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  • richardmitnick 10:29 am on April 15, 2019 Permalink | Reply
    Tags: "Earth’s Magnetopause Vibrates Like Giant Drum When Hit by Strong Impulses", , , , , , Science News   

    From Science News: “Earth’s Magnetopause Vibrates Like Giant Drum When Hit by Strong Impulses” 

    From Science News

    Feb 13, 2019 [Just found this.]

    As strong impulses strike the Earth’s magnetopause, the abrupt boundary between the planet’s magnetosphere and the surrounding plasma, ripples travel along its surface which then get reflected back when they approach the magnetic poles. The interference of the original and reflected waves leads to a standing wave pattern, in which specific points appear to be standing still while others vibrate back and forth. A drum resonates like this when struck in exactly the same way. A new study, published in the journal Nature Communications, describes the first time this effect has been observed after it was theoretically proposed 45 years ago.

    1
    Illustration of a plasma jet impact (yellow) generating standing waves at the boundary (blue) of Earth’s magnetic shield (green). Image credit: E. Masongsong, UCLA / M. Archer, QMUL / H. Hietala, UTU.

    Inside the Earth’s magnetosphere, planetary researchers have long been listening in on space sounds created by various electromagnetic waves.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

    This veritable orchestra of waves can be heard as sound when processed correctly, and they even exhibit similar behaviors to certain musical instruments.

    So-called magnetosonic waves pulse through plasma in the same way sound bounces through wind instruments.

    Another type of wave, known as an Alfvén wave, resonates along magnetic field lines, just like string instruments’ vibrating strings.

    While both of these types of waves can travel anywhere in space, the newly-discovered waves are a type of surface waves — waves that require some sort of boundary to travel along.

    In this case the magnetopause acted as the boundary. When a plasma jet — the drumstick — strikes the magnetopause, surface waves form a standing wave pattern — where the ends appear to be standing still while other points vibrate back and forth — just like a drumhead.

    The fixed points in the wave, which are the rim or edge of the drum, are near Earth’s magnetic poles; the waves vibrate the surface of the magnetopause in between.

    While the wave itself remains on the surface, the vibrations ultimately work their way down into the magnetosphere and trigger other types of waves.


    “The waves likely penetrate far into the inner magnetosphere causing ultra-low frequency waves, which affect things like radiation belts, the aurora, and even the ionosphere,” said lead author Dr. Martin Archer, space physicist at Queen Mary University, UK.

    Dr. Archer and colleagues used observations from five NASA’s Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites when they were ideally located as a strong isolated plasma jet slammed into the magnetopause.

    The probes were able to detect the boundary’s oscillations and the resulting sounds within the Earth’s magnetic shield, which agreed with the theory and gave the researchers the ability to rule out all other possible explanations.

    “Given the lack of evidence over the 45 years since they were proposed, there had been speculation that these drum-like vibrations might not occur at all,” Dr. Archer said.

    “Now we see that waves on the magnetopause’s surface reflect between two points near the magnetic poles — acting very much like a drum.”

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 1:35 pm on April 3, 2019 Permalink | Reply
    Tags: "Metal asteroids may have once had iron-spewing volcanoes", , , , , Science News   

    From Science News: “Metal asteroids may have once had iron-spewing volcanoes” 

    From Science News

    April 3, 2019
    Lisa Grossman

    An upcoming NASA mission could look for signs of past ‘ferrovolcanism’ on asteroid Psyche.

    1
    FULL METAL ASTEROID Long ago, molten iron could have erupted from the metal asteroid Psyche (illustrated in cross section) in a process dubbed ferrovolcanism, new studies suggest.
    Elena Hartley

    Imagine a metal asteroid spewing molten iron, and you’ve got the gist of ferrovolcanism — a new type of planetary activity proposed recently by two research teams.

    When NASA launches a probe to a metal asteroid called Psyche in 2022, planetary scientists will be able to search for signs of such volcanic activity in the object’s past.

    1
    Image of asteriod Psyche

    NASA Psyche spacecraft

    The new research “is the first time anyone has worked out what volcanism is likely to look like on these asteroids,” says planetary scientist Jacob Abrahams of the University of California, Santa Cruz.

