Earth’s oceans may have withstood the smash-up that made the moon Todd Gipstein/National Geographic/Getty

Earth may have had water for far longer than we thought. The planet may have had lakes and oceans even before the giant impact that created the moon, and it could have survived that colossal collision.

Previously it was thought that most, or even all, of Earth’s ocean water was carried to the planet on comets and asteroids after the moon was formed. But Richard Greenwood at the Open University in Milton Keynes and his colleagues found that it might have already been here.

Greenwood and his colleagues compared the oxygen composition of moon rocks brought back to Earth by Apollo astronauts with that of volcanic rocks from the ocean floor.

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The presence of liquid water alters the amounts of different oxygen isotopes in the rock. So, if most of the water on Earth had arrived after the giant impact, the rocks should have distinctly different oxygen compositions. The moon rocks should show little sign of being altered by water.

But Greenwood and his team detected only a small difference between the lunar and terrestrial rocks.

Early water

This suggests that liquid water must have existed on Earth before its moon-forming collision with a body the size of Mars, which is thought to have occurred about 100 million years after the solar system formed. The researchers found that most of the water we have now may have already been here, and then between 5 and 30 per cent of it was brought later by asteroids and comets.

Other work has shown that many distant worlds in other star systems underwent similar collisions early in their evolution, events which we thought meant they could not have liquid water unless it was delivered later on.

The fact that liquid water can survive catastrophic impacts by planet-sized bodies means it should be abundant on worlds in other star systems, Greenwood says. Life as we know it requires water, so this could make those exoplanets more hospitable.

“Exoplanets with water on their surfaces may be much more common than we previously thought. And where there is water, there could also be life,” says Greenwood.

Journal reference: Science Advances, DOI: 10.1126/sciadv.aao5928

Read more: The moon may have formed in a vaporised, doughnut-shaped Earth </s> The history of lakes and oceans on Earth is highly speculative. We know they have been around for quite a while, but the exact origin of water has never been confirmed. Perhaps, the most common explanation is the one involving comets and asteroids, space rocks that crashed onto our world bringing water in the process.

Many believe the impacts happened after our planet’s catastrophic collision with another massive celestial body, nearly as big as Mars, some four and a half billion years ago. This crash, dubbed The Giant Impact, was so energetic it threw our moon into existence and started the cycle of life as we know it.

However, there might be a small twist in the story. According to a new study, water might have been present on Earth much earlier than any of us thought, even before the moon-forming collision.

Richard Greenwood from the Open University and his colleagues posited this idea after analyzing and comparing lunar rocks with rocks from Earth.

“We compared the oxygen composition of lunar rocks brought back from all six of the NASA Apollo landings on the Moon with volcanic basalt collected from all of the deep oceans on Earth to help us understand how the Moon formed,” Greenwood, who is also the lead author of the study, said in a statement.

Though this appears more like differentiating between chalk and cheese, there is a whole lot of science involved, the researcher noted. Essentially, it’s the quality of liquid water to alter oxygen isotopes in rocks. If water came on Earth after the moon-forming collision, there should be a vast difference of oxygen content in the two samples.

But, the team hardly noticed any difference after analyzing the results, which suggests water might have existed way before The Giant Impact.

“Our research shows that even an event as catastrophic as two planets colliding doesn’t cause all of the water to be dispersed into space,” the researcher added. “The water stayed in the mix of debris, which gave birth to our planet and its only moon.”

The theory of water-delivering asteroids wasn't taken completely off the table either. The group found most of the water was present on Earth before the collision, but about 5-30 percent was carried by asteroid and comet impacts, New Scientist reported.

That said, knowing more about the chaotic past of water on Earth could help astronomers find exoplanets that may have necessary conditions to host life. If water on Earth can survive a major crash like the one forming the moon, even other planets may also follow the same path. In fact, records suggest, many planets have already undergone collisions like these during the evolution.

“Exoplanets with water on their surfaces may be much more common than we previously thought. And where there is water, there could also be life," Greenwood concluded.

