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Researchers doing in depth analysis of Martian Meteorite ALH 84001 show that organic compounds were formed on Mars, but that's it, they don't think it came from primitive microbial life.

"The results of this study show that volcanic activity in a freezing climate can produce organic compounds. This implies that building blocks of life can form on cold rocky planets throughout the Universe - co-author Hans E.F. Amundsen from Earth and Planetary Exploration Services.

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Chemicals in a Martian meteorite that were once held up as possible evidence of life on ancient Mars were more likely the product of heat, water and chemistry, according to a new study. Researchers from the Carnegie Institution of Washington and the University of Oslo in Norway reached that conclusion after comparing the four-pound (two-kilogram) extraterrestrial rock, ALH84001, with samples of earthly volcanic materialand discovering a matching pattern of minerals consistent with a chemical process that yields carbon compounds after rapid heating and cooling.
Although the study does not support the existence of life on Mars, researchers say it shows that some of the chemical precursors of lifeat least as we know itwere kicking around on the Red Planet some 4.5 billion years ago.


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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 aliensalbeit of bacterial dimensions.

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Title: Observations from a 4-Year Contamination Study of a Sample Depth Profile Through Martian Meteorite Nakhla
Authors: Jan Toporski, Andrew Steele

Morphological, compositional, and biological evidence indicates the presence of numerous well-developed microbial hyphae structures distributed within four different sample splits of the Nakhla meteorite obtained from the British Museum (allocation BM1913,25). By examining depth profiles of the sample splits over time, morphological changes displayed by the structures were documented, as well as changes in their distribution on the samples, observations that indicate growth, decay, and reproduction of individual microorganisms. Biological staining with DNA-specific molecular dyes followed by epifluorescence microscopy showed that the hyphae structures contain DNA. Our observations demonstrate the potential of microbial interaction with extraterrestrial materials, emphasize the need for rapid investigation of Mars return samples as well as any other returned or impactor-delivered extraterrestrial materials, and suggest the identification of appropriate storage conditions that should be followed immediately after samples retrieved from the field are received by a handling/curation facility. The observations are further relevant in planetary protection considerations as they demonstrate that microorganisms may endure and reproduce in extraterrestrial materials over long (at least 4 years) time spans. The combination of microscopy images coupled with compositional and molecular staining techniques is proposed as a valid method for detection of life forms in martian materials as a first-order assessment. Time-resolved in situ observations further allow observation of possible (bio)dynamics within the system.

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Stop search for life on Mars
A NASA research team of scientists at the Johnson Space Centre and at Stanford University has found evidence that strongly suggests primitive life may have existed on Mars more than 3.6 billion years ago.
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Possible signs of alien life have been found inside a Martian meteorite.
Scientists have discovered tiny tunnels in the rock that may have been bored by micro-organisms on Mars.
But researchers are cautious after the embarrassment over another Martian meteorite once alleged to contain signs of life.
Ten years ago, scientists from NASA said they had found small rod-like structures in the meteorite that were believed to be fossil bacteria.
But most experts now believe there is no evidence of life in the 1.9 kilogram rock, ALH 84001. The rods and other "biosignatures" could all have been produced by inorganic processes, scientists say.
The new meteorite, called Nakhla, fell to Earth on June 28, 1911, exploding into dozens of fragments over Egypt.
Nakhla was one of the first meteorites confirmed to have come from Mars by its chemical composition.
The meteorite is estimated to be 1.3 billion years old and shows signs of being altered by the water once thought to have flowed on Mars. It spent some 11 million years drifting through space before entering Earth's atmosphere.
Scientists are now quietly taking seriously the possibility that Nakhla contains signs of Martian life, according to a US biology professor writing in New Scientist magazine.
A team led by Martin Fisk at Oregon State University found tiny tubular holes similar to those in volcanic Earth rocks believed to be caused by bacteria or ancient organisms called archaeans.

Averaging one to three micrometres in diameter and up to 100 micrometres long, the tunnels often contain biomolecules such as nucleic acids.

"When Fisk's team examined volcanic minerals inside Nakhla, to their surprise they found small tunnels virtually identical in size and shape to those in Earth rocks" - Peter Ward, from the University of Washington in Seattle.

John McKay, from the Johnson Space Centre in Houston, Texas, later found carbon-rich matter in the rock's tunnels. Analysis suggested that it was carbon originating on Mars an intriguing finding since all known life is based on carbon.

"Those involved have been careful not to get carried away by this new evidence" - Dr Peter Ward.

Professor Fisk and his colleagues have stopped short of claiming the tunnels are proof of life on Mars.
Instead they say the features might be a "useful biosignature" given the abundance of volcanic rock in the solar system.

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It was a science fiction fantasy come true: Ten years ago this summer, NASA announced the discovery of life on Mars.

At a Washington, D.C., news conference, scientists showed magnified pictures of a four-pound Martian meteorite riddled with wormy blobs that looked like bacterial colonies. The researchers explained how they had pried numerous clues from the rock, all strongly supporting their contention that microscopic creatures once occupied its nooks and crannies.

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When scientists examined ALH84001, the meteorite from Mars under a microscope, they discovered tiny mineral spheres that, some argued, were produced by living organisms. Now, researchers working in the high Arctic have found similar mineral features, produced not by microbes, but by a volcano.

