Author	Topic:   Mars Ancient Biosphere?
Beach rover uncovers Mars's ancient oceans	posted 3/26/04 2:38 AM     Wednesday March 24, 12:00 PM Beach rover uncovers Mars's ancient oceans By David L Chandler The landing site of the Mars rover Opportunity was once the shore of a shallow, salty sea, NASA scientists have declared. The weight of evidence now gathered makes the conclusion unequivocal, they say. It is the first time direct evidence has been found that a body of standing, liquid water ever existed on the surface of Mars. Many planetary scientists have long believed that was the case, but having solid proof on the ground will change how future exploration of the red planet proceeds, as ideas about its potential for life. NASA is jubilant about the success. The team has "accomplished something that we dared only dream of", said NASA chief Sean O'Keefe, while chief scientist Ed Weiler said the results are " beyond our wildest expectations". The clinching factor was the observation of distinctively curved lines of sediment, the result of the gentle sweeping motion of a current of water. Material deposited by wind shows quite distinctly different patterns. Although the team had collected these images almost three weeks ago, they said, they decided to take the extra step of sending it out for peer review by specialists in the field of marine sedimentology who were not involved in the research. After two weeks, the reviews came back uniformly positive. Finding fossils Furthermore, although nobody is claiming to have found any signs of life, the scientists have now begun talking openly about the possibility of finding fossils in the kind of rocks Opportunity is studying. "If you have an interest in finding fossils on Mars, this is the place you should go," said Weiler, at Tuesday's press conference at NASA headquarters in Washington, DC. Steve Squyres, the rover mission's chief scientist, emphasised the difference between this finding and the report on 2 March that the Martian soil had contained water. "It's like the difference between water you can draw for a well, versus water you can swim in," he said. "Opportunity is now parked on what was once the shoreline of a salty sea on Mars." Northern ocean One word about Opportunity's landing site that no-one is using is "lake." Unlike the twin rover Spirit's landing site at Gusev crater, there is no obvious rim that could have contained a lake. The chemical and mineral evidence also points very strongly toward extremely salty, briny water, perhaps part of a very large body of water. This might be the northern ocean some researchers have said once existed on Mars. Further exploration by Opportunity could help to answer another crucial question: how long did this salty sea exist? Opportunity emerged from the 22-metre crater called Eagle on Monday, to see an incredibly smooth, rippling plain. It will now head rapidly across the 750 metres to a 200-metre crater, where tens of metres of sediments are likely to be exposed, providing a peek into the much longer-term history of water on Mars. But, as of Tuesday, the fact that bodies of liquid water existed on Mars is no longer in dispute. Now, it is just a question of when, and where, and for how long. http://uk.news.yahoo.com/040324/12/epcxi.html
Life on Mars Likely, Scientist Claims	posted 8/4/04 1:31 PM     Life on Mars Likely, Scientist Claims Tue Aug 3,12:40 PM ET By Leonard David Senior Space Writer SPACE.com DENVER, COLORADO -- Those twin robots hard at work on Mars have transmitted teasing views that reinforce the prospect that microbial life may exist on the red planet. Results from NASAs Spirit and Opportunity rovers are being looked over by a legion of planetary experts, including a scientist who remains steadfast that his experiment in 1976 proved the presence of active microbial life in the topsoil of Mars. "All factors necessary to constitute a habitat for life as we know it exist on current-day Mars," explained Gilbert Levin, executive officer for science at Spherix Incorporated of Beltsville, Maryland. Levin made his remarks here Monday at the International Symposium on Optical Science and Technology, the 49th annual meeting of Society of Photo-Optical Instrumentation Engineers (SPIE). Provocative find Levin has a long-standing interest in time-weathered Mars and the promise of life today on that distant and dusty world. NASAs 1976 Viking mission to Mars was geared-up to look for possible martian life. And it was Levins Labeled Release experiment that made a provocative find: The presence of a highly reactive agent in the surface material of Mars. Levin concluded in 1997 that this activity was triggered by living microorganisms lurking in the martian soil -- a judgment he admits has not been generally accepted by the scientific community. Now roll forward to 2004. Consider the findings of Spirit and Opportunity, the golf-cart sized robots wheeling over Mars at Gusev Crater and Meridiani Planum. "Those rovers have been absolutely sensational, pouring out thousands of images. Those images have lots of information in them. And Ive tried to deduce something in there relative to life...and I think I found a lot," Levin told SPACE.com. Squeezed out of the soil In perusing rover imagery, Levin reports there is clear evidence for liquid water existing under Martian environmental conditions. "The images should be reviewed against the background of surface temperatures as varying from below to above freezing reported by both Spirit and Opportunity," he explained. Levin points to the potential for mud puddles on Mars, showing an image of clearly disturbed martian soil after rover airbags bounced across Mars surface. Possible standing water and sinkholes can also be seen in rover imagery, according to his analysis. In some pictures, the often-discussed "blueberries, " tiny spheres of material, disappear as if submerged underneath mud-like surroundings, he added. Then there are tracks left by the machines as they roll across the martian terrain. Self-taken shots by the robots show what Levin said appears to be water squeezed out of the soil which then freezes into a whitish residue left in embedded tread marks. Similarly, Levin added, are images taken by Opportunity of the results from an operation of the robots Rock Abrasion Tool, or RAT. The center of that particular RAT hole is largely white, possibly indicating the formation of frost since the hole was drilled, he noted. Organisms there now? "The evidence presented strongly indicates the presence of liquid water or moisture at the Mars Exploration Rover sites," Levin reported at the SPIE meeting. "Mars today could support many forms of terrestrial microbial life." Other scientists are cautious to point out that the presence of water does not guarantee life. Rather, it means one crucial ingredient exists. There is clear evidence for frost or ice on Mars, the former Viking experimenter stated. At some point of the day -- when temperatures climb above