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  • richardmitnick 8:16 am on June 25, 2019 Permalink | Reply
    Tags: "The highest-energy photons ever seen hail from the Crab Nebula", , , , , , , Science News, , The Tibet AS-gamma experiment, When a high-energy photon hits Earth’s atmosphere it creates a shower of other subatomic particles that can be detected on the ground.   

    From Science News: “The highest-energy photons ever seen hail from the Crab Nebula” 

    From Science News

    June 24, 2019
    Emily Conover

    Some of the supernova remnant’s gamma rays have more than 100 trillion electron volts of energy.

    1
    CRAB FISHING Scientists hunting for high-energy photons raining down on Earth from space have found the most energetic light yet detected. It’s from the Crab Nebula, a remnant of an exploded star (shown in an image combining light seen by multiple telescopes).

    Physicists have spotted the highest-energy light ever seen. It emanated from the roiling remains left behind when a star exploded.

    This light made its way to Earth from the Crab Nebula, a remnant of a stellar explosion, or supernova, about 6,500 light-years away in the Milky Way. The Tibet AS-gamma experiment caught multiple particles of light — or photons — from the nebula with energies higher than 100 trillion electron volts, researchers report in a study accepted in Physical Review Letters. Visible light, for comparison, has just a few electron volts of energy.

    Tibet AS Gamma Expeiment

    “This energy regime has not been accessible before,” says astrophysicist Petra Huentemeyer of Michigan Technological University in Houghton, who was not involved with the research. For physicists who study this high-energy light, known as gamma rays, “it’s an exciting time,” she says.

    In space, supernova remnants and other cosmic accelerators can boost subatomic particles such as electrons, photons and protons to extreme energies, much higher than those achieved in the most powerful earthly particle accelerators (SN: 10/1/05, p. 213). Protons in the Large Hadron Collider in Geneva, for example, reach a comparatively wimpy 6.5 trillion electron volts. Somehow, the cosmic accelerators vastly outperform humankind’s most advanced machines.

    “The question is: How does nature do it?” says physicist David Hanna of McGill University in Montreal.

    In the Crab Nebula, the initial explosion set up the conditions for acceleration, with magnetic fields and shock waves plowing through space, giving an energy boost to charged particles such as electrons. Low-energy photons in the vicinity get kicked to high energies when they collide with the speedy electrons, and ultimately, some of those photons make their way to Earth.

    When a high-energy photon hits Earth’s atmosphere, it creates a shower of other subatomic particles that can be detected on the ground. To capture that resulting deluge, Tibet AS-gamma uses nearly 600 particle detectors spread across an area of more than 65,000 square meters in Tibet. From the information recorded by the detectors, researchers can calculate the energy of the initial photon.

    But other kinds of spacefaring particles known as cosmic rays create particle showers that are much more plentiful. To select photons, cosmic rays, which are mainly composed of protons and atomic nuclei, need to be weeded out. So the researchers used underground detectors to look for muons — heavier relatives of electrons that are created in cosmic ray showers, but not in showers created by photons.

    Previous experiments have glimpsed photons with nearly 100 TeV, or trillion electron volts. Now, after about three years of gathering data, the researchers found 24 seemingly photon-initiated showers above 100 TeV, and some with energies as high as 450 TeV. Because the weeding out process isn’t perfect, the researchers estimate that around six of those showers could have come from cosmic rays mimicking photons, but the rest are the real deal.

    Researchers with Tibet AS-gamma declined to comment for this story, as the study has not yet been published.

    Looking for photons of ever higher energies could help scientists nail down the details of how the particles are accelerated. “There has to be a limit to how high the energy of the photons can go,” Hanna says. If scientists can pinpoint that maximum energy, that could help distinguish between various theoretical tweaks to how the particles get their oomph.

    See the full article here .


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  • richardmitnick 9:42 am on June 22, 2019 Permalink | Reply
    Tags: "The cosmic ‘Cow’ may be a strange supernova", , , , , Science News   

    From Science News: “The cosmic ‘Cow’ may be a strange supernova” 

    From Science News

    June 21, 2019
    Lisa Grossman

    1
    HOLY COW The cosmic oddity called the Cow may be a supernova that exploded in a dense environment. This image from the Sloan Digital Sky Survey shows the Cow’s host galaxy 200 million light-years away. The Cow itself is a bright spot at about 4 o’clock in the galaxy’s disk. R. Margutti/W. M. Keck Observatory

    The cosmic oddity known as the Cow may have been a dying star that shed its skin like a snake before it exploded.

    Newly released observations support the idea that the burst occurred in a dense environment with strong magnetic fields, astronomer Kuiyun Huang and colleagues report in The Astrophysical Journal Letters June 12.

    These new measurements “for the mysterious transient … provide one of the strong hints of its nature,” says Huang, of the Chung Yuan Christian University in Taoyuan City, Taiwan.

    Since the Cow appeared in June 2018 as a brief burst of light in a galaxy about 200 million light-years away, astronomers haven’t been sure what to think of it. The initial glow flared more quickly and seemed 10 times brighter than an ordinary supernova, the violent explosion that marks the death of a massive star (SN: 2/18/17, p. 20).

    Follow-up observations of the Cow — which got its nickname from the randomly assigned name “AT2018cow” — left two main theories for what it could be: a strange sort of supernova, or an exotic star being shredded by a black hole (SN: 2/2/19, p. 13). But neither theory alone could explain all the Cow’s weird features.

    Astronomer Anna Ho of Caltech and colleagues published work in April at arXiv.org that analyzed light from the Cow in a range of wavelengths, from short gamma rays to long radio waves. That work suggested that the light was getting distorted on its journey. So if the Cow is a supernova, it must have exploded in a very dense environment that squashed some of the light emerging from the dying star. But to come to that conclusion, the team had to simplify assumptions about how the explosion’s energy was released.

    Now, Huang and colleagues have released new radio wave observations that back up the findings by Ho’s team, without relying on those assumptions. In June and July 2018, Huang’s group used the Atacama Large Millimeter-submillimeter Array in Chile to look at the way the Cow’s light was polarized, a measurement of the light’s preferred direction.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Imagine holding a jump rope: If you swing your arm up and down, the jump rope will take on an up-down wave pattern. Swinging left to right gives the rope a side-to-side wave.

