Scientists find water microdroplets can transform into hydrogen peroxide when condensing on cold surfaces

Scientists find water microdroplets can transform into hydrogen peroxide when condensing on cold surfaces
Photo shows water microdroplet condensate formed on the surface of a glass container containing cold water (left) and an image of water microdroplets formed on a polished silicon surface (right). Credit: Jae Kyoo Lee and Hyun Soo Han

In its bulk liquid form, whether in a bathtub or an ocean, water is a relatively benign substance with little chemical activity. But down at the scale of tiny droplets, water can turn surprisingly reactive, Stanford researchers have discovered.

In microdroplets of water, just millionths of a meter wide, a portion of the H2O molecules present can convert into a close chemical cousin, hydrogen peroxide, H2O2, a harsh chemical commonly used as a disinfectant and hair bleaching agent.

Stanford scientists first reported this unexpected behavior in forcibly sprayed microdroplets of water last year. Now in a new study, the research team has shown the same Jekyll-and-Hyde transformation happens when microdroplets simply condense from the air onto cold surfaces. The new results suggest that water’s hydrogen peroxide transformation is a general phenomenon, occurring in fogs, mists, raindrops and wherever else microdroplets form naturally.

The surprising discovery could lead to greener methods for disinfecting surfaces or promoting chemical reactions. “We’ve shown that the process of forming hydrogen peroxide in water droplets is a widespread and surprising phenomenon that’s been happening right under our noses,” said study senior author Richard Zare, the Marguerite Blake Wilbur Professor in Natural Science and a professor of chemistry in the Stanford School of Humanities and Sciences.

The researchers also speculate that this newly recognized chemical ability of water could have played a key role in jumpstarting the chemistry for life on Earth billions of years ago, as well as produced our planet’s first atmospheric oxygen before life emerged. “This spontaneous production of hydrogen peroxide may be a missing part of the story of how the building blocks of life were formed on early,” Zare said.

The co-lead authors of the new study, published in Proceedings of the National Academy of Sciences, are Stanford staff scientists Jae Kyoo Lee and Hyun Soo Han.

Along with Zare and other Stanford colleagues, Lee and Han made the initial discovery of hydrogen peroxide production in water microdroplets last year. Some outside researchers who went over the study’s results were skeptical, Zare said, that such a potentially common phenomenon could have gone undiscovered for so long. Debate also ensued over just how the hydrogen peroxide would ever actually form.

“The argument was that people have been studying water aerosols for years, and of course water is ubiquitous and has been intensively studied since the dawn of modern science, so if this hydrogen peroxide formation in microdroplets were real, surely someone would have seen it already,” said Zare. “That led us to want to explore the phenomenon further, to see in what other circumstances it might occur, as well as learn more about the fundamental chemistry going on.”

A sped-up video shows hydrogen peroxide forming amidst condensed water
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Researchers Uncover 2,000-Year-Old Maya Water Filtration System | Smart News

More than 2,000 years ago, the Maya built a complex water filtration system out of materials collected miles away. Now, reports Michelle Starr for Science Alert, researchers conducting excavations at the ancient city of Tikal in northern Guatemala have discovered traces of this millennia-old engineering marvel.

As detailed in the journal Scientific Reports, the study’s authors found that the Maya built the Corriental reservoir filtration system as early as 2,185 years ago, not long after settlement of Tikal began around 300 B.C.

The system—which relied on crystalline quartz and zeolite, a compound of silicon and aluminum, to create what the researchers call a “molecular sieve” capable of removing harmful microbes, heavy metals and other pollutants—remained in use until the city’s abandonment around 1100. Today, the same minerals are used in modern water filtration systems.

“What’s interesting is this system would still be effective today and the Maya discovered it more than 2,000 years ago,” says lead author Kenneth Barnett Tankersley, an archaeologist at the University of Cincinnati, in a statement.

According to Science Alert, archaeologists previously thought that the first use of zeolite for water filtration dated to the early 20th century. Researchers have documented other types of water systems—including ones centered on sand, gravel, plants and cloth—used in Egypt, Greece and South Asia as early as the 15th century B.C.