The results of the comparison have been detailed in a paper published in journal Science Advances. </s> A discovery about the origin of the Earth’s oceans makes it more likely that life exists beyond the solar system.

Scientists now know that liquid surface water was present on Earth before the planet-scale “giant impact” that created the moon.

Previously it was thought that most if not all the ocean water was carried to the Earth in later asteroid and comet bombardments.

The fact that liquid water can survive catastrophic impacts by planet-sized bodies means it should be abundant on worlds in other star systems.

And the presence of liquid surface water in the form of lakes and oceans greatly increases the chances of finding life, experts believe.

Lead researcher Dr Richard Greenwood, from the Open University, said: “Because water is such a vital ingredient for life, we rightly see it as precious. Our research shows that water is also extremely resilient and can survive an event as catastrophic as two planets colliding.”

The scientists compared the oxygen composition of moon rocks brought back to Earth by Apollo astronauts with that of volcanic rocks from the ocean floor.

They detected only a small difference between the lunar and terrestrial rocks. If most of the water on Earth had arrived after the giant impact, the rocks should have distinctly different oxygen compositions.

The findings, reported in the journal Science Advances, suggests that liquid water must have existed on Earth before its moon-forming collision with a body the size of Mars.

The giant impact is thought to have occurred about 100 million years after the solar system formed out of a swirling cloud of dust and gas.

Scientists know that many exoplanets in other star systems experienced similar high energy collisions early in their evolution.

Dr Greenwood added: “Because this worked for the Earth and the moon, it must also work for planets beyond our solar system.

“Exoplanets with water on their surfaces may be much more common than we previously thought. And where there is water, there could also be life.” </s> March 29 (UPI) -- Based on an extensive collection of lunar and terrestrial samples, researchers have determined that most of the water on Earth was already present at the time of the impact that created the moon.

Scientists from the United States, Britain and France studied moon rocks brought back to Earth by astronauts on the six Apollo missions and volcanic rocks retrieved from the ocean floor by Earth-bound scientists. They published their findings Thursday in the journal Science Advances.

"The research discovered only a small difference in oxygen composition between the lunar and terrestrial rocks," Dr. Richard Greenwood, a research fellow at The New University in England and lead author of the new study, said in a press release. "This demonstrates how well mixed all of the pieces of rock created from the catastrophic impact were, and places strict limits on the types of material that could have been added to the Earth afterwards."

Oxygen isotopes in the rocks were examined by researchers to determine their origin. Material from different distinct origins such as asteroids, planets or comets tend to have their own unique composition signature.

The researchers found that oxygen isotopes from both surfaces are similar, carrying a three- to four-ppm difference. They also found no significant difference between the lunar samples and terrestrial olivine, a common mineral in Earth's subsurface.

The researchers suggest the difference can be explained by a "late veneer," or input of stony meteorite material to Earth, subsequent to the impact of the moon-forming object.

They believe much of the Earth's water was present earlier than the giant impact, and no more than 5 percent to 30 percent of water contributed to Earth from the late veneer process.

The researchers say their evidence bolsters a theory that a Mars-sized protoplanet slammed into protoplanetary Earth and the coalesced material formed the moon, but disputes a theory water came to Earth via asteroids and comets.

If the water came from space, the researchers say isotopes in rocks from the ocean would have differed from those in rocks from the moon. Based on what they found, they theorize the water likely survived the impact.

"Because water is such a vital ingredient for life, we rightly see it as precious. Our research shows that even an event as catastrophic as two planets colliding doesn't cause all of the water to be dispersed into space. The water stayed in the mix of debris, which gave birth to our planet and its only moon," Greenwood said.

"What's even more fascinating is that, because this worked for the Earth and Moon, it must also work for planets beyond our solar system. Exoplanets with water on their surfaces may be much more common than we previously thought. And where there is water, there could also be life!" </s> This image shows the far side of the Moon, illuminated by the Sun. Credit: NASA A team of researchers from the U.K., France and the U.S. has found evidence that suggests that most of the water on Earth was present before the impact that created the moon. In their paper published on the open access site Science Advances, the group describes their study and comparison of moon and Earth rocks, and what they found.