freezing -- theres going to be moisture..."and thats enough to support microorganisms," he said. None of the many new findings about Mars revealed by Spirit and Opportunity, Levin concluded, conflict with, or render untenable, his long-held belief that the Viking Labeled Release experiment in 1976 detected living microorganisms in the soil of Mars. "I contend that today you could take a great many Earth microorganisms, put them on Mars, and theyd grow," Levin said. "And I think there are organisms there now. They may have come from Earth. They may have originated on Mars. They may have come from a third place that populated both Mars and Earth." Rocks can be kicked up from one planet by an asteroid impact, drift through space for eons, then land on the other. Other studies have shown that these rocks could potentially transport life, in a dormant phase, from one planet to the other. Levin said that he thinks the "greatest speculation" would be to say there can be no life on Mars. Moon used as Earth bio-shield If indeed Mars is rife with life, care should be taken in hauling back to Earth specimens of rock and surface materials from the red planet. NASA (news - web sites) has indicated that, next decade, robotic craft could be dispatched to gather and return to Earth select samples of Mars for detailed laboratory study. Could those bits of Mars, perhaps laden with martian microbes, act as dangerous cargo? As a precaution, Levin advocates a kind of bio-shield strategy for Earth -- but using the Moon. The new NASA vision to reestablish a human presence on the Moon is good timing, Levin said. "Bring samples of Mars not to Earth but to the Moon," he said. "There we would have built a scientific laboratory in which scientists could examine the samples and determine whether or not there is a hazard." http://story.news.yahoo.com/news?tmpl=story&cid=96&e=2&u=/space/20040803/sc_space/lifeonmarslikelyscientistclaims
Some Mars Researchers See Life in Planet's Dunes	posted 8/4/04 2:04 PM     Some Mars Researchers See Life in Planet's Dunes By Leonard David Senior Space Writer posted: 12:20 pm ET 30 January 2002 A Hungarian research team claims that Martian organisms dot certain areas of the Red Planet. Calling the intriguing blemishes "dark dune spots", the scientists argue that these changing features are "probable Martian surface organisms." Their evidence is based on studies of imagery snapped by NASA's Mars Global Surveyor (MGS), a spacecraft now orbiting that planet. However, this is at odds with the published conclusions of the MGS team, and at least one leading Mars researcher and astrobiology expert deems the life-form assertion "premature". This is also not the first time that images of Martian surface features from MGS have sparked the life debate. One region of Mars has been picked by the Hungarian team as a "test field" for the dark dune spots, with sets of Mars Global Surveyor pictures of the selected landscape analyzed. That study area is a rectilinear ridged landform known as "Inca City", an informal name ascribed to the terrain from Mariner 9 images taken in the early 1970s. Mars experts, Mike Malin and Ken Edgett at Malin Space Science Systems, say this defrosting, over time, causes leopard-like spots that can be wrongly interpreted as something growing. Dark-spotted dunes in the southern hemisphere are the result of springtime defrosting process on Mars, not signs of biology, say Mars researchers Mike Malin and Ken Edgett of Malin Space Science Systems. Using the MGS pictures, the shape, pattern changes, fading and reappearance of the spots were catalogued. The Hungarian Mars analysts contend that the changes support a biological link to the alternations over a geological interpretation. Constellation of patches Team member, Eors Szathmary, a permanent fellow at the Institute for Advanced Study in Budapest, Hungary told SPACE.com that the Mars biology viewpoints are to be presented in several papers at the upcoming 33rd Lunar and Planetary Science Conference. That meeting is to be held by the Lunar and Planetary Institute this coming March in Houston, Texas. Their assessments utilize MGS photos clicked from 1999 to 2001, from winter to summer of the southern hemisphere. Also used to help probe the dark dune area was information gleaned by a laser-scanning device toted by the MGS. That instrument yielded height information about the terrain, helping to discern various Sun illuminations that strike the area over periods of time. Szathmary and his colleagues observed seasonal changes -- from early spring till early summer -- of the dark dune spots on frosted and defrosted Martian dunes. Each spring, they report, "gray fuzzy spots" appear in the bottom of the ice cover. By the middle of the first half of spring, these spots become darker, are bounded, and grow in size. By early summer defrosting, the naked dark soil of the dune is visible, and surrounded by a lighter ring. Year by year, the dark dune spots "renew" on the same place with almost the same configuration, or "constellation" of patches. This repeat action, the team asserts, strengthens their suggestion of fixed, biological causes of spot formation. Szathmary and others on the study group believe biology is at work on Mars. "We interpret the sequence of dark dune spot formation and changes as a result of…probable Martian surface organisms," they report. The Martian organisms "survive below the surface ice, sunlight heats them up and they generate their living conditions." Premature interpretation? The Hungarian researchers concede, however, that other Mars researchers don't share a biological interpretation of the spots. That's the case for Bruce Jakosky, a Mars researcher at the University of Colorado in Boulder. He also heads the university's Center for Astrobiology. "Given our understanding of Mars volatile- and dust-related processes, it seems premature to attribute the characteristics that they identify to biological activity when other, simpler processes have not been ruled out," Jakosky told SPACE.com. "In evaluating competing hypotheses, it is important to ask which is the most plausible by virtue of relying on well-understood processes that are likely to be occurring on Mars. It would be inadequate, for example, to treat all hypotheses that have not yet been absolutely ruled out as being of equal likelihood," Jakosky said. Mars experts Mike Malin and Ken Edgett of Malin Space Science Systems in San Diego, California have also eyed the features. They report that straightforward defrosting of the Martian ice cover is responsible for the origin and development of the spots. But the Hungarian team counters this view. After studying several thousand such spots, defrosting processes cannot be the sole explanation for the splotches in question, they say. More information needed Taking a measured, but too-early-to-tell attitude about the features is James Garvin, Mars Exploration Program Scientist at NASA Headquarters in