    The radio waves emitted in the wreckage of a supernova should do the same thing, Ho explains. But if the waves travel through an environment filled with gas, charged particles and magnetic fields, the waves’ preferred direction can get rotated or smeared out. “By the time it all gets out at the end, it can look like a blurred mess,” Ho says.

    That’s what Huang and colleagues saw from the Cow: The radio waves essentially had no polarization by the time they reached Earth, suggesting the waves had been tossed about in a dense and turbulent environment.

    That environment probably came from the Cow itself, Ho says. Toward the end of the star’s life, it started shedding outer layers of gas, similar to a snake shedding its skin. Those discarded layers were still nearby when the star finally ran out of fuel and exploded, so the light and material from the explosion plowed through the debris from the star’s death throes.

    “That might actually be a common thing that stars do,” Ho says. She and her colleagues observed another stellar explosion in September, SN2018gep, that first appeared to be a Cow-like event. It ended up looking more like a straightforward supernova, with ordinary speed and brightness — but one that was also surrounded by the dense layers the star tossed off before it died.

    The new polarization observations by Huang’s team aren’t the final word on the Cow’s identity, though, says astronomer Daniel Perley of Liverpool John Moores University in England. “It supports one argument,” he says, “but doesn’t overall change the balance of the somewhat contradictory evidence pointing in different directions for this event.” More work on the shredded star theory could help break the tie, he says.

    See the full article here .


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  • richardmitnick 11:55 am on June 13, 2019 Permalink | Reply
    Tags: "Astronomers may have spotted the ghost galaxy that hit the Milky Way long ago", , , , , Science News, The dim galaxy Antlia 2   

    From Science News: “Astronomers may have spotted the ghost galaxy that hit the Milky Way long ago” 

    From Science News

    June 12, 2019
    Lisa Grossman

    Discovered in Gaia data, Antlia 2 could be the star system scientists have been looking for.

    The Milky Way survived a galactic hit and run millions of years ago — and astronomers may have finally found the culprit.

    2
    The Large Magellanic Cloud, the Milky Way Galaxy and Antlia 2 (from left to right). Image credit: V. Belokurov / Marcus and Gail Davies / Robert Gendler.
    GHOSTLY GALAXY The dim galaxy Antlia 2 (faint glow shown at right in this illustration) was found orbiting the Milky Way (center) in 2018. It’s a bit bigger than the Large Magellanic Cloud, another satellite galaxy (left), but contains far fewer stars. V. Belokurov/Univ. of Cambridge/CCA, based on the images by Marcus and Gail Davies and Robert Gendler

    Ten years ago, astrophysicists Sukanya Chakrabarti and Leo Blitz of the University of California, Berkeley, suggested that ripples in the outer gas disk of the Milky Way were caused by a collision with a dwarf galaxy that shook the Milky Way’s gas like a pebble dropped in a pond. The pair made predictions for how massive and distant the galaxy had to be, as well as roughly where it should be found. But none of the known dwarf galaxies that orbit the Milky Way fit the bill (SN: 4/4/15, p. 6).

    Now, Chakrabarti thinks she’s found her quarry, she reported June 12 in St. Louis at the American Astronomical Society meeting and in a study posted on arXiv.org.

    Last year, astronomers using data from the Gaia space telescope discovered a new dwarf galaxy called Antlia 2, which has so few visible stars that its discoverers called it a hidden giant (SN Online: 5/9/18). Antlia 2’s location is “stupidly close” to where Chakrabarti, now at the Rochester Institute of Technology in N.Y., and Blitz predicted that the offending dwarf galaxy should be today, she says.

    Its mass is also close to what the surviving remnant of the colliding galaxy’s mass would be, she estimates. And the collision could even explain why Antlia 2 has so few stars — the encounter with the Milky Way could have stripped many of them away.

    To make sure Antlia 2 is the culprit, Chakrabarti and her colleagues have predicted where its stars should be in the next set of Gaia data, due out in 2020 or 2021. “If this is what’s observed a year from now, I’d say it’s indisputable really that Antlia 2 is the dwarf galaxy that we predicted,” she says.

    See the full article here .


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  • richardmitnick 7:39 am on June 2, 2019 Permalink | Reply
    Tags: "In a first scientists took the temperature of a sonic black hole", In quantum mechanics information can never be destroyed., Science News, , , , They’ve measured the temperature of a lab-made sonic black hole which traps sound instead of light.   

    From Science News: “In a first, scientists took the temperature of a sonic black hole” 

    From Science News

    May 29, 2019
    Emily Conover

    Lab experiments characterize a phenomenon predicted by cosmologist Stephen Hawking.

    1
    NOT BLACK Stephen Hawking first proposed that black holes (illustrated) aren’t fully black, but emit a faint haze of particles that came to be known as Hawking radiation. Now scientists have measured the radiation’s temperature in a lab analog of a black hole. NASA’s Goddard Space Flight Center; Background: DPAC/Gaia/ESA

    Taking a black hole’s temperature is a seemingly impossible task. But now, physicists report the next best thing. They’ve measured the temperature of a lab-made sonic black hole, which traps sound instead of light.

    If the result holds up, it will confirm a prediction of cosmologist Stephen Hawking, who first proposed a surprising truth about black holes: They aren’t truly black. Instead, a relatively small stream of particles bleeds from each black hole’s margin at a temperature that depends on how massive the black hole is. Such Hawking radiation is too faint to observe in true black holes. But physicists have spotted hints of similar radiation from analogs of black holes created in the lab (SN: 12/18/10, p. 28). In the new study, the sonic black hole’s temperature agrees with that predicted by Hawking’s theory, the team reports in the May 30 Nature.

    “It’s a very important milestone,” says physicist Ulf Leonhardt of the Weizmann Institute of Science in Rehovot, Israel, who was not involved with the study. “It’s new in the entire field. Nobody has done such an experiment before.”

