Ice age could help predict oceans' response to global warming

A team of scientists led by a Tulane University oceanographer has found that deposits deep under the ocean floor reveal a way to measure the ocean oxygen level and its connections with carbon dioxide in the Earth's atmosphere during the last ice age, which ended more than 11,000 years ago.

The findings, published in Science Advances, help explain the role oceans played in past glacial melting cycles and could improve predictions of how ocean carbon cycles will respond to global warming.

Oceans adjust atmospheric CO2 as ice ages transition to warmer climates by releasing the greenhouse gas from carbon stored within the deep ocean.

The research demonstrates a striking correlation between global ocean oxygen contents and atmospheric CO2 from the last ice age to today -- and how carbon release from the deep sea may rise as the climate warms.

"The research reveals the important role of the Southern Ocean in controlling the global ocean oxygen reservoir and carbon storage," said Yi Wang, lead researcher and an assistant professor of Earth and Environmental Sciences at Tulane University School of Science and Engineering.

Wang specializes in marine biogeochemistry and paleoceanography.

"This will have implications for understanding how the ocean, especially the Southern Ocean, will dynamically affect the atmospheric CO2 in the future," she said.

Wang conducted the study with colleagues from the Woods Hole Oceanographic Institution, the world's leading independent nonprofit organization dedicated to ocean research, exploration and education.

She worked for the institute before joining Tulane in 2023.

The team analyzed seafloor sediments collected from the Arabian Sea to reconstruct average global ocean oxygen levels thousands of years ago.

They precisely measured isotopes of the metal thallium trapped in the sediments, which indicate how much oxygen was dissolved in the global ocean at the time the sediments formed.

"Study of these metal isotopes on glacial-interglacial transitions has never been looked at before, and these measurements allowed us to essentially recreate the past," Wang said.

The thallium isotope ratios showed the global ocean lost oxygen overall during the last ice age compared to the current warmer interglacial period.

Their study revealed thousand-year global ocean deoxygenation during abrupt warming in the Northern Hemisphere, whereas the ocean gained more oxygen when abrupt cooling occurred during the transition from the last ice age to today.

The researchers attributed the observed ocean oxygen changes to Southern Ocean processes.

"This study is the first to present an average picture of how the oxygen content of the global oceans evolved as Earth transitioned from the last glacial period into the warmer climate of the last 10,000 years," said Sune Nielsen, associate scientist at WHOI and co-author of the research.

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Window to the past: New microfossils suggest earlier rise in complex life

Microfossils from Western Australia may capture a jump in the complexity of life that coincided with the rise of oxygen in Earth's atmosphere and oceans, according to an international team of scientists.

The findings, published in the journal Geobiology, provide a rare window into the Great Oxidation Event, a time roughly 2.4 billion years ago when the oxygen concentration increased on Earth, fundamentally changing the planet's surface. The event is thought to have triggered a mass extinction and opened the door for the development of more complex life, but little direct evidence had existed in the fossil record before the discovery of the new microfossils, the scientists said.

"What we show is the first direct evidence linking the changing environment during the Great Oxidation Event with an increase in the complexity of life," said corresponding author Erica Barlow, an affiliate research professor in the Department of Geosciences at Penn State. "This is something that's been hypothesized, but there's just such little fossil record that we haven't been able to test it."

When compared to modern organisms, the microfossils more closely resembled a type of algae than simpler prokaryotic life -- organisms like bacteria, for example -- that existed prior to the Great Oxidation Event, the scientists said. Algae, along with all other plants and animals, are eukaryotes, more complex life whose cells have a membrane-bound nucleus.

More work is required to determine if the microfossils were left behind by eukaryotic organisms, but the possibility would have significant implications, the scientists said. It would push back the known eukaryotic microfossil record by 750 million years.

"The microfossils have a remarkable similarity to a modern family called Volvocaceae," Barlow said. "This hints at the fossil being possibly an early eukaryotic fossil. That's a big claim, and something that needs more work, but it raises an exciting question that the community can build on and test."

Barlow discovered the rock containing the fossils while conducting her undergraduate research at the University of New South Wales (USNW) in Australia, and she conducted the current work as part of her doctoral work at UNSW and then while a postdoctoral researcher at Penn State.

