NASA confirms discovery of liquid water on Mars
Fresh observations of surface features known as recurring slope lineae (RSL) appear to have confirmed the presence of liquid water on Mars. The evidence of surface water may have profound implications in the ongoing search for Martian life, both ancient and present, and as a resource to be used in a future manned mission to the Red Planet.
Previous observationsof RSLs, which were first discovered in 2010, drew many scientists tothe theory that they may be the result of active water flows presenton the Martian surface. The features appear as dark lines streakingdown steep slopes such as Hale Crater. The running water theory wasbased on factors such as the RSLs' appearance at certain times of theyear, with the streaks appearing to flow downhill during warmerseasons, where temperatures rise above -10 °F (-23 °C) ,and subsequently fade in cooler periods.
However, though theobservations were compelling, the scientific community lacked theevidence to conclusively point to water as the cause of the RSLs – that is, until today. New observations carried out by NASA's MarsReconnaissance Orbiter (MRO) have provided strong evidence that theRSLs are indeed the result of seasonal water flows emanating fromslopes present on the Red Planet.
The observations madeuse of the spacecraft's Compact Reconnaissance Imaging Spectrometerfor Mars (CRISM) to sample the light absorption characteristics ofthe RSLs. NASA scientists then analyzed the readings back on Earth,and it was found that the absorption rates matched thecharacteristics of hydrated minerals called perchlorates. Based onthe chemical signature returned by the MRO, it is believe that theflows are composed of a mixture of magnesium perchlorate, magnesiumchlorate and sodium perchlorate.
"Our quest on Marshas been to 'follow the water,' in our search for life in theuniverse, and now we have convincing science that validates whatwe’ve long suspected," said John Grunsfeld, associateadministrator of NASA’s Science Mission Directorate in Washington. "This is a significant development, as it appears to confirm thatwater – albeit briny – is flowing today on the surface of Mars."
The chemical signatureof hydrated salts was detected on a number of RSL points across theMartian globe, but only where the features were found to be verywide, with narrower RSL's exhibiting no traces of hydration.
"We found thehydrated salts only when the seasonal features were widest, whichsuggests that either the dark streaks themselves or a process thatforms them is the source of the hydration" stated Lujendra Ojhaof the Georgia Institute of Technology, Atlanta, and lead author of areport on the findings published on Sept. 28 by Nature Geoscience."In either case, the detection of hydrated salts on these slopesmeans that water plays a vital role in the formation of thesestreaks."
The leading theory onhow RSLs are formed revolves around a process known as deliquescence.This process describes the ability of perchlorate salts to absorbatmospheric water. When the humidity in the Martian atmosphere ishigh enough, the salts will absorb atmospheric water until theydissolve and create a liquid solution
Ordinarily, pure,unfrozen water would quickly boil off in to space, however thebrine-like solution detected on theMartian surface would give the water enough stability to survive andflow downhill. The briny mixture detected in the RSLs should keep thewater from freezing until it reaches below -94 °F (-70°C). In terms of quantity, the flows are predictedto be mostly subsurface, meaning that we could expect a thin layer ofwet soil rather than actual flowing water.
Arguably the mostexciting aspect of the announcement are the implications that thediscovery has in regard to the existence of life on Mars, either nowor in the ancient past. The presence of water on our planet was oneof the key factors in the development of early life, and thediscovery of this briny mixture on Mars means that the Red Planet maybe much more conducive to near-surface microbial life. Mostimportantly, it has given future missions to the Red Planet an idealtarget in the search for extraterrestrial life.
During the briefing, itwas mooted that Curiosity may be sent to examine the flows, howeverthe panel was unsure of whether the mobile laboratory had theability to reach or carry out the necessary experiments. Furthermorethere was a danger of contamination of microbial life from the roveritself. The panel outlined a scenario in which we make a breakingdiscovery, that turns out to be life that we brought with us in thefirst place.
There isalso significant potential of using the newly-discovered water as aresource during future manned missions, for example as a source ofoxygen and drinking water.
"All of thescientific discoveries that we are making on the surface of Mars,Curiosity at Gale Crater, observations from the Mars ReconaissanceOrbiter are giving us a much better view that Mars has resourcesthat are useful to future travelers" explained Grunsfeld."When you have water, you have hydrogen and oxygen – that's whatwe make rocket fuel out of."
The ramifications oftoday's announcement will undoubtedly inform future efforts, both mannedand unmanned seeking to explore and understand the Red Planet,especially regarding to Mankind's ongoing mission to discoverextraterrestrial life. Mars is now a more attractive candidate thanever as a site to make this historic discovery, and serves as yetanother incentive to extend manned exploration beyond low-Earthorbit.