“A lot of people look at Native Americans in the Western Hemisphere as not having the same engineering or technological muscle of places like Greece, Rome, India or China,” says Tankersley. “But when it comes to water management, the Maya were millennia ahead.”

Per the statement, water quality would have been a major concern for the ancient Maya, as Tikal and other cities across the empire were built on porous limestone that left little water available during seasonal droughts. Without a purification system, drinking from the Corriental reservoir would have made people sick due to the presence of cyanobacteria and similarly toxic substances.

water system
The Tikal filtration system used quartz and zeolite to remove both heavy metals and biological contaminants.

(Kenneth Barnett Tankersley / University of Cincinnati)

Members of the research team previously found that other reservoirs in the area were polluted with mercury, possibly from pigment the Maya used on walls and in burials. As Kiona N. Smith reported for Ars Technica in June, drinking and cooking water for Tikal’s elite appear to have come from two sources that contained high levels of mercury: the Palace and Temple Reservoirs. Comparatively, the new research shows that Corriental was free of contamination.

The researchers write that the Maya probably found the quartz and zeolite about 18 miles northeast of the city, around the Bajo de Azúcar, where the materials naturally purified the water.

“It was probably through very clever empirical observation that the ancient Maya saw this particular material was associated with clean water and made some effort to carry it back,” says co-author Nicholas P. Dunning, a geographer at the University of Cincinnati, in the statement. “They

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Analysis of a Martian meteorite reveals evidence of water 4.4 billion years ago

Water on ancient Mars
Martian meteorite NWA 7533 is worth more than its weight in gold. Credit: © NASA/Luc Labenne

A meteorite that originated on Mars billions of years ago reveals details of ancient impact events on the red planet. Certain minerals from the Martian crust in the meteorite are oxidized, suggesting the presence of water during the impact that created the meteorite. The finding helps to fill some gaps in knowledge about the role of water in planet formation.

There’s a longstanding question in planetary science about the origin of water on Earth, Mars and other large bodies such as the moon. One hypothesis says that it came from asteroids and comets post-formation. But some planetary researchers think that water might just be one of many substances that occur naturally during the formation of planets. A new analysis of an ancient Martian meteorite adds support for this second hypothesis.

Several years ago, a pair of dark meteorites were discovered in the Sahara Desert. They were dubbed NWA 7034 and NWA 7533, where NWA stands for North West Africa and the number is the order in which meteorites are officially approved by the Meteoritical Society, an international planetary science organization. Analysis showed these meteorites are new types of Martian meteorites and are mixtures of different rock fragments.

The earliest fragments formed on Mars 4.4 billion years ago, making them the oldest known Martian meteorites. Rocks like this are rare and can fetch up to $10,000 per gram. But recently 50 grams of NWA 7533 was acquired for analysis by the international team in which Professor Takashi Mikouchi at the University of Tokyo was participating.

“I study minerals in Martian meteorites to understand how Mars formed and its crust and mantle evolved. This is the first time I have investigated this particular meteorite, nicknamed Black Beauty for its dark color,” said Mikouchi. “Our samples of NWA 7533 were subjected to four different kinds of spectroscopic analysis, ways of detecting chemical fingerprints. The results led our team to draw some exciting conclusions.”

It’s well known to planetary scientists that there has been water on Mars for at least 3.7 billion years. But from the mineral composition of the meteorite, Mikouchi and his team deduced it’s likely there was water present much earlier, at around 4.4 billion years ago.

“Igneous clasts, or fragmented rock, in the meteorite are formed from magma and are commonly caused by impacts and oxidation,” said Mikouchi. “This oxidation could have occurred if there was water present on or in the Martian crust 4.4 billion years ago during an impact that melted part of the crust. Our analysis also suggests such an impact would have released a lot of hydrogen, which would have contributed to planetary warming at a time when Mars already had a thick insulating atmosphere of carbon dioxide.”