    To produce the sonic black hole, the researchers used ultracold atoms of rubidium, chilled to a state known as a Bose-Einstein condensate, and set them flowing. Analogous to a black hole’s gravity trapping light, the flowing atoms prevent sound waves from escaping, like a kayaker rowing against a current too strong to overcome. Previous experiments with this setup have shown signs of Hawking radiation, but it wasn’t yet possible to measure its temperature (SN: 11/15/14, p. 14).

    Hawking radiation comes from pairs of quantum particles that constantly pop up everywhere, even in empty space. Normally, those particles immediately annihilate one another. But at a black hole’s edge, if one particle falls in, the other could escape, resulting in Hawking radiation. In the sonic black hole, a similar situation occurs: Pairs of sound waves known as phonons can appear, with one falling in and the other escaping.

    Measurements of the phonons that escaped and those that fell in allowed the researchers to estimate the temperature, 0.35 billionths of a kelvin. “We found very good agreement with the predictions of Hawking’s theory,” says physicist Jeff Steinhauer of the Technion-Israel Institute of Technology in Haifa.

    2
    CHASM CREATOR Physicist Jeff Steinhauer and colleagues created a sonic black hole in the lab (experimental setup shown) to study Hawking radiation. Technion-Israel Institute of Technology.

    The result also agrees with Hawking’s prediction that the radiation would be thermal, meaning that the particles’ energies would have a distribution like that of the glow emitted by a warm object, such as the reddish light of a hot electric stove.

    After Hawking proposed his theory, this predicted thermal property of the radiation led to a conundrum known as the black hole information paradox. In quantum mechanics, information can never be destroyed. But particles escaping black holes would slowly sap the behemoth’s mass, and over a long period of time, the black hole would shrink into nothingness.

    That means that the information that fell into the black hole (in the form of particles, encyclopedias or otherwise) would no longer be contained within it. And if Hawking radiation is thermal, the information couldn’t have been carried away by the fleeing particles. That’s because the emitted particles are indistinguishable from those radiated by a commonplace object with a given temperature, or even by a different black hole of the same mass. That suggests that information can be lost as a black hole evaporates away, a violation of quantum mechanics.

    It’s unclear whether the new study could help scientists resolve the information paradox. A solution will probably demand a new theory that combines gravity and quantum mechanics into one new theory of quantum gravity — a task that is one of the biggest outstanding problems in physics. But that theory wouldn’t apply to sonic black holes, since they aren’t created by gravity. “The solution to the information paradox is in the physics of a real black hole, not in the physics of an analog black hole,” Steinhauer says.

    See the full article here .


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  • richardmitnick 11:55 am on May 23, 2019 Permalink | Reply
    Tags: "Big black holes can settle in the outskirts of small galaxies", , , , , Science News   

    From Science News: “Big black holes can settle in the outskirts of small galaxies” 

    From Science News

    May 23, 2019
    Lisa Grossman

    The first surveys of massive black holes in dwarf galaxies turn up surprises.

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)


    ON THE HUNT Astronomers are using the Very Large Array of radio telescopes in New Mexico (shown) to look for big black holes in small galaxies.

    Big galaxies like the Milky Way have correspondingly big black holes. But small galaxies might have massive ones, too. A new survey picked up dozens of massive black hole candidates in diminutive dwarf galaxies.

    Surprisingly, some of those potential black holes aren’t at their galaxy’s center, but instead appear to roam the outskirts, astronomer Amy Reines said May 20 at the Black Hole Initiative Conference 2019 at Harvard University. Studying these wonky monsters could help astronomers figure out the mystery of how supermassive black holes in bigger galaxies form.

    “Contrary to conventional wisdom, dwarf galaxies can, and at least some do, have massive black holes,” said Reines, of Montana State University in Bozeman. These black holes could “hold clues to the formation of the first black hole seeds in the early universe.”

    Almost every massive galaxy ever observed has a supermassive black hole at its center. These behemoths, including the Milky Way’s, weigh between 100,000 and a few billion times the mass of the sun. And that mass is closely related to the mass of the host galaxy. “In general, bigger galaxies have bigger black holes,” Reines said.

    So when Reines, as a graduate student in 2011, stumbled upon a supermassive black hole in the dwarf galaxy Henize 2-10 [Nature], she was stunned. Reines had been looking for signs of star formation, and instead found the actively feeding black hole, some 30 million light-years from Earth.

    “This discovery marked a whole new environment for a massive black hole, and I was motivated to look for more objects like this,” she said.

    Peering into thousands of dwarf galaxies, Reines and colleagues have since found roughly 100 massive black holes, given away by the glowing disks of gas that swirl around the black holes as they feed.

    Those black holes “are likely the tip of the iceberg,” Reines said. Only the most actively feeding black holes show up in visible wavelengths, and only in galaxies with relatively low star formation. So there may be many others that are harder to spot.

    The researchers are now focusing their search on longer, invisible radio wavelengths, which can reveal black holes that feed less aggressively. Using the Very Large Array of radio telescopes in New Mexico, the team has already found 39 possible black holes in 111 dwarf galaxies. At least 14 of those candidates are likely to be black holes, Reines said. Some of the others might be other objects that emit brightly glowing radio waves, such as supernova remnants.

    Weirdly, some of the newly found black holes are not at their galactic centers, but instead are “wandering around in the outskirts of their host galaxies,” Reines said. Computer simulations had suggested that up to half of all dwarf galaxies might have off-center black holes. Still, “I was very surprised” by the finds, she said. “This hasn’t been seen before.” She suggested that the black holes could have been knocked askew in a galaxy merger, or kicked off-center when two smaller black holes merged within a galaxy (SN: 4/29/17, p. 16).

    2
    ON ITS WAY OUT A radiation-gushing supermassive black hole, quasar 3C 186 (second brightest blob in the blue oval), appears to be zooming away from its galaxy’s center (brightest blob in blue oval). The extreme exit may be a result of gravitational waves from merging black holes.

    The work “identifies a new and unique population [of black holes] that may have been missed by other selection techniques,” says astrophysicist Vivienne Baldassare of Yale University, who uses other techniques to search for black holes in dwarf galaxies.

