feen5 said:Your right we could be fooled by our own contamination, and bacteria has been found to survive trips to space. Bacteria on lenses of cameras on the moon landing space craft were revived after their trip. I believe though that the probes sent to detect life especially on mars are not looking for actual organisms more for signs of the existance of life (such as methane in a planets atmosphere can be an indication of life). I doubt if even bacteria from the very early space probes could produce enough evidence to contaminate any findings though you would never know.
It is a big problem in particular with the planned mission to Europa. Because if, as it is believed, that a liquid ocean exists under the ice a machine to drill into through the crust could unwittingly take earthly organisms into the ocean and harm anytjing that maybe living there. I think that the russians found a lake in Antartica that has been completely cut off from the outside world for millions of years and they also have to plan very carefully for any probe that maybe used to research this lake. I will have a look around for some more information on this and post some links when i have a chance.
A large and previously unknown reservoir of water ice may have been found below the surface of Mars, new radar observations suggest.
Gaping canyons and river-like channels attest to the fact that large amounts of water once flowed on Mars. But today most of that water has disappeared, and finding out where it went is one of the main aims of research on the Red Planet.
Scientists are using the radar antenna onboard Europe's Mars Express spacecraft as a divining rod to scout for any water that may have seeped underground.
MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) works by sending out pulses of radio waves from its main, 40-metre-long antenna and analysing the time delay and strength of the signals that bounce back. Radio waves that penetrate the surface rebound when they encounter a subsurface boundary between materials with different electrical properties – such as rock and water.
The antenna was deployed in June 2005 and quickly detected what appeared to be water ice stretching 1.8 kilometres below the surface of the northern polar ice cap. Now, it has found what looks like water ice extending as deep as 3.5 kilometres below the southern polar cap.
Water ice was expected in the polar caps, since they represent the largest known reservoirs of water on Mars. Estimates suggest that if they melted, they would cover the planet in a layer of water up to 33 metres deep.
But as it scanned the region around the south pole, MARSIS also turned up an unexpected ice source. It lies near the southern polar cap and is underneath a region of Martian surface that shows no visible signs of ice. The radar signals reveal what appear to be relatively thin layers of underground water ice – layers that may contain water of a equivalent to half of that locked up in the entire southern polar cap.
"If we can confirm the thinner layers are, in fact, ice rich, we've put our finger on another reservoir of water that is significant in the global water matrix," says MARSIS co-leader Jeff Plaut of NASA's Jet Propulsion Laboratory in Pasadena, California, US. He presented the new data at the Lunar and Planetary Science Conference (LPSC) in Houston, Texas, on Monday.
He says the interpretation of the radar boundaries as layers of ice is bolstered by the fact that they are so near the confirmed ice in the polar cap, but he cautions that the signals could simply be layers of dust.
If they are actually water ice, they may shed light on the planet's past climate. The polar ice caps themselves are made of icy layers that researchers believe were laid down as snow during periodic swings in the planet's tilt – and therefore its climate – every 50,000 years. Plaut says studying the shape and thickness of the layers could reveal more about the nature of these climatic shifts.
And MARSIS is already rewriting how researchers interpret Martian history. It has revealed about 10 buried impact craters – some as wide as 470 kilometres – in the planet's northern lowlands. Only one of these craters is visibly detectable on the planet's surface.
That is important because researchers date Martian surfaces by counting the number of craters embedded within them. The planet's northern lowlands show relatively few craters, while the southern highlands are pockmarked by impacts. That had long suggested that the northern lowlands had been resurfaced by lava and were thus younger than the southern highlands.
But recent orbital observations with a laser altimeter have challenged this conclusion. The altimeter revealed some craters whose rims had eroded so much that they were undetectable by sight, suggesting these surfaces were actually older than they appeared.
The new MARSIS data further supports this idea, says Thomas Watters at the National Air and Space Museum in Washington DC, US, who led the team that discovered the buried craters. "It suggests there is only a small age difference between the highlands' and lowlands' crust," he said at the LPSC meeting.
http://www.newscientistspace.com/articl ... -mars.html
New Analysis of Viking Mission Results Indicates Presence of Life on Mars
We may already have ‘met’ Martian organisms, according to a paper presented Sunday (Jan. 7) at the meeting of the American Astronomical Society in Seattle.
Dirk Schulze-Makuch of Washington State University and Joop Houtkooper of Justus-Liebig-University, Giessen, Germany, argue that even as new missions to Mars seek evidence that the planet might once have supported life, we already have data showing that life exists there now—data from experiments done by the Viking Mars landers in the late 1970s.
“I think the Viking results have been a little bit neglected in the last 10 years or more,” said Schulze-Makuch. “But actually, we got a lot of data there.” He said recent findings about Earth organisms that live in extreme environments and improvements in our understanding of conditions on Mars give astrobiologists new ways of looking at the 30-year-old data.
The researchers hypothesize that Mars is home to microbe-like organisms that use a mixture of water and hydrogen peroxide as their internal fluid. Such a mixture would provide at least three clear benefits to organisms in the cold, dry Martian environment, said Schulze-Makuch. Its freezing point is as low as -56.5o C (depending on the concentration of H2O2); below that temperature it becomes firm but does not form cell-destroying crystals, as water ice does; and H2O2 is hygroscopic, which means it attracts water vapor from the atmosphere—a valuable trait on a planet where liquid water is rare.
Schulze-Makuch said that despite hydrogen peroxide’s reputation as a powerful disinfectant, the fluid is also compatible with biological processes if it is accompanied by stabilizing compounds that protect cells from its harmful effects. It performs useful functions inside cells of many terrestrial organisms, including mammals. Some soil microbes tolerate high levels of H2O2 in their surroundings, and the species Acetobacter peroxidans uses hydrogen peroxide in its metabolism.
Possibly the most vivid use of hydrogen peroxide by an Earth organism is performed by the bombardier beetle (Brachinus), which produces a solution of 25 percent hydrogen peroxide in water as a defensive spray. The noxious liquid shoots from a special chamber at the beetle’s rear end when the beetle is threatened.
He said scientists working on the Viking projects weren’t looking for organisms that rely on hydrogen peroxide, because at the time nobody was aware that such organisms could exist. The study of extremophiles, organisms that thrive in conditions of extreme temperatures or chemical environments, has just taken off since the 90s, well after the Viking experiments were conducted.