If there was water on Mars earlier than thought, that suggests water is possibly a natural byproduct of some process early on in planet formation. This finding could help researchers answer the

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So, How Long Until We Can Drink Moon Water?

When I heard that water was recently discovered on the surface of the moon, I’m not going to lie: My first thought was, I bet it tastes great.

I’m not alone in this, right? As a water lover — yes, we exist — I’m always chasing what food critic Jeffrey Steingarten refers to in his 1997 book, The Man Who Ate Everything: “that pure, clear, ethereal Alpine spring of our imaginations.” I picture moon water to be my ethereal Alpine spring: glacially cold and crisp; satisfyingly thirst-quenching; achingly crystalline. 

Sadly, I may never know the joys of sipping on a refreshing glass of lunar liquid. The water isn’t hidden away in small ice-cold grottos tucked below the moon’s surface, like I was hoping. Instead, these water molecules are spread so far away from each other that they don’t even technically form a liquid. “To be clear, this is not puddles of water, but instead water molecules that are so spread apart that they do not form ice or liquid water,” Casey I. Honniball, the lead author of the study published in Nature Astronomy, said in a phone press briefing. A NASA press release stated that the Sahara desert has 100 times the amount of water than what was detected on the moon.

It will take scientists a long time to figure out how to gather up and mash together enough of those molecules to fill up the first Lunar Water™ bottle. (I think that’s how it’ll work, anyway.) Until then, here’s everything we know about the liquid that we really should be calling Moon Juice.

How exactly do we know that the moon is wet? 

Scientists have suspected that there’s been water on the moon for a while now — they just didn’t know what kind: H2O (the stuff we drink) and hydroxyl (the stuff you find in drain cleaner). Big difference — and something you probably want to know before you take a swig. 

That’s where NASA’s flying observatory, SOFIA, came in. (Yes, it took a womxn!). SOFIA, aka Stratospheric Observatory for Infrared Astronomy, is a modified Boeing that NASA uses as an observational aircraft. It allowed the scientists to study the moon’s surface in more detail — using a six micron wavelength, versus the puny three micron wavelength they’d been relying on before. This confirmed that the chemical signature of much of what’s on the surface of the moon is, indeed, the good ol’ H2O, said Honniball.

Even better? That water is cold. Another study confirmed that ice covers more of the moon than we once thought. It’s not just sticking at the moon’s poles, but scattered in shadowed pockets across the moon’s surface. 

Where does the moon water come from? 

Okay, so we now know the moon is a WAPlanet. But how? “The water that we observed has two potential sources,” Honniball explained during the press briefing. “It could be either from the solar wind or micrometeorites.” In other words, solar wind

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AirTalk | Studies Confirm Longstanding Theory That There’s Water On The Moon. Why Does It Matter?

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Two different teams, each consisting of a network of scientists from all across the globe, had their studies published Monday in peer-reviewed journal Nature Astronomy. Their work, although differing in methodology, led both teams to confirm that there is water on the moon.

Scientists with the Stratospheric Observatory for Infrared Anatomy, better known as SOFIA, used three independent spacecraft to detect “widespread hydration” on the lunar surface. A second study simultaneously found evidence of water on shadowed regions near the moon’s poles. However, these molecules are trapped in ice due to extreme temperatures.

According to the Washington Post, launching water to space costs thousands of dollars per gallon, and future explorers may be able to use lunar water not only to quench their own thirst but to refuel their rockets.

We’ll discuss the findings with members of both teams, as well as their significance in the fields of astronomy and space exploration. Questions? Give us a call at 866-893-5722.


Bethany L. Ehlmann, professor of planetary science at Caltech and associate director of the Keck Institute for Space Studies

Paul Hayne,  co-author of study ‘Micro cold traps on the Moon’ and assistant professor of astrophysical and planetary sciences at the University of Colorado-Boulder; he tweets @phayne


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Lunar water discovery may have limited effect on NASA exploration plans

WASHINGTON — Water ice may be more prevalent on the surface of the moon that previously thought, but that discovery appears unlikely to have any near-term effect on NASA’s lunar exploration plans.