    Studying massive black holes in small galaxies could help scientists figure out how supermassive black holes in larger galaxies got so big over cosmic time. One possibility is that black holes bulk up by adding their masses together when their host galaxies merge, or they could have started out relatively massive long ago (SN Online: 3/16/18).

    3
    TOO BIG, TOO SOON Supermassive black holes that are actively feeding on gas and dust, like the one shown in this artist’s rendition, have been spotted in the early universe — before they should have had time to grow.

    Dwarf galaxies, which are small enough that they probably haven’t gone through many mergers, may preserve relics of those ancient massive black holes. Knowing how big those relic black holes can get could help link up the supermassive monsters astronomers see in the present-day universe with their ancient counterparts.

    See the full article here .


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  • richardmitnick 10:37 am on May 12, 2019 Permalink | Reply
    Tags: , By 2025 as much as half of the demand for lithium will be from the electric vehicle industry., , Global demand for the metal is expected to rise at least 300 percent in the next 10 to 15 years., Lithium in its elemental form is soft and silvery and light with a density about half that of water., Lithium is useful for a lot more than batteries: a mood stabilizer for bipolar disorder; cosmetics; Military industrial automotive aircraft and marine applications; shock-resistant cookware and alumin, Lithium prices in global markets have been on a roller coaster in the last few years with a sharp spike in 2018 due to fears that there just might not be enough of the metal to go around., Lithium-the lightest metal on the periodic table-Period 2 Group 1, , Prospecting for new sources of lithium is booming., Science News, The basic recipe for any kind of lithium-rich deposit includes volcanic rocks plus a lot of water and heat., The future of lithium is electrifying., The hunt to find and extract this “white gold” is also spurring new basic geology geochemistry and hydrology research., Worldwide there are three main sources of lithium: pegmatites; brines and clays.   

    From Science News- “Looking for Lithium: The lightest metal on the periodic table is key to clean energy’s future” 

    From Science News

    Carolyn Gramling
    May 7, 2019

    There’s a lot to learn about where and how to mine the lightest metal on the periodic table.

    Periodic Table 2014 NIST


    Lithium:Period 2 Group 1

    1
    LOOKING FOR LITHIUM Flamingos feast on tiny shrimp in the saline lagoons of Chile’s Salar de Atacama. Lithium and copper mining operations compete with the protected birds for the region’s scant water resources. Credit: saxlerb/iStock/Getty Images Plus

    The future of lithium is electrifying. Cars and trucks powered by lithium batteries rather than fossil fuels are, to many people, the future of transportation. Rechargeable lithium batteries are also crucial for storing energy produced by solar and wind power, clean energy sources that are a beacon of hope for a world worried about the rapidly changing global climate.

    Prospecting for new sources of lithium is booming [MDPI], fueled by expectations that demand for lightweight, rechargeable lithium batteries — to power electric vehicles, cell phones, laptops and renewable energy storage facilities — is about to skyrocket.

    Even before electric cars, lithium was a hot commodity [USGS], mined for decades for reasons that had nothing to do with batteries. Thanks to lithium’s physical properties, it is bizarrely useful, popping up in all sorts of products, from shock-resistant glass to medications. In 2018, those products accounted for nearly half of the global lithium demand, according to analyses by the Frankfurt-based Deutsche Bank. Batteries for consumer electronics, such as cell phones or laptops, accounted for another 25 percent or so of the demand. Electric vehicles accounted for most of the rest.

    That breakdown will soon be turned on its head: By 2025, as much as half of the demand for lithium will be from the electric vehicle industry, some projections suggest. Global demand for the metal is expected to rise at least 300 percent in the next 10 to 15 years, in large part because sales of electric vehicles are expected to increase dramatically. Right now, there are about 2 million electric vehicles on the road worldwide; by 2030, that number is projected to grow to over 24 million, according to the industry research firm Bloomberg New Energy Finance. Electric vehicle giant Tesla has been on a worldwide quest for lithium, inking deals to obtain lithium supplies from mining operations in the United States, Mexico, Canada and Australia.

    As a result, lithium prices in global markets have been on a roller coaster in the last few years, with a sharp spike in 2018 due to fears that there just might not be enough of the metal to go around. But those doomsday scenarios are probably a bit overwrought, says geologist Lisa Stillings of the U.S. Geological Survey in Reno, Nev. Lithium makes up about 0.002 percent of Earth’s crust, but in geologic terms, it isn’t particularly rare, Stillings says. The key, she adds, is knowing where it is concentrated enough to mine economically.

    2
    Demand for lightweight, rechargeable lithium batteries to power electric vehicles and other modern electronics is expected to climb. Credit:Tramino/iStock/Getty Images Plus

    To answer that question, researchers are studying how and where the forces of wind, water, heat and time combine to create rich deposits of the metal. Such places include the flat desert basins of the “lithium triangle” of Chile, Argentina and Bolivia; volcanic rocks called pegmatites in Australia, the United States and Canada; and lithium-bearing clays in the United States.

    The hunt to find and extract this “white gold” is also spurring new basic geology, geochemistry and hydrology research. Stillings and other scientists are examining how clays and brines form, how lithium might move between the two deposits when both occur in the same basin and how lithium atoms tend to position themselves within the chemical structure of the clay.

    Seeking simpler sources

    Lithium, in its elemental form, is soft and silvery and light, with a density about half that of water. It’s the lightest metal on the periodic table. The element was discovered in 1817 by Swedish chemist Johan August Arfwedson, who was analyzing a grayish mineral called petalite. Arfwedson identified aluminum, silicon and oxygen in the mineral, which together made up 96 percent of the mineral’s mass.

    The rest of the petalite, he determined, was made up of some sort of element that had chemical properties similar to potassium and sodium. All three elements are highly reactive with other charged particles, or ions, to form salts, are solid but soft at room temperature, have low melting points and tend to dissolve readily in water. Thanks to their similarities, these elements, along with rubidium, cesium and francium, were later grouped together as “alkali metals,” forming most of the periodic table’s Group 1 (SN: 1/19/19, p. 18). Lithium’s affinity for water helps explain how it moves through Earth’s crust and how it can become concentrated enough to mine.