Washington, D.C. Garvin said that there are many physically plausible ways to generate the features that the Hungarian researchers are studying. Many of those ways are associated with the thermodynamics of materials at places on Mars where detailed measurements of the associated micro-environments are lacking. "The dark spots on the polar dunes that are discussed deserve more attention, due to their intriguing time-variable behavior," Garvin said. "But we have to recognize that we are examining features at scales no finer than 10-20 feet, certainly not adequate to draw definitive conclusions about whether biological processes were involved in their origin," he said. "To fully appreciate what is going on, it's imperative that we continue measurements of such localities with orbital and surface-based systems," Garvin said. Those include the Mars Reconnaissance Orbiter, as well as Scout landers and perhaps the Mars Smart Lander, he said. The Hungarian team offers an interesting appraisal of what's causing the dark dune spots, said Ronald Greeley, a leading planetary geologist at Arizona State University in Tempe. "Certainly the discovery of these features in the images rank with the most intriguing features revealed by Mars Global Surveyor's high-resolution camera. The Hungarians work through a set of logical descriptions and analyses of how the features might form, then draw the conclusion that dark dune spots are indicative of biological activity. Unfortunately, this last step is not convincing. It is not that this hypothesis is not possible, it is just that the data do not support it," Greeley said. "No doubt, [this research] will generate much discussion, as is true for any suggestion of extraterrestrial life made by qualified planetary scientists. What the ensuing discussion will point to is the need for definitive (or at least reasonable) criteria for the detection of life, either with available instruments/data, or as a means to define new instruments," Greeley said. Martian communities Sizes of the various dark dune spots vary, and can be dozens of miles across. Their thickness varies from some 30 feet (10 meters) to over 650 feet (200 meters) on average. "The shape, location, development and other features of the dark dune spots prompt us to suggest that some fluid phase must be involved in their explanation, which under the given circumstances cannot be anything else but liquid water. Dark dune spots are circular on flat surfaces. Defrosting cannot be responsible for this since it is affected by various surface conditions," one of the team's research paper's points out. "We think that necessary melting of the ice is influenced by some biological factors," the researchers suggest. They propose one scenario, supporting their view that organisms are alive and well and at work on Mars. If the Martian surface organisms do exist, they could dwell below the surface ice, the study team believes. When that ice is heated up by the organisms absorbing sunlight, they then grow and reproduce through photosynthesis. In this process, they generate their own living conditions. "Not only liquid water, but even water vapor can sustain this form of life. Water vapor can migrate in the soil below the carbon dioxide frost cover supporting the living conditions for endolithic type communities and this activity enhances the defrosting/melting process on the top of the dark dune surface," the team concludes. http://www.space.com/scienceastronomy/solarsystem/mars_blotches_020130.html
Scientists Seek Scent of Life in Methane at Mars	posted 8/29/04 8:28 AM     Scientists Seek Scent of Life in Methane at Mars By Leonard David Senior Space Writer posted: 24 August, 2004 07:00 a..m. ET Sniffing out any whiff of biology on Mars has become a scientific battle of the bands – spectral bands that is. The purported detection of methane in the martian atmosphere by Mars Express, the European Space Agency (ESA) probe now orbiting the red planet, has sparked measurable debate. ESA announced late last March that the Mars Express Planetary Fourier Spectrometer (PFS) had observed methane. That instrument is built to detect the presence of particular molecules by analyzing their 'spectral fingerprints' - the specific way each molecule absorbs the sunlight it receives. While the amount of methane seen by the PFS is very small – about 10 parts in a thousand million – the implications of the detection are large. Perhaps Mars isn’t a planet waiting to exhale, but one that is a thriving world of panting microbes? According to ESA experts, methane, unless it is continuously produced by a source, only survives in the martian atmosphere for a few hundreds of years because it quickly oxidizes to form water and carbon dioxide - both present in the martian atmosphere. So what’s refilling the atmosphere with methane? Methane measurements On the one hand, methane production could be linked to volcanic or hydrothermal activity on Mars, although no volcanic activity has been detected on the planet to date. Alternatively, many types of microbes produce a signature of methane. On Earth, methane is a by-product of biological activity, such as fermentation. Biological sources, such as those associated with peat bogs, rice fields and cud-chewing animals constantly supply fresh gas to replace that destroyed by oxidation. "The first thing to understand is how exactly the methane is distributed in the martian atmosphere," says Vittorio Formisano, principal investigator for the PFS instrument at the Istituto Fisica Spazio Interplanetario in Rome, Italy. "Since the methane presence is so small, we need to take more measurements. Only then will we have enough data to make a statistical analysis and understand whether there are regions of the atmosphere where methane is more concentrated," Formisano explained in an ESA press statement. Ground-based looks Adding to the Mars Express methane saga are reports from scientists using ground-based telescopes that, indeed, traces of the gas have also been spotted. One independent U.S. team, led by Michael Mumma of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, has also weighed in on the methane on Mars question. Mumma reported last year at the American Astronomical Society’s Division for Planetary Sciences that methane had been detected using super-sensitive infrared spectrometers mounted to the Gemini South telescope on Cerro Pachón in Chile and at the W.M. Keck Observatory on Mauna Kea, Hawaii. The bottom line, Mumma said, is that sorting out the signature of methane is not an easy task. "I've looked at some of the PFS spectra in the methane region, and am skeptical," Mumma said. "I think they have not yet convinced the community they are detecting CH4 (methane)." More work is needed to model and strip out the spectra from known constituents within the martian atmosphere, and then compare the residuals with synthesized CH4 spectra, Mumma said. At this point in time, "the community has reserved judgment on the PFS