In a paper published in the journal Nature Astronomy Oct. 26, scientists reported detecting traces of water in the crater Clavius on the near side of the moon using NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft. SOFIA detected an infrared emission feature at a wavelength of 6 microns consistent with water on the surface in the vicinity of the crater.

The detection is not the first time that water has been seen on the moon. Over the last quarter-century, scientists have built up evidence, primarily from spacecraft missions, that water ice exists on the moon. That included the Lunar Crater Observation and Sensing Satellite (LCROSS) mission in 2009 that detected water in a plume of material created when a Centaur upper stage impacted the south polar region of the moon.

Those previous studies, though, have focused on the polar regions, which have permanently shadowed regions that serve as “cold traps” where ice is stable for extended periods. Clavius, by contrast, has no such shadowed regions, and is in direct sunlight for the two-week lunar day.

“The expectation is that any water present on a sunlit surface of the moon would not survive the lunar day,” said Paul Hertz, director of NASA’s astrophysics division, in a call with reporters. “This discovery reveals that water might be distributed across the lunar surface and not be limited to the cold shadowed places near the lunar poles.”

Scientists involved in the discovery don’t know for certain how the water got there. “It could be either from the solar wind or micrometeorites,” said Casey Honniball of NASA’s Goddard Space Flight Center, who led the study.

It likely survives there because it is trapped in glass beads created in micrometeoroid impacts. “These glass beads are about the size of a pencil tip and protect the water from the harsh lunar environment,” she said.

The discovery has implications for both lunar science and future exploration. NASA has emphasized the importance of water ice as a means of making human exploration of the moon sustainable. That water could be a resource to both sustain astronauts and be converted into liquid hydrogen and liquid oxygen propellants for spacecraft.

With water thought to exist only at the poles, NASA has concentrated its lunar exploration activities there. The south pole of the moon remains the preferred landing site for the first Artemis crewed landing, Artemis 3, despite comments by NASA Administrator Jim Bridenstine in September that suggested he was open to landing elsewhere on the moon. He subsequently stated that the south pole is still the primary landing area.

Water elsewhere on the moon could create new opportunities for human lunar missions beyond the polar regions. One challenge, though, is the tiny amount of water available: the concentrations detected by SOFIA are the equivalent of a 355-milliliter bottle

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Moon holds more water in more places than ever thought

CAPE CANAVERAL, Fla. (AP) — The moon’s shadowed, frigid nooks and crannies may hold frozen water in more places and in larger quantities than previously suspected. And for the first time, the presence of water on the moon’s sunlit surface has been confirmed, scientists reported Monday.

That’s good news for astronauts at future lunar bases who could tap into these resources for drinking and making rocket fuel.

While previous observations have indicated millions of tons of ice in the permanently shadowed craters of the moon’s poles, a pair of studies in the journal Nature Astronomy take the availability of lunar surface water to a new level.

More than 15,400 square miles (40,000 square kilometers) of lunar terrain have the capability to trap water in the form of ice, according to a team led by the University of Colorado’s Paul Hayne. That’s 20% more area than previous estimates, he said.

The presence of water in sunlit surfaces had been previously suggested, but not confirmed. The molecules are so far apart that they are in neither liquid nor solid form, said lead researcher Casey Honniball, a postdoctoral fellow at NASA’s Goddard Space Flight Center in Maryland.

“To be clear, this is not puddles of water,” she stressed at a news conference.

NASA’s astrophysics director Paul Hertz said it’s too soon to know whether this water — found in and around the southern hemisphere’s sunlit Clavius Crater — would be accessible. The surface could be harder there, ruining wheels and drills.

These latest findings, nonetheless, expand the possible landing spots for robots and astronauts alike — “opening up real estate previously considered ‘off limits’ for being bone dry,” Hayne said in an email to The Associated Press.