    The basic recipe for any kind of lithium-rich deposit includes volcanic rocks plus a lot of water and heat, mixed well by active tectonics. Worldwide, there are three main sources of lithium: pegmatites, brines and clays.

    3
    Pegmatite rocks have large crystals and often contain minerals not found elsewhere, such as lithium-bearing spodumene or petalite. Credit:Géry Parent/Wikimedia Commons (CC BY 3.0)

    Most pegmatites are a type of granite formed out of molten magma. What makes pegmatites interesting is that they tend to contain a lot of incompatible elements, which resist forming solid crystals for as long as possible. The rocks form as the magma beneath a volcano cools very slowly. The magma’s chemical composition evolves over time. As elements drop out of the liquid to form solid crystals, other elements, like lithium, tend to linger in the liquid, becoming more and more concentrated. But eventually, even that magma cools and crystallizes, and the incompatibles are locked into the pegmatite.

    Before the 1990s, pegmatites in the United States were the primary source of mined lithium. But extracting lithium ore, primarily a mineral called spodumene, from the rock is costly. On top of the cost of actual mining, the rock has to be crushed and treated with acid and heat to extract the lithium in a commercially useful form.

    In the 1990s, a much cheaper source of lithium became an option. Just beneath the arid salt flats spanning large swaths of Chile, Argentina and Bolivia circulates salty, lithium-enriched groundwater. Miners pump the salty water to the surface, sequestering it into ponds and letting it evaporate in the sun. “Mother Nature does most of the work, so it’s really cheap,” Stillings says.

    What’s left behind after the evaporation is a sludgy, yellowish brine. To extract battery-grade lithium in commercially useful forms, particularly lithium carbonate and lithium hydroxide, the miners add different minerals to the brine, such as sodium carbonate and calcium hydroxide. Reactions with those minerals cause different types of salts to precipitate out of the solution, ultimately producing lithium minerals.

    4
    Pieces of a sediment core drilled at one potential future mining site in Clayton Valley, Nev., revealed a promising lithium-rich clay. Credit: Cypress Development Corp

    Compared with pegmatite extraction, the process for extracting lithium from the brine is extremely cheap; as a result, brine mining currently dominates the lithium market. But in the hunt for more lithium, the next generation of prospectors are looking to a third type of deposit: clay.

    Clays are the hardened remnants of ancient mud, produced by the slow settling of tiny grains of sediment, such as within a lake bed. To get lithium-enriched clay requires the right starting ingredients, particularly lithium-bearing rocks such as pegmatite and circulating groundwater. The groundwater leaches the lithium from the rocks and transports it to a lake where it becomes concentrated in the sediments.

    The western United States, it turns out, has all the right ingredients to make lithium-rich clay. In fact, in 2017 in Nature Communications, researchers suggested that some ancient supervolcano craters that became lakes, such as the Yellowstone caldera, would be excellent sources of lithium [Nature Communication].

    ______________________________________________________
    White gold

    Most of the world’s lithium sources (orange) are pegmatite mines in Australia and China and brine mines in Chile and Argentina. But planned mining ventures (blue) mean that the lithium rush will soon spread to the United States, Canada and Mexico.

    Known sources of lithium around the world

    5

    Source: USGS
    ______________________________________________________

    Several other types of lithium extraction may be on the horizon, Stillings says. Lithium-rich brines can also form in tectonically active geothermal regions, where there is a lot of heat in the subsurface. Geothermal power plants already pump up the superheated water to generate energy, then inject it back into the subsurface. Some facilities are experimenting with extracting other commercially valuable elements from the brine, including lithium, manganese and zinc. Hydraulic fracturing, or fracking, also involves pumping up brines from the subsurface that may contain high levels of dissolved metals, possibly including lithium. Although the lithium may not be present in very high concentrations, the extraction could still be economically worthwhile, if it’s a by-product of mining already going on.

    Revitalized research

    In December 2017, the White House issued an executive order directing the U.S. Department of the Interior to ramp up research on new sources of certain “critical minerals,” including ores bearing lithium. Citing the economy and national security, the order instructed government scientists to analyze each link in the minerals’ supply chains, from exploration to mining to production, in hopes that new sources could be found within U.S. borders.

    The United States isn’t alone in the rush to find lithium. China, the European Union and others are on the hunt for new sources. In January, a consortium of EU researchers launched a two-year initiative called the European Lithium Institute to become competitive in the lithium market.

    To kick off this new phase in lithium research, Stillings helped convene a symposium at the American Geophysical Union’s annual meeting in Washington, D.C., last December. “We would like to understand how lithium cycles through Earth’s crust,” Stillings says. “Lithium is very soluble; it likes to be in solution. However, we’ve learned that as it moves through the crust, it does interact with clays.”

    ______________________________________________________
    A multipurpose element

    Lithium is useful for a lot more than batteries. Below are some common products and the lithium compounds they contain.

    Mood stabilizer for bipolar disorder: Lithium has been used as a medication for conditions ranging from gout to mental disorders since the mid-19th century. Taken as lithium carbonate or lithium citrate, lithium has been in widespread use to treat acute mania, an aspect of bipolar disorder, since the 1970s.

    However, scientists still aren’t sure why the treatment works. Due to their smaller size, charged particles, or ions, of lithium may substitute for potassium, sodium or calcium ions in certain enzymes and chemicals in the brain. Substituting lithium may reduce the sensitivity of certain receptors, making them less likely to connect to brain chemicals such as norepinephrine, which is known to be overabundant during mania.

    Cosmetics: Lithium stearate acts as an emulsifier, keeping oils and liquids from separating in foundations, face powders, eye shadows and lipsticks. When added to face creams, a soft, greasy, lithium-bearing mineral called hectorite keeps the product smooth and spreadable.

    Military, industrial, automotive, aircraft and marine applications: When added to petroleum, lithium stearate creates a thick lubricating grease that is waterproof and tolerant of high and low temperatures.

