A Tale Of Two Deserts on Earth that are Mars like

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A Tale Of Two Deserts
http://www.marsdaily.com/reports/A_Tale_Of_Two_Deserts_999.html
University Valley, one of Antarctica's Upper Dry Valleys, where liquid water is a scarce commodity because the ground remains frozen year-round. Credit: M. Marinova.
by Henry Bortman
for Astrobiology Magazine
Moffett Field CA (SPX) Apr 19, 2011

Because the surface of Mars today is bone-dry and frozen all year round, it's difficult to find any place on Earth that is truly Mars-like. But two locations, Antarctica's Upper Dry Valleys and the hyper-arid core of Chile's Atacama Desert, come close. They have become magnets for scientists who want to understand the limits of life on Earth and the prospects for life on Mars.
Jocelyne DiRuggiero, an associate professor of biology at Johns Hopkins University in Baltimore, Maryland, studies samples from both locations. She's interested in the similarities and the differences between the microbial communities that live in these two extreme desert regions. In both places, very little liquid water is present.

In the core of the Atacama, years can go by between one rainfall and the next, but it is warm, so when there is precipitation, a significant amount of liquid water is available for a very short time.

In University Valley, one of Antarctica's Upper Dry Valleys, the availability of liquid water is limited in a different way. University Valley receives more regular precipitation than the Atacama, but it's so cold there that any precipitation falls in the form of snow and remains frozen.

"What we do in those environments is try to understand who is there, what those organisms might be doing, how they are distributed," and whether the organisms are "really active metabolically," or if instead they're "just sitting there, because they've been brought by the wind."

DiRuggiero's primary tool is DNA sequencing. Working with soil samples that weigh one- to two-tenths of a gram each (about a teaspoonful), she extracts the DNA from any microbes present in each sample. She then sends the DNA off to a lab for sequencing.

Sample preparation is a difficult process because there aren't many microbes in her samples. Each gram of soil contains perhaps one hundred to one thousand, an extremely low number. The same size sample of ordinary soil typically contains ten million to a billion organisms.

Because the microbial populations she's working with are so small, contamination is a serious problem. She has to be careful not to let skin cells or hair fall into her samples. Sneezing or coughing on them could pollute them.

So DiRuggiero does her work under a special hood that prevents contact with outside air. And even then she has problems, because some of the silica filters she uses to extract DNA from her samples arrive from the manufacturer with microbial cells clinging to them.

Although she has had more time to work with samples from the Atacama, DiRuggiero says the University Valley samples are particularly interesting. Because University Valley is both near the South Pole and more than a mile above sea level, the ground there stays frozen even in summer. There are few places in the world where this is true. "It's about 40 degrees Celsius colder than the Atacama soil," she says. That's about 70 degrees Fahrenheit colder.

That temperature difference results in a significant difference in habitability. There are more microbes in University Valley soil than in Atacama soil.

"Right now the only parameter ... we have measured that differentiates the populations, Antarctica and the Atacama, is the temperature," DiRuggiero says. In both locations, "the soils are very dry, the soils are very low in organics, they contain a fair amount of salt. The big difference is the temperature."

"We don't really know what it means yet."

It may seem odd that microbes are happier in sub-freezing conditions than in a warm desert. "This is counter to human experience but makes sense for microbes," Chris McKay, a planetary scientist at NASA Ames Research Center in Moffett Field, California, wrote in an email.

"Cold allows them to sleep, which is a good survival mechanism," he explained, adding that "this result bodes well for life in the cold deserts of Mars." McKay heads the NASA-funded IceBite team, which is testing a prototype coring drill for possible use on a future Mars mission. The IceBite team obtained the University Valley samples that DiRuggiero studies.

So far DiRuggiero has been working with University Valley samples collected during the IceBite team's first season in the field, in 2009. She's looking forward to getting her hands on more-extensive samples collected at the end of 2010, samples that are still making their way back from Antarctica.

Beneath the dry soil layer in University Valley is "what we call ice-cemented ground, which is basically frozen mud. And that mud has been frozen for thousands and thousands of years," says DiRuggiero.

"So the question is, Is there any water available for the micro-organisms, and do we see a difference in the microbial community between the soil above and this ice-cemented ground right underneath?"