    Metal asteroids are thought to be the exposed iron-rich cores of planetesimals that suffered a catastrophic collision as the solar system was developing, before they could grow into full-sized planets. The naked core would have been exposed to cold space while still molten. And it would have cooled and solidified from the outside in, forming a solid iron crust that would be denser than the underlying molten iron, say Abrahams and planetary scientist Francis Nimmo, also of the University of California, Santa Cruz.

    https://www.hou.usra.edu/meetings/lpsc2019/pdf/1598.pdf

    That kind of density mismatch is part of what can create volcanoes on Earth — lighter, more buoyant material rising up through cracks in the crust — and could have led to iron-spewing volcanoes on metal asteroids as the objects cooled long ago, the researchers speculate.

    Another way that ferrovolcanism could have occurred on metal asteroids was described by planetary scientist Brandon Johnson of Brown University in Providence, R.I.

    If a cooling iron core also contained a little bit of rock and sulfur, he theorizes, the core could have been cocooned beneath a rocky, not iron, crust. As the core cooled further, pockets of iron-rich liquid with extra sulfur dissolved in them would have hardened more slowly than surrounding materials. Those pockets would be more buoyant than the rock above them, so they’d force their way up and out, Johnson says.

    https://www.hou.usra.edu/meetings/lpsc2019/pdf/1625.pdf

    If Psyche has such a rocky veneer over iron, that could explain why the asteroid appears much less dense than expected, Johnson says. The two groups, which worked independently from one another, presented their ideas March 21 at the Lunar and Planetary Science Conference in The Woodlands, Texas.

    “We kept thinking, ‘It’s too wild, it can’t be right,’ ” says Johnson, of the idea of ferrovolcanism. “But we couldn’t prove to ourselves that it wouldn’t work. Because another group came up with the same idea at the same time, it can’t be too wild.”

    The Psyche spacecraft can look for signs of past ferrovolcanism when it arrives at the eponymous asteroid, located in the main asteroid belt between Mars and Jupiter, in 2026, says mission principal investigator and planetary scientist Lindy Elkins-Tanton.

    What’s more, if Psyche were rotating while it cooled, its molten core could have generated a magnetic field. Volcanic flows that cooled on the asteroid’s surface would have recorded evidence of that magnetic field. “We might actually be able to see these things,” says Elkins-Tanton, of Arizona State University in Tempe. “I think it’s really cool.”

    See the full article here .


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  • richardmitnick 5:06 pm on March 29, 2019 Permalink | Reply
    Tags: , , Science News, , SO-2 and SO-38 circle SGR A*Image UCLA Galactic Center Groupe via S. Sakai and Andrea Ghez at Keck Observatory   

    From Science News: “4 things we’ll learn from the first closeup image of a black hole” 

    From Science News

    March 29, 2019
    Lisa Grossman

    Event Horizon Telescope data are giving scientists an image of the Milky Way’s behemoth.

    1
    FIRST LOOK The first image from the Event Horizon Telescope may show that the black hole at the center of our galaxy looks something like this simulation.

    The Event Horizon Telescope, a network of eight radio observatories spanning the globe, has set its sights on a pair of behemoths: Sagittarius A*, the supermassive black hole at the Milky Way’s center, and an even more massive black hole 53.5 million light-years away in galaxy Messier 87 (SN Online: 4/5/17).

    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    SgrA* NASA/Chandra supermassive black hole at the center of the Milky Way

    Sgr A* from ESO VLT

    SGR A and SGR A* from Penn State and NASA/Chandra

    Event Horizon Telescope Array

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM NOEMA interferometer
    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Hawaii SAO
    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    NSF CfA Greenland telescope

    Greenland Telescope

    Future Array/Telescopes

    Plateau de Bure interferometer
    Plateau de Bure interferometer

    In April 2017, the observatories teamed up to observe the black holes’ event horizons, the boundary beyond which gravity is so extreme that even light can’t escape (SN: 5/31/14, p. 16). After almost two years of rendering the data, scientists are gearing up to release the first images in April.

    Here’s what scientists hope those images can tell us.

    What does a black hole really look like?

    Black holes live up to their names: The great gravitational beasts emit no light in any part of the electromagnetic spectrum, so they themselves don’t look like much.