The researchers argue that hydrogen peroxide-containing organisms could have produced almost all of the results observed in the Viking experiments.
• Hydrogen peroxide is a powerful oxidant. When released from dying cells, it would sharply lower the amount of organic material in their surroundings. This would help explain why Viking’s gas chromatograph-mass spectrometer detected no organic compounds on the surface of Mars. This result has also been questioned recently by Rafael Navarro-Gonzalez of the University of Mexico, who reported that similar instruments and methodology are unable to detect organic compounds in places on Earth, such as Antarctic dry valleys, where we know soil microorganisms exist.
• The Labeled Release experiment, in which samples of Martian soil (and putative soil organisms) were exposed to water and a nutrient source including radiolabeled carbon, showed rapid production of radiolabeled CO2 which then leveled off. Schulze-Makuch said the initial increase could have been due to metabolism by hydrogen peroxide-containing organisms, and the leveling off could have been due to the organisms dying from exposure to the experimental conditions. He said that point has been argued for years by Gilbert Levin, who was a primary investigator on the original Viking team. The new hypothesis explains why the experimental conditions would have been fatal: microbes using a water-hydrogen peroxide mixture would either “drown” or burst due to water absorption, if suddenly exposed to liquid water.
• The possibility that the tests killed the organisms they were looking for is also consistent with the results of the Pyrolytic Release experiment, in which radiolabeled CO2 was converted to organic compounds by samples of Martian soil. Of the seven tests done, three showed significant production of organic substances and one showed much higher production. The variation could simply be due to patchy distribution of microbes, said Schulze-Makuch. Perhaps most interesting was that the sample with the lowest production—lower even than the control—had been treated with liquid water.
The researchers acknowledge that their hypothesis requires further exploration. “We can be absolutely wrong, and there might not be organisms like that at all,” said Schulze-Makuch. “But it’s a consistent explanation that would explain the Viking results.”
He said the Phoenix mission to Mars, which is scheduled for launch in August, 2007, offers a good chance to further explore their hypothesis. Although the mission’s experiments were not designed with peroxide -containing organisms in mind, Phoenix will land in a sub-polar area, whose low temperatures and relatively high atmospheric water vapor (from the nearby polar ice caps) should provide better growing conditions for such microbes than the more “tropical” region visited by Viking. Schulze-Makuch said the tests planned for the mission, including the use of two microscopes to examine samples at high magnification, could reveal whether we had the answer all along—and if we’ve already introduced ourselves to our Martian neighbors in a harsher way than we intended.
“If the hypothesis is true, it would mean that we killed the Martian microbes during our first extraterrestrial contact, by drowning—due to ignorance,” said Schulze-Makuch.
Source: Washington State University
Sensor Being Developed To Check For Life On Mars
ExoMars is planned as a rover to be launched in 2013 and search on Mars for signs of life. Samples of Martian soil collected by a drill on the rover will be delivered to the Urey instrument. The instrument component called the sub-critical water extractor adds water and heats the sample, getting different types of organic compounds to dissolve into the water at different temperatures. The Mars organic detector uses a fluorescent reagent and laser to detect organic chemicals. The micro-capillary electrophoresis component separates different types of organic chemicals from each others for identifying which ones are present in the sample. The Mars oxidant instrument, part of which is on a separately mounted deck unit not pictured, assesses how readily organic material would be broken down by the radiation, atmosphere and soil chemistry of the site.
Mars News and Information at MarsDaily.com
Pasadena CA (JPL) Feb 27, 2007
NASA-funded researchers are refining a tool that could not only check for the faintest traces of life's molecular building blocks on Mars, but could also determine whether they have been produced by anything alive.
The instrument, called Urey: Mars Organic and Oxidant Detector, has already shown its capabilities in one of the most barren climes on Earth, the Atacama Desert in Chile. The European Space Agency has chosen this tool from the United States as part of the science payload for the ExoMars rover planned for launch in 2013. Last month, NASA selected Urey for an instrument-development investment of $750,000.
The European Space Agency plans for the ExoMars rover to grind samples of Martian soil to fine powder and deliver them to a suite of analytical instruments, including Urey, that will search for signs of life. Each sample will be a spoonful of material dug from underground by a robotic drill.
"Urey will be able to detect key molecules associated with life at a sensitivity roughly a million times greater than previous instrumentation," said Dr. Jeffrey Bada of Scripps Institution of Oceanography at the University of California, San Diego. Bada is the principal investigator for an international team of scientists and engineers working on various components of the device.
To aid in interpreting that information, part of the tool would assess how rapidly the environmental conditions on Mars erase those molecular clues.
Dr. Pascale Ehrenfreund of the University of Leiden in the Netherlands, said, "The main objective of ExoMars is to search for life. Urey will be a key instrument for that because it is the one with the highest sensitivity for organic chemicals." Ehrenfreund, one of two deputy principal investigators for Urey, coordinates efforts of team members from five other European countries.
Urey can detect several types of organic molecules, such as amino acids, at concentrations as low as a few parts per trillion.
All life on Earth assembles chains of amino acids to make proteins. However, amino acids can be made either by a living organism or by non-biological means. This means it is possible that Mars has amino acids and other chemical precursors of life but has never had life.
To distinguish between that situation and evidence for past or present life on Mars, the Urey instrument team will make use of the knowledge that most types of amino acids can exist in two different forms. One form is referred to as "left-handed" and the other as "right-handed." Just as the right hand on a human mirrors the left, these two forms of an amino acid mirror each other.
Amino acids from a non-biological source come in a roughly 50-50 mix of right-handed and left-handed forms. Life on Earth, from the simplest microbes to the largest plants and animals, makes and uses only left-handed amino acids, with rare exceptions.
Comparable uniformity -- either all left or all right -- is expected in any extraterrestrial life using building blocks that have mirror-image versions because a mixture would complicate biochemistry.
"The Urey instrument will be able to distinguish between left-handed amino acids and right-handed ones," said Allen Farrington, Urey project manager at NASA's Jet Propulsion Laboratory, which will build the instrument to be sent to Mars.
If Urey were to find an even mix of the mirror-image molecules on Mars, that would suggest life as we know it never began there. All-left or all-right would be strong evidence that life now exists on Mars, with all-right dramatically implying an origin separate from Earth life.