results," he concluded. Near the limits of detection There’s no doubt that detecting methane eking out of Mars would be extremely important if true. The implication, if it turns out to be really there, is that the methane can only be produced by some active process that churns out new methane - such as volcanic activity or certain types of living organisms: methanogens. A methanogen is a microorganism that produces methane from the reaction of hydrogen and carbon dioxide. "In either case, we would have discovered that Mars is an active planet today," said Benton Clark, a Mars Exploration Rover team scientist from Lockheed Martin Space Systems Company, Denver, Colorado. "Localizing the source would be of great interest and would point to future exploration." However, measurements taken to date from Earth and by the Mars Express can be challenged because they are near the limits of detection, Clark told SPACE.com. Taking to the air Clark said that the proposed NASA Mars Volcanic Emission and Life (MARVEL) Scout mission would detect methane with 100 to 1000 times better sensitivity from orbit, and also be able to localize it on the red planet. In addition, taking to the air – by literally flying over the martian surface -- is another way to spot methane. For example, Clark said, a proposed Mars airplane, the Aerial Regional-scale Environmental Survey (ARES), is under the wing of NASA's Langley Research Center in Hampton, Virginia. It is designed to tote instruments that can target methane and other gases for measurement as it flies over red planet real estate. "I think too much has been written about these [Mars Express] observations in the press in the absence of formal scientific review," said Mark Allen, an Earth and planetary atmospheres Research scientist in the Earth and Space Sciences Division at the Jet Propulsion Laboratory (JPL) in Pasadena, California. He is also the principal investigator for the proposed MARVEL Scout. Without peer reviewed assessments of the Mars Express findings, Allen said, any comment on the observations would be premature. "At best these observations are tantalizing, since the experiment seems to be operating at the limit of its sensitivity. However, the implications for extant habitability and inhabitance of Mars are tremendous," Allen said. "I would hope that NASA is interested in pursuing this subject and might find a mission with much more sensitivity and capability for locating surface point sources -- such as MARVEL -- highly attractive for selection next time," he suggested. Proceed with caution Also in the still to be convinced category in regards to the Mars Express methane finding is James Garvin, NASA Chief Scientist for Mars and the Moon, in the Science Mission Directorate at NASA Headquarters, Washington, D.C. "Most of what we have seen from the Mars Express PFS does not yet suggest that it is wholly reproducible and even localizable," Garvin suggested. His advice, as a NASA scientist steeped in ever-growing volumes of new Mars data: proceed with caution, examine multiple lines of detection and then the basic chemistry of the processes - before leaping to conclusions. Garvin noted that the PFS on Mars Express is an outstanding Fourier spectrometer which could, under appropriate circumstances, detect methane at 10's of parts per billion levels - but across a large control volume of the martian atmosphere which is relatively well mixed. There is far more evidence, Garvin continued, for the possibility of recent, highly localized volcanism -- as fumaroles or local hydrothermal vents -- than for anything to do with subsurface microbial systems. "If you were to ask me, any methane we may be seeing must be volcanogenic on the basis of what scant real scientific evidence we have... or it could even be some sort of ‘oddball’ result of asteroidal impact that we have not fully understood," Garvin speculated. Looking to the future, Garvin pointed to the launchings of NASA’s Mars Reconnaissance Orbiter in 2005, the Phoenix lander in 2007, and the wheeled Mars Science Laboratory in 2009. Each will help puzzle out further the red planet’s past history and present-day condition. And each will, at least in part, address the existence of disequilibrium trace gases – such as methane – using new approaches, including on-the-spot mass spectrometry, he said. http://www.space.com/scienceastronomy/mars_methane_040824.html
Water coursed through Martian hills	posted 10/10/04 7:39 AM     New Scientist | AFP Friday October 8, 04:30 PM Water coursed through Martian hills By David L. Chandler Polygonal cracks were carved on the "Escher" rock by a second wet episode (image: NASA/JPL/Cornell) The twin rovers on Mars - now reviving having survived the freezing depths of Martian winter - have found new signs that water was once plentiful on Mars. The Mars rover Opportunity, which has nearly reached the bottom of the 160-metre-diameter Endurance crater, has now found clear signs that the area was drenched twice in the past, say NASA scientists. Its twin, Spirit, which landed in what was thought to be an ancient lakebed, had failed to find direct signs of water for months as it crossed two kilometres of pure basaltic plains. The rovers landed on the Red Planet in January 2004. But since Spirit reached Mars’ Columbia Hills in July, the rocks have changed completely, showing evidence of abundant water. "We have not seen a single fresh volcanic rock since we crossed the line" from the plain to the hills, says rover chief scientist Steven Squyres of Cornell University, US. "Every single one shows signs of alteration by water." The hills, Squyres explains, are like islands of much older rock that stick up from the basaltic lava flows that later filled the basin's depths, creating the smooth plains on which Spirit landed. Soluble elements By measuring the differences between the spectra of rocks on the plains and those in the hills - using Spirit’s Alpha Proton X-Ray Spectrometer - the team discovered that the hillside rocks were all significantly depleted in potassium, sulphur, bromine, and chlorine. These are the most soluble elements and would be the first to go if the rocks got wet. Meanwhile, Opportunity has discovered one of the most interesting rocks seen so far, says Squyres. While attempting to retreat from the lower levels of the Endurance crater, the rover happened upon a slab of rock - dubbed Escher by the team - which is fractured into polygonal shapes (see image). It later found another rock, called Earhart, showing similar shapes. The rock itself is made up of fine layers that run across the direction of the polygonal cracks, explains John Grotzinger, a sedimentologist at MIT and a member of the science team. Dry spells The shapes suggest that the original sedimentary rock formed in a lake or shallow sea - which then dried and solidified - before undergoing a second wet episode and yet another drying out. And large timescales may have been involved. The latter drying episode must have come after the impact that formed the Endurance crater, Grotzinger says. Spectral data show that the concentration of chlorine, sodium and other soluble elements is far heavier on the surface of the rock than just beneath it, as it would be if the rock had been bathed in water long after it formed, leaching out the salts. Both rovers are now heading towards other stimulating targets. Spirit is heading into the hills, towards what appear to be extensive exposures of layered bedrock while Opportunity will attempt to exit its deep crater by way of a steep, heavily layered dark cliff of interesting looking rock. http://uk.news.yahoo.com/041008/12/f473x.html