    But astronomers know the objects are there because of a black hole’s entourage. As a black hole’s gravity pulls in gas and dust, matter settles into an orbiting disk, with atoms jostling one another at extreme speeds. All that activity heats the matter white-hot, so it emits X-rays and other high-energy radiation. The most voraciously feeding black holes in the universe have disks that outshine all the stars in their galaxies (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. NAOJ.


    A CAMERA THE SIZE OF EARTH How did scientists take a picture of a black hole? Science News explains.

    The EHT’s image of the Milky Way’s Sagittarius A*, also called SgrA*, is expected to capture the black hole’s shadow on its accompanying disk of bright material. Computer simulations and the laws of gravitational physics give astronomers a pretty good idea of what to expect. Because of the intense gravity near a black hole, the disk’s light will be warped around the event horizon in a ring, so even the material behind the black hole will be visible.

    And the image will probably look asymmetrical: Gravity will bend light from the inner part of the disk toward Earth more strongly than the outer part, making one side appear brighter in a lopsided ring.

    Does general relativity hold up close to a black hole?

    The exact shape of the ring may help break one of the most frustrating stalemates in theoretical physics.

    The twin pillars of physics are Einstein’s theory of general relativity, which governs massive and gravitationally rich things like black holes, and quantum mechanics, which governs the weird world of subatomic particles. Each works precisely in its own domain. But they can’t work together.

    “General relativity as it is and quantum mechanics as it is are incompatible with each other,” says physicist Lia Medeiros of the University of Arizona in Tucson. “Rock, hard place. Something has to give.” If general relativity buckles at a black hole’s boundary, it may point the way forward for theorists.

    Since black holes are the most extreme gravitational environments in the universe, they’re the best environment to crash test theories of gravity. It’s like throwing theories at a wall and seeing whether — or how — they break. If general relativity does hold up, scientists expect that the black hole will have a particular shadow and thus ring shape; if Einstein’s theory of gravity breaks down, a different shadow.

    Medeiros and her colleagues ran computer simulations of 12,000 different black hole shadows that could differ from Einstein’s predictions. “If it’s anything different, [alternative theories of gravity] just got a Christmas present,” says Medeiros, who presented the simulation results in January in Seattle at the American Astronomical Society meeting. Even slight deviations from general relativity could create different enough shadows for EHT to probe, allowing astronomers to quantify how different what they see is from what they expect.


    CONSIDERING ALL POSSIBILITIES Physicists expect black holes to follow Einstein’s rules of general relativity, but it might be more interesting if they don’t. This computer simulation shows one possibility for how a black hole would look if it behaved unexpectedly.

    Do stellar corpses called pulsars surround the Milky Way’s black hole?

    Another way to test general relativity around black holes is to watch how stars careen around them. As light flees the extreme gravity in a black hole’s vicinity, its waves get stretched out, making the light appear redder. This process, called gravitational redshift, is predicted by general relativity and was observed near SgrA* last year (SN: 8/18/18, p. 12). So far, so good for Einstein.

    5
    BLACK HOLE SUN Einstein’s theory of gravity was upheld in measurements of a star that recently made a close pass by the supermassive black hole at the center of the Milky Way, as shown in this artist’s conception illustrating the star’s trajectory over the past few months.

    SO-2 and SO-38 circle SGR A*Image UCLA Galactic Center Groupe via S. Sakai and Andrea Ghez at Keck Observatory

    An even better way to do the same test would be with a pulsar, a rapidly spinning stellar corpse that sweeps the sky with a beam of radiation in a regular cadence that makes it appear to pulse (SN: 3/17/18, p. 4). Gravitational redshift would mess up the pulsars’ metronomic pacing, potentially giving a far more precise test of general relativity.

    “The dream for most people who are trying to do SgrA* science, in general, is to try to find a pulsar or pulsars orbiting” the black hole, says astronomer Scott Ransom of the National Radio Astronomy Observatory in Charlottesville, Va. “There are a lot of quite interesting and quite deep tests of [general relativity] that pulsars can provide, that EHT [alone] won’t.”

    Women in STEM – Dame Susan Jocelyn Bell Burnell

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Dame Susan Jocelyn Bell Burnell at work on first plusar chart 1967 pictured working at the Four Acre Array in 1967. Image courtesy of Mullard Radio Astronomy Observatory.