Something between 50-50 and uniformity could result if Martian life once existed, because amino acids created biologically gradually change toward an even mixture in the absence of life.
The 1976 NASA Viking mission discovered that strongly oxidizing conditions at the Martian surface complicate experiments to search for life. The Urey instrument has a component, called the Mars oxidant instrument, for examining those conditions.
The oxidant instrument has microsensors coated with various chemical films. "By measuring the reaction of the sensor films with chemicals present in the Martian soil and atmosphere, we can establish if organisms could survive and if evidence of past life would be preserved," said Dr. Richard Quinn, a co-investigator on Urey from the SETI Institute, Mountain View, Calif., who also works at NASA Ames Research Center, Moffett Field, Calif.
"In order to improve our chances of finding chemical evidence of life on Mars, and designing human habitats and other equipment that will function well on Mars' surface, we need to improve our understanding of oxidants in the planet's surface environment," said Dr. Aaron Zent, a Urey co-investigator at NASA Ames.
A Urey component called the sub-critical water extractor handles the task of getting any organic compounds out of each powdered sample the ExoMars rover delivers to the instrument.
"It's like an espresso maker," explained JPL's Dr. Frank Grunthaner, a deputy principal investigator for Urey. "We bring the water with us. It is added to the sample, and different types of organic compounds dissolve into the liquid as the temperature increases. We keep it under pressure the whole time."
The dissolved compounds are highly concentrated by stripping away water in a tiny oven. Then a detector checks for fluorescent glowing, which would indicate the presence of amino acids, some components of DNA and RNA, or other organic compounds that bind to a fluorescing chemical added by the instrument.
A Urey component called the micro-capillary electrophoresis unit has the critical job of separating different types of organic compounds from one another for identification, including separation of mirror-image amino acids from each other.
"We have essentially put a laboratory onto a single wafer," said Dr. Richard Mathies of the University of California, Berkeley, a Urey co-investigator. The device for sending to Mars will be a small version incorporating this detection technology, which is already in use for biomedical procedures such as law-enforcement DNA tests and checking for hazardous microbes.
Switzerland will provide electronics design and packaging expertise for Urey. Micro-Cameras and Space Exploration S.A., Neuchatel, will collaborate with JPL and the European Space Agency to accomplish this significant contribution to the heart of the instrument. Dr. Jean-Luc Josset, Urey co-investigator at the University of Neuchatel will coordinate this effort and help provide detector selection and support. JPL is a division of the California Institute of Technology in Pasadena.
www.marsdaily.com/reports/Sensor_Being_ ... s_999.html
Tuesday, March 20, 2007
Is There Life on Mars?
A sensitive chemical detector will look for signs of life on Mars and perform reconnaissance for future manned missions.
By Katherine Bourzac
In 2013, a chemical detector called Urey will travel to Mars with the European Space Agency's ExoMars mission. Developed by researchers at NASA, the University of California, San Diego, and the University of California, Berkeley, Urey will search for chemical evidence of past or present life in the form of protein building blocks called amino acids. Urey, which will travel on a solar-powered rover, will also assess how long organic compounds can survive on the planet's harsh, dusty surface.
The two things necessary for life as we know it are water and organic compounds like amino acids and the nucleic acids in DNA and RNA. "We now have clear evidence that there was, and still is, water on Mars," says Jeffrey Bada, principal investigator on the Urey project. A recent study in the journal Science demonstrated that if the water on Mars's south pole melted, it would cover the entire planet to a depth of 36 feet. If there are also organic compounds on Mars, says Bada, it's possible that some form of life has existed or continues to exist on the planet.
So far no evidence of organic compounds on Mars has been found. The 1976 Viking missions tested for them using mass spectrometry. But, Bada says, "in that mission, they only scratched the surface of Mars." Viking's two landers probed 10 centimeters below the planet's surface. Bada, a professor of marine chemistry at the University of California, San Diego, says researchers now believe that intense radiation and oxidizing conditions on the Martian surface would have destroyed any evidence of organic compounds at this depth.
A drill on the ExoMars rover will penetrate two meters into the planet and bring up samples for analysis. Urey processes samples as an espresso machine processes coffee grounds: using high-temperature, high-pressure water brought from Earth. The resulting concentrated brew is heated in an oven to evaporate the water, leaving behind a residue of potential organic compounds. The residue is heated under tremendous pressure until it vaporizes, then is passed over a "cool finger"--a cold rod covered with fluorescent tags. Any organic compounds present condense onto the tags and are detected by a laser.
Urey then strips the tagged organic compounds from the cool finger and puts them into solution. The solution is run through a tiny channel. An electrical field applied across the channel then causes the compounds to separate according to their molecular mass. After the compounds separate, the position of each tagged compound is read using laser light and sent to remote researchers on Earth who can use this information to identify the compounds.
Urey's main target is amino acids, which come in two forms: left-handed and right-handed. Like human hands, the two are mirror images of each other. When researchers make amino acids from raw ingredients like water and ammonia in the lab, a 50-50 distribution of left and right results. But life on Earth makes and uses only left-handed amino acids. There's no particular reason for this, says Bada, but it is a defining characteristic of Earth life. "The selection of handedness is a matter of chance," he says.
A 50-50 mix of the two forms of amino acids on Mars would suggest that although the planet meets the necessary conditions, there is not currently life on Mars, says Allen Farrington, Urey project manager at NASA's Jet Propulsion Laboratory, in Pasadena, CA. A strong deviation from a 50-50 mix, however, would be evidence of current or recently extinct life on Mars. Bada says the most unambiguous result would be the discovery of a preponderance of right-handed amino acids. This would suggest the presence of life on Mars completely independent of life on Earth. A preponderance of left-handed amino acids would be more mysterious. It could mean that life on Mars also selected the left-handed form by chance. "Or it could imply either that we're Martians or that the Martian bugs are from Earth," says Bada. The two planets swap meteorites--and it's possible that past Mars missions have contaminated the planet with Earth microbes.
Urey will also test how long organic compounds can persist on the Martian surface. President Bush has declared manned missions to Mars a long-term goal. But before human beings or more robots are sent to the planet, it's crucial to have a better understanding of the Martian environment, says Bada. "If the oxidants on Mars are so potent that [organic compounds] get immediately destroyed, astronauts would have to be in a sheltered environment all the time," he says. "Space suits would immediately fall apart."