    Shock-resistant cookware and aluminum foil: Compared with the other alkali metals, lithium atoms are small, particularly in their charged state. Lithium ions expand relatively little as they get hotter, so adding some lithium carbonate to glass or ceramics can make those products stronger and less likely to shatter when hot.
    ______________________________________________________

    Lithium isotopes — it has two, lithium-6 and lithium-7 — are one way to track this exchange. “They are like a fingerprint,” says Romain Millot, a geologist with the French Geological Survey and the University of Orléans in France. The different masses of the two isotopes influence how they move between water and solid rock: Lithium-6 prefers to leave the water and bind into clay grains, compared with lithium-7. The isotopes are also proving useful at revealing the influences of weathering, water flow and heat on concentrating lithium, Millot says.

    Because water is so important for concentrating lithium, researchers are shifting away from a classic “find the ore” framework, says Scott Hynek, a USGS geologist based in Salt Lake City. Instead, “we’re taking a more petroleum-like perspective,” he says. Scientists are tracking not just where deposits are, but how they might move: where the water flows, where the lithium-rich fluid could become trapped beneath a layer of hard, impermeable rock.

    Lithium prospecting is also taking a page from the hydrology playbook, using some classic tools of that trade to track the circulation of groundwater through the subsurface to suss out where lithium-rich deposits might end up. Isotopes of hydrogen, oxygen and helium are used to track how long the groundwater has been traveling through the subsurface as well as the types of rocks that the water has been in contact with.

    Faults, for example, can channel subsurface water, and therefore may play a big role in shaping where lithium deposits might form. “It’s an unresolved question,” Hynek says. “These are big-scale geologic controls on where high-lithium water goes.” He presented data at the AGU symposium suggesting that the highest lithium concentrations in a Chilean salt flat known as the Salar de Atacama occur near certain fault lines. That, he says, suggests the faults are helping to channel the groundwater and thereby concentrating the deposits.

    Do no harm

    One looming problem for lithium mining is that even “clean” energy isn’t completely clean. Extracting lithium from its ore and converting it into a commercially usable form such as lithium carbonate or lithium hydroxide can produce toxic waste, which can leak into the environment. Chemical leaks from a lithium mine in China’s Tibetan Plateau have repeatedly wreaked havoc on the environment since 2009, killing fish and livestock that drank from a nearby river.

    Even when Mother Nature is doing much of the work, such as in evaporation ponds, there can be negative effects on the environment. In South America, for example, the problem is water supply. The lithium triangle, which includes Salar de Atacama, is one of the driest places on Earth — and mining consumes a lot of water. And that’s producing a worrisome confluence of events. Just at the edges of the Salar de Atacama salt flats is a flamingo nesting habitat: brackish lagoons filled with brine shrimp. “One of the major oppositions to this mining activity is the impact it has potentially on flamingo populations,” Hynek says. The same water source in the Andes that feeds the subsurface lithium brine reservoir also, ultimately, fills the lagoons.

    5
    Brine mining in the Salar de Atacama consists of pumping salty, lithium-rich water into evaporation ponds (shown). The post-evaporation sludge is treated with minerals such as sodium carbonate to extract the lithium. Credit: Hemis/Alamy Stock Photo

    In fact, the water table is already dropping in some places in the region, and indigenous communities, as well as both Chilean and Argentinian authorities, are on high alert, Hynek says. “Chilean authorities are worried that [miners] will pump so much that the lagoon water levels will also drop.” In February, Chile announced new restrictions on water rights for miners operating in Salar de Atacama.

    Who’s to blame is the subject of a lot of debate. In addition to the lithium brine mining, copper mines high up in the Andes — where the groundwater originates — are extracting a substantial amount of water from the system. “The flamingos and the indigenous communities are literally stuck in the middle,” Hynek adds.

    Such big environmental concerns could hamper future prospects for mining in the region. “You’re making the brine in the same area where you’re sustaining these important biodiversity habitats,” says David Boutt, a hydrologist at the University of Massachusetts Amherst.

    There is so far little research on how water moves through the subsurface in dry areas with very low precipitation rates, such as South America’s lithium triangle, Boutt adds. “There are a lot of questions about where the water is coming from,” such as how variable the water flow rate is through the ground. “It can take a very long time for these systems to respond” to perturbations such as groundwater pumping.

    The effects of withdrawing the briny waters now might not be felt for perhaps decades. “A concern,” Boutt says, “is whether we are going to be waiting 100 years before something bad happens.”

    See the full article here .


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  • richardmitnick 10:46 am on May 9, 2019 Permalink | Reply
    Tags: "Dying stars called collapsars may forge much of the universe’s gold", , , , , r-process: atomic nuclei rapidly absorb neutrons and undergo radioactive decay to create new elements, Science News   

    From Science News: “Dying stars called collapsars may forge much of the universe’s gold” 

    From Science News

    May 8, 2019
    Emily Conover

    Spinning stellar objects collapsing into black holes could help explain heavy elements’ origins.

    1
    BLAST FROM COLLAPSE A collapsar occurs when a massive, spinning star collapses into a black hole, powering a blast of light known as a long gamma ray burst (illustrated) and exploding the star’s outer layers. NASA Goddard Space Flight Center.

    The gold in your favorite jewelry could be the messy leftovers from a newborn black hole’s first meal.

    Heavy elements such as gold, platinum and uranium might be formed in collapsars — rapidly spinning, massive stars that collapse into black holes as their outer layers explode in a rare type of supernova. A disk of material, swirling around the new black hole as it feeds, can create the conditions necessary for the astronomical alchemy, scientists report online May 8 in Nature.

    “Black holes in these extreme environments are fussy eaters,” says astrophysicist Brian Metzger of Columbia University, a coauthor of the study. They can gulp down only so much matter at a time, and what they don’t swallow blows off in a wind that is rich in neutrons — just the right conditions for the creation of heavy elements, computer simulations reveal.