"These specific fossils are remarkably well preserved, which allowed for the combined study of their morphology, composition, and complexity," said Christopher House, professor of geosciences at Penn State and a co-author of the study. "The results provide a great window into a changing biosphere billions of years ago."

The scientists analyzed the chemical makeup and carbon isotopic composition of the microfossils and determined the carbon was created by living organisms, confirming that the structures were indeed biologic fossils. They also uncovered insights into the habitat, reproduction and metabolism of the microorganisms.

Barlow compared the samples to microfossils from before the Great Oxidation Event and could not find comparable organisms. The microfossils she found were larger and featured more complex cellular arrangements, she said.

"The record seems to reveal a burst of life -- there's an increase in diversity and complexity of this fossilized life that we are finding," Barlow said.

Compared to modern organisms, Barlow said, the microfossils have explicit similarities with algal colonies, including in the shape, size and distribution of both the colony and individual cells and membranes around both cell and colony.

"They have a remarkable similarity and so, by that way of comparison, we could say these fossils were relatively complex," Barlow said. "There is nothing like them in the fossil record, and yet, they have quite striking similarities to modern algae."

The findings have implications for both how long it took complex life to form on early Earth -- the earliest, uncontroversial evidence of life is 3.5 billion years old -- and what the search for life elsewhere in the solar system may reveal, the scientists said.

"I think finding a fossil that is this relatively large and complex, relatively early on in the history of life on Earth, kind of makes you question -- if we do find life elsewhere, it might not just be bacterial prokaryotic life," Barlow said. "Maybe there's a chance there could be something more complex preserved -- even if it's still microscopic, it could be something of a slightly higher order."

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Tiny mineral inclusions picture the chemical exchange between Earth's mantle and atmosphere

Using synchrotron techniques, scientists have unveiled important information on The Great Oxidation Event by studying apatite inclusions in zircon crystals from old magmas with the ESRF -- Extremely Brilliant Source. The results are published in Nature Geoscience.

Around 2.4 billion years ago, a pivotal moment in Earth's history took place: The Great Oxidation Event. During this period, a significant amount of oxygen accumulated in the atmosphere. This surge in oxygen production led to a dramatic shift in the composition of the atmosphere, altering the chemistry of the planet. The event marked a turning point as oxygen levels rose, enabling the development of more complex multicellular life forms and fundamentally reshaping Earth's ecosystems.

Plate tectonics are an effective mechanism for the cycling and interchange of elements among Earth's surface, atmosphere, and mantle. As mountains undergo weathering and erosion through interactions with water and the atmosphere, they break down into sediments. These sediments are then partially returned to the mantle through subduction processes (one tectonic plate sinking beneath another). The formation of magmas in the mantle above subduction zones provides a unique opportunity to explore how the atmosphere could have impacted the mantle by assimilating materials from subducted sediments, offering insights into this intriguing geological relationship.

Scientists have long tried to study the interaction between atmosphere and the Earth's mantle. The mission is already complicated to be accomplished in the modern Earth, and even more so in the early Earth, when the atmosphere and plate tectonics were changing at rapid rates. A team led by the University of Montpellier and University of Portsmouth teamed up with the ESRF -- The European Synchrotron- and found a way to overcome obstacles by studying apatite inclusions in zircon from subduction zones.

"In 2017, a paper on the mineral apatite unveiled that when it grows at reduced conditions, meaning there is little or no free oxygen for chemical reactions, its sulphur would show a very specific signature. However, if it crystalised in oxidised conditions, the sulphur inside the apatite would look very different. This means that apatite is a proxy for redox conditions," explains Hugo Moreira, a CNRS postdoctoral researcher at the University of Montpellier and first author of the paper.

Moreira and colleagues decided to explore inclusions of phosphate-mineral apatite in zircon grains that are crystallized in magmas formed in an ancient subduction zone, and measured their sulphur valence speciation using X-ray absorption near edge structure (XANES) at the ESRF, the brightest synchrotron light source.

Sulphur incorporation and speciation in apatite is intrinsically dependent on the oxygen fugacity of the magma and therefore ideal for assessing the oxidation state during the evolution of magmatic systems. "Using apatite inclusions in zircons rather than apatite from the rock matrix was paramount, as the inclusions have been shielded by the extremely robust zircon crystals, preserving their original composition," explains Moreira.