    Dame Susan Jocelyn Bell Burnell 2009

    Dame Susan Jocelyn Bell Burnell (1943 – ), still working from http://www. famousirishscientists.weebly.com

    Despite careful searches, no pulsars have been found near enough to SgrA* yet, partly because gas and dust in the galactic center scatters their beams and makes them difficult to spot. But EHT is taking the best look yet at that center in radio wavelengths, so Ransom and colleagues hope it might be able to spot some.

    “It’s a fishing expedition, and the chances of catching a whopper are really small,” Ransom says. “But if we do, it’s totally worth it.”

    How do some black holes make jets?

    Some black holes are ravenous gluttons, pulling in massive amounts of gas and dust, while others are picky eaters. No one knows why. SgrA* seems to be one of the fussy ones, with a surprisingly dim accretion disk despite its 4 million solar mass heft. EHT’s other target, the black hole in galaxy M87, is a voracious eater, weighing in at about 2.4 trillion solar masses. And it doesn’t just amass a bright accretion disk. It also launches a bright, fast jet of charged subatomic particles that stretches for about 5,000 light-years.

    “It’s a little bit counterintuitive to think a black hole spills out something,” says astrophysicist Thomas Krichbaum of the Max Planck Institute for Radio Astronomy in Bonn, Germany. “Usually people think it only swallows something.”

    Many other black holes produce jets that are longer and wider than entire galaxies and can extend billions of light-years from the black hole. “The natural question arises: What is so powerful to launch these jets to such large distances?” Krichbaum says. “Now with the EHT, we can for the first time trace what is happening.”

    EHT’s measurements of Messier 87’s black hole will help estimate the strength of its magnetic field, which astronomers think is related to the jet-launching mechanism. And measurements of the jet’s properties when it’s close to the black hole will help determine where the jet originates — in the innermost part of the accretion disk, farther out in the disk or from the black hole itself. Those observations might also reveal whether the jet is launched by something about the black hole itself or by the fast-flowing material in the accretion disk.

    Since jets can carry material out of the galactic center and into the regions between galaxies, they can influence how galaxies grow and evolve, and even where stars and planets form (SN: 7/21/18, p. 16).

    “It is important to understanding the evolution of galaxies, from the early formation of black holes to the formation of stars and later to the formation of life,” Krichbaum says. “This is a big, big story. We are just contributing with our studies of black hole jets a little bit to the bigger puzzle.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

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  • richardmitnick 12:35 pm on March 25, 2019 Permalink | Reply
    Tags: "How a proton gets its spin is surprisingly complicated", , , RHIC-BNL Relativistic Heavy Ion Collider, Science News   

    From Science News: “How a proton gets its spin is surprisingly complicated” 

    From Science News

    March 25, 2019
    Emily Conover

    1
    SPIN SURPRISE Protons are composed of smaller particles, called quarks and antiquarks, which contribute angular momentum, or spin. Now scientists report that a rarer type of antiquark adds more to the proton’s spin than a more common variety.

    In an odd twist, rarer up quarks add more angular momentum than more plentiful down quarks.

    Like a quantum version of a whirling top, protons have angular momentum, known as spin. But the source of the subatomic particles’ spin has confounded physicists. Now scientists have confirmed that some of that spin comes from a frothing sea of particles known as quarks and their antimatter partners, antiquarks, found inside the proton.

    Surprisingly, a less common type of antiquark contributes more to a proton’s spin than a more plentiful variety, scientists with the STAR experiment report March 14 in Physical Review D.

    Quarks come in an assortment of types, the most common of which are called up quarks and down quarks. Protons are made up of three main quarks: two up quarks and one down quark. But protons also have a “sea,” or an entourage of transient quarks and antiquarks of different types, including up, down and other varieties (SN: 4/29/17, p. 22).

    Previous measurements suggested that the spins of the quarks within this sea contribute to a proton’s overall spin. The new result — made by slamming protons together at a particle accelerator called the Relativistic Heavy Ion Collider, or RHIC — clinches that idea, says physicist Elke-Caroline Aschenauer of Brookhaven National Lab in Upton, N.Y., where the RHIC is located.