Scientists face the fact of Mars me	posted 11/22/04 9:35 AM     Scientists face the fact of Mars methane 15:27 15 November 04 NewScientist.com news service There is methane on Mars, scientists have concluded from the latest data. And one group of researchers argue there may be a lot more methane being produced than previously thought. Methane is of great interest because on Earth, almost all of it comes from living things - everything from rotting plants to bovine flatulence. But there are other possible sources of methane on Mars. While one researcher, Vladimir Krasnopolsky at Catholic University of America, argued that those other sources are so unlikely that the methane must be biologically produced, most scientists at the American Astronomical Society's Division for Planetary Sciences meeting in Louisville, Kentucky, said they are concentrating on the non-biological mechanisms. Whatever is creating the gas, these reports have dissipated the initial scepticism that met early reports of Martian methane over the past year. Methane does not survive long in the Red Planet’s atmosphere, so the source must be recent. One idea is that Mars was struck very recently by a comet containing frozen methane. Though such strikes are relatively rare, Sushil Atreya of the University of Michigan, US, has calculated that gas from a comet with only 2% methane content could persist on Mars for up to 2000 years. This could produce atmospheric levels of methane comparable to the roughly 60 parts per billion detected by astrobiologist Michael Mumma at NASA's Goddard Space Flight Center, and his colleagues. Alternatively, the gas could be buried in methane-ice mixes called clathrates, perhaps being released by geothermally melted water and bubbling up to the surface through natural pores and cracks in Mars’s crust. While not a sign of life itself, it might indicate a place where life could survive. Double lines The existence of the methane has been largely settled by a set of detailed, high-resolution spectral observations from the 8-metre Gemini telescope, recorded by Mumma's team. They clearly identified two separate methane lines, making a much firmer case than their previous single-line detections, and similar findings of two other groups. "It's real," say Stephen Squyres, science team leader for NASA's twin Mars rovers. The important thing now, he told New Scientist, is to figure out where it's coming from and where it's going.” Adding to the intrigue are new calculations by Atreya showing that dust devils and storms on Mars - known to be frequent and intense - must be producing vast quantities of hydrogen peroxide. This highly reactive oxidant was inferred to exist on Mars after the 1976 Viking experiments, but not actually detected until 2003. All this oxidant must be destroying the methane at a very high rate, Atreya said on Friday. That could explain Mars’s uneven distribution of methane - observed by Mumma’s team and others - as the storms are local and temporary. But it also implies that methane is being produced at a much higher rate than its present concentration would suggest. If so, cometary or volcanic sources become even more unlikely, and the prospect of a living source becomes slightly more plausible. David L Chandler, Louisville, Kentucky http://www.newscientist.com/news/news.jsp?id=ns99996669 Scientists face the fact of Mars methane
Life-Swapping Scenarios for Earth and Mars (Moderator)	posted 12/14/04 2:07 PM     Life-Swapping Scenarios for Earth and Mars Mon Dec 13, 2:34 PM ET Science - Space.com Leonard David Senior Space Writer SPACE.com Evidence is mounting that the time-weathered red planet was once a warm and water-rich world. And a Mars awash with water gives rise to that globe possibly being fit for habitation in its past - and perhaps a distant dwelling for life today. As sensor-laden orbiters circle the planet, NASA (news - web sites)'s twin Mars rovers -- Spirit and Opportunity -- have been tooling about and carrying out exhaustive ground studies for nearly a year. The Opportunity robot at Meridiani Planum, for instance, has found telltale signs that water came and went repeatedly within that stretch of Martian real estate. While that intermittent water at Meridiani Planum is thought to be highly acidic and salty, its ability to sustain life for some period of time cannot be ruled out. What scientists now see is a Mars different in its first billion years of geologic history than once thought - and conceivably an extraterrestrial address for home-grown life. Mars is one complex and perplexing world. That was strikingly evident at the Second Conference on Early Mars: Geologic, Hydrologic, and Climate Evolution and the Implications for Life, held Oct. 11-15 in Jackson Hole, Wyoming. Nearly 140 terrestrial and planetary scientists took part in that seminal meeting hosted by the Lunar and Planetary Institute (LPI), NASA, and NASA's Mars Program Office. "One of the most significant new findings reported at the meeting was that it appears Mars underwent many of its most important changes much earlier in its history than previously thought," said Steve Clifford, an LPI planetary scientist. That includes core formation, the development of the crustal dichotomy, a rapid decline in geothermal heat flow, and the loss of a planetary magnetic field. "Surprisingly, all of these events appear to have occurred within the planet's first 50 million to 100 million years of existence," Clifford explained. A related discovery is the potential role played by large impacts during this same period, he said, a topographic record of which is preserved in the ancient cratered highlands and has now also been detected beneath the planet's northern plains. Clifford said simulations indicate that the very largest of these impacts may have blown away a significant fraction of the early Martian atmosphere. Impacts that produced craters greater than some 60 miles (100 kilometers) in diameter might have affected the climate on a regional and global scale, creating transient environmental conditions capable of sustaining continuous rainfall lasting from years to decades, he said. Water-rich world "There now appears to be overwhelming evidence that early Mars was water-rich - and may have possessed standing bodies of water and ice that ranged from large