There is some evidence, based on climate data collected last year by the IceBite team, that at the interface between the dry soil and the frozen mud, "there might be some melting in the summer," says DiRuggiero. "There might be water available at least part of the time" and microbes might be "actively growing and metabolizing at least during a small portion of the year."

"Melting," in this case, doesn't mean the soil gets soggy or muddy, or that the temperature gets above freezing. Rather, it means that thin layers of liquid water can form between the sand grains that make up the soil and the ice below it. But that's plenty of water for microbes. They're small. They don't need a lot of water.

"At temperatures above -20 degrees C (-4 degrees F) there is a layer of unfrozen water between the sand grains and the ice. These layers can support microbial life at least [down] to -15 degrees C (5 degrees F)," McKay explained.

"On Mars today the temperatures of the ground ice are much too cold for this effect to be useful," he wrote. But Mars wobbles. At present Mars is tilted on its axis at about the same angle as Earth's. Five million years ago, however, Mars leaned over at an angle of about 45 degrees , and for nearly half of each martian year (equivalent to about one Earth year), the polar regions received constant sunlight. Back then "the ground ice at the polar regions," like the site where NASA's Phoenix spacecraft landed in 2008, "would have been much warmer. We think it would have been in the range of -15 degrees C to -20 degrees C. So liquid water layers" in the past were "a possibility."

The question then is this: If life ever took hold on Mars, back when the planet was warmer and wetter, did a few hardy microbes evolve a survival strategy that let them go into a deep sleep, and then every 10 or 20 million years, when the ground warmed up to -20 degrees C or so, wake up and put on a little growth spurt?

The answer will have to wait until a follow-up mission to the martian polar regions can dig deeper than Phoenix did. It is just such deep polar drilling that McKay's IceBite project is working to make possible.

In the meantime, DiRuggiero will have no problem staying busy. There is still much left to learn about the dry limit of life, in both Antarctica and the Atacama.

Other Blogs... Other Spaceports. SAM heading for MARS.

Dr. Paul Mahaffy is the Principle Investigator for the SAM analysis suite on Mars Science Laboratory Rover (Curiosity). An important goal of upcoming missions to Mars is to understand if life could have developed there. The vehicle should land in 2012.

MORE AT SPACEPORTS

The task of the Sample Analysis at Mars (SAM) suite of instruments and the other Curiosity investigations is to move us steadily toward that goal with an assessment of the habitability of our neighboring planet through a series of chemical and geological measurements. SAM is designed to search for organic compounds and inorganic volatiles and measure isotope ratios.

http://spaceports.blogspot.com/2011/01/mars-rover-will-check-for-ingredients.html



Other instruments on Curiosity will provide elemental analysis and identify minerals. Dr. Mahaffy discusses how SAM will analyze both atmospheric samples and gases evolved from powdered rocks that may have formed billions of years ago with Curiosity providing access to interesting sites scouted by orbiting cameras and spectrometers.

Announcing that there are Space Aliens 'wouldn't faze modern world'

Astronomers are now able to detect planets orbiting stars other than the Sun where life may exist, and living generations could see the signatures of extra-terrestrial life being detected. Should it turn out that we are not alone in the Universe, it will fundamentally affect how humanity understands itself—and we need to be prepared for the consequences. A Discussion Meeting held at the Royal Society in London, 6–9 Carlton House Terrace, on 25–26 January 2010, addressed not only the scientific but also the societal agenda, with presentations covering a large diversity of topics.

Aliens 'wouldn't faze modern world'
http://rsta.royalsocietypublishing.org/content/current/
The comments are part of an extraterrestrial-themed edition of the Philosophical Transactions of the Royal Society A published today. In it, scientists examine all aspects of the search for extraterrestrial life, from astronomy and biology to the political and religious fallout that would result from alien contact.

Proof that intelligent life exists elsewhere in the universe is unlikely to upset modern Earthlings: times have changed dramatically since 1961 when the US Congress was warned that evidence of extra-terrestrials would lead to widespread panic, argued psychologist Dr Albert Harrison.
First contact with ET, or the discovery of ancient alien relics on Earth or Mars, would probably be met with delight or indifference today, he believes.