    Astronomers have long puzzled over the origins of the heaviest elements in the universe. Lighter elements like carbon, oxygen and iron form inside stars, before being spewed out in stellar explosions called supernovas. But to create elements further down the periodic table, an extreme environment densely packed with neutrons is required. That’s where a chain of reactions known as the r-process can occur, in which atomic nuclei rapidly absorb neutrons and undergo radioactive decay to create new elements.

    Scientists had suspected that when two dead stars known as neutron stars collide, the r-process could occur in material churned up by the merger. Astronomers recently clinched the case for that idea when they spotted a collision between two neutron stars that produced spacetime ripples known as gravitational waves and light. The fireworks show revealed signs of the formation of a medley of heavy elements including gold, silver and platinum (SN: 11/11/17, p. 6).

    2
    BRIGHT BURST After two neutron stars slammed together, scientists detected gravitational waves, a burst of gamma rays and a glow from ejected material, shown in this artist’s by now iconic conception. NSF, LIGO, A. Simonnet/Sonoma State University

    The neutron star explanation has shortcomings, though. These dense dead stars can take a long time to coalesce. But heavy elements have been found in ancient stars that formed early in the universe’s history. It’s not clear whether a neutron star merger could happen fast enough to explain the elements’ presence in those early stars.

    Collapsars, however, can occur shortly after stars begin to form. And the phenomenon could be a prolific producer of heavy elements. A single collapsar might generate 30 times as much r-process material as a neutron star merger, and could generate a few hundred times the Earth’s mass in gold, Metzger says. The researchers report that collapsars might be responsible for 80 percent of the r-process elements in the universe, with neutron star mergers making up the rest.

    The study sheds new light on the 2016 discovery that a dwarf galaxy called Reticulum II experienced a cataclysm early in the history of the universe that left r-process elements in its stars (SN: 5/14/16, p. 9). Scientists had proposed that an ancient neutron star merger seeded the galaxy with those elements. Now, a collapsar is another candidate.

    “It’s very exciting,” says astrophysicist Anna Frebel of MIT, a coauthor of the 2016 study. Neutron star mergers are rare, so “it felt a little bit like we were proposing to win the lottery.” But collapsars are about 10 times as rare, so if they are the explanation, “it feels like we’ve won the lottery twice.”

    But it’s still not clear if collapsars happen frequently enough, or if they produce the right amount of material, to explain the abundances of heavy elements seen in the universe. “I think the jury’s still out,” says astrophysicist Alexander Ji of Carnegie Observatories in Pasadena, Calif., who coauthored the 2016 paper on Reticulum II.

    “Now we’re really excitedly thinking about how you might be able to tell the difference” — whether collapsars or neutron stars better explain galaxies like Reticulum II, Ji says. Future observations of the aftermath of the supernovas produced by collapsars could also help nail down their role.

    See the full article here .


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  • richardmitnick 10:29 am on May 8, 2019 Permalink | Reply
    Tags: "What a nearby kilonova would look like", , , , , Science News   

    From Science News: “What a nearby kilonova would look like” 

    From Science News

    May 8, 2019
    Lisa Grossman

    Physicists imagined what we’d see if two neutron stars merged 1,000 light-years from Earth.

    1
    NEARBY NOVA A kilonova — the bright burst following a crash between two neutron stars — would shine brighter than the stars over the New York City skyline, even during the day. This simulated image shows the kilonova after one day (left) and after seven days (right). N. Gupte, I. Bartos/arXiv.org 2019, King of Hearts/Wikimedia Commons (CC-BY-SA-3.0)

    If two dense neutron stars collided relatively close to Earth, the resulting kilonova would shine day and night with the brightness of the moon squeezed into a small dot.

    “At night, it would be by far the brightest thing up there,” says physicist Imre Bartos of the University of Florida in Gainesville, who describes what the bright burst would look like in a study posted May 7 at arXiv.org.

    The first such burst of light and energetic particles seen in real time was spotted in 2017, after physicists detected gravitational waves from a neutron star crash (SN: 11/11/17, p. 6). That discovery, which occurred 130 million light-years away and was visible only with telescopes, proved that kilonovas sprinkle the universe with heavy elements like gold, silver, platinum and uranium.

    While it’s unlikely a kilonova will happen nearby anytime soon, one occurred about 1,000 light-years from where Earth is now (although 80 million years before the solar system formed), Bartos and physicist Szabolcs Marka of Columbia University reported May 1 in Nature. That event seeded the solar system with elements that make up planets today. https://sciencesprings.wordpress.com/2019/02/26/from-science-news-colliding-neutron-stars-shot-a-light-speed-jet-through-space/

    “We wanted to make this more visual, what this distance means,” Bartos says. So he and Nihar Gupte, also at the University of Florida, simulated the light spectrum emitted by the 2017 kilonova as it would appear if it were just 1,000 light-years away. It would start out bluish in color, but would turn red over a few days to a week as debris from the kilonova smothered bluer wavelengths of light (SN: 3/30/19, p. 7). After about a week, the kilonova would fade to nothing.

    A kilonova could happen that close to Earth once every 100 million years, astrophysicists estimate. So we’re not likely to see one, but some may have occurred over Earth’s 4.5-billion-year history. That could have had painful consequences for anything alive on the planet at the time. If the kilonova released a gamma-ray burst, like the 2017 kilonova did, that torrent of high-energy particles of light could have indirectly wiped out life on Earth (SN: 1/10/15, p. 15).

    See the full article here .


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  • richardmitnick 3:39 pm on May 6, 2019 Permalink | Reply
    Tags: , , , , , , Science News   

    From Science News: “LIGO [and VIRGO] on the lookout for these 8 sources of gravitational waves” 

    From Science News

    May 6, 2019
    Lisa Grossman

    Astronomers still hope to catch a star going supernova and a bumpy neutron star, among others.

    1
    BANG, CRASH Physicists using the LIGO and Virgo observatories are catching all sorts of cosmic collisions, including of pairs of neutron stars (illustrated). But scientists hope to bag even more exotic quarry. NASA’s Goddard Space Flight Center/CI Lab

    Seekers of gravitational waves are on a cosmic scavenger hunt.

    Since the Advanced Laser Interferometer Gravitational-wave Observatory turned on in 2015, physicists have caught these ripples in spacetime from several exotic gravitational beasts — and scientists want more.