Passive sensors on the ExoMars rover's deck will test how corrosive the Martian environment is. As an array of about 45 postage-stamp-size thin films of organic compounds, which have been coated on cells on a plate, degrade, the electrical potential across the cells will change measurably. Researchers on Earth will track the degradation in real time: slower degradation means more-hospitable conditions.
Urey prototypes have uncovered organic compounds in the deserts of California and Peru. Technicians at the Jet Propulsion Laboratory are building a sterile, space-worthy iteration of the detector. ExoMars is currently scheduled to launch in 2013. The orbiter will take a two-and-a-half-year route to the planet; after landing, the rover carrying Urey will explore the planet's surface for about 180 days.
Lodestones, not life
Dec 13th 2007
From The Economist print edition
No sign of aliens after all
FOR a dull lump of greyish rock, ALH 84001 has had an eventful life. The meteorite, which was retrieved from the Allan Hills of Antarctica in 1984, is certainly well travelled. Experts in the field think it came from Mars, having been blasted off the surface of that planet by a collision with an even bigger meteorite. More than that, it contains minerals that some researchers believed, in a flurry of publicity when the rock was properly examined just over a decade ago, must have been made by living things on the Martian surface. The number constituting “some” has been dwindling since then, but there are still a few hold-outs who think ALH 84001 is indeed the first evidence of extraterrestrial aliens—albeit of bacterial dimensions.
The reason why ALH 84001 is so interesting is that it contains organic compounds. Life is thought to have emerged on Earth from a primordial soup of such compounds, which are based on carbon, hydrogen and oxygen, though just how it did so is obscure. When ALH 84001 was analysed, however, some astrobiologists suggested that the conventional explanation might be wrong. Perhaps life had evolved on Mars first and the red planet had then “seeded” its blue neighbour when rocky projectiles similar to ALH 84001 were blasted off its surface in abundance in an era when the solar system had a lot of loose asteroids flying around.
To test these claims, a group of researchers led by Andrew Steele of the Carnegie Institution in Washington, DC, decided to identify precisely what ALH 84001 contains and then compare the results with those from rocks that definitely formed on Earth. Using a number of different techniques, they discovered that the tiny spheres of carbonate minerals within the meteorite which had caused such a stir were surrounded by an iron-oxide mineral called magnetite.
Some true believers had seen the presence of magnetite in the meteorite as evidence supporting their cause. That was because certain earthly bacteria make small grains of the mineral, in order to navigate their habitats using the Earth's magnetic field, much as human navigators once used lodestone compasses made of magnetite to find their way around. However, most of the magnetite on Earth is not bacterial. Instead, it was ejected in liquid form from volcanoes. If this magnetite cools in an environment rich in water and carbon dioxide (which terrestrial volcanoes usually are), it can act as a catalyst for the formation of organic compounds from the carbon, hydrogen and oxygen atoms in those two raw ingredients.
Dr Steele and his colleagues thus decided to compare ALH 84001 with volcanic rocks collected in Svalbard, the northernmost territory of Norway. These rocks are thought to have formed when volcanoes erupted in freezing, pristine conditions a million years or so ago.
The researchers found that the earthly boulders, too, contained carbonates encircled by magnetite. Writing in a forthcoming issue of Meteoritics and Planetary Science, they conclude that the organic material in ALH 84001 was made not by Martian microbes but, rather, by chemical reactions within the rock.
Such a conclusion may be disappointing to astrobiologists, who seek to study life on other planets, so far without success. But it also offers them hope. If Dr Steele and his colleagues are correct, then volcanic activity in a place other than Earth has produce interesting-looking organic compounds. That means the building blocks of life could form on cold, rocky volcanic planets throughout the universe. And the universe is a very big place.
http://www.economist.com/science/displa ... d=10283348
Rock Varnish: A Promising Habitat For Martian Bacteria
www.marsdaily.com/reports/Rock_Varnish_ ... a_999.html
by Staff Writers
Tucson AZ (SPX) Dec 19, 2008
As scientists search for life on Mars, they should take a close look at rock varnish, according to a paper in the current issue of the "Journal of Geophysical Research."
The paper describes how a research team led by Kimberly R. Kuhlman, of the Tucson-based Planetary Science Institute, found bacteria associated with rock varnish in an area where the surrounding soils were essentially devoid of life.
The study suggests that rock varnish could provide a niche habitat for microbial life on Mars and in other extraterrestrial environments devoid of liquid water.
Rock varnish is an extremely slow-growing coating that forms on the surfaces of rocks in arid and semiarid climates. In Southwestern deserts, it often appears as a tough, dark stain on light-colored canyon walls. Ancient petroglyphs are often found etched into rock varnishes.
Kuhlman's team analyzed samples of rock varnish collected from the Yungay region of Chile's Atacama Desert, which is the closest analog to Martian environments found on Earth.
The bacteria apparently get most if not all of their moisture from fog, said Kuhlman, who lives in Madison, Wis.
The bacteria also are aerobic. So if Martian forms exist, they would have adapted to survive their planet's low-oxygen atmosphere, she added.
Rock varnish, which consists of clay glued together with iron and manganese oxides, forms very slowly and is very thin. It adds only 1 to 40 nanometers in thickness per year, and tends to be no more than 500 millimeters thick, regardless of age.
Similar rock coatings may exist on Mars because photos returned by every Martian lander show what looks like rock varnish coating the rocky surfaces. However, Kuhlman cautions that these coatings might not actually be rock varnish.
"A number of different coatings, like silica, can masquerade as rock varnish," Kuhlman observed. "So you can't really identify it for sure until you crack it open and look at a cross section under the microscope."
If it is rock varnish, it could provide bacteria with the same benefit it does on Earth - protection form ultraviolet radiation.
Whether the bacteria help create the varnish that protects them isn't known. Some believe bacteria are involved in its formation, while others think it's abiotic. Actually, both scenarios could be true, Kuhlman said.
Rock varnish could consist of layers formed by entirely different processes, depending on the prevailing environmental conditions at the time.
Since many bacteria cannot be cultivated in the lab, Kuhlman's team used culture-independent methods to identify many of the species found in the Atacama varnish.