The experiment results show that apatite inclusions in zircons from magmas that crystallised prior to the Great Oxidation Event have a relatively reduced sulphur redox state, whereas after the Great Oxidation Event they are more oxidised. The analysis on zircon shows that these magmas shared a similar source and that the younger samples had incorporated a sediment component. Overall, the clear implication is that sediments affected by an increasingly oxidised atmosphere modified the mantle and shifted the fugacity of magmas towards more oxidised conditions.

"Our study shows that investigating apatite inclusions in zircon using synchrotron X-rays is a powerful tool to constraint a critical magma parameter," concludes Moreira.

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Atmospheric research provides clear evidence of human-caused climate change signal associated with CO2 increases

New research provides clear evidence of a human "fingerprint" on climate change and shows that specific signals from human activities have altered the temperature structure of Earth's atmosphere.

Differences between tropospheric and lower stratospheric temperature trends have long been recognized as a fingerprint of human effects on climate. This fingerprint, however, neglected information from the mid to upper stratosphere, 25 to 50 kilometers above the Earth's surface.

"Including this information improves the detectability of a human fingerprint by a factor of five. Enhanced detectability occurs because the mid to upper stratosphere has a large cooling signal from human-caused CO2 increases, small noise levels of natural internal variability, and differing signal and noise patterns," according to the journal article, "Exceptional stratospheric contribution to human fingerprints on atmospheric temperature," published in the Proceedings of the National Academy of Sciences (PNAS). Noise in the troposphere can include day-to-day weather, interannual variability arising from El Niños and La Niñas, and longer-term natural fluctuations in climate. In the upper stratosphere, the noise of variability is smaller, and the human-caused climate change signal is larger, so the signal can be much more easily distinguished.

"Extending fingerprinting to the upper stratosphere with long temperature records and improved climate models means that it is now virtually impossible for natural causes to explain satellite-measured trends in the thermal structure of the Earth's atmosphere," the paper states.

"This is the clearest evidence there is of a human-caused climate change signal associated with CO2 increases," according to lead author Benjamin Santer, an adjunct scientist in the Physical Oceanography Department at the Woods Hole Oceanographic Institute (WHOI) in Massachusetts.

"This research undercuts and rebuts claims that recent atmospheric and surface temperature changes are natural, whether due to the Sun or due to internal cycles in the climate system. A natural explanation is virtually impossible in terms of what we are looking at here: changes in the temperature structure of the atmosphere," added Santer, who has worked on climate fingerprinting for more than 30 years. "This research puts to rest incorrect claims that we don't need to treat climate change seriously because it is all natural."

The research was motivated by earlier work by Suki Manabe and Richard Wetherald, who in 1967 used a simple climate model to study how CO2 from fossil fuel burning might change atmospheric temperature. Their modeling found a very distinctive feature: an increase in CO2 levels led to more trapping of heat in the troposphere (the lowest layer of Earth's atmosphere) and less heat escaping higher up into the stratosphere (the layer above the troposphere), thus warming the troposphere and cooling the stratosphere. This prediction of tropospheric warming and stratospheric cooling in response to increasing CO2 has been confirmed many times by more complex models and verified by comparing model results with global-mean atmospheric temperature observations from weather balloons and satellites.

Although these earlier studies considered global-mean temperature changes in the middle and upper stratosphere, roughly 25 to 50 kilometers above Earth's surface, they did not look at detailed patterns of climate change in this layer. This region can be better studied now because of improved simulations and satellite data. The new research is the first to search for human-caused climate change patterns -- also called "fingerprints" -- in the middle and upper stratosphere.

"The human fingerprints in temperature changes in the mid to upper stratosphere due to CO2 increases are truly exceptional because they are so large and so different from temperature changes there due to internal variability and natural external forcing. These unique fingerprints make it possible to detect the human impact on climate change due to CO2 in a short period of time (~10 -- 15 years) with high confidence," stated co-author Qiang Fu, a professor in the Department of Atmospheric Sciences at the University of Washington.

"The world has been reeling under climate change, so being as confident as possible of the role of carbon dioxide is critical," said co-author Susan Solomon, Martin Professor of Environmental Studies at the Massachusetts Institute of Technology. "The fact that observations show not only a warming troposphere but also a strongly cooling upper stratosphere is unique tell-tale evidence that nails the dominant role of carbon dioxide in climate change and greatly increases confidence."