    This week, LIGO and its partner observatory Virgo announced five new possible gravitational wave detections in a single month, making what was once a decades-long goal almost commonplace (SN Online: 5/2/19).

    _____________________________________________________
    Picking up

    In just one month, scientists have already spotted 5 possible gravitational wave events, plotted here as a function of their approximate distance from Earth. That’s compared to 11 events from all previous observations combined. Most detections are from merging black holes, but neutron star mergers (red) are also in the mix. And one event (yellow) might be a mash up between a black hole and a neutron star.

    Gravitational wave detections by LIGO and Virgo are becoming more frequent

    4
    E. Otwell, T. Tibbitts

    _____________________________________________________

    “We’re just beginning to see the field of gravitational wave astronomy open,” LIGO spokesperson Patrick Brady from the University of Wisconsin–Milwaukee said May 2 in a news conference. “Opening up a new window on the universe like this will hopefully bring us a whole new perspective on what’s out there.”

    The speed and pitch of gravitational wave signals allow astronomers to make out what’s stirring up the waves. Here are the sources of gravitational waves that scientists that already have in their nets, and what they’re still hoping to find.
    1. Pairs of colliding black holes

    Status: Found

    7
    SWEET SUCCESS For the first time, physicists have directly observed gravitational waves, caused by two black holes colliding (illustrated here). SXS collaboration.

    2. Pairs of colliding neutron stars

    Status: Found

    3. A neutron star crashing into a black hole

    Status: Maybe

    3
    TOUGH STUFF An exotic substance thought to exist within a type of collapsed star called a neutron star (illustrated) may be stronger than any other known material.
    Casey Reed/Penn State University, Wikimedia Commons

    4. A collision involving an intermediate-mass black hole

    Status: Not yet

    9
    HIDDEN FIGURE An intermediate-mass black hole about 2,200 times as heavy as the sun may lurk at the center of this dense ball of stars, a globular cluster called 47 Tucanae.
    NASA, ESA, Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, J. Mack/STScI, G. Piotto/University of Padua

    5. A bumpy neutron star

    Status: Not yet

    6. Supernova explosions

    Status: Not yet

    LIGO and Virgo might also be able to pick up gravitational waves from supernova explosions, the bright cataclysms at the end of massive stars’ lives.

    6
    SHINE BRIGHT Supernova 1987A shone as a brilliant point of light near the Tarantula Nebula (pink cloud) in the Large Magellanic Cloud, as pictured from an observatory in Chile.

    Supernovas emit many types of light and particles, including ghostly subatomic particles called neutrinos that are born deep in the heart of the explosions (SN: 2/18/17, p. 20). But scientists still don’t know exactly what makes a star explode as a supernova in the first place.

    What they do know is that during a supernova explosion, the central core of the star collapses, and the resulting proto-neutron star gathers material from the remainder of the collapsing core. The turbulence at the surface of the proto-neutron star makes it vibrate like a bell, sending off gravitational waves. That specific gravitational wave signal is strongly related to the strength of the turbulence and the structure of the nascent neutron star, astrophysicist David Radice of Princeton University and colleagues report April 29 in the Astrophysical Journal Letters.

    7. Waves triggered by the Big Bang

    Status: Not yet

    8. New sources?

    Status: Not yet

    LIGO Caltech. LIGO and Virgo detect neutron star smash-ups. May 2, 2019.
    See https://sciencesprings.wordpress.com/2019/05/06/from-mit-caltech-advanced-aligo-ligo-and-virgo-detect-neutron-star-smash-ups/

    See the full article here .


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  • richardmitnick 3:22 pm on May 3, 2019 Permalink | Reply
    Tags: , For the first time researchers have performed a version of the famous double-slit experiment with antimatter particles., Particles of matter like electrons are also waves, , Positrons, Science News, The famous double-slit experiment   

    From Science News: “Antimatter keeps with quantum theory. It’s both particle and wave” 

    From Science News

    May 3, 2019
    Maria Temming

    A variation of the classic double-slit experiment is applied to a positron for the first time.

    1
    MAKING WAVES The famous double-slit experiment (illustrated) has revealed that particles of matter, like electrons, are also waves. Now, researchers have performed a similar experiment to demonstrate antimatter’s wavelike behavior. RUSSELL KIGHTLEY/Science Source

    For the first time, researchers have performed a version of the famous double-slit experiment with antimatter particles.

    The double-slit experiment demonstrates one of the fundamental tenets of quantum physics: that pointlike particles are also waves. In the standard version of the experiment, particles travel through a pair of slits in a solid barrier. On a screen on the other side, an interference pattern typical of waves appears. Crests and troughs emerging from each slit reinforce each other or cancel each other out as they overlap, creating alternating bands of high and low particle density on the screen.

    This kind of experiment has revealed the wave-particle duality of photons, electrons, atoms and even large molecules (SN: 11/20/10, p. 20). But it’s very difficult to generate a strong, uniform beam of antiparticles to do the experiment with antimatter. Now, a new double-slit–style experiment, reported online May 3 in Science Advances, has confirmed the wavelike nature of the electron’s antimatter counterpart: the positron.

    The researchers designed a device in which positrons, generated through the radioactive decay of the isotope sodium-22, travel through two successive rows of vertical rods less than a micrometer thick. The gaps between these rods, each a few hundred nanometers across, work like the slits in the classic double-slit experiment. The positron waves propagate out to a nuclear emulsion detector, where the antiparticles alter the chemical structure of silver bromide crystals.

    The nuclear emulsion detector “is like a photographic film,” says study coauthor Marco Giammarchi, a physicist at the National Institute of Nuclear Physics in Milan. Developing the nuclear emulsion film in a darkroom and viewing it under a microscope reveals the positrons’ chemical footprints. Sure enough, Giammarchi’s team found a positron interference pattern, with alternating stripes of high and low positron density.

    Giammarchi and colleagues hope to use their new technique to probe the nature of other antimatter conglomerates, such as positronium (SN: 9/15/07, p. 163).

    See the full article here .


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