Dr Harrison, from the University of California at Davis, US, wrote in the journal Philosophical Transactions of the Royal Society: "The discovery of ETI (extra-terrestrial intelligence) may be far less startling for generations that have been brought up with word processors, electronic calculators, avatars and cell phones as compared with earlier generations used to typewriters, slide rules, pay phones and rag dolls."

People had been getting used to the idea of ET since the Seti (Search for Extra-Terrestrial Intelligence) project first began listening out for alien radio signals 50 years ago, said Dr Harrison.

Today, surveys suggest that half the population of the US and Europe believe extra-terrestrials exist, and a "substantial proportion" were convinced alien spacecraft had already visited the Earth.

As long ago as the 1840s a popular New York newspaper reported on the discovery of "batmen" on the Moon. Later it was widely accepted that astronomers had found evidence of canals built by a dying civilisation on Mars.

In the 1960s scientists suspected that quasars and pulsars, galaxies and stars that emit powerful bursts of energy, might be intelligently controlled, said Dr Harrison. And in 1996 the American space agency Nasa announced it had found fossil evidence of life on Mars, in the form of a meteorite containing alien bugs.

"Society has been unfazed by batmen on the Moon, the canals of Mars, discoveries of quasars and pulsars, claims that a fossil arrived from Mars, and bogus announcements of Seti detections," Dr Harrison wrote.

In North America and Europe at least, neither the discovery of an alien specimen nor the detection of a "dial tone at a distance" were likely to lead to "widespread psychological disintegration and collapse".

NASA announces "an astrobiology finding that will impact the search for evidence of extraterrestrial life"

BY FRED TASKER
ftasker@MiamiHerald.com

The NASA announcement created an enormous Internet buzz: The space agency was going to reveal Thursday ``an astrobiology finding that will impact the search for evidence of extraterrestrial life.''

Was the government about to say it had found liquid water on a moon of Jupiter? Microbes on Mars? Something even stranger -- say, ET?

Sci-fi bloggers speculated the announcement ``could prove the existence of aliens'' or ``the theory of shadow creatures that exist in tandem with our own.''

But then the announcement came and it was about . . . bacteria right here on Earth.

At a 2 p.m. news conference streamed live over the Web, scientists at the National Aeronautics and Space Administration said they found microbes in the mud beneath a California lake that can use arsenic -- usually considered toxic -- rather than phosphorus as one of the building blocks of its DNA. Phosphorus is one of the elements that sustains all other life forms on earth.

After their great anticipation, sci-fi fans were told the discovery might help cut pollution of waterways like Lake Okeechobee by replacing the phosphorus in fertilizers that run off into the lake, creating fish-choking algae blooms.

One of the NASA researchers acknowledged the frustration after the build-up: ``I can see you're disappointed, that some of you were expecting walking, talking aliens,'' said Felisa Wolfe-Simon, a NASA astrobiology researcher and co-author of the study.

``It would be incredible to announce that we have found an alien. But from our understanding of biology, this is a phenomenal finding. You're taking the fundamental building blocks of life and replacing one of them with another compound.''

She even tried to put a sci-fi spin on it: ``This is the equivalent of the Star Trek episode in which they found life forms on a distant planet that substituted silica for carbon in their basic makeup.

``Maybe we can find ET now because we have a better idea of what we're looking for.''

After the news conference, a University of Miami scientist good-naturedly speculated on what Thursday's announcement might mean for the shape of life on other planets.

``This is a pretty big deal,'' said Athula Wikramanayake, a UM expert in evolutionary biology. ``We've always believed that the basic elements needed for life are carbon, nitrogen, hydrogen, oxygen, sulfur and phosphorus,'' he said.

On a planet whose atmosphere is rich in arsenic, ``we wouldn't expect anything resembling humanoids. It's very unlikely they would look like humans.

Wikramanayake agreed with famed physicist Stephen Hawking, who in a newspaper interview in May pointed out that any aliens who arrive on earth from billions of miles away logically will be far more advanced than planet-bound earthlings.

``If aliens ever visit us,'' Hawking warned, ``I think the outcome would be much as when Columbus first landed in America -- which didn't turn out very well for the Native Americans.''