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    A proton’s sea contains more down antiquarks than up antiquarks. But, counterintuitively, more of the proton’s spin comes from up than down antiquarks, the researchers found. In fact, the down antiquarks actually spin in the opposite direction, slightly subtracting from the proton’s total spin.

    “Spin has surprises. Everybody thought it’s simple … and it turns out it’s much more complicated,” Aschenauer says.

    See the full article here .


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  • richardmitnick 7:57 am on March 22, 2019 Permalink | Reply
    Tags: Burgess Shale in Canada, Cambrian explosion of life, Paleoarchaeology, , , Qingjiang and Chengjiang fossils in China, Science News   

    From Science News: “Newfound fossils in China highlight a dizzying diversity of Cambrian life” 

    From Science News

    March 21, 2019
    Carolyn Gramling

    1
    ANCIENT IMPRINTS The newly described Qingjiang biota, a rich fossil site dating to about 518 million years ago, helps document a rapid flourishing of diverse invertebrate life known as the Cambrian explosion. The fossils include abundant jellyfish (left) and comb jellies (middle), as well as a segmented, spiny animal that may be a kinorhynch (right).

    Along the banks of China’s Danshui River lies a treasure trove of fossils that may rival the most famous Cambrian fossil assemblage of all, Canada’s Burgess Shale. The roughly 518-million-year-old site contains a dizzying abundance of beautifully preserved weird and wonderful life-forms, from jellyfish and comb jellies to arthropods and algae.

    So far, researchers led by paleontologist Dongjing Fu of Northwest University in Xian, China, have collected 4,351 specimens at the new site, representing 101 different taxa, or groups of organisms. Of those taxa, about 53 percent have never before been observed, Fu and her colleagues report in the March 22 Science — not even at other well-known Cambrian fossil sites such as the 508-million-year-old Burgess Shale or a 518-million-year-old site known as Chengjiang, also in China.

    “It’s an exciting discovery,” says Jean-Bernard Caron, a paleontologist at the Royal Ontario Museum in Toronto who wasn’t involved in the study. During the Cambrian Period, which began about 542 million years ago, life diversified extremely rapidly. So many new forms appeared in such a relatively short period of time that this diversification is known as the Cambrian explosion. The find “shows that there’s hope for new discoveries” of other Cambrian fossil sites, he says.

    2
    FOSSIL FINDS Researchers discovered the Qingjiang fossils along the bank of China’s Danshui River in Hubei Province. Dong King Fu

    Such sites represent snapshots of life long ago, and no one site can portray the true diversity of life on Earth at any given time, Caron says. “It’s a giant jigsaw puzzle, and we only have a few pieces…. But the more pieces we have, the better chance we have to understand life during that time.”

    The new fossil trove, called the Qingjiang biota, was first spotted in 2007, says coauthor Xingliang Zhang, a paleontologist also at Northwest University. “I have been working on Burgess Shale–type fossils for many years, and know what kind of rocks preserve [them],” Zhang says.

    During a field expedition that year, he and his students were investigating a different rock layer dating to the Cambrian. At lunchtime, he says, he happened to sit on the next lower layer of rocks as it was being lapped by the river’s water — and immediately recognized that the fine clay layer was the perfect preservation setting for fossils. “We split the clay stone and I found a Leanchoilia [a kind of segmented arthropod] quickly.” Many more discoveries soon followed.

    The site is remarkable for the quality of the preservation of the animals, says Allison Daley, a paleontologist at the University of Lausanne in Switzerland who was not involved in the new study but wrote a Science commentary that accompanies it in Science. “There was very little metamorphism or weathering effect, which does affect some other [Cambrian fossil] sites, like Burgess or Chengjiang. We see almost pristine fossils at this site.” She mentions one startlingly clear image of a jellyfish. “I mean, if you were going to smack a jellyfish on a rock, that’s how it would look.”

    ________________________________________________________
    Weird wonders
    The excellent preservation of the Qingjiang fossils reveals fine morphological details of some of the life-forms that lived in Cambrian seas, such as a branched alga (left) and the segmented body of an arthropod called a megacherian (right).
    3
    ________________________________________________________

    Unlike other Cambrian fossil troves, the Qingjiang biota appears to contain a high proportion of jellyfish, or cnidarians, and comb jellies, also called ctenophores. These species, particularly the comb jellies, are extremely rare at other sites.