seas to a primordial ocean, perhaps covering a third of the planet," Clifford said. Supporting evidence ranges from orbital observations of extensive layered terrains within, and possible paleoshorelines surrounding, the northern plains to on-the-spot investigations of the mineralogy and sedimentary record recently discovered by the Opportunity rover in Meridiani Planum. "The implications of these findings are just beginning to be absorbed by the Mars community, yet they have already substantially revised our understanding of the planet's early evolution. They are sure to be a continued focus of attention as the intensity and scope of Mars exploration increases over the next decade," Clifford observed. Now mix in recent findings about the origin and range of life here on our own planet. "Life is incredible and the envelope for what we know about where life can live -- data from planet Earth -- is ever expanding and is far beyond what we might have hypothesized," suggested Lynn Rothschild, a scientist in the Ecosystem Science and Technology Branch of NASA's Ames Research Center, Moffett Field, California. "There is a difference in perspective between planetary folks and biologists regarding where life might thrive. Organisms don't look for a global average. As a microbe, just give me 100 microliters of liquid water and I am happy. In any case, I certainly don't need an ocean! So think microenvironment," Rothschild advised. Water and energy for microorganisms Given the wealth of Mars Exploration Rover (MER) data, the likelihood that life could have existed on Mars -- or still does -- is viewed as more probable according to Carrine Blank, Assistant Professor of Molecular Geobiology in the Department of Earth & Planetary Sciences at Washington University, St. Louis, Missouri. The MER results indicate that there were both large bodies of liquid water on Mars and there were fluids carrying redox (oxidizing and reducing) gradients through the near surface which resulted in precipitation of the blueberries, Blank told SPACE.com. "Life not only requires liquid water, but it also needs a source of metabolic energy," she added, "and redox gradients are great sources of energy for microorganisms. Blank said in her mind the really big question is just how long was this liquid water and energy present on the surface of Mars. Be it brief or extended, so goes drawing the life line in the sands of Mars. "If it was for just a brief time in the geologic history of Mars, then perhaps the potential for life is low," Blank said. "If, on the other hand, it was for an extended period of time, then the potential for life at the surface becomes much higher." What is needed now, Blank noted, is more information about how widespread sedimentary deposits are on Mars, and then identify age constraints on the presence of liquid water at the surface. Planet swapping microbes The idea that the seeds of life hobnob between far-flung celestial localities is known as panspermia. Could Mars be a domain for both microbes flung off Earth due to asteroid and comet impacts, as well as a planet where a "second genesis" might have also occurred? Furthermore, if this was the case, could external life and made-on-Mars biology co-exist? "Absolutely," advised Blank, adding yet another scenario: That life originated on Mars and was transferred to the Earth, and then went extinct on Mars. "At present, there is no geologic evidence that the origin of life occurred on the Earth. So one hypothesis is that the origin could have occurred elsewhere, like Mars, and then transferred to the Earth," Blank suggested. Alternatively, life could have originated on the Earth -- but left no evidence since we don't have any rocks for the first billion years of Earth history -- and then transferred to Mars, she said. "If life was transferred between the planets, then Martian life, past and present, should have similar characteristics to early Earth life," Blank said. "On the other hand, if there was a second genesis, then life on Mars should be very different than life on Earth, and may in fact be quite difficult to detect or even recognize as lifeparticularly if it has gone extinct!" Deepest branches on the tree of life Meanwhile back on Earth, Blank said that more research is needed to understand whether interplanetary transfer of life could have been possible. In particular, additional work on hyperthermophiles -- microbes that live at very high temperatures and that form the deepest branches on the tree of life -- is required, as they were the early inhabitants of the Earth and therefore were the ones most likely to have been transferred around the solar system by impacts, she said. "We know very little about the origin of life on the Earthhow it happened, what kind of environment it might have happened in, and how long it look to go from the origin to the last common ancestor of life as we know it - a very complex organism very much like modern life," Blank said. Casting her eye back on Mars, Blank also said an unknown is whether conditions on early Mars were similar to what they were like on the early Earth when the origin of life likely happened. "If they were similar, then perhaps a 'second genesis' could have been possible on Mars. Even if conditions were different on Mars, there could still have been a second genesis only with a very different result than what happened on the Earth," Blank stated. "If these different life forms were spread throughout the solar system, then they might have co-existed if they could learn to depend upon each other. If, on the other hand, they were in direct competition for resources, then you might expect that one would 'win' and survive, and the other go extinct," she advised. War of the worlds? Jack Farmer, an astrobiologist at Arizona State University in Tempe, also contends that the chance for life having existed on Mars is definitely in the cards. He is a Mars Exploration Rover science team member. "We now have what I consider to be definitive evidence for standing bodies of water on Mars and this has opened up a serious and focused discussion of habitable environments on Mars early in the planet's history. This discovery marks a first step in implementing a strategy for Mars exopaleontology," Farmer told SPACE.com. Farmer said the idea that Mars could have played host to Earth-launched microbes, as well as being a planet where a second genesis might have also taken place "are both contenders for an origin of Martian life and deserve serious consideration." "I also think the idea of a 'War of the Worlds' on Mars between life forms that originated there and those that arrived from Earth is a serious possibility," Farmer said. And that prospect, he continued, raises some key questions: Who would win? Is there the possibility for a competitive co-existence between life forms that originated on a different basis? "The good news is [that] these alternative hypotheses appear to be testable in the context of future missions. But this discussion also points, again, to the importance of planetary protection and the potential for back-contamination arising from a Martian sample return," Farmer concluded. http://story.news.yahoo.com/news?tmpl=story&cid=96&e=1&u=/space/20041213/sc_space/lifeswappingscenariosforearthandmars