``It's possible,'' said Wikramanayake.

``Some planets are billions of years older than earth. They've had a lot of time to evolve.''

Does he agree such aliens would be hostile?

He left a ray of hope: ``It's hard to say whether they would be as aggressive as humans. Humans evolved because of tribal fighting. Aliens might not have the same social history.''



Read more:
http://www.miamiherald.com/2010/12/02/1954921/nasa-new-find-a-big-deal-really.html#ixzz173uPcPyq

Science fiction lovers aren’t the only ones captivated by the possibility of colonizing another planet. Scientists are engaging in numerous research projects that focus on determining how habitable other planets are for life. Mars, for example, is revealing more and more evidence that it probably once had liquid water on its surface, and could one day become a home away from home for humans






Can we grow crops on other planets?

Science fiction lovers aren’t the only ones captivated by the possibility of colonizing another planet. Scientists are engaging in numerous research projects that focus on determining how habitable other planets are for life. Mars, for example, is revealing more and more evidence that it probably once had liquid water on its surface, and could one day become a home away from home for humans.


“The spur of colonizing new lands is intrinsic in man,” said Giacomo Certini, a researcher at the Department of Plant, Soil and Environmental Science (DiPSA) at the University of Florence, Italy. “Hence expanding our horizon to other worlds must not be judged strange at all. Moving people and producing food there could be necessary in the future.”

Humans traveling to Mars, to visit or to colonize, will likely have to make use of resources on the planet rather than take everything they need with them on a spaceship. This means farming their own food on a planet that has a very different ecosystem than Earth’s. Certini and his colleague Riccardo Scalenghe from the University of Palermo, Italy, recently published a study in Planetary and Space Science that makes some encouraging claims. They say the surfaces of Venus, Mars and the Moon appear suitable for agriculture.

Defining Soil

Before deciding how planetary soils could be used, the two scientists had to first explore whether the surfaces of the planetary bodies can be defined as true soil.

“Apart from any philosophical consideration about this matter, definitely assessing that the surface of other planets is soil implies that it ‘behaves’ as a soil,” said Certini. “The knowledge we accumulated during more than a century of soil science on Earth is available to better investigate the history and the potential of the skin of our planetary neighbors.”

One of the first obstacles in examining planetary surfaces and their usefulness in space exploration is to develop a definition of soil, which has been a topic of much debate.

“The lack of a unique definition of ‘soil,’ universally accepted, exhaustive, and (one) that clearly states what is the boundary between soil and non-soil makes it difficult to decide what variables must be taken into account for determining if extraterrestrial surfaces are actually soils,” Certini said.


At the proceedings of the 19th World Congress of Soil Sciences held in Brisbane, Australia, in August, Donald Johnson and Diana Johnson suggested a “universal definition of soil.” They defined soil as “substrate at or near the surface of Earth and similar bodies altered by biological, chemical, and/or physical agents and processes.”

On Earth, five factors work together in the formation of soil: the parent rock, climate, topography, time and biota (or the organisms in a region such as its flora and fauna). It is this last factor that is still a subject of debate among scientists. A common, summarized definition for soil is a medium that enables plant growth. However, that definition implies that soil can only exist in the presence of biota. Certini argues that soil is material that holds information about its environmental history, and that the presence of life is not a necessity.

“Most scientists think that biota is necessary to produce soil,” Certini said. “Other scientists, me included, stress the fact that important parts of our own planet, such as the Dry Valleys of Antarctica or the Atacama Desert of Chile, have virtually life-free soils. They demonstrate that soil formation does not require biota.”

The researchers of this study contend that classifying a material as soil depends primarily on weathering. According to them, a soil is any weathered veneer of a planetary surface that retains information about its climatic and geochemical history.

On Venus, Mars and the Moon, weathering occurs in different ways. Venus has a dense atmosphere at a pressure that is 91 times the pressure found at sea level on Earth and composed mainly of carbon dioxide and sulphuric acid droplets with some small amounts of water and oxygen. The researchers predict that weathering on Venus could be caused by thermal process or corrosion carried out by the atmosphere, volcanic eruptions, impacts of large meteorites and wind erosion.