Santer said that although it is intellectually gratifying to be able to extend fingerprinting higher up into the atmosphere to test the prediction by Manabe and Wetherald, it is also deeply concerning.

"As someone who tries to understand the kind of world that future generations are going to inhabit, these results make me very worried. We are fundamentally changing the thermal structure of Earth's atmosphere, and there is no joy in recognizing that," Santer said.

"This study shows that the real world has changed in a way that simply cannot be explained by natural causes," Santer added. "We now face important decisions, in the United States and globally, on what to do about climate change. I hope those decisions are based on our best scientific understanding of the reality and seriousness of human effects on climate."

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Diverse approach key to carbon removal

Diversification reduces risk. That's the spirit of one key takeaway from a new study led by scientists at the Department of Energy's Pacific Northwest National Laboratory. The effective path to limiting global warming to 1.5 degrees Celsius by the end of this century likely requires a mix of technologies that can pull carbon dioxide from Earth's atmosphere and oceans.

Overreliance on any one carbon removal method may bring undue risk, the authors caution. And we'll likely need them all to remove the necessary amount of carbon dioxide -- 10 gigatons annually -- to secure just 1.5 degrees of warming by 2100.

The new work, published today in the journal Nature Climate Change, outlines the carbon-removing potential of six different methods. They range from restoring deforested lands to spreading crushed rock across landscapes, a method known as enhanced weathering.

This study marks the first attempt to incorporate all carbon dioxide removal approaches recognized in U.S. legislation into a single integrated model that projects how their interactions could measure up on a global scale. It does so while demonstrating how those methods could influence factors like water use, energy demand or available crop land.

The authors explore the potential of these carbon removal methods by modeling decarbonization scenarios: hypothetical futures that demonstrate what kind of interactions could crop up if the technologies were deployed under varying conditions. They explore pathways, for example, where no climate policy is applied (and warming rises to 3.5 degrees as a result).

A second pathway demonstrates what amount of carbon would need to be removed using the technologies under an ambitious policy in which carbon emissions are constrained to decline to net-zero by mid-century and net-negative by late-century to limit end-of-century warming to below 1.5 degrees.

The third scenario follows the same emissions pathway but is paired with behavioral and technological changes, like low material consumption and rapid electrification. In this scenario, these societal changes translate to fewer overall emissions released, which helps reduce the amount of residual greenhouse gas emissions that would need to be offset with carbon removal to meet the 1.5-degree goal.

To meet that target -- the original goal of the Paris Agreement -- the authors find that roughly 10 gigatons of carbon dioxide must be removed per year. That amount remains the same even if countries were to strengthen efforts to reduce carbon dioxide emissions from all sources.

"Bringing us back down to 1.5 degrees by the end of the century will require a balanced approach," said lead author PNNL scientist Jay Fuhrman, whose work stems from the Joint Global Change Research Institute. "If one of these technologies fails to materialize or scale up, we don't want too many eggs in that basket. If we use a globally diverse portfolio of carbon removal strategies, we can mitigate risk while mitigating emissions."

Some of the technologies stand to contribute a great deal, with the potential to remove several gigatons of carbon dioxide per year. Others offer less, yet still stand to play an important role. Enhanced weathering, for example, could remove up to four gigatons of carbon dioxide annually by mid-century.

Under this method, finely ground rock spread over cropland converts carbon dioxide in the atmosphere into carbonate minerals on the ground. It is among the most cost-effective methods identified in the study.

In comparison, direct ocean capture with carbon storage, where carbon dioxide is stripped from seawater and stored in Earth's subsurface, would likely remove much less carbon. On its own, the nascent technology is prohibitively expensive, according to the authors. Pairing this method with desalination plants in regions where demand for desalinated water is high, however, could drive down the cost while delivering more meaningful carbon reductions.

In addition to the removal methods mentioned above, the technologies under study include biochar, direct air capture with carbon storage, and bioenergy paired with carbon capture and storage.

Each of the technologies modeled brings unique advantages, costs and consequences. Many of those factors are tied to specific regions. The authors point out Sub-Saharan Africa as an example, where biochar, enhanced weathering and bioenergy with carbon capture and storage stand to contribute significant reductions.