The prevailing theory regarding how the moon's origin is that a Mars-sized protoplanet slammed into protoplanetary Earth, and the ejected material coalesced to form the moon. The prevailing theory regarding how water came to exist on Earth is that most of it was delivered by asteroids and comets. In this new effort, the researchers present evidence that bolsters the first theory but conflicts strongly with the second.

The team studied both moon rocks brought back to Earth by the Apollo astronauts and volcanic rocks retrieved by others from the ocean floor. The researchers looked specifically at oxygen isotopes. Studying isotopes in rocks offers scientists a means for comparing material from different origins such as asteroids, planets or even comets—each tends to have its own unique composition signature.

The researchers report that oxygen isotopes from the moon and Earth are remarkably similar—they found just a three to four ppm difference between them. This finding bolsters the theory that the moon was formed from material from the Earth due to a collision. But it runs counter to the idea that water came from comets or asteroids, because if it had come from such sources, the isotopes would have differed from those found in rocks on the moon. Thus, most of the water that was present in the protoplanetary Earth likely survived the impact, suggesting it did not come from elsewhere.

The idea that water could survive such an impact has implications for the search for life beyond our solar system—exoplanets that are thought to have suffered collisions are typically removed from lists describing possible life-sustaining celestial bodies. Now, they may have to be included.

Explore further: Gallium in lunar samples explains loss of moon's easily vaporized elements

More information: Richard C. Greenwood et al. Oxygen isotopic evidence for accretion of Earth's water before a high-energy Moon-forming giant impact, Science Advances (2018). DOI: 10.1126/sciadv.aao5928

Abstract 

The Earth-Moon system likely formed as a result of a collision between two large planetary objects. Debate about their relative masses, the impact energy involved, and the extent of isotopic homogenization continues. We present the results of a high-precision oxygen isotope study of an extensive suite of lunar and terrestrial samples. We demonstrate that lunar rocks and terrestrial basalts show a 3 to 4 ppm (parts per million), statistically resolvable, difference in Δ17O. Taking aubrite meteorites as a candidate impactor material, we show that the giant impact scenario involved nearly complete mixing between the target and impactor. Alternatively, the degree of similarity between the Δ17O values of the impactor and the proto-Earth must have been significantly closer than that between Earth and aubrites. If the Earth-Moon system evolved from an initially highly vaporized and isotopically homogenized state, as indicated by recent dynamical models, then the terrestrial basalt-lunar oxygen isotope difference detected by our study may be a reflection of post–giant impact additions to Earth. On the basis of this assumption, our data indicate that post–giant impact additions to Earth could have contributed between 5 and 30% of Earth's water, depending on global water estimates. Consequently, our data indicate that the bulk of Earth's water was accreted before the giant impact and not later, as often proposed. </s> Living on the Moon may be easier than first thought, after scientists discovered large amounts of water trapped beneath the surface.

It was generally assumed that the Moon was a fairly dry lump of rock, although ice still exists at the poles.

Both Nasa and the European Space Agency are keen to establish a lunar base to act as a stepping stone for the rest of the Solar System, and have been looking into whether water could be mined.

Researchers at Brown University in the US began to suspect there might be more water than previously thought after reexamining volcanic glass beads brought back by the Apollo 15 and 17 missions.

They discovered that the beads contain similar amounts of water as basalt rocks on Earth, suggesting that parts of the Moon’s crust contain as much water as our own planet. </s> We've long known that water ice is holed up in the darkest, coldest craters on the moon, but now scientists think the story of lunar water runs much deeper, far below its surface. And this is good news if humanity wants to build that moon base we've been promising ourselves for so long.

Here's the backstory: In 2008, scientists analyzed small glass beads found in the samples of moon rock brought back to Earth by the Apollo 15 and 17 missions in 1971 and 1972. These volcanic beads originated from the moon's interior, and the crystalline structures contained a small, yet surprising amount of water, overturning the idea that the moon's subsurface was largely devoid of water.