For now, NASA said it still aims to send astronauts to the lunar south pole, especially rich in frozen water. The White House deadline is 2024.

As for the shadowed areas believed to be brimming with frozen water near the moon’s north and south poles, temperatures are so low that they could hold onto the water for millions or even billions of years. These so-called cold traps get down to minus 261 degrees Fahrenheit (minus 163 degrees Celsius).

Using data from NASA’s Lunar Reconnaissance Orbiter, the researchers identified cold traps as small as a few yards (meters) across and as wide as 18 miles (30 kilometers) and more, and used computer models to get all the way down to micrometers in size.

“Since the little ones are too small to see from orbit, despite being vastly more numerous, we can’t yet identify ice inside them,” Hayne said. “Once we’re on the surface, we will do that experiment.”

For the second study, scientists used NASA’s airborne infrared observatory Sofia to conclusively identify water molecules on sunlit portions of the moon just outside the polar regions. Most of these molecules are likely stored in the voids between moon dust and other particles or entombed in the glassy residue of of micrometeorite impacts. In this way, the molecules can

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NASA Finds Water and Ice on Moon in More Places Than Thought

Observations by spacecraft a decade ago had also suggested a more widespread distribution of water on the moon. Those measurements focused on a shorter, three-micron wavelength that was more ambiguous, unable to differentiate between a water molecule, which consists of two hydrogen atoms and one oxygen atom or hydroxyl, which has one hydrogen atom and one oxygen atom.

“Hydroxyl is actually the active ingredient in drain cleaners,” said Casey I. Honniball, a postdoctoral researcher at NASA’s Goddard Spaceflight Center in Greenbelt, Md., and lead author of the study that used SOFIA. “Hypothetically, if drain cleaner were on the moon, we could not tell the difference between the drain cleaner and water using the three-micron wavelength.”

The six-micron emissions are a “distinct chemical fingerprint” for water, Dr. Honniball said.

These observations cannot be performed from Earth’s surface because there is too much water in the lower atmosphere. Also, no lunar spacecraft, present or planned, has an instrument to examine this particular wavelength.

But SOFIA can. The aircraft, NASA’s Stratospheric Observatory for Infrared Astronomy, is a 747 with a sliding door that opens to allow a 106-inch, 17-ton telescope to peer into the night sky. But the observatory, a collaboration between NASA and the German Aerospace Center that has been in operation since 2010, is expensive, and the Obama and Trump administrations both sought to end the program. Each time, Congress has restored financing and SOFIA has continued flying.

Monday’s reported findings would not have been possible without it. At an altitude of some 45,000 feet, SOFIA rises above 99.9 percent of the water vapor in the atmosphere, said Naseem Rangwala, SOFIA’s project scientist.

The SOFIA results are in rough agreement with the earlier measurements and do not change the estimate of the amount of water on the moon. The concentration at Clavius is low — “roughly equivalent to a 12 ounce bottle of water within a cubic meter,” Dr. Honniball said.

“To be clear, it’s not puddles of water, but instead water molecules that are so spread apart that they do not form ice or liquid water,” Dr. Honniball said.

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What water on the moon means for the future of exploration

Water on the Moon
Water on the Moon

This illustration highlights the Moon’s Clavius Crater with an illustration depicting water trapped in the lunar soil there, along with an image of NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) that found sunlit lunar water. NASA/Daniel Rutter

This article originally appeared here on

Earth news is a bit anxiety-provoking these days, which might be one reason why the Internet pulled out all the stops to communicate collective enthusiasm over the discovery of vast amounts of water on the moon.

The finding could be useful to humans who want to leave Earth immediately and live on the moon. (We’re only half-joking).

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While scientists previously suspected that water existed in the shadowy, cold parts of the moon — such as its poles, where it would stay frozen — a pair of studies published on Monday in the journal Nature Astronomy confirm that there is a large amount of water on its sunlit regions, too. 

“We had indications that H₂O – the familiar water we know – might be present on the sunlit side of the Moon,” Paul Hertz, director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters in Washington, said in a statement. “Now we know it is there. This discovery challenges our understanding of the lunar surface and raises intriguing questions about resources relevant for deep space exploration.”