They looked for adenosine triphosphate, a molecule that provides energy for cells that is found in all living things on Earth, and they also identified DNA from 32 species. In addition, they were able to produce live cultures of other bacteria.
Many species were related to bacteria found in the air or water, suggesting that their ancestors may have been carried into the area during wetter periods and then evolved in the varnish niche as conditions changed. A similar scenario might have played out on Mars, with varnish bacteria surviving from the planet's wetter eras.
Now Kuhlman would like to discover exactly where the bacteria live. No one knows if they are found on the surface, in the middle, at the bottom or between the varnish and the rock.
Similarly, scientists don't yet know if the bacteria are simply using the varnish for sunscreen or if they exist as a community within the varnish.
The ultra-thin varnish coatings have made it difficult to answer these questions, but Kuhlman hopes to secure research grants to pursue these problems and to give planetary scientists a better understanding of how to pursue the search for Martian bacteria.
Those working with Kuhlman on the Atacama rock-varnish project include Parth Venkat, of the Planetary Science Institute; Myron T. La Duck, of the California Institute of Technology; Gregory M. Kuhlman, of the University of Wisconsin; and Christopher P. McKay, of the NASA Ames Research Center.
Britain’s top space expert Nick Pope last night hailed the new evidence of life as “the most important discovery of all time”.
First liquid water may have been spotted on Mars
www.newscientist.com/article/dn16620-fi ... -mars.html
by David Shiga
NASA's Phoenix lander may have captured the first images of liquid water on Mars - droplets that apparently splashed onto the spacecraft's leg during landing, according to some members of the Phoenix team.
The controversial observation could be explained by the mission's previous discovery of perchlorate salts in the soil, since the salts can keep water liquid at sub-zero temperatures. Researchers say this antifreeze effect makes it possible for liquid water to be widespread just below the surface of Mars, but point out that even if it is there, it may be too salty to support life as we know it.
A few days after Phoenix landed on 25 May 2008, it sent back an image showing mysterious splotches of material attached to one of its legs. Strangely, the splotches grew in size over the next few weeks, and Phoenix scientists have been debating the origin of the objects ever since.
One intriguing possibility is that they were droplets of salty water that grew by absorbing water vapour from the atmosphere. Arguments for this idea are laid out in a study by Phoenix team member Nilton Renno of the University of Michigan in Ann Arbor, and co-authored by 21 other researchers, including the mission's chief scientist, Peter Smith of the University of Arizona in Tucson. The study (pdf) will be presented in March at the Lunar and Planetary Science Conference in Houston, Texas.
Gaping canyons and river-like channels attest to the fact that large amounts of liquid water once flowed on Mars. The surface now appears dry, though the changing appearance of some crater gullies over a period of several years has hinted at the existence of subsurface aquifers that occasionally release bursts of water.
Certainly, at Phoenix's landing site in the Martian arctic, it is too cold for pure water to exist in liquid form - the temperature never rose above -20° C during the five-month-long mission.
But salty water can stay liquid at much lower temperatures. And perchlorate salts, which were detected for the first time on Mars by Phoenix, would have an especially dramatic 'antifreeze' effect. An extremely salty mixture of water and perchlorates could stay liquid all the way down to -70° C.
If perchlorates are widespread on Mars at high concentrations, then pockets of liquid water might also be widespread below the planet's surface. "According to my calculations, you can have liquid saline solutions just below the surface almost anywhere on Mars," Renno told New Scientist.
And Phoenix may have already snapped images of water kept liquid thanks to perchlorate salts.
The clumps may have come from ice melted by the lander's thrusters. Phoenix's thrusters cleared away the topsoil at the landing site, exposing an ice layer below.
Laboratory experiments the team carried out on Earth suggest the thrusters would have melted the top millimetre or so of this layer and then could have splashed the melted water onto the lander's leg. If enough perchlorate was mixed into the droplets, they could have stayed liquid during the daytime, though they may have frozen each night.
Alternatively, Renno says the clumps may have come from a thin layer of perchlorate-rich water that was already liquid.
Why does the team think the clumps might be liquid water in the first place? The argument rests on the fact that salt is hygroscopic, meaning it attracts water. So droplets of salty fluid on Mars would tend to absorb water vapour from the atmosphere, explaining why the clumps grew over time. Indeed, at the temperatures and humidity observed at the Phoenix site, the expected growth rate of salty droplets matches the observations, the team says.
Most provocatively, a series of images (pictured here) appears to show one candidate droplet growing after absorbing the liquid from its neighbour - a behaviour the team ascribes to liquid water.
Mark Bullock of the Southwest Research Institute in Boulder, Colorado, who has experimented with salty water under Martian conditions but was not involved in Renno's study, is impressed with the results. "I think it makes a pretty convincing story for the existence of exotic brines on the Phoenix lander leg," he told New Scientist.
But Phoenix team member Michael Hecht of NASA's Jet Propulsion Laboratory in Pasadena, California, disagrees. He says the clumps were probably patches of ice that formed and grew from water vapour freezing onto the leg.
Renno counters that ice would be more likely to sublimate than grow on the leg, which would have been warmed by heat leaking from the spacecraft's body. Indeed, the layer of ice exposed beneath Phoenix was observed to vaporise over time.
But Hecht argues that the leg may have been colder than its surroundings. Though there were no temperature sensors on the leg, he says the surface of the ice patch was warmed by direct sunlight, whereas the lander leg was in shadow. Water vapour that sublimated from the ice below Phoenix might have recondensed as ice on its cold leg, he argues.
Too salty for life?
Phoenix, which ran out of solar power five months after landing, is not expected to wake up again, so there is no way to further investigate the bumps on its leg. But Renno hopes to bolster the case for salty droplets with future experiments on perchlorate-rich water under Mars-like conditions. He says those tests should be completed in a few months.
Regardless of their outcome, the discovery of perchlorates in the Martian soil suggests that pockets of liquid water may dot the planet. Could life eke out an existence in such pockets? "It's possible," Renno says, pointing out that there are microorganisms on Earth that can survive extreme conditions, including very salty water.
But it may be difficult. One way to describe salt concentrations is with a number called the water activity, which is 1 for pure water, and smaller for saltier solutions. The most salt-tolerant organism known on Earth is a fungus that can survive down to a water activity of 0.61.