Mars Volcanoes Possibly Still Active, Pictures Show (Moderator)	posted 12/24/04 10:38 AM     Mars Volcanoes Possibly Still Active, Pictures Show Wed Dec 22, 2:11 PM ET Robert Roy Britt Senior Science Writer SPACE.com Images from a European space probe reveal recent glacial deposits and lava flows on Mars that suggest the red planet is more active than many scientists had thought. The European Space Agency's Mars Express orbiter photographed lava flows that must have occurred within the past two million years and imply, scientists say, that volcanoes on Mars might still pump molten rock to the surface now and then. And on the flanks of Olympus Mons, the largest volcano on Mars, pictures reveal material left by glaciers that were active within the past four million years or so. The gargantuan volcano -- taller than any in the entire solar system -- may still harbor dust-covered snow and ice at its higher altitudes, researchers conclude. Age spots Estimating the age various surface layers on Mars is tricky business. But the new high-resolution, stereo images provide a detailed view not available before. Mars Express sent back its first pictures in January 2004. Here's what scientists looked for: Mars has been rattled by asteroids throughout its history, and the resulting craters -- some too small to be seen by other spacecraft -- are like age spots on human skin. Regions that are smooth as a baby's bottom must have been "resurfaced" recently, in geologist's parlance. The resurfacing can be done by lava, the scraping of glaciers, or even wind erosion. Telltale geologic features reveal the sort of process at work. Some of the Martian lava fields must have been created very recently in geologic time, because of the very small number of impact craters on them, said study leader Gerhard Neukum of the Free University in Berlin. But if volcanoes on Mars are still active, as Neukum and his 10 colleagues from institutions in several countries suspect, why has the activity never been spotted? "Outbreaks happen from time to time over a short period of time," Neukum told SPACE.com. "We would be extremely lucky if it happened while Mars Express is in orbit and we are right over the site where it is happening." Five volcanoes seen from above and the ages of various lava flows. Click to View. He said the orbiter might get lucky in coming years and "see some action, but the chances are slim." Evidence of past glacial activity includes features carved into the surface in much the same manner as terrestrial glaciers in Antarctica, along with rocky material transported down slopes. In particular, one high-altitude ridge on Olympus Mons juts more than 1,300 feet (400 meters) above the surrounding terrain. Neukum and his colleagues think it is an ice cap covered by dust. Other studies have shown that both poles of Mars are packed with water ice, and that ice also persists underground away from the poles. Similar to Earth Scientists have long sought to determine how geologically active Mars has been in recent times. A study in 2001 based on images from NASA (news - web sites)'s Mars Global Surveyor spacecraft hinted at recent volcanic activity. The new work, reported in the Dec. 23 issue of the journal Nature, involved five volcanoes: Olympus Mons, Ascraeus Mons, Arsia Mons, Albor Tholus and Hecates Tholus. Each of the mountains is dominated by a caldera, a depression at the top that is the collapsed remains of eruptions past. Multiple episodes of activity -- up to five in some cases -- were found to have occurred in each caldera. The lava flows are similar to those that roll out of volcanoes in Hawaii, Neukum said. By determining various ages of different lava flows, the researchers found that some of the volanoces appear to have been active for roughly 80 percent of the 4.5-billion-year history of Mars. Terrestrial volcanoes, by contrast, typically are born and become extinct within a million years. "The very long activity of Martian volcanoes implies correspondingly long lifetimes of 'hot spots' in the planet's interior," the researchers write in the journal. One challenge now, they say, is to figure out how these hot spots differ within the two planets. http://story.news.yahoo.com/news?tmpl=story&cid=96&e=3&u=/space/20041222/sc_space/marsvolcanoespossiblystillactivepicturesshow
Exclusive: NASA Researchers Claim Evidence of Present Life on Mars (Moderator)	posted 2/18/05 8:59 AM     Exclusive: NASA Researchers Claim Evidence of Present Life on Mars Wed Feb 16, 3:26 PM ET Brian Berger Space News Staff Writer SPACE.com WASHINGTON -- A pair of NASA (news - web sites) scientists told a group of space officials at a private meeting here Sunday that they have found strong evidence that life may exist today on Mars, hidden away in caves and sustained by pockets of water. The scientists, Carol Stoker and Larry Lemke of NASA's Ames Research Center in Silicon Valley, told the group that they have submitted their findings to the journal Nature for publication in May, and their paper currently is being peer reviewed. What Stoker and Lemke have found, according to several attendees of the private meeting, is not direct proof of life on Mars, but methane signatures and other signs of possible biological activity remarkably similar to those recently discovered in caves here on Earth. Stoker and other researchers have long theorized that the Martian subsurface could harbor biological organisms that have developed unusual strategies for existing in extreme environments. That suspicion led Stoker and a team of U.S. and Spanish researchers in 2003 to southwestern Spain to search for subsurface life near the Rio Tinto river—so-called because of its reddish tint—the product of iron being dissolved in its highly acidic water. Stoker did not respond to messages left Tuesday on her voice mail at Ames. Stoker told SPACE.com in 2003, weeks before leading the expedition to southwestern Spain, that by studying the very acidic Rio Tinto, she and other scientists hoped to characterize the potential for a chemical bioreactor in the subsurface - an underground microbial ecosystem of sorts that might well control the chemistry of the surface environment. Making such a discovery at Rio Tinto, Stoker said in 2003, would mean uncovering a new, previously uncharacterized metabolic strategy for living in the subsurface. For that reason, the search for life in the Rio Tinto is a good analog for searching for life on Mars, she said. Stoker told her private audience Sunday evening that by comparing discoveries made at Rio Tinto with data collected by ground-based telescopes and orbiting spacecraft, including the European Space Agency's Mars Express, she