Yet the authors find much work is needed to address greenhouse gases other than carbon dioxide, like methane and nitrous oxide. Many of these non-CO2 gases are several times more potent while simultaneously more difficult to target than carbon dioxide.

While some of the removal methods examined within the new paper are well-studied, their interactions with other, newer methods are less clearly understood. The work originates from the Joint Global Change Research Institute, a partnership between PNNL and the University of Maryland where researchers explore interactions between human, energy and environmental systems.

Their work focuses on projecting what tradeoffs may flow from a range of possible decarbonization scenarios. The authors seek to better understand how these methods interact so that policymakers may be informed in their efforts to decarbonize.

"This study underscores the need for continued research on carbon dioxide removal approaches and their potential impacts," said corresponding author and PNNL scientist Haewon McJeon. "While each approach has its own unique benefits and costs, a diverse portfolio of carbon dioxide removal approaches is essential for effectively addressing climate change. By better understanding the potential impacts of each approach, we can develop a more comprehensive and effective strategy for reducing greenhouse gas emissions and limiting global warming."

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Mexican mangroves have been capturing carbon for 5,000 years

Researchers have identified a new reason to protect mangrove forests: they've been quietly keeping carbon out of Earth's atmosphere for the past 5,000 years.

Mangroves thrive in conditions most plants cannot tolerate, like salty coastal waters. Some species have air-conducting, vertical roots that act like snorkels when tides are high, giving the appearance of trees floating on stilts.

A UC Riverside and UC San Diego-led research team set out to understand how marine mangroves off the coast of La Paz, Mexico, absorb and release elements like nitrogen and carbon, processes called biogeochemical cycling.

As these processes are largely driven by microbes, the team also wanted to learn which bacteria and fungi are thriving there.

The team expected that carbon would be found in the layer of peat beneath the forest, but they did not expect that carbon to be 5,000 years old. This result, along with a description of the microbes they identified, is now published in the journal Marine Ecology Progress Series.

"What's special about these mangrove sites isn't that they're the fastest at carbon storage, but that they have kept the carbon for so long," said Emma Aronson, UCR environmental microbiologist and senior co-author of the study. "It is orders of magnitude more carbon storage than most other ecosystems in the region."

Peat underlying the mangrove trees is a combination of submerged sediment and partially decayed organic matter. In some areas sampled for this study, the peat layer extended roughly 10 feet below the coastal water line.

Little oxygen makes it to the deepest peat layer, which is likely why the team did not find any fungi living in it; normally fungi are found in nearly every environment on Earth. However, oxygen is a requirement for most fungi that specialize in breaking down carbon compounds. The team may explore the absence of fungi further in future mangrove peat studies.

There are more than 1,100 types of bacteria living beneath the mangroves that consume and excrete a variety of chemical elements. Many of them function in extreme environments with low or no oxygen. However, these bacteria are not efficient at breaking down carbon.

The deeper you go into the peat soils, the fewer microorganisms you find. Not much can break down the carbon down there, or the peat itself, for that matter," said Mia Maltz, UCR microbial ecologist and study author. "Because it persists for so long, it's not easy to make more of it or replicate the communities of microbes within it."

There are other ecosystems on Earth known to have similarly aged or even older carbon. Arctic or Antarctic permafrost, where the ice hasn't yet thawed allowing a release of gases, are examples. Potentially, other mangrove forests as well. The researchers are now scouting mangrove research sites in Hawaii, Florida and Mexico's Yucatan Peninsula as well.

"These sites are protecting carbon that has been there for millennia. Disturbing them would cause a carbon emission that we wouldn't be able to repair any time soon," said Matthew Costa, UC San Diego coastal ecologist and first author on the paper.

Carbon dioxide increases the greenhouse effect that is causing the planet to heat up. Costa believes that one way to keep this issue from worsening is to leave mangroves undisturbed.

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Scientists release first analysis of rocks plucked from speeding asteroid

After a six-year journey, a plucky spacecraft called Hayabusa2 zinged back into Earth's atmosphere in late 2020 and landed deep in the Australian outback. When researchers from the Japanese space agency JAXA opened it, they found its precious payload sealed and intact: a handful of dirt that Hayabusa2 managed to scoop off the surface of a speeding asteroid.

