid brine were first photographed on one of the MarsPhoenix lander's legs.

Microbial life on Mars: Could saltwater make it possible?

A mounting body of evidence suggests the presence of liquid saltwater on the Red Planet.
How common are droplets of saltwater on Mars? Could microbial life survive and
reproduce in them?

A new million-dollar NASA project led by the University of Michigan aims to
answer those questions.

"On Earth, everywhere there's liquid water, there is microbial life," said Nilton Renno, a professor in the Department of Atmospheric, Oceanic and Space Sciences who is the principal investigator. Researchers from NASA, the University of Texas at Dallas, the University of Georgia and the Centro de Astrobiologia in Madrid are also involved.

Scientists in the United States will create Mars conditions in lab chambers and study how and when brines form. These shoe-box-sized modules will have wispy carbon dioxide and water vapor atmospheres with 99 percent lower air pressure than the average pressure on Earth at sea level. Temperatures will range from -100 to -80 Fahrenheit and will be adjusted to mimic daily and seasonal cycles. Instruments will alert theresearchers to the formation of brine pockets, which could potentially be habitable by certain forms of microbial life.

Their colleagues overseas will seed similar chambers with salt-loving "extremophile" microorganisms from deep in Antarctic lakes and the Gulf of Mexico. The will observe whether these organisms survive, grow and reproduce in brines just below the surface of the soil. All known forms of life need liquid water to live. But microbes don't need much. A droplet or a thin film could suffice, researchers say.

"If we find microbes that can survive and replicate in brines at Mars conditions, we would have demonstrated that microbes could exist on Mars today," Renno said.
With his colleagues on the Mars Phoenix mission in 2008, Renno theorized that globules that moved and coalesced on the spacecraft's leg were liquid saltwater. Independent physical and thermodynamic evidence as well as follow-up experiments have confirmed that the drops were liquid and not frost or ice.

The Phoenix photos are believed to be the first pictures of liquid water outside the Earth.

The median temperature at the Phoenix landing site was -70 degrees Fahrenheit during the mission—too cold for liquid fresh water. But "perchlorate" salts found in the site's soils could lower water's freezing point dramatically, so that it could exist as liquid brine. The salts are also capable of absorbing water from the atmosphere in a process called deliquescence.

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The content is provided for information purposes only.
"Microbial life on Mars: Could saltwater make it possible?." . 17 Aug 2011

Sunday, August 7, 2011

NASA: Possible Seasonal Salty Water Flows on Mars

An image combining orbital imagery with 3-D modeling shows flows that appear in spring and summer on a slope inside Mars' Newton crater. Sequences of observations recording the seasonal changes at this site and a few others with similar flows might be evidence of salty liquid water active on Mars today. Evidence for that possible interpretation is presented in a report in the Aug. 5, 2011, edition of Science. (NASA)

During warm months on Mars, salty water might run freely down the planet’s slopes.

Scientists are calling saltwater the most likely reason the Martian surface shows dark streaks during its warm seasons. “Finger-like features” appear on Martian terrain during the springtime, according to researchers.

“The best explanation for these observations so far is the flow of briny water,” said Alfred McEwen of the University of Arizona in a statement.

McEwen is the lead author or a report in the journal Science that examines the seasonal flows on Mars. He thinks that since salt lowers the freezing temperature of water, it’s possible that the planet seems liquid flows — perhaps just under its surface.

No signs of water are present on the surface of the slopes, according to data gathered by the Mars Reconnaissance Orbiter.

“The flows are not dark because of being wet,” McEwen said. “They are dark for some other reason.”

More from NASA:

A flow initiated by briny water could rearrange grains or change surface roughness in a way that darkens the appearance. How the features brighten again when temperatures drop is harder to explain.

These results are the closest scientists have come to finding evidence of liquid water on the planet’s surface today. Frozen water, however has been detected near the surface in many middle to high-latitude regions. Fresh-looking gullies suggest slope movements in geologically recent times, perhaps aided by water. Purported droplets of brine also appeared on struts of the Phoenix Mars Lander. If further study of the recurring dark flows supports evidence of brines, these could be the first known Martian locations with liquid water.

Tuesday, August 2, 2011

Space may be the final frontier, but Mars should be the next one.

At a spaceflight propulsion conference held by the American Institute of Aeronautics and Astronautics on Tuesday, Elon Musk -- the billionaire founder of PayPal and the man behind leading private spaceflight company SpaceX -- spoke about just how to get humanity there.

"Are we on the path to becoming a multi-planet species or not?" Musk asked the crowd at the event. "If we're not, it's really not that exciting after all."

The challenge to getting to Mars is transporting significant tons of cargo and people, Musk noted, a task that will require what he described as a rapidly and fully reusable rocket.

"There's a reason no one has invented a fully reusable rocket before," Musk explained. "It's super-damn hard."

Still, the inventor has a plan for interplanetary travel, and a name for it: Falcon.

Musk described several of the recent advances made by his company's Falcon 9 rockets, which were tested successfully for the first time June 4, 2010. The rocket is designed to generate 3.8 million pounds (1,700 metric tons) of thrust -- making it easily capable of carrying satellites, cargo, and even humans to other planets, he said.

"It's got potential as a generalized science delivery platform for other planets in the solar system," Musk noted.

While he believes there will be a single vehicle for transporting humans to the Red Planet and back -- at least at first -- a Mars base could dramatically change the game.

"As soon as you've got a base on Mars, you've got a 'forcing function' for improving the transportation capability," he noted.

The company did not explain prior to the 4 p.m. EST speech what Musk would discuss, other than referencing the title of his brief speech: "Getting to Mars." But the SpaceX founder has often publicly stated his desire to have humans on Mars within 20 years.

According to a story at, NASA has been tentatively discussing work with the company and its Dragon capsule on an exploratory mission to Mars, a so-called "Red Dragon" mission.

In that mission, NASA's science hardware would fly to the Red Planet aboard SpaceX's Dragon capsule, which the company is developing to ferry cargo and astronauts to and from the International Space Station, reported.

The Dragon capsule is designed to work in concert with the company's multistage Falcon 9 rocket, either on short range resupply trips to the International Space Station or on longer range missions to other planets.

This so-called "Red Dragon" mission, which could be ready to launch by 2018, would carry a cost of about $400 million or less. And the Dragon capsule clearly fits Musk's description of "rapidly and fully reusable."

At the AIAA speech, Musk also teased a new engine development -- needed to bring cargo and people to Mars, he noted -- which he promised to unveil later this year.

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