and Lemke have made a very a strong case that life exists below Mars' surface. The two scientists, according to sources at the Sunday meeting, based their case in part on Mars' fluctuating methane signatures that could be a sign of an active underground biosphere and nearby surface concentrations of the sulfate jarosite, a mineral salt found on Earth in hot springs and other acidic bodies of water like Rio Tinto that have been found to harbor life despite their inhospitable environments. One of NASA's Mars Exploration Rovers, Opportunity, bolstered the case for water on Mars when it discovered jarosite and other mineral salts on a rocky outcropping in Merdiani Planum, the intrepid rover's landing site chosen because scientists believe the area was once covered by salty sea. Stoker and Lemke's research could lead the search for Martian biology underground, where standing water would help account the curious methane signatures the two have been analyzing. They are desperate to find out what could be producing the methane, one attendee told Space News. Their answer is drill, drill, drill. NASA has no firm plans for sending a drill-equipped lander to Mars, but the agency is planning to launch a powerful new rover in 2009 that could help shed additional light on Stoker and Lemke's intriguing findings. Dubbed the Mars Science Laboratory, the nuclear-powered rover will range farther than any of its predecessors and will be carrying an advanced mass spectrometer to sniff out methane with greater sensitivity than any instrument flown to date. 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. http://story.news.yahoo.com/news?tmpl=story&cid=96&e=3&u=/space/20050216/sc_space/exclusivenasaresearchersclaimevidenceofpresentlifeonmars
New Signs of Recent Glaciers, Volcanoes and Flowing Water on Mars (Moderator)	posted 3/20/05 5:12 AM     New Signs of Recent Glaciers, Volcanoes and Flowing Water on Mars By Robert Roy Britt Senior Science Writer posted: 16 March, 2005 1:00 p.m. ET New images of Mars reveal that flowing water, large glaciers and active volcanoes have scoured the planet in recent geologic times. Scientists say Mars has been geologically active in the past few million years -- an eyeblink in the planet's 4.5-billion-year history. Three studies appearing in the March 17 issue of the journal Nature add to a growing body of evidence that points to recent liquid water and present vast stores of underground ice near the planet’s equator. Combined, the research provides further impetus to search Mars for signs of life, scientists said. Hot spots Billions of years ago, Mars was warmer and wetter than today, according to evidence of past water seen by NASA's two Mars rovers currently exploring the planet. Scientists are eager to learn whether water has graced the planet in recent times, because liquid water is a key ingredient for life as we know it. Likewise, if the red planet remains volcanically active, local hot spots could serve as incubators for microbial life, as they do in otherwise desolate places on Earth. No firm evidence for life on Mars has been presented, but in recent months signs of methane in the Martian atmosphere have piqued the curiosity of astrobiologists. The methane could be generated by volcanic activity or mark the signature of subsurface life, but its detection remains controversial nonetheless. In the three new papers, researchers lay out the strongest case yet that volcanism may be ongoing and glacial activity recent. The observations were made by the High Resolution Stereo Camera (HRSC) on the European Space Agency’s Mars Express Mission. Explosive eruptions about 350 million years ago created depressions on the flanks of the volcano Hecates Tholus, according to a study led by Ernst Hauber of the German Aerospace Center. And just five million years ago, glacial deposits formed inside these depressions, the scientist concludes. The finding adds to a December study showing five volcanoes on Mars had been active as recently as two million years ago. Equatorial glaciers A group led by geologist James Head of Brown University reanalyzed landforms first thought to be glacial during the Viking missions of the 1970s. Head and his colleagues found the features are indeed evidence of geologically recent glacial activity near the equator. "Mars is very dynamic," according to Head. "We see that the climate change and geological forces that drive evolution on Earth are happening there." Glaciers appear to have moved from the Martian poles to the tropics between 350,000 years ago and 4 million years ago. "This glaciation may be a response to recent changes in the incidence of sunlight induced by variations in obliquity of the planet’s spin axis," said Victor Baker, who was not involved in the research. The new studies suggest that Mars is currently in an interglacial period. As the planet tilts closer to the sun, ice near the equator is expected to vaporize. In a third paper, additional detail is provided on a previous announcement of a frozen chunk of water - roughly the size of the North Sea - that formed in the last five million years near the Martian equator. The area is thought to have been flooded by liquid water carried along by volcanic eruptions in a region called Cerberus Fossae. "The three papers provide an overwhelming case for new thinking about recent geological activity on Mars," writes Baker in an analysis of the work. Cataclysmic flooding Baker said the findings support a 1991 hypothesis, then considered outrageous, that Mars has experienced episodes of cataclysmic flooding in modern times. Water is thought to have formed temporary seas, but researchers had long assumed it all evaporated into the thin Martian air. Many scientists now agree that much of the water remained. "The evidence from HRSC for recent aqueous activity suggests that the water is still present, as ice on the ground and water deep beneath the surface," Baker said. In early May, Mars Express will deploy a radar instrument that should be able to detect subsurface water and ice several miles down. "Evidence from the latest pictures indicates that the water will surely be there," Baker said. Where there is water, there could be life. Many investigations on Earth have turned up extremophiles -- microbes living in frigid conditions, thriving in extremely salty water, and gathering around volcanic vents. Last month scientists announced the discovery of bacteria that had survived in a state of frozen suspension for 32,000 years. "We're now seeing geological characteristics on Mars that could be related to life," Head said. "But we're a long way from knowing that life does indeed exist. The glacial deposits we studied would be accessible for sampling in future space missions. If we had ice to study, we would know a lot more about climate change on Mars and whether life is a possibility there." http://www.space.com/scienceastronomy/050316_mars_geology.html

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