The Red Planet is in the news again this week: it appears that the planet which is in line for a bashing next year from Comet Siding Spring could once have supported life, as there is ice in the Martian soil. Does it support life now? There's no evidence of natural life there, and the lack of free methane in the atmosphere suggests that not even bacteria live on Mars now. But generally dismissed and debunked features such as the Mars Face remain as a testament to the planet's mysteries. For example, the photo accompanying this story was debunked as a 'tiny rock' on BadAstronomy.com and false stories that it had been 'photoshopped,' such as the one linked here, were widely circulated. The image was taken by the Rover Spirit in Gusev Crater in 2008, and this copy of it was drawn directly from NASA's record, and is unretouched. Had it been taken on Earth, it would have been accepted as that of a figure in a black heat-absorbing suit leaping out of sight. No second shot of the feature was ever released, and NASA did not respond to our request that this be done. Obviously, if the feature was no longer visible, the question of whether or not Mars has living inhabitants right now would have been answered.
Any colony on Mars would require water, and this latest finding means that it would be easy to obtain. The first scoop of soil analyzed by NASA’s Curiosity rover reveals that fine materials on the surface of the planet contain several percent water by weight. The results were published today in Science as one article in a five-paper special section on the Curiosity mission.
Dean of Science at the Rensselaer Polytechnic Institute, Laurie Leshin, is the study’s lead author says,“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 Leshin. “About 2 percent of the soil on the surface of Mars is made up of water, which is a great resource, and interesting scientifically.” So, the next question to be posed is: "Could Mars have ever supported life?"
Curiosity is the first rover on Mars to carry equipment for gathering and processing samples of rock and soil, but it is not capable of detecting life directly and so could not confirm the existence of either modern life or ancient fossil organisms. It can, and has, determined that the environment was habitable, however, and can check for associated organic compounds.
“We find that organics are not likely preserved in surface soils, which are exposed to harsh radiation and oxidants,” said Leshin. “We didn’t necessarily expect to find organic molecules in the surface fines, and this supports Curiosity’s strategy of drilling into rocks to continue the search for organic compounds. Finding samples with a better chance of organic preservation is key.”
One of the instruments employed in the current research: Sample Analysis at Mars, or SAM, includes a gas chromotograph, a mass spectrometer, and a tunable laser spectrometer enabling it to identify a wide range of chemical compounds and determine the ratios of different isotopes of key elements.
“This work not only demonstrates that SAM is working beautifully on Mars, but also shows how SAM fits into Curiosity’s powerful and comprehensive suite of scientific instruments,” said Paul Mahaffy, principal investigator for SAM at NASA’s Goddard Space Flight Center in Maryland. "By combining analyses of water and other volatiles from SAM with mineralogical, chemical, and geological data from Curiosity’s other instruments, we have the most comprehensive information ever obtained on martian surface fines. These data greatly advance our understanding of surface processes and the action of water on Mars.”
In the study, scientists used the rover to collect dust, dirt, and finely grained soil from a sandy patch known as “Rocknest.”, some of which was fed into SAM and heated to 835 degrees Celsius.The sample was baked to revealed a compound containing chlorine and oxygen, likely chlorate or perchlorate, previously known only from high-latitude locations on Mars, which suggests a more global distribution. The analysis also found carbonate materials which are known to form in the presence of water.
The results gave an insight into the composition of the planet’s surface, whilst offering a focus for future research.
“Mars has kind of a global layer, a layer of surface soil that has been mixed and distributed by frequent dust storms. So a scoop of this stuff is basically a microscopic Mars rock collection,” said Leshin. “If you mix many grains of it together, you probably have an accurate picture of typical martian crust. By learning about it in any one place, you’re learning about the entire planet.”
These results have implications for future Mars explorers: Leshin suggested that if a manned expedition was ever to land on Mars, they would have a readily available water source by merely heating the Martian soil. Good news then for the 'Mars One' colony, a non-profit-making group hoping to establish a permanent human settlement on Mars by 2023. A total of 165,000 Mars enthusiasts have already signed up for the planned space mission, though experts say that, whilst the journey is technically possible, it would be impossibly expensive at around 70 billion dollars, and the full impact of living in a weightless atmosphere with extreme temperatures should not be under-estimated. If they do make it to Mars, the group's long-term survival potential is thought to be very limited.
Scientists are also interested in the presence of methane gas on Mars, which could be a further indicator of the planet's habitability. About 90% to 95% of the methane in Earth's atmosphere is biologically derived, said Sushil Atreya, a University of Michigan researcher and co-investigator for SAM, said in November 2012. But the rover still has not detected methane gas, and, even if it had, the gas could have been produced by other sources such as volcanic activity. Scientists believe that there is still the potential for methane to be discovered, however.
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