However, to lower water's freezing point all the way down to -70 °C with perchlorates, the necesssary concentration of perchlorate salts would give a water activity of just 0.5. "If you tried to put any kind of life-form you can imagine on Earth in a brine solution of that sort, the water would be sucked out of the cells," mission leader Peter Smith told New Scientist.
More on that story, here:ramonmercado said:First liquid water may have been spotted on Mars
www.newscientist.com/article/dn16620-fi ... -mars.html
by David Shiga
Life on Mars?
BBC Blogs. Tom Feilden. Wed 18 Mar 09
Take a good look at these pictures.
It could be you're looking at the first evidence that liquid water is present on the surface of Mars. If that's right then life - at least in bacterial form - could well be there too.
The images come from the Phoenix Lander, and appear to show liquid droplets scattered along one of its supporting struts. But what's got Dr Nilton Renno, who's a co-investigator on the Phoenix Mission and professor of Astronomy at the University of Michigan, so excited is the way the droplets seem to run in rivulets through the sequence of pictures.
He's convinced the liquid is forming a droplet, and that the reason it suddenly vanishes is because it has dropped back to the surface. It adds up to overwhelming evidence, Dr Renno believes, that water exists in liquid form in the surface layers of the Martian soil.
Others are not so sure. Dr Michael Hecht from NASA's Jet Propulsion Laboratory says there are other simpler explanations for the bumps and blobs on the Phoenix's struts. And he says Dr Renno's explanation for why the water hasn't frozen - that it's contaminated with perchlorates, or salts that are acting like antifreeze - is flat out wrong.
What raises this above the level of an arcane dispute between academics are the stakes. We've known for some time that ice may be present beneath the surface of Mars, meaning that life might have been possible in the dim and distant past. Liquid water raises the possibility that bacterial life could survive on the surface of the red planet today.
We still don't know if there is life on Mars, but liquid water means it is at least possible.
Destruction of Martian methane may be bad news for life
www.newscientist.com/article/dn17562-de ... -life.html
21:31 05 August 2009 by Jessica Griggs
Methane gas on Mars may be destroyed 600 times faster than it is on Earth – and possibly in as little as one hour, new calculations suggest. If so, whatever process is responsible for the destruction may be wiping out other organic molecules, which are necessary for life as we know it.
In 2003, researchers detected methane on Mars. Since sunlight destroys methane on Earth in about 330 years, the discovery suggested that the gas was being replenished by geological processes or possibly even methane-producing bacteria.
The mystery deepened when researchers reported that the methane is not spread evenly through the atmosphere, but is concentrated in certain areas. That is a puzzle because atmospheric currents are expected to spread the gas evenly around the planet in a matter of weeks or months.
To see if these methane pockets could be explained by atmospheric chemistry, Franck Lefevre and Francois Forget of the Pierre and Marie Curie University in Paris tried to recreate the observations with a global climate model that accounted for the winds, turbulence and chemistry of all the known compounds in the Martian atmosphere.
But the model, which was based on methane's behaviour on Earth, failed to generate the pockets of methane gas observed, even though it perfectly reproduced the observed distribution of other atmospheric gases.
By introducing idealised methane molecules, or 'tracers', with lifetimes ranging from a few days to thousands of years into the model, the team found that the only way to reproduce the observations was to have an intense source of methane that is destroyed within 200 terrestrial days – 600 times faster than on Earth.
Methane is the simplest organic molecule, so if something is destroying it, then other, more complex organic molecules could suffer the same fate.
The nature of this destructive mechanism is still a mystery. Theories range from electrochemical processes caused by dust storms in the atmosphere to a reaction with oxidants, such as hydrogen peroxide or perchlorates, in the soil.
In the latter case, the team estimated that methane would only be destroyed in the 10 metres directly above the surface. That limitation means the destruction process would have to be even more extreme – occurring in as little as one hour – to explain the observations.
"This would leave little hope that life as we know it can exist at present or that evidence of past life can be preserved in the shallow surface layer," the authors write in the new study.
Sushil Atreya of the University of Michigan favours the soil scenario, with peroxide acting as the oxidant, since it can transform into even more reactive molecules, such as superoxides, which would destroy methane or organics even faster.
But he remains unconvinced about the calculated timescale of the destruction. "Whether the lifetime of methane is really one hour or one year is debatable," Atreya told New Scientist. "The quality of the [observational] data is not good enough to nail the lifetime that accurately."
Lefevre too admits that some of his results are extreme: "It's hard to imagine that methane could be destroyed in one hour without the other gases also being affected," he says. "Our first priority should be the confirmation of the methane variation."
Further observations of Mars's methane are planned for later this year. And future landers, including the Mars Science Laboratory set to launch in 2011, will study the Martian soil to find out if it contains oxidants such as hydrogen peroxide, which has been found in small amounts in the planet's atmosphere.
Journal reference: Nature (vol 460, p 720)
Fossils of Martian bugs found on meteorite that landed on Earth 13,000 years agoAnonymous said:LIFE ON MARS!!!!
In 1996 a team of NASA and Stanford University researchers created a stir when they published findings that meteorites recovered from the Allen Hills region of Antarctica contained evidence of possible past life on Mars. Those findings remain controversial, with many researchers unconvinced that those meteorites held even possible evidence that very primitive microbial life had once existed on Mars.
The meteorite also preserves evidence of liquid water on Mars, suggesting that the planet may have had more suitable conditions for life to develop in the past. The investigation was published in the November issue of Geochimica et Cosmochimica Acta, the journal of the Geochemical and Meteoritic Society. Nasa is expected to announce the findings formally on Monday.
The team has also been studying two other Martian meteorites — Nakhla, which landed in Egypt in 1911, and Yamato 593, which was found by a Japanese expedition to Antarctica. In research due to be published shortly, the scientists claim that both of these fossils also show evidence of microbial life.
Bill Clinton, then the US President, said of the research in 1997: “It speaks of the possibility of life. If this discovery is confirmed, it will surely be one of the most stunning insights into our Universe that science has ever uncovered. Its implications are as far-reaching and awe-inspiring as can be imagined.”
Mars may not be lifeless, say scientists
By Katia Moskvitch Science reporter, BBC News
Viking lander on Mars The Vikings probed the Martian soil back in 1976
Carbon-rich organic molecules, which serve as the building blocks of life, may be present on Mars after all, say scientists - challenging a widely-held notion of the Red Planet as barren.
