Could Martian Life Have Seeded the Earth?

The astronauts who blasted off from Kennedy Space Center in Florida aboard the final flight of the space shuttle Endeavour this morning weren't alone—thousands of travelers are accompanying them. These passengers are a collection of microorganisms, and this morning's launch was the beginning of a trip that could show the plausibility of an even more amazing journey: Microbes traveling from Mars to Earth billions of years ago to seed our planet with life.

For the collection of five hardy species—including the radiation-resistant "water bear" and Halomonadaceae bacteria, which can survive in high-salt environments—traveling to the International Space Station and back aboard Endeavour is the first leg of a long journey. Bruce Betts, a project director at the Planetary Society, is one of the scientists planning to send a similar set of organisms, plus a few additional species, all the way to a Martian moon as part of the Living Interplanetary Flight Experiment. The society has reserved a spot on the Russian Phobos-Grunt mission ("grunt" means soil in Russian), which is set to take off for Mars' moon Phobos this November. By practicing on Endeavour, the scientists will ensure that things run as smoothly as possible as the microorganisms make their way to Mars.

This trip is intended as a test of the transpermia hypothesis: that Mars may have held life billions of years ago, and that organisms could have survived the trip to Earth and seeded this planet with life. Those organisms may have invaded the Earth by traveling inside rocks that were blasted off the Martian surface by meteorites. "Whether you can populate planets from other planets is one of the more profound questions," Betts says. "It's intriguing, and it's worth understanding whether the theory is really plausible."

Wayne Nicholson, a microbiologist at the University of Florida, says that evidence so far suggests it's possible. Mars and Earth have exchanged millions of tons rocks, and that exchange has mostly been from Mars to Earth. Earthly microbes can live inside rock, and microbes launched into space (both by accident and for research purposes) have lived to tell the tale—they survive particularly well when sheltered within soil or rock. Laboratory tests show microbes can even survive the shock of crash-landing on a planet after traveling through space.

But, Nicholson says, no experiment has ever gone this far: "There has never been an experiment where organisms have been exposed to the deep space environment, between planets, for such a long period of time." While previous studies have launched microbes into space, sometimes inadvertently, he says that most of those samples never left low-Earth orbit. By remaining within the Earth's atmosphere and magnetic fields, those organisms were partially shielded from the damaging effects of cosmic radiation. The few missions that transported microbes beyond Earth orbit did so for only a few days at a time—a far cry from the years required for interplanetary travel.

The microorganisms' trip to Phobos and back will be a bit more complicated than the shuttle flight. Samples of each organism will enjoy the flight separately from inside sealed tubes. The tubes will be wrapped in a titanium shell that's about the size of a hockey puck, with four strong seals to prevent any contamination of Mars or its moons with Earthly life.

The microbes will ride inside the Russian spacecraft in a dormant form—the excruciating conditions of interplanetary space causes the microorganisms to shut down most of their functions, as during hibernation. And although they won't be directly exposed to the space vacuum, they will suffer high levels of radiation exposure and temperature extremes on their three-year journey. According to the Planetary Society, these conditions will simulate the conditions the microorganisms would encounter if they were traveling toward Earth inside a rock that came from Mars.

The Phobos-Grunt mission's main goal is to collect soil and rock samples. Once that's done, it will blast its sample container (including the microorganisms and the rock samples) to a designated landing spot in Kazakhstan. Since the experiment will come hurtling back to Earth at 4000 g's, the titanium container is built to be nearly indestructible.

If the microbes survive their trip to Mars and back, it won't mean for sure that Earthly organisms are descended from Martians—but it does leave that possibility open. "However it turns out, it is going to be interesting," Nicholson says.



Read more: - Space Shuttle Endeavour Final Flight - Popular Mechanics http://www.popularmechanics.com/science/space/moon-mars/could-martian-life-have-seeded-the-earth

Life on Mars has been the subject of much debate and speculation that has gripped our minds since we gazed upon the stars.

Many years ago, the discovery of ice in the red planet offered some clues as to whether it once had water and was able to support life sometime in the distant past.

NASA scientists recently discovered an underground dry ice lake containing more carbon dioxide than originally thought. The trapped carbon dioxide is thought to have come from the planet’s atmosphere earlier in its history when it was conducive for life on Mars to exist.

“It really is a buried treasure,” said Jeffrey Plaut, a scientist of the NASA Jet Propulsion Laboratory, in a report appearing in the journal Science. “We found something underground that no one else realized was there.”

The discovery was made possible through ground-penetrating radar of the Mars Reconnaissance Orbiter who is searching for clues of life on Mars.

Dry ice on Mars is not a new discovery, but the recent finding suggests that what is locked down there is about 30 times more than originally thought.

Scientists have often wondered where atmospheric gases capable of supporting life on Mars went and resulted to the present thin atmosphere of the planet. They speculate that some gases became trapped in dry ice as part of a seasonal cycle.

Still, even the enormous amounts of dry ice discovered will not be able recreate an atmosphere thick enough to support life on Mars, the scientists said.

The polar ice caps as well as existing canyons, gullies and river channels who have carved the surface of the planet are the other possible signs of past life on Mars.

A Tale Of Two Deserts on Earth that are Mars like

.
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