Scientists have now begun to announce the first results from the analysis of this extraordinary sample. What they found suggests that this asteroid is a piece of the same stuff that coalesced into our sun four-and-a-half billion years ago.

"We previously only had a handful of these rocks to study, and all of them were meteorites that fell to Earth and were stored in museums for decades to centuries, which changed their compositions," said geochemist Nicolas Dauphas, one of the three University of Chicago researchers who worked with a Japan-led international team of scientists to analyze the fragments. "Having pristine samples from outer space is simply incredible. They are witnesses from parts of the solar system that we have not otherwise explored."

'It's spectacular'

In 2018, Hayabusa2 landed atop a moving asteroid named Ryugu and collected particles from above and below its surface. After spending a year and a half orbiting the asteroid, it returned to Earth with a sealed capsule containing about five grams of dust and rock. Scientists around the world have been eagerly anticipating the unique sample -- one that could help redefine our understanding of how planets evolve and how our solar system formed.

Scientists are particularly excited because these particles would never have reached Earth without the protective barrier of a spacecraft.

"Usually, all we get to study of asteroids is the pieces that are big enough to make it to the ground as meteorites," said UChicago geochemist Andrew M. Davis, another member of the analysis team. "If you took this handful and dropped it in the atmosphere, it would burn up. You would lose it, and a lot of evidence about the history of this asteroid would go with it.

"We really haven't had a sample like this before. It's spectacular."

Davis, Dauphas and UChicago colleague Reika Yokochi are all part of a team assembled to help Japanese researchers analyze the samples. Each part of the capsule's contents is being rigorously studied. Yokochi is part of a team that is analyzing the gases that were trapped in the capsule or in the dirt. Dauphas and Davis are part of a team that is studying the chemical and isotopic compositions grains to reveal their history.

The first compilation of these results, reported in Science on June 9, reveal the makeup of Ryugu.

The rock is similar to a class of meteorites known as "Ivuna-type carbonaceous chondrites." These rocks have a similar chemical composition to what we measure from the sun and are thought to date back to the very beginnings of the solar system approximately four-and-a-half billion years ago -- before the formation of the sun, the moon and Earth. [should Moon be capitalized to distinguish it from other moons?]

Back then, all that existed was a gigantic, rotating cloud of gas. Scientists think that most of that gas was pulled into the center and formed the star we know as the sun. As the remnants of that gas expanded into a disk and cooled, it transformed into rocks, which still float around the solar system today; it appears Ryugu may be one of them.

Scientists said the fragments show signs of having been soaked in water at some point. "One must picture an aggregate of ice and dust floating in space, that turned into a giant mudball when ice was melted by nuclear energy from the decay of radioactive elements that were present in the asteroid when it formed," said Dauphas. But surprisingly, today the rock itself appears to be relatively dry.

Using radioisotope dating, they estimated that Ryugu was altered by water circulation only about five million years after the solar system formed.

These findings are particularly interesting to researchers because they hint at similar formation conditions between comets and some asteroids such as Ryugu.

"By examining these samples, we can constrain the temperatures and conditions that must have been occurring in their lifetimes, and try to understand what happened," Yokochi explained.

She compared the process to trying to figure out how a soup was made, but with only the final result rather than the recipe: "We can take the soup and separate the ingredients, and try to tell from their conditions how much it was heated and in what order."

The scientists noted that a percentage of the find will be set aside so that we can analyze them in the future with more advanced technology -- much as we did with lunar samples from Apollo.

"After we got moon samples from Apollo 50 years ago, our ideas about how the moon formed completely changed," Davis said. "We're still learning new things from them, because our instruments and technology have advanced.

"The same will be true for these samples. This is a gift that keeps on giving."

This mission is the first of several international missions that will bring back samples from another asteroid named Bennu, as well as unexplored areas on our moon, Mars, and Mars' moon Phobos. This should all be taking place in the next 10 to 20 years.

Read more at Science Daily

Researchers hunt for one-pole magnets by combining cosmic rays and particle accelerators

Some of the world's most powerful particle accelerators have helped researchers draw new leading limits on the existence of long theorized magnetic monopoles from the collisions of energetic cosmic rays bombarding the Earth's atmosphere, reports a new study published in Physical Review Letters.

