Credit: NASA 
 
 SYDNEY: Water originating from solar winds has been found in the Moon’s soil, U.S. researchers have announced. 
 
 Water on the Moon is not a new discovery – there are known sources in craters at the polar regions – but this finding has revealed a new source: the solar winds. 
 
 In a report published in Nature Geoscience, researchers claimed that hydrogen ejected from the Sun’s atmosphere is carried in solar winds and implanted in the lunar soil, where it reacts with oxygen already present on the Moon’s surface. 
 
 Colonising the Moon 
 
 The finding could be a useful resource for future human settlement on the Moon, according to Yang Liu from the University of Tennessee, lead author of the paper. 
 
 “Now we have ready sources of water that can not only be consumed by plants and humans, but also electrolysed into its constituent elements – hydrogen and oxygen – to make rocket fuel,” she said. 
 
 However, geochemist Ross Taylor from the Australian Academy of Science, who was not involved in the research, said harvesting water from lunar soil would be complicated and using it for human settlement probably unrealistic. 
 
 “I think it’s a pretty long shot, extracting the water might be as much trouble as it’s worth,” he said. 
 
 Water origin unknown until now 
 
 With no atmosphere to protect it, the lunar surface is buffeted by solar winds and comet collisions, which create a soil of crushed materials called the ‘regolith’. 
 
 Researchers analysed a collection of cemented regolith grains – a glass-like material – to find reacting hydrogen and oxygen molecules which they attributed to solar winds. 
 
 Three independent studies observed water on the surface of the Moon in 2009, but the origin was unknown until now, said Liu. 
 
 “We did have the understanding that the Moon is a very dry place, what this work has done is look at a new source of lunar water,” added planetary scientist Michele Bannister from Australian National University (ANU) in Canberra, who was not involved in the study. 
 
 “The researchers have proved you can generate water on the surface of the Moon purely from the impact of the wind of the Sun,” she said. 
 
 Beyond the snow line 
 
 Initially, it was believed all water in the inner Solar System was delivered via icy bodies such as micrometeorites or comets that came from further out in space – beyond the ‘snow line’ where it is cold enough for water to condense. 
 
 Having established another source of water that originates at the centre of the Solar System, the report said it “reshapes this perspective”. 
 
 It is also not known what percentage of the lunar soil contains water, and Bannister said a bigger sample is needed. 
 
 “What they’re working with is a tiny fraction of lunar soil brought back by the Apollo missions, so it’s very hard to generalise from a couple of grains of sand – or glass, which is essentially what they have,” she said. 
 
 Water in the Universe 
 
 Liu said a source of water in the solar winds “emphasises the possibility of finding water on the surface of other similar airless bodies”. 
 
 “It extends our concept of the presence of water in the inner Solar System,” she said. 
 
 Although the study has introduced a new source of water relevant to the wider universe, Taylor explained it is really just chemistry. 
 
 “It’s a very interesting scientific finding and it takes a lot of modern technology and instrumentation to reach that, but it doesn’t alter the overall picture,” he said. 
 
 “The reason everyone’s interested in water is partly because water has a sort of ‘sacred cow’ status. It’s essential to life as we know it and this gives it importance, but it’s just another chemical compound.” ||||| SPACE.com reader George Garcia sent in his photo of the September 2012 harvest moon taken on Sept. 29, 2012, in Montebello, CA. 
 
 Glass beads within moon rocks suggest that water seen on the lunar surface originates from the solar wind, researchers say. 
 
 These findings suggest that other airless bodies in the solar system may also possess water on their surfaces, investigators added. 
 
 Arguments raged for years as to whether the moon harbored frozen water or not. Recent findings confirmed that water does wet the moon, although its surface remains drier than any desert on Earth. 
 
 "With the cost of $25,000 for taking one pint of water to the moon, it is essential that we develop processes of producing water from the materials on the moon," said the study's lead author, Yang Liu, at the University of Tennessee at Knoxville. "This is paramount to human settlement of the moon in the near future." [Gallery: Our Changing Moon] 
 
 "This water would be of most value as rocket fuel — liquid hydrogen and liquid oxygen," Liu added. "Until the recent discovery of water in and on the moon, this was going to be a very energy-intensive endeavor to separate these elements from the lunar rocks and soil. Now we have ready sources of water that can be consumed by plants and humans, but also broken up into its constituent elements — oxygen and hydrogen. Thus, we could use the moon as a jump-board for missions to Mars and beyond." 
 
 It remained uncertain where all of this water might come from, although some apparently came from ice-rich comets. To find out more, scientists analyzed lunar surface dust, or regolith, that astronauts on the Apollo missions brought from the moon. 
 
 "Most samples actually come from an Apollo 11 soil collected by Neil Armstrong," Liu told SPACE.com. 
 
 Lunar regolith is created by meteoroids and charged particles constantly bombarding lunar rock. The researchers focused on grains of glass in the samples that were created in the heat of countless micrometeoroid impacts on the moon. They reasoned this glass might have captured any water in the regolith before it cooled and solidified. 
 
 The investigators found that a large percentage of this glass contained traces of wetness — between 200 and 300 parts per million of water and the molecule hydroxyl, which is much like water, save that each of its molecules possesses just one hydrogen atom, not two. 
 
 To figure out where this water and hydroxyl originated from, the scientists looked at their hydrogen components. Hydrogen atoms come in a variety of isotopes, each with a different number of neutrons in their nuclei — regular hydrogen has no neutrons, while the isotope known as deuterium has one in each atomic nucleus. 
 
 The sun is naturally low in deuterium because its nuclear activity rapidly consumes the isotope. All other objects in the solar system possess relatively high levels of it, remnants of deuterium that existed in the nebula of gas and dust that gave birth to the solar system. 
 
 The researchers found that the water and hydroxyl seen in the lunar glass were both low in deuterium. This suggests their hydrogen came from the sun, probably blasted onto the moon via winds of charged particles from the sun, which continuously streams from the sun at a rate of 2.2 billion pounds (1 billion kilograms) per second. The moon, lacking a significant atmosphere or magnetic field, slowly captures all the particles striking it. The hydrogen particles then bonded with oxygen bound in rocks on the lunar surface. 
 
 "The origin of surface water on the moon was unclear," Liu said. "We provide robust evidence for a solar wind origin. This finding emphasizes the potential in finding such water on the surface of other similar airless bodies, such as Eros, Deimos, Vesta." 
 
 The scientists detailed their findings online Sunday (Oct. 14) in the journal Nature Geoscience. 
 
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– There is water on the moon, and it comes from an unlikely source: the sun. That's the conclusion of a new study, after studying soil samples brought back from the original Apollo 11 mission, Cosmos reports. While studies dating back to 2008 have pointed to the existence of water on the moon, until now no one was sure where it came from. Now, University of Tennessee researchers believe that solar winds carry hydrogen ejected from the sun's atmosphere to the moon. The study will force scientists to rethink the conventional wisdom that water in the inner solar system generally comes from icy meteors or comets. This more reliable source of water could make a lunar colony more feasible, the lead author says. "This water would be of most value as rocket fuel—liquid hydrogen and liquid oxygen," she tells Space.com. "We could use the moon as a jump-board for missions to Mars and beyond." Others aren't as sure. "Extracting the water might be as much trouble as it's worth," one independent geochemist warns.