For the past two summers, a group of scientists has travelled to the largest islands in the Svalbard archipelago to study an environment that sheds light on a notorious meteorite, discovered at the opposite end of the Earth, in Antarctica.
Sverrefjell volcano erupted about a million years ago, forcing magma up through an overlying glacier. The carbonate globules in the Svalbard rocks were found embedded inside material that was spewed out when the volcano erupted. An analysis of the material surrounding the globules - a mineral known as olivine, for its dull green colour - showed that it came from the Earth's mantle, some 40 to 50 kilometres beneath the surface. Before the eruption, it was in a molten state, deep underground. Within a few days of being ejected onto the surface, it had cooled and hardened in the freezing glacial environment aboveground. During this cooling process, the carbonate globules became deeply embedded within the surrounding rock.

"That doesn't mean to say that (the Svalbard globules) are exactly the same as the Martian globules and are formed in exactly the same conditions, but it gives us a window into that formation process. There is a formation mechanism for them that doesn't rely on biology" - Andrew Steele

Andrew Steele, who is with the Carnegie Institution of Washington, is a member of AMASE (Arctic Mars Analog Svalbard Expedition), an international team of scientists who for the past three years have been studying the Svalbard environment. The major aspect of their work is to test out life-detection instruments that will be used on future missions to Mars. But it was the discovery of Svalbard's carbonate globules that first caught their attention.

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A new study of a meteorite that originated from Mars has revealed a series of microscopic tunnels that are similar in size, shape and distribution to tracks left on Earth rocks by feeding bacteria.

And though researchers were unable to extract DNA from the Martian rocks, the finding nonetheless adds intrigue to the search for life beyond Earth.
Results of the study were published in the latest edition of the journal Astrobiology.
Martin Fisk, a professor of marine geology in the College of Oceanic and Atmospheric Sciences at Oregon State University and lead author of the study, said the discovery of the tiny burrows do not confirm that there is life on Mars, nor does the lack of DNA from the meteorite discount the possibility.

"Virtually all of the tunnel marks on Earth rocks that we have examined were the result of bacterial invasion. In every instance, we've been able to extract DNA from these Earth rocks, but we have not yet been able to do that with the Martian samples. There are two possible explanations: One is that there is an abiotic way to create those tunnels in rock on Earth, and we just haven't found it yet. The second possibility is that the tunnels on Martian rocks are indeed biological in nature, but the conditions are such on Mars that the DNA was not preserved" - Martin Fisk.

More than 30 meteorites that originated on Mars have been identified. These rocks from Mars have a unique chemical signature based on the gases trapped within. These rocks were "blasted off" the planet when Mars was struck by asteroids or comets and eventually these Martian meteorites crossed Earth's orbit and plummeted to the ground.
One of these is Nakhla, which landed in Egypt in 1911, and provided the source material for Fisk's study. Scientists have dated the igneous rock fragment from Nakhla which weighs about 20 pounds at 1.3 billion years in age. They believe that the rock was exposed to water about 600 million years ago, based on the age of clay found inside the rocks.

"It is commonly believed that water is a necessary ingredient for life, so if bacteria laid down the tunnels in the rock when the rock was wet, they may have died 600 million years ago. That may explain why we can't find DNA it is an organic compound that can break down"- Martin Fisk.

Other authors on the paper include Olivia Mason, an OSU graduate student; Radu Popa, of Portland State University; Michael Storrie-Lombardi, of the Kinohi Institute in Pasadena, California; and Edward Vicenci, from the Smithsonian Institution.
Fisk and his colleagues have spent much of the past 15 years studying microbes that can break down igneous rock and live in the obsidian-like volcanic glass. They first identified the bacteria through their signature tunnels then were able to extract DNA from the rock samples which have been found in such diverse environments on Earth as below the ocean floor, in deserts and on dry mountaintops.
They even found bacteria 4,000 feet below the surface in Hawaii that they reached by drilling through solid rock.
In all of these Earth rock samples that contain tunnels, the biological activity began at a fracture in the rock or the edge of a mineral where the water was present. Igneous rocks are initially sterile because they erupt at temperatures exceeding 1,000 degrees C. and life cannot establish itself until the rocks cool. Bacteria may be introduced into the rock via dust or water, Fisk pointed out.

"Several types of bacteria are capable of using the chemical energy of rocks as a food source. One group of bacteria in particular is capable of getting all of its energy from chemicals alone, and one of the elements they use is iron which typically comprises 5 to 10 percent of volcanic rock"- Martin Fisk.

Another group of OSU researchers, led by microbiologist Stephen Giovannoni, has collected rocks from the deep ocean and begun developing cultures to see if they can replicate the rock-eating bacteria. Similar environments usually produce similar strains of bacteria, Fisk said, with variable factors including temperature, pH levels, salt levels, and the presence of oxygen.
The igneous rocks from Mars are similar to many of those found on Earth, and virtually identical to those found in a handful of environments, including a volcanic field found in Canada.

One question the OSU researchers hope to answer is whether the bacteria begin devouring the rock as soon as they are introduced. Such a discovery would help them estimate when water and possibly life may have been introduced on Mars.

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