More research found that the beads contained similar quantities of water as some basalts on Earth – another clue that the moon was formed from the debris of Earth after a massive ancient impact with another planetary body.

Now, in a new study published in the journal Nature Geoscience, spectroscopic data from the Moon Mineralogy Mapper onboard India's Chandrayaan-1 lunar orbiter was used to map the lunar surface; specifically it sought regions where there are elevated concentrations of water deposits in lunar rock that originated from volcanic activity. And guess what? It looks like the water-rich Apollo samples weren't an anomaly, which is welcome news.

"By looking at the orbital data, we can examine the large pyroclastic deposits on the moon that were never sampled by the Apollo or Luna missions. The fact that nearly all of them exhibit signatures of water suggests that the Apollo samples are not anomalous, so it may be that the bulk interior of the moon is wet," said planetary geologist Ralph Milliken, in the press release. Milliken is the lead author of the new study and works at Brown University.

These spectrometer data were recorded by studying the reflected sunlight bouncing off the moon's surface. Some wavelengths of light are absorbed by certain chemicals, so when the reflected light is received, the Moon Mineralogy Mapper could identify which materials were present. But to tease out the signal of water in the pyroclastic flows, the researchers had to carefully remove the interference of thermal emissions caused by the sun's heating of the daytime surface.

"That thermally emitted radiation happens at the same wavelengths that we need to use to look for water," Milliken said in the statement. "So in order to say with any confidence that water is present, we first need to account for and remove the thermally emitted component."

Using the Apollo samples in tandem with detailed thermal models of the moon's surface, the scientists corrected the map, revealing the distribution of water trapped in these ancient volcanic flows.

As these pyroclastic deposits contain a surprisingly high proportion of water, this likely means the moon's interior contains a lot more water than previously thought, a finding that has huge implications for our theories of how the moon formed. If the moon was formed from the molten debris of a massive Earth impact, how did the hydrogen required in water molecules survive the extreme heating?

"The growing evidence for water inside the moon suggest that water did somehow survive, or that it was brought in shortly after the impact by asteroids or comets before the moon had completely solidified," said co-author and postdoctoral researcher Shuai Li, who works at the University of Hawaii. "The exact origin of water in the lunar interior is still a big question."

There are obvious implications for the future of possible human missions to the moon. If the moon was bone-dry, setting up any form of long-term human presence on the surface would be difficult, possibly unsustainably so. Launching supplies, materials and fuel from Earth to the lunar surface requires powerful and expensive rockets, but if we can source building materials and water from the lunar surface, we may eventually establish a self-sustaining, permanent moon base.

The researchers emphasize that the quantity of water is small – only 0.05 percent of the material by weight is water – but there's a lot of it on or close to the surface with, potentially, a huge supply in the moon's mantle. So, if we do set up a long-duration presence on the lunar surface, perhaps we can develop an efficient water extraction process that could make it sustainable – producing drinking water and fuel, and driving some form of space agriculture.

"Anything that helps save future lunar explorers from having to bring lots of water from home is a big step forward, and our results suggest a new alternative," Li concluded. </s> But the Apollo moon rocks were only a sample. They could be anomalies, poor representatives of what really lies beneath the surface.

These tiny beads became a lot more interesting in 2008, when scientists discovered they contained water . In 2011, researchers found that the beads contained similar amounts of water as some basalts on Earth, which form when volcanic rock from the planet’s mantle cools rapidly. For decades, scientists had thought the moon was a dry world. The clues inside the glass beads suggested a different story. There’s water on the moon, and some of it may still exist in ancient deposits deep within its interior.

In the 1970s, the Apollo astronauts returned from the moon with tiny beads of volcanic glass they had picked out of the lunar soil. The beads are remnants of the moon’s early history billions of years ago, when eruptions spewed magma onto the surface. The magma, exposed to the vacuum of space, cooled rapidly. Some droplets froze as they fell, hitting the ground as glass.