When Nasa's two Viking landers picked up and examined samples of Martian soil in 1976, scientists found no evidence for carbon-rich molecules or biology.
But after the Phoenix Mars Lander discovered the chlorine-containing chemical perchlorate in the planet's "arctic" region in 2008, scientists decided to re-visit the issue.
Continue reading the main story
This doesn't say anything about the question of whether or not life has existed on Mars”
End Quote Chris McKay Nasa's Ames Research Center
They travelled to the Atacama Desert in Chile, where conditions are believed to be similar to those on Mars.
After mixing the soil with perchlorate and heating it, they found that the gases produced were carbon dioxide and traces of chloromethane and dichloromethane - just like the gases released by the chemical reactions after the Viking landers heated the Martian soil more than three decades ago.
They also found that chemical reactions effectively destroyed all organic compounds in the soil.
"Our results suggest that not only organics, but also perchlorate, may have been present in the soil at both Viking landing sites," said the study's lead author, Rafael Navarro-González of the National Autonomous University of Mexico, Mexico City.
But despite the excitement about the finding, the researchers warn it is too early to conclude that the Red Planet has ever had life.
"This doesn't say anything about the question of whether or not life has existed on Mars, but it could make a big difference in how we look for evidence to answer that question," said Chris McKay of Nasa's Ames Research Center, California.
He explained that organics can come from either biological and non-bio sources - many meteorites that have fallen on Earth have organic material.
Perchlorate, an ion of chlorine and oxygen, could have been present on Mars for billions of years and only manifest itself when heated, destroying all the organics in the soil.
The Atacama desert, Chile The soil of the Atacama desert is believed to resemble that of Mars
When scientists originally examined the data from the Viking probes, they interpreted the chlorine-containing organic compounds as contaminants from cleaning fluids carried on the spacecraft.
It is not yet clear whether the organic molecules are indigenous to the Red Planet or have been brought by meteorites.
This will be one of the goals of upcoming missions to Mars. In 2011, Nasa is planning to kick off its Mars Science Laboratory (MSL) mission, with the Curiosity rover designed to search for organic material on the planet.
Viking landers did detect organics on Mars
http://www.physorg.com/news/2011-01-vik ... -mars.html
January 6th, 2011 in Space & Earth / Space Exploration
A boulder-strewn field of red rocks stretches across the horizon in this self-portrait of Viking 2 on Mars' Utopian Plain. (3 September 1976) Image: NASA
(PhysOrg.com) -- In 1976 the NASA Viking landers took samples of soil on Mars and tested them for signs of organic carbon. A reinterpretation of the results now suggests the samples did contain organic compounds, but the results were not understood because of the strong oxidation effects of perchlorate, a salt now known to be found in Martian soils.
In the Viking tests the Martian soil was heated sufficiently to vaporize organic molecules in the soil and the resultant gases and vapors were analyzed by gas chromatography-mass spectrometry. Chlorohydrocarbons were found at landing site 1 and 2, but they were dismissed at the time as terrestrial contaminants, even though they were not found at the same levels in blank runs. Then, in 2008 the Phoenix lander discovered perchlorate in the Martian arctic soil. Perchlorates are well known as powerful oxidizing compounds that combust organics, but their presence in Martian soils was not suspected in the 1970s.
After the Martian soils were found to contain perchlorates, scientists from Ciudad Universitaria in Mexico City, and NASA’s Space Science Division at Moffett Field, California, decided to test the soils of the Atacama Desert in Chile, which is considered more like Mars than anywhere else on Earth.
The research, reported in the Journal of Geophysical Research, found that when soil samples containing organic carbon were mixed with magnesium perchlorate and then heated, the same kind of combusted chlorohydrocarbons were found as had been detected on Mars by the Viking lander and dismissed as contaminants.
Reinterpreting the Viking results in the light of the new findings suggests the samples from landing site 1 contained 1.5 to 6.5 ppm organic carbon, while those from landing site 2 contained 0.7 to 2.6 ppm organic carbon.
The presence of organic material does not provide evidence of life or past life on Mars but only of the presence of organic compounds. NASA is now planning a new mission for November 2011 to have another look for organics and other chemicals on Mars in an effort to better understand the chemistry of Martian soils.
More information: Navarro?González, R., E. Vargas, J. de la Rosa, A. C. Raga, and C. P. McKay (2010), Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars, J. Geophys. Res., 115, E12010, doi:10.1029/2010JE003599
Capitalism killed life on Mars, Chávez tells 'water day' event
http://www.irishtimes.com/newspaper/wor ... 56524.html
TOM HENNIGAN in São Paulo
Thu, Mar 24, 2011
CAPITALISM MAY be responsible for the lack of civilisation on Mars, according to Venezuelan president Hugo Chávez.
“I have always said, heard, that it would not be strange that on Mars there had been civilisation, but then probably capitalism arrived, imperialism arrived, and did for this planet,” he said at an event on Tuesday to mark World Water Day.
There was laughter in the audience before Mr Chávez turned to his main point: a warning that a similar process of environmental degradation was already under way on Earth.
“Look. Be careful. Here on planet Earth where hundreds of years ago or less there had been great forests, now there is desert. Where there were great rivers, now there is desert on much of the planet. There is an advanced process of desertification which puts at risk life on the planet in the medium term.”
Mr Chávez frequently uses folksy analogies and humour to communicate with his audiences. During his 12 years in power, the populist leader has lashed capitalism and what he sees as US imperialism.
In his speech he said the military operation by western governments against Libya was motivated by the North African country’s oil and water reserves.
Mr Chávez is one of few world leaders to openly support Libyan leader Muammar Gadafy. The two forged a close relationship as allies within the Opec oil cartel.
Rebels in the Libyan city of Benghazi changed the name of the main sports stadium from Hugo Chávez Stadium to the Martyrs of February Stadium in honour of those killed in the uprising against Col Gadafy.
Also on Tuesday two Venezuelan students sewed up part of their mouths as part of a campaign demanding more funding for the country’s universities, which protesters say has not increased since 2006.
The two are part of a group undertaking a hunger strike outside the UN’s offices in the capital Caracas.