Magnets are intimately familiar to everyone, with wide-ranging applications within daily life, from TVs and computers to kids toys. However, breaking any magnet, such as a navigation compass needle consisting of north and south poles in half, will result in just two smaller two-pole magnets. This mystery has eluded researchers for decades since 1931, when physicist Paul Dirac theorized the existence of one-pole "magnetic monopoles'' -- particles comparable to electrons but with a magnetic charge.

To explore whether magnetic monopoles exist, an international team of researchers, including the University of Tokyo's Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Fellow Volodymyr Takhistov, studied available data from a variety of terrestrial experiments and have carried out the most sensitive searches to date for monopoles over a broad range of possible masses. The researchers focused on an unusual source of monopoles -- atmospheric collisions of cosmic rays that have been occurring for eons.

The interdisciplinary research required bringing together expertise from several distinct corners of science -- including accelerator physics, neutrino interactions and cosmic rays.

Cosmic ray collisions with the atmosphere have already played a central role in advancing science, especially the exploration of ghostly neutrinos. This lead to Kavli IPMU Senior Fellow Takaaki Kajita's 2015 Nobel Prize in Physics for the discovery by the Super-Kamiokande experiment that neutrinos oscillate in flight, implying that they have mass.

Partially inspired by the results of Super-Kamiokande, the team set to work on monopoles. Particularly intriguing were light monopoles with masses around the electroweak scale, which can be readily accessible to conventional particle accelerators.

By carrying out simulations of cosmic ray collisions, analogously to particle collisions at the LHC at CERN, the researchers obtained a persistent beam of light monopoles raining down upon different terrestrial experiments.

This unique source of monopoles is especially interesting, as it is independent of any pre-existing monopoles such as those potentially left over as relics from the early Universe, and covers a broad range of energies.

By re-analyzing data from a wide range of previous experimental monopole searches, the researchers identified novel limits on monopoles across a wide range of masses, including those beyond the reach of conventional collider monopole searches.

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Earth's atmosphere may be source of some lunar water

Hydrogen and oxygen ions escaping from Earth's upper atmosphere and combining on the moon could be one of the sources of the known lunar water and ice, according to new research by University of Alaska Fairbanks Geophysical Institute scientists.

The work led by UAF Geophysical Institute associate research professor Gunther Kletetschka adds to a growing body of research about water at the moon's north and south poles.

Finding water is key to NASA's Artemis project, the planned long-term human presence on the moon. NASA plans to send humans back to the moon this decade.

"As NASA's Artemis team plans to build a base camp on the moon's south pole, the water ions that originated many eons ago on Earth can be used in the astronauts' life support system," Kletetschka said.

The new research estimates the moon's polar regions could hold up to 3,500 cubic kilometers -- 840 cubic miles -- or more of surface permafrost or subsurface liquid water created from ions that escaped Earth's atmosphere. That's a volume comparable to North America's Lake Huron, the world's eighth-largest lake.

Researchers based that total on the lowest volume model calculation -- 1% of Earth's atmospheric escape reaching the moon.

A majority of the lunar water is generally believed to have been deposited by asteroids and comets that collided with the moon. Most was during a period known as the Late Heavy Bombardment. In that period, about 3.5 billion years ago when the solar system was about 1 billion years old, it is argued that the early inner planets and Earth's moon sustained unusually heavy impact from asteroids.

Scientists also hypothesize that the solar wind is a source. The solar wind carries oxygen and hydrogen ions, which may have combined and been deposited on the moon as water molecules.

Now there's an additional way to explain how water accumulates on the moon.

The research was published March 16 in the journal Scientific Reports in a paper authored by Kletetschka and co-authored by Ph.D. student Nicholas Hasson of the Geophysical Institute and UAF Water and Environmental Research Center at the Institute for Northern Engineering. Several colleagues from the Czech Republic are also among the co-authors.

Kletetschka and his colleagues suggest hydrogen and oxygen ions are driven into the moon when it passes through the tail of the Earth's magnetosphere, which it does on five days of the moon's monthly trip around the planet. The magnetosphere is the teardrop-shaped bubble created by Earth's magnetic field that shields the planet from much of the continual stream of charged solar particles.