Mars is currently dominated by physical weathering caused by meteorite impacts and thermal variations rather than chemical processes. According to Certini, there is no active volcanism that affects the martian surface but the temperature difference between the two hemispheres causes strong winds. Certini also said that the reddish hue of the planet’s landscape, which is a result of rusting iron minerals, is indicative of chemical weathering in the past.

On the Moon, a layer of solid rock is covered by a layer of loose debris. The weathering processes seen on the Moon include changes created by meteorite impacts, deposition and chemical interactions caused by solar wind, which interacts with the surface directly.

Some scientists, however, feel that weathering alone isn’t enough and that the presence of life is an intrinsic part of any soil.

“The living component of soil is part of its unalienable nature, as is its ability to sustain plant life due to a combination of two major components: soil organic matter and plant nutrients,” said Ellen Graber, researcher at the Institute of Soil, Water and Environmental Sciences at The Volcani Center of Israel’s Agricultural Research Organization.

One of the primary uses of soil on another planet would be to use it for agriculture—to grow food and sustain any populations that may one day live on that planet. Some scientists, however, are questioning whether soil is really a necessary condition for space farming.

Soilless Farming – Not Science Fiction

Growing plants without any soil may conjure up images from a Star Trek movie, but it’s hardly science fiction. Aeroponics, as one soilless cultivation process is called, grows plants in an air or mist environment with no soil and very little water. Scientists have been experimenting with the method since the early 1940s, and aeroponics systems have been in use on a commercial basis since 1983.

“Who says that soil is a precondition for agriculture?” asked Graber. “There are two major preconditions for agriculture, the first being water and the second being plant nutrients. Modern agriculture makes extensive use of ‘soilless growing media,’ which can include many varied solid substrates.”

In 1997, NASA teamed up with AgriHouse and BioServe Space Technologies to design an experiment to test a soilless plant-growth system on board the Mir Space Station. NASA was particularly interested in this technology because of its low water requirement. Using this method to grow plants in space would reduce the amount of water that needs to be carried during a flight, which in turn decreases the payload. Aeroponically-grown crops also can be a source of oxygen and drinking water for space crews.

“I would suspect that if and when humankind reaches the stage of settling another planet or the Moon, the techniques for establishing soilless culture there will be well advanced,” Graber predicted.

Soil: A Key to the Past and the Future


The surface and soil of a planetary body holds important clues about its habitability, both in its past and in its future. For example, examining soil features have helped scientists show that early Mars was probably wetter and warmer than it is currently.

“Studying soils on our celestial neighbors means to individuate the sequence of environmental conditions that imposed the present characteristics to soils, thus helping reconstruct the general history of those bodies,” Certini said.

In 2008, NASA’s Phoenix Mars Lander performed the first wet chemistry experiment using martian soil. Scientists who analyzed the data said the Red Planet appears to have environments more appropriate for sustaining life than was expected, environments that could one day allow human visitors to grow crops.

“This is more evidence for water because salts are there,” said Phoenix co-investigator Sam Kounaves of Tufts University in a press release issued after the experiment. “We also found a reasonable number of nutrients, or chemicals needed by life as we know it.”

Researchers found traces of magnesium, sodium, potassium and chloride, and the data also revealed that the soil was alkaline, a finding that challenged a popular belief that the martian surface was acidic.

This type of information, obtained through soil analyses, becomes important in looking toward the future to determine which planet would be the best candidate for sustaining human colonies.


Source: Astrobio.net
http://www.astrobio.net/exclusive/3689/can-we-grow-crops-on-other-planets

Exploration Rover Spirit got stuck in a pile of red planet mud... where there is mud there might be life...

Scientist believe that they have found new evidence of life on mars after the Mars Exploration Rover Spirit got stuck in a pile of red planet mud. Scientists believe that the discovery shows that water formed on the planet more recently than previously thought.

The Telegraph reports that scientists believed previously that water formed on mars more than a billion years ago. But the new Mars mud has changed that thought, and now it is believed that water may have formed as recently as a few thousand years ago.