A pro-Chávez deputy has claimed the protesters are financed by three bankers being sought by local courts. Last week state television showed footage of what it said were hunger strikers secretly eating food.
Galloping inflation and shortages of basic foodstuffs has led to increasing domestic discontent with Mr Chávez in recent months.
© 2011 The Irish Times
Underground oasis found below Earth's driest desert
http://www.newscientist.com/article/dn2 ... esert.html
00:25 18 February 2012 by Lisa Grossman
A thriving community of micro-organisms nestles two metres below the surface of the ultra-arid Atacama desert in Chile. The discovery, made as part of a dry run for a potential robotic Mars mission, suggests microbes could find a toehold on the Red Planet – but that rovers may have to dig deep to find them.
The Atacama desert, the most parched place on the planet, has long been considered a good Earthly analogue for Mars. The region gets rain only a few times a century, and the soil is full of salts similar to those found on the Red Planet.
Mars is even more extreme, with freezing surface temperatures and harsh ultraviolet radiation streaming in through its thin atmosphere. "On Mars, the scientific agreement is that it is very difficult, if not impossible, to find life on the surface," says Victor Parro of the Centre for Astrobiology in Madrid, Spain. "If we want to find any life on Mars, we need to go deeper."
To test an instrument called SOLID (Signs of Life Detector) that might one day hunt for subsurface Martian life, Parro and colleagues took soil samples from as far as five metres below the Atacama's surface.
SOLID searches for molecules associated with anything alive – such as sugars, proteins, and DNA – using 300 antibodies that bind to these molecules. When the antibody finds its target molecule, it grabs hold of it, and a special CCD camera then photographs the linked pair. Pregnancy tests, which look for a hormone associated with the early stages of pregnancy, employ a similar strategy.
Parro and colleagues found bacteria, archaea, DNA, and other molecules associated with life in soil collected two metres below the surface. "This is a kind of oasis in the Atacama," Parro says.
Previously, researchers had found similar life forms within the top 30 centimetres of soil in the Atacama. Those microbes, along with the new finds, survive thanks to thin films of water that form on salt crystals in the soil. The water may have been pulled from the atmosphere, or from subsurface aquifers. "For these microbes, the most important thing is to get some water," Parro says. "If they have some water, they have everything they need to live."
Although the newly found microbes are too deeply buried to use sunlight as fuel, Parro says the soil is full of other potential fuel sources, like acetic acid and formic acid, as well as ions that could be used for respiration instead of oxygen.
If Mars does have life, might it be similar to that found in the Atacama – and therefore detectable with SOLID? Parro thinks so. "Our hypothesis is, microbes that have to deal with similar environmental problems [on Earth and on Mars] probably have to deal with similar molecular mechanisms, so they have to produce similar biological polymers or compounds," he says.
A mission-ready version of his device could be built for around $15 million, and could be part of a relatively low-budget mission, Parro says. A similar instrument, which would use 40 antibodies to search mainly for small, fossil relics of Martian life, is already planned to fly on the European Space Agency's ExoMars rover mission in 2018.
But with NASA pulling out of the ExoMars mission and the future of Mars exploration in flux, it's unclear whether the instruments will ever get off the ground.
Parro remains hopeful. "The space race is a marathon, it's a long-distance race," he says. "Let's see what happens."
Journal Reference: Astrobiology, DOI: 10.1089/ast.2011.0654
Astrobiologist Proposes Fleet of Probes to Seek Life On Mars:
Sensors Would Punch Into Soil, Run Range of Tests
http://www.sciencedaily.com/releases/20 ... 143124.htm
Dirk Schulze-Makuch, a WSU astrobiologist, proposes a fleet of probes to Mars to search for life. (Credit: Image courtesy of Washington State University)
ScienceDaily (Apr. 23, 2012) — A Washington State University astrobiologist is leading a group of 20 scientists in calling for a mission to Mars with "a strong and comprehensive life detection component." At the heart of their proposal is a small fleet of sensor packages that can punch into the Martian soil and run a range of tests for signs of ancient or existing life.
They call the mission BOLD. It's both an acronym for Biological Oxidant and Life Detection and a nod to the proposal's chutzpah. The proposal, which comes as NASA is reevaluating its Mars exploration program, appears in the journal Planetary and Space Science.
"We really want to address the big questions on Mars and not fiddle around," says Dirk Schulze-Makuch, whose earlier proposals have included an economical one-way trip to the red planet. "With the money for space exploration drying up, we finally have to get some exciting results that not only the experts and scientists in the field are interested in but that the public is interested too."
The BOLD mission would feature six 130-pound probes that could be dropped to various locations. Shaped like inverted pyramids, they would parachute to the surface and thrust a soil sampler nearly a foot into the ground upon landing. On-board instrumentation would then conduct half a dozen experiments, transmitting data to an orbiter overhead.
The soil analyzer would moisten a sample and measure inorganic ions, pH and light characteristics that might get at the sample's concentration of hydrogen peroxide. Schulze-Makuch has hypothesized that microbial organisms on Mars could be using a mixture of water and hydrogen peroxide as their internal fluid. The compound might also account for several of the findings of the Viking Mars landers in the late 1970s.
The probe's microscopic imager would look for shapes similar to known terrestrial microfossils.
Another instrument would look for single long molecules similar to the long nucleic acids created by life on earth.
Some experiments would repeat work done by the Viking landers but with a greater precision that could detect previously overlooked organic material.
Each probe would have about a 50-50 chance of landing successfully. But with the redundancy of six probes, the chance of one succeeding is better than 98 percent.
The above story is reprinted from materials provided by Washington State University. The original article was written by Eric Sorensen.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Dirk Schulze-Makuch, James N. Head, Joop M. Houtkooper, Michael Knoblauch, Roberto Furfaro, Wolfgang Fink, Alberto G. Fairén, Hojatollah Vali, S. Kelly Sears, Mike Daly, David Deamer, Holger Schmidt, Aaron R. Hawkins, Henry J. Sun, Darlene S.S. Lim, James Dohm, Louis N. Irwin, Alfonso F. Davila, Abel Mendez, Dale Andersen. The Biological Oxidant and Life Detection (BOLD) mission: A proposal for a mission to Mars. Planetary and Space Science, 2012; DOI: 10.1016/j.pss.2012.03.008