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. 
 
 Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook & Google+. 
 
 For most of human history, the moon was largely a mystery. It spawned awe and fear and to this day is the source of myth and legend. But today we know a lot about our favorite natural satellite. Do you? Start the Quiz 0 of 10 questions complete ||||| Getty Images 
 
 The moon is home to some of the most lyrically named bodies of water that never existed. The Sea of Tranquility is familiar enough, but what about the Ocean of Storms, the Sea of Nectar, the Lake of Forgetfulness, the Bay of Rainbows? Altogether, the lunar map features 20 seas, 14 bays, 20 lakes and one ocean. That’s both poetic and ironic, because a world that’s positively drenched in aquatic names has not a drop of actual water. 
 
 Or that’s what we always thought. In recent years, however, evidence for a watery moon has been mounting—particularly from NASA’s Lunar Reconnaissance Orbiter and its sister probe, the Lunar Crater Observation and Sensing Satellite. The moon is hardly a sodden place—it’s wetter than the Sahara Desert, but that’s about it. Still, that’s huge compared to what we once believed. Now, a paper in Science explains in greater detail than ever how water got to so unlikely a place and how it survived the fiery violence that gave birth to the moon in the first place. 
 
 The prevailing—and now all-but universally accepted—theory for how the Earth-moon system came to be was first proposed in 1975 and quickly became known as the Big Whack theory. About 4.5 billion years ago, a Mars-sized planetesimal careered through the solar system and collided with the infant Earth, sending up a massive cloud of molten and vaporous debris. The hit-and-run world sailed on its way and the cloud of debris slowly accreted into the moon, eventually retreating to a stable orbit roughly 239,000 mi. (385,000 km) away, where it has remained ever since. 
 
 “The angular momentum, the distance, the size of the moon,” says Brown University geochemist Alberto Saal, the lead author of the Science paper, “there is no other model that can explain the physics of the Earth-Moon system than the Big Whack.” 
 
 (MORE: The Universe’s Biggest, Baddest Gamma Ray Burst Ever) 
 
 Physics isn’t chemistry, however, and none of this explained with any precision the elements and compounds—particularly water—that would have survived aboard the early moon. The inner solar system as a whole ought to be a very dry place. When the planets and moons that orbit the sun were first accreting, it took a very particular environment for water molecules to form. Anything too close to the sun would simply be too hot and energetic for H2O molecules to assemble themselves. You’d have to get about 3 astronomical units away (1 AU is the distance from the sun to the Earth) to reach what Saal calls the “snow line,” the place water could form. That boundary is roughly between Mars and Jupiter. 
 
 Nothing, however, would prevent water from being imported from the wet zone into the dry zone aboard comets or water-rich meteors known as carbonaceous chondrites. In recent years, comets have gained traction as the source of Earthly water. They’re mostly made of water ice and rock after all, and we now understand just how many billions—perhaps trillions—of them there are surrounding the solar system in the formations known as the Kuiper Belt and the Oort Cloud. 
 
 But there’s a good case to make for the carbonaceous chondrites too. They’re hardly the sodden snowballs comets are, and the little bit of water they do contain is integrated deep in their matrices. But there are a great, great many of the meteors flying around out there, and there’s nothing to say a downpour of rocks, rather than two or three comets, could not have watered us too. The growing study of exoplanets is helping to explain just how this could happen. 
 
 (MORE: Hopeful New Signs of Duplicate Earths) 
 
 “In 2011,” Saal says, “there were observations in other solar systems of large planets like Jupiter that probably migrated in towards their suns and then migrated back out, due to gravitational resonance. This would affect overall gravitational fields causing materials from deeper out to move in.” That material would likely include meteors. That same scenario could have played out here too, and there’s a relatively straightforward way to prove it. 
 
 Water comes in more than one form. So-called heavy water is not simple H2O, but 2H2O, containing a hydrogen isotope, known as deuterium. Unlike ordinary hydrogen, with just a proton in its nucleus, deuterium also contains a neutron. Heavy water and ordinary water are present on comets, carbonaceous chondrite meteors and Earth, but in different ratios, known as their deuterium/hydrogen, or D/H ratio. Studies since 1998 have shown that Earth’s D/H ratio is more similar to that of the meteors than of the comets, making a strong case for meteoric origins for Earth’s water. That case is not closed: a 2011 study of Comet Hartley 2 drew the opposite conclusion. Still, at the moment, the meteor camp is winning. 
 
 (PHOTOS: Windows on Infinity: Pictures from Space) 
 
 What Saal and his colleagues succeeded in doing was analyzing the D/H ratios in tiny beads of volcanically cooked glass in lunar samples brought back by Apollo 15 and Apollo 17 to see how closely they parallel Earth’s. The answer: exceedingly closely. “The moon’s D/H rations are similar to Earth’s and they’re both similar to the chondrites’,” says Saal. “What difference there is is probably due to the impact.” 
 
 So the moon’s water came from the Earth and maybe the impactor. But the fact that any water at all survived that collision is something of a surprise, since water’s extreme volatility should have caused it simply to vanish into space. Saal, however, cites research by Caltech astrophysicist David Stevenson and others that the blast might have created a sort of envelope of hot gasses, protecting the water while the moon accreted. 
 
 Of course, just as the Earth and moon drew apart in distance over time, so too did they part ways developmentally. The Earth’s greater gravity allowed it to retain an atmosphere, protecting the water that was there, as well as any that barreled in later. The moon could keep enough only to achieve its decidedly humbler wetter-than-the-Sahara status. Lunar gravity may turn the tides in our distant oceans, but the moon’s own seas and lakes and bays were—and always will be—mere phantasms. 
 
 (FROM THE ARCHIVES: Moon: From the Good Earth to the Sea of Rains)
– 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.