சனி, 31 டிசம்பர், 2016

LIFE ON MARS: NASA’S CURIOSITY ROVER HITS ‘JACKPOT’ IN CRATER, STRONG INDICATORS OF HABITABILITY

Detecting alien life in the universe has been a seeming thankless and frustratingly nonproductive chore thus far, but NASA’s Mars Curiosity Rover has gathered what looks to be quite a bit of promising data regarding the Red Planet’s former habitability, scientists revealed recently. In fact, they are referring to the findings as a “jackpot” of mineral deposits that present a geological history of the planet for millions of years and everything is pointing to Mars having once — if not actually being a home to living organisms — had the capability of sustaining life.
Astrobiology magazine reported this month that NASA’s Mars Curiosity Rover, in its steady journey ascension up Gale Crater’s central peak, has, according to its mission handlers, gathered considerable evidence from ancient lake beds and groundwater environments that are promising for the possibility of life. Announcing the rover’s Mars findings at the American Geophysical Union’s annual fall meeting in San Francisco, scientists said they had “hit a jackpot” of mineral deposits.
John Grotzinger, a geologist from the California Institute of Technology, said it “all” looked good for Mars’ habitability in the long-term.
“We see all of the properties in place that we really like to associate with habitability. There’s nothing extreme here. This is all good for habitability over time.”
The Curiosity Rover is now taking samples of the Martian surface every 25 feet as it makes its way uphill. As it progresses, the rover obtains samples of younger and younger rock.
Scientists believe Gale Crater is one of the most likely spots on Mars to have supported living organisms. It is the lowest point on the planet within thousands of miles, and scientists believe a lake of water was once present in the crater and that it also seeped underground. It is believed that groundwater may have lingered after the surface water dried up or evaporated. This would have provided more time for life to persist in the area.
The changing conditions are evident in the type of iron oxide that has been detected in the rocks as the NASA rover ascends the peak. The lower, older layers of Gale Crater have a preponderance of mineral magnetite, which is indicative of less weathering. The upper layers of the crater show evidence of a greater amount of oxidizing hematite, which indicates a more acidic environment (though not one too extreme). Grotzinger said it was “acidic but never super acidic. It’s totally the kind of environment where an acidophilic organism could enjoy it.”
NASA’s Mars Curiosity Rover is collecting samples to better determine if life has ever existed on the Red Planet. [Image by Kirschner/Thinkstock/Getty Images]

Besides the iron oxides, the element boron has been found on Mars for the first time inside the crater. Although good news in that boron, when found on Earth, is often found in arid sites (like Death Valley in California) and is associated with the formation of RNA (ribonucleic acid), the type of boron being found on Mars is as yet unknown. If it is found to be like the boron on Earth, it would suggest that the crater was able to at least at some point sustain life.
All the different minerals and the boron, which was identified by firing the Mars Curiosity’s laser (the ChemCam) and spectrographically analyzing the elemental components of a sample, all point to complexity. And in the search for alien life, complexity is good, according to Grotzinger.
“We are seeing chemical complexity indicating a long, interactive history with the water. The more complicated the chemistry is, the better it is for habitability. The boron, hematite and clay minerals underline the mobility of elements and electrons, and that is good for life.”
The element boron has been detected on Mars for the first time and may, along with other mineral deposits, indicate life may have once existed on Mars. [Image by Shocktrek Images/Thinkstock/Shutterstock]
It is all indicative of “a dynamic system,” Grotzinger said, according to Astronomy magazine. “They interact with groundwater as well as surface water. The water influences the chemistry of the clays, but the composition of the water also changes. The more complicated the chemistry is, the better it is for habitability.”
As complex and complicated as the habitability indicators might be on Mars, there still exists no empirical proof that life is extant or has ever prevailed there. At the same time, it is in the ever-increasing number of tantalizing findings that offer the promise of the possibility of discovering life on Mars that continue to provide scientists with the fuel to persist in their search.