Recent measurements from multiple space agencies -- NASA, European Space Agency, Japan Aerospace Exploration Agency and Indian Space Research Organization -- revealed significant numbers of water-forming ions present during the moon's transit through this part of the magnetosphere.

These ions have slowly accumulated since the Late Heavy Bombardment.

The presence of the moon in the magnetosphere's tail, called the magnetotail, temporarily affects some of Earth's magnetic field lines -- those that are broken and which simply trail off into space for many thousands of miles. Not all of Earth's field lines are attached to the planet at both ends; some have only one attachment point. Think of each of these as a thread tethered to a pole on a windy day.

The moon's presence in the magnetotail causes some of these broken field lines to reconnect with their opposing broken counterpart. When that happens, hydrogen and oxygen ions that had escaped Earth rush to those reconnected field lines and are accelerated back toward Earth.

The paper's authors suggest many of those returning ions hit the passing moon, which has no magnetosphere of its own to repel them.

"It is like the moon is in the shower -- a shower of water ions coming back to Earth, falling on the moon's surface," Kletetschka said.

The ions then combine to form the lunar permafrost. Some of that, through geologic and other processes such as asteroid impacts, is driven below the surface, where it can become liquid water.

Read more at Science Daily

Researchers discover source of super-fast electron 'rain'

UCLA scientists have discovered a new source of super-fast, energetic electrons raining down on Earth, a phenomenon that contributes to the colorful aurora borealis but also poses hazards to satellites, spacecraft and astronauts.

The researchers observed unexpected, rapid "electron precipitation" from low-Earth orbit using the ELFIN mission, a pair of tiny satellites built and operated on the UCLA campus by undergraduate and graduate students guided by a small team of staff mentors.

By combining the ELFIN data with more distant observations from NASA's THEMIS spacecraft, the scientists determined that the sudden downpour was caused by whistler waves, a type of electromagnetic wave that ripples through plasma in space and affects electrons in the Earth's magnetosphere, causing them to "spill over" into the atmosphere.

Their findings, published March 25 in the journal Nature Communications, demonstrate that whistler waves are responsible for far more electron rain than current theories and space weather models predict.

"ELFIN is the first satellite to measure these super-fast electrons," said Xiaojia Zhang, lead author and a researcher in UCLA's department of Earth, planetary and space sciences. "The mission is yielding new insights due to its unique vantage point in the chain of events that produces them."

Central to that chain of events is the near-Earth space environment, which is filled with charged particles orbiting in giant rings around the planet, called Van Allen radiation belts. Electrons in these belts travel in Slinky-like spirals that literally bounce between the Earth's north and south poles. Under certain conditions, whistler waves are generated within the radiation belts, energizing and speeding up the electrons. This effectively stretches out the electrons' travel path so much that they fall out of the belts and precipitate into the atmosphere, creating the electron rain.

One can imagine the Van Allen belts as a large reservoir filled with water -- or, in this case, electrons, said Vassilis Angelopolous, a UCLA professor of space physics and ELFIN's principal investigator. As the reservoir fills, water periodically spirals down into a relief drain to keep the basin from overflowing. But when large waves occur in the reservoir, the sloshing water spills over the edge, faster and in greater volume than the relief drainage. ELFIN, which is downstream of both flows, is able to properly measure the contributions from each.

The low-altitude electron rain measurements by ELFIN, combined with the THEMIS observations of whistler waves in space and sophisticated computer modeling, allowed the team to understand in detail the process by which the waves cause rapid torrents of electrons to flow into the atmosphere.

The findings are particularly important because current theories and space weather models, while accounting for other sources of electrons entering the atmosphere, do not predict this extra whistler wave-induced electron flow, which can affect Earth's atmospheric chemistry, pose risks to spacecraft and damage low-orbiting satellites.

The researchers further showed that this type of radiation-belt electron loss to the atmosphere can increase significantly during geomagnetic storms, disturbances caused by enhanced solar activity that can affect near-Earth space and Earth's magnetic environment.

"Although space is commonly thought to be separate from our upper atmosphere, the two are inextricably linked," Angelopoulos said. "Understanding how they're linked can benefit satellites and astronauts passing through the region, which are increasingly important for commerce, telecommunications and space tourism."

Read more at Science Daily