Mars  

NASA's Mars Curiosity rover on Mars has produced new results—methane and other organic chemicals. Researchers do not know what caused the spikes, but the most intriguing  possible explanation is "biological."

NASA's Mars Curiosity rover has found a tenfold spike in methane, an organic chemical, in the atmosphere around it and detected other organic molecules in a rock-powder sample collected by the robotic laboratory’s drill.

The research is published in the journal Science.

"This temporary increase in methane—sharply up and then back down—tells us there must be some relatively localized source," said Sushil Atreya of the University of Michigan, Ann Arbor, and Curiosity rover science team.

"There are many possible sources, biological or non-biological, such as interaction of water and rock."

Researchers used Curiosity’s onboard Sample Analysis at Mars (SAM) laboratory a dozen times in a 20-month period to sniff methane in the atmosphere. During two of those months, in late 2013 and early 2014, four measurements averaged seven parts per billion. Before and after that, readings averaged only one-tenth that level.

NASA's Mars rover Curiosity drilled into the rock target, "Cumberland," (shown above) during the 279th Martian day, or sol, of the rover's work on Mars and collected a powdered sample of material from the rock's interior.

Curiosity also detected different Martian organic chemicals in powder drilled from the rock, the first definitive detection of organics in surface materials of Mars. These Martian organics could either have formed on Mars or been delivered to Mars by meteorites.

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Organic molecules, which contain carbon and usually hydrogen, are chemical building blocks of life, although they can exist without the presence of life. Curiosity's findings from analyzing samples of atmosphere and rock powder do not reveal whether Mars has ever harbored living microbes, but the findings do shed light on a chemically active modern Mars and on favorable conditions for life on ancient Mars.

"We will keep working on the puzzles these findings present," said John Grotzinger, Curiosity project scientist of the California Institute of Technology in Pasadena (Caltech). "Can we learn more about the active chemistry causing such fluctuations in the amount of methane in the atmosphere? Can we choose rock targets where identifiable organics have been preserved?"

"This first confirmation of organic carbon in a rock on Mars holds much promise. Organics are important because they can tell us about the chemical pathways by which they were formed and preserved. In turn, this is informative about Earth-Mars differences."

Researchers worked many months to determine whether any of the organic material detected in the Cumberland sample was truly Martian. Curiosity’s SAM lab detected in several samples some organic carbon compounds that were, in fact, transported from Earth inside the rover. However, extensive testing and analysis yielded confidence in the detection of Martian organics.

Identifying which specific Martian organics are in the rock is complicated by the presence of perchlorate minerals in Martian rocks and soils. When heated inside SAM, the perchlorates alter the structures of the organic compounds, so the identities of the Martian organics in the rock remain uncertain.

"This first confirmation of organic carbon in a rock on Mars holds much promise," said Curiosity participating scientist Roger Summons of the Massachusetts Institute of Technology in Cambridge. "Organics are important because they can tell us about the chemical pathways by which they were formed and preserved. In turn, this is informative about Earth-Mars differences and whether or not particular environments represented by Gale Crater sedimentary rocks were more or less favorable for accumulation of organic materials. The challenge now is to find other rocks on Mount Sharp that might have different and more extensive inventories of organic compounds."

Researchers also reported that Curiosity's taste of Martian water, bound into lakebed minerals in the Cumberland rock more than three billion years ago, indicates the planet lost much of its water before that lakebed formed and continued to lose large amounts after.

SAM analyzed hydrogen isotopes from water molecules that had been locked inside a rock sample for billions of years and were freed when SAM heated it, yielding information about the history of Martian water. The ratio of a heavier hydrogen isotope, deuterium, to the most common hydrogen isotope can provide a signature for comparison across different stages of a planet's history.

"It's really interesting that our measurements from Curiosity of gases extracted from ancient rocks can tell us about loss of water from Mars," said Paul Mahaffy, SAM principal investigator of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of a the report.


SOURCE  NASA

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 Mars  

The first scoop of soil analyzed by the SAM instrument of NASA's Curiosity rover reveals that fine materials on the surface of the planet contain two percent water by weight. The discovery reveals new insights into the conditions on Mars and the planet's ability to support life.

NASA has announced that the Mars Curiosity rover has successfully found water in a sample of soil taken from a digging site known as "Rocknest." This isn't the first proof of water on Mars, but it could be the proof NASA needs to start realistically considering sending people to the Red Planet.

The announcement supports research from the Mars Reconnaissance Orbiter (MRO), a NASA probe, say they've observed seasonally varying features on the surface of the Red Planet that could be carved by briny water.

Previously ice has been found on Mars at the planet's poles, inside some craters and sitting beneath the surface across vast swaths of the middle latitudes. Also, there is ample evidence that liquid water formed vast oceans on Mars in the distant past, carving valleys and other surface features.

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With a handful of exceptions, water is necessary for life as we know it. Not only is most of Earth's life water-based, but most scientists think life wouldn't have arisen in the first place if not for the watery "primordial soup" that covered the young Earth. Water makes it easier for organic molecules to swirl around and bump into each other to form interesting compounds.

"One of the most exciting results from this very first solid sample ingested by Curiosity is the high percentage of water in the soil," said Laurie Leshin, lead author of one paper and dean of the School Science at Rensselaer Polytechnic Institute. "About 2 percent of the soil on the surface of Mars is made up of water, which is a great resource, and interesting scientifically." The sample also released significant carbon dioxide, oxygen and sulfur compounds when heated.

According to NASA, each cubic foot of Martian soil contains around two pints of liquid water, though the molecules are not freely accessible; they are bound to other minerals in the soil.

Sample Analysis at Mars instrument suite

The Curiosity rover has been on Mars for a little over a year now, landing in an area near the equator of the planet known as Gale Crater. Its target is to circle and climb Mount Sharp, which is near the center of the crater, a five kilometer high mound of layered rock that will help scientists unravel the history of the planet.

Now, NASA scientists published a series of five papers in the journal Science, which detail the experiments carried out by the various scientific instruments aboard Curiosity in its first four months on the martian surface. Though highlights from the year-long mission have been released at conferences and press conferences, these are the first set of formal, peer-reviewed results from the Curiosity mission.

One of those instruments was employed in the current research: the Sample Analysis at Mars (SAM) instrument suite, which includes a gas chromatograph, a mass spectrometer and a tunable laser spectrometer. These tools enable SAM to identify a wide range of chemical compounds and determine the ratios of different isotopes of key elements.

"We tend to think of Mars as this dry place – to find water fairly easy to get out of the soil at the surface was exciting to me," said Laurie Leshin, dean of science at Rensselaer Polytechnic Institute and lead author on the Science paper which confirmed the existence of water in the soil. "If you took about a cubic foot of the dirt and heated it up, you'd get a couple of pints of water out of that – a couple of water bottles' worth that you would take to the gym."

About 2% of the soil, by weight, was water. Curiosity made the measurement by scooping up a sample of the Martian dirt under its wheels, sieving it and dropping tiny samples into an oven in its belly, an instrument called Sample Analysis at Mars. "We heat [the soil] up to 835C and drive off all the volatiles and measure them," said Leshin. "We have a very sensitive way to sniff those and we can detect the water and other things that are released."

Aside from water, the heated soil released sulphur dioxide, carbon dioxide and oxygen as the various minerals within it were decomposed as they warmed up.

Along with discoveries of organic chemicals on Mars, the existence of ample water on the planet further strengthens the impetus for humans to explore and eventually colonize Mars.


SOURCE  NASA

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