The Nasa team, who are based at Nasa’s Jet Propulsion Laboratory in Pasadena, California, said:

“On Earth … hydrothermal systems provide the environmental conditions, water, nutrients and energy sources


needed to sustain robust microbial communities. It seems likely the region (on Mars) … may have likewise supported a habitable environment.”

The Mars Exploration Rover Spirit got stuck last April. The rover broke through the surface crust of Mars, and got stuck in a soft sand below. The incident provided clues that Mars may still be wet.



Read The Full Story: Life on Mars? Rover Gets Stuck in Red Planet Mud

Researchers at the American space agency made the discovery after the Mars Exploration Rover Spirit became stuck in wet ground on the red planet earlier this year.

Astronomers have become excited by the latest discovery, which they say proves that water favourable for life formed on the red planet more recently than previously thought.

Nasa’s latest study, reported in the Journal of Geophysical Research, concluded the liquid likely formed from melting snow, which then trickled into the subsurface and dissolved.

It contained several minerals including hematite, silica and gypsum while ferric sulphates, which are more soluble, also were carried down by the water.

None of these minerals are exposed at the surface, which is covered by windblown sand and dust.

“On Earth … hydrothermal systems provide the environmental conditions, water, nutrients and energy sources needed to sustain robust microbial communities,” concluded the Nasa team, who are based at Nasa’s Jet Propulsion Laboratory, Pasadena, California.

“It seems likely the region (on Mars) … may have likewise supported a habitable environment.”

According to Nasa, the Mars explorer became stuck in April last year when its left wheels broke through the surface’s crust called “Troy” and fell into soft sand below.

The soil exposed by Spirit’s spinning wheels carries clues that Mars may still be wet.

The seepage could have happened during cyclical climate changes in periods when Mars tilted farther on its axis.

"Liquid water and life kind of go together," said Ray Arvidson, of Washington University in St. Louis, who was involved in the project.

Nasa abandoned plans to extract the rover earlier this year

First stop - moons of Mars

Planetary travel "within few years" Funded by DARPA, NASA

A SENIOR NASA official has promised to deliver a spaceship that will travel between alien worlds "within a few years".

Speaking at a conference in San Francisco on Saturday, NASA Ames director Simon Worden said his division had started a project with Defense Advanced Research Projects Agency called the "Hundred Year Starship”.

The project was kicked off recently with $1 million funding from DARPA and $100K from NASA and hopes to utilise new propulsion ideas being explored by NASA.

Star Trek fans, prepare to get excited - electric propulsion is here, according to Mr Worden.

“Anybody that watches the (Star Trek) Enterprise, you know you don’t see huge plumes of fire," he said.

"Within a few years we will see the first true prototype of a spaceship that will take us between worlds.”


“You heard it here,” he told the crowd at the “Long Conversation”.

“Twenty years ago you had to whisper that in dark bars and get fired.”

Mr Worden said he hoped to "inveigle some billionaires" such as Google founder Larry Page to help with further funding for the project.

Another possible source of propulsion being funded by NASA was by using microwave power from a planetary base to heat hydrogen propellants on board an orbiting spaceship.

"You don’t have to carry all the fuel," he said. "You use that energy from a laser or microwave power to heat a propellant; it gets you a pretty big factor of improvement. I think that’s one way of getting off the world.”

Mr Worden had an interesting take on how we would settle other worlds when we found them, suggesting it would be easier to adapt humans to an alien planet than changing the planet to suit humans.

“How do you live in another world? I don’t have the slightest idea,” he said.

“If you’re a conservative, you worry about it killing us; if you’re a liberal, you worry about us killing it."

Despite his ambitious vision to push further out into the galaxy, Mr Worden said there was still plenty of work to do in our own backyard first.

First stop, he said, was the moons of Mars, from where the planet itself can be explored using telerobotics.

“I think we’ll be on the moons of Mars by 2030 or so," he said.

"Larry (Page) asked me a couple weeks ago how much it would cost to send people one way to Mars and I told him $10 billion, and his response was, ‘Can you get it down to 1 or 2 billion?’

"So now we’re starting to get a little argument over the price.”



http://www.news.com.au/technology/nasa-preps-100-year-spaceship-programme-to-boldly-go-where-none-have-gone-before/story-e6frfro0-1225941547507#ixzz13D8IALAk