Yet even the data on water in the moon’s darker, colder regions was always iffy. Part of the challenge of finding water on the moon is that the Earth’s atmosphere, which has plenty of evaporated water, interferes with ground-based attempts to see water on the moon without the atmosphere interfering. Space telescopes or very high altitude telescopes can alleviate this problem. In this case, NASA used the Stratospheric Observatory for Infrared Astronomy (SOFIA), an infrared observatory mounted on a Boeing 747 airplane, which takes observations from the air. SOFIA data suggests strongly that yes, water is present on the sunlit surface of the moon.

That’s particularly unusual given the temperature cycles on the moon: the moon during the day is a scalding 250 degrees Fahrenheit, well above water’s boiling point. So why doesn’t said water immediately evaporate? As explained in the study, titled “Molecular water detected on the sunlit Moon by SOFIA,” scientists detail evidence that hypothesizes the water observed may be trapped in naturally-formed glass on the moon’s sunlit regions. Being encased in glass means that the water is impervious to the heating and cooling cycles that would usually evaporate the water. Since the moon doesn’t have an atmosphere and there’s very little gravity, it’s impossible for water to just hang out on its surface like it does here on Earth.

The second study, titled “Micro Cold Traps on the Moon,” catalogs all the potential sites that are cold enough for ice to remain stable, and where water could exist without being trapped in glass.

“Our results suggest that water trapped at the lunar poles may be more widely

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Water on the Moon could sustain a lunar base

Artwork: Nasa wants to return to the Moon, but this time it wants to stay

Artwork: Nasa wants to return to the Moon, but this time it wants to stay

Having dropped tantalising hints days ago about an “exciting new discovery about the Moon”, the US space agency has revealed conclusive evidence of water on our only natural satellite.

This “unambiguous detection of molecular water” will boost Nasa’s hopes of establishing a lunar base.

The aim is to sustain that base by tapping into the Moon’s natural resources.

The findings have been published as two papers in the journal Nature Astronomy.

While there have previously been signs of water on the lunar surface, these new discoveries suggest it is more abundant than previously thought. “It gives us more options for potential water sources on the Moon,” said Hannah Sargeant, a planetary scientist from the Open University in Milton Keynes, told BBC News.

“Where to put a Moon base is largely focused on where the water is.”

The US space agency has said it will send the first woman and next man to the lunar surface in 2024 to prepare for the “next giant leap” – human exploration of Mars as early as the 2030s.

Dr Sargeant explained that this meant developing “a more sustainable way of doing space exploration”.

“Part of that is using these local resources – especially water,” she told BBC News.

How did scientists find this lunar water?

The first of these new discoveries was made from an airborne infrared telescope known as Sofia. This observatory, on board a modified Boeing 747, flies above 99%of Earth’s atmosphere, giving a largely unobstructed view of the Solar System.

By bouncing infrared light off the Moon’s surface, scientists are able to decode exactly what is reflecting that light. Different substances will show up as different colours and in this case, the researchers picked up the exact “signature” colour of water molecules.

The researchers think it is stored in bubbles of lunar glass or between grains on the surface that protect it from the harsh environment.

In the other study, scientists looked for permanently shadowed areas – known as cold traps – where water could be captured and remain permanently. They found these cold traps at both poles and concluded that “approximately 40,000 metres squared of the lunar surface has the capacity to trap water”.

What does this discovery mean?

Dr Sargeant said this could “broaden the list of places where we might want to build a base”.

There are quite a few one-off missions to the Moon’s polar regions coming up in the next few years. But in the longer term, there are plans to build a permanent habitation on the lunar surface,

“This could have some influence. It gives us some time to do some investigation,” said the Open University researcher.

“It doesn’t give us much time because we’re already working on Moon base ideas and where we’re going to go, but it’s more promising.

“We were going to go to the Moon anyway. But this gives us more options and makes

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