Ralph Milliken, a professor in Brown University’s geological sciences department, decided to widen the search. Milliken and his collaborator, Shuai Li, a researcher at the University of Hawaii, used satellite data to study numerous volcanic deposits across the lunar surface where water, if it exists, would be contained in glass beads like the ones the Apollo astronauts collected.

“Sure enough, we found it,” Milliken said.

The researchers detected trapped water in dozens of the volcanic deposits, some measuring thousands of square kilometers. These regions also contained far more water than surrounding terrain. The data came from the Moon Mineralogy Mapper, a NASA spectrometer that flew aboard India’s first lunar mission in 2008. The instrument measures the wavelengths of light absorbed or reflected by a surface, which scientists can use to determine the composition of the object. The findings were published Monday in Nature Geoscience.

Milliken said the findings suggest the moon holds significant amounts of water, but it’s difficult to estimate how much. “That’s a very difficult question to answer," Milliken said. “I think it’s hard for the average person to understand what [this] means.” He said his research supports the conclusion from the 2011 study on the beads’ composition, that parts of the moon’s mantle could contain as much water as Earth’s.

Scientists don’t yet know how the moon got the water they've observed, and there are several possible sources. “To me, that’s still one of the biggest questions out there,” Milliken said. Most scientists believe water couldn’t have survived the heat of the violent impact between Earth and a Mars-sized object that created the moon 4.5 billion years ago—but maybe it did, somehow, Milliken said. Water-rich asteroids and comets could have struck the moon early on, when it was still cooling, or later in life. Other research has also shown water may be created on the moon’s surface when hydrogen atoms from solar wind react with oxygen atoms buried in moon rocks.

Whatever the origin, the water-rich deposits on the moon will come in handy for any future thirsty astronauts. “Even though an individual glass bead doesn’t have a lot of water in it, the size of these deposits is enormous, so you have a lot of material to work with,” Milliken said. </s> Scientists who retested mineral samples collected during the Apollo moon missions now believe there’s a massive amount of water under the lunar surface – a discovery which may make manned missions to the moon easier than previously thought.

Researchers at Brown University in the US examined glass beads, a type of volcanic crystal gathered during the Apollo 15 and 17 missions in the 1970s, and found they contained similar volumes of water to Earth’s basalt rock.

The leaders of the study, which has been published in Nature Geoscience, cite the parallels as evidence that parts of the moon contain a similarly large amount of water. This, they believe, could be useful for future lunar missions as it means water could potentially be extracted rather than carried from home.

“Other studies have suggested the presence of water ice in shadowed regions at the lunar poles, but the pyroclastic deposits are at locations that may be easier to access,” said lead author Dr. Shuai Li, formerly of Brown University and now at the University of Hawaii.

“Anything that helps save future lunar explorers from having to bring lots of water from home is a big step forward, and our results suggest a new alternative."

Scientists used instruments and images from India’s Chandrayaan-1 lunar orbiter which bounced light off the moon to see which minerals are present.

It was previously thought that water could only be found on each of the moon’s two poles, but deposits of volcanic beads, formed when magma crystallized after rising to the surface, have been found far and wide across the lunar surface.

“The fact that they see this feature associated with the glasses tells us that there was indeed quite a bit of water in the interior of the moon when these volcanic eruptions were occurring,” says Anthony Colaprete, a NASA scientist who reviewed the paper.

The race to create the first manned lunar base has been heating up in recent years.

In April, the European Space Agency announced plans to partner with China on a 'Moon Village,' a 3D-printed cluster of lunar outposts that could one day serve as a stop-off point on a journey to Mars.

Groundwork for the Moon Village mission will begin in November, when China plans to send a probe to the moon to retrieve rock and soil samples. The Chang’e-5 mission will be China’s first ever attempt at sample retrieval in space.
Research published in the journal Science Advances implies the Earth may have had water earlier than thought, and that terrestrial water could have survived the impact that created the Moon, the event which was previously hypothesised to be responsible for our planet's water.