    With so many ctenophore fossils preserved so well, Daley says, studying their shapes may help to answer a long-standing debate: Whether comb jellies or sponges are the most primitive animal on their family tree. Scientists have thought that sponges appear closer to the base of the tree, based on their very simple shapes. But some molecular analyses have hinted that comb jellies may be at the base of the tree.

    “It’s hard to disentangle the exact relationships of these [creatures],” Daley says. “These early branching groups diverged from each other such a long time ago…. So getting more info on [them] at this new site, where the preservation is really amazing, is really going to fill a gap.”

    The Burgess Shale, a vast deposit of fossil-bearing rocks in the Canadian Rockies, was discovered in 1909. It was this site that first gave scientists a glimpse into the Cambrian explosion, the rapid diversification of life that occurred during that period. The Burgess and Chengjiang sites, separated by 10 million years and half a world today, share only about 15 percent of the same taxa.

    That might be expected, Daley says, given their differences in both space and time. But the Qingjiang and Chengjiang sites, which date to the same time period and are separated by only 1,050 kilometers today, share only 8 percent of their taxa, she says. The researchers, however, suggest that the Qingjiang site may have been a slightly deeper marine environment. If so, that difference in ancient environment may have been the reason why the assemblage of creatures is so different, Daley says.

    The new work is preliminary, representing just the first of what is likely to be a deluge of studies describing fossils found at the site, Zhang says. “We’re just beginning!”

    Even after 110 years of digging in the Burgess Shale region, paleontologists are still turning up rich new sites and bizarre new creatures, adds Caron, of Canada’s Royal Ontario Museum. Just last summer, he and colleagues made new discoveries, including an enigmatic shield-shaped critter that he dubbed “the mothership.” Unlike other Cambrian fossil troves, the Qingjiang biota appears to contain a high proportion of jellyfish, or cnidarians, and comb jellies, also called ctenophores. These species, particularly the comb jellies, are extremely rare at other sites.

    With so many ctenophore fossils preserved so well, Daley says, studying their shapes may help to answer a long-standing debate: Whether comb jellies or sponges are the most primitive animal on their family tree. Scientists have thought that sponges appear closer to the base of the tree, based on their very simple shapes. But some molecular analyses have hinted that comb jellies may be at the base of the tree.

    “It’s hard to disentangle the exact relationships of these [creatures],” Daley says. “These early branching groups diverged from each other such a long time ago…. So getting more info on [them] at this new site, where the preservation is really amazing, is really going to fill a gap.”

    The Burgess Shale, a vast deposit of fossil-bearing rocks in the Canadian Rockies, was discovered in 1909. It was this site that first gave scientists a glimpse into the Cambrian explosion, the rapid diversification of life that occurred during that period. The Burgess and Chengjiang sites, separated by 10 million years and half a world today, share only about 15 percent of the same taxa.

    That might be expected, Daley says, given their differences in both space and time. But the Qingjiang and Chengjiang sites, which date to the same time period and are separated by only 1,050 kilometers today, share only 8 percent of their taxa, she says. The researchers, however, suggest that the Qingjiang site may have been a slightly deeper marine environment. If so, that difference in ancient environment may have been the reason why the assemblage of creatures is so different, Daley says.

    The new work is preliminary, representing just the first of what is likely to be a deluge of studies describing fossils found at the site, Zhang says. “We’re just beginning!”

    Even after 110 years of digging in the Burgess Shale region, paleontologists are still turning up rich new sites and bizarre new creatures, adds Caron, of Canada’s Royal Ontario Museum. Just last summer, he and colleagues made new discoveries, including an enigmatic shield-shaped critter that he dubbed “the mothership.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 2:30 pm on March 20, 2019 Permalink | Reply
    Tags: "X-ray ‘chimneys’ connect the Milky Way to mysterious gamma-ray bubbles", , , , , Science News   

    From Science News: “X-ray ‘chimneys’ connect the Milky Way to mysterious gamma-ray bubbles” 

    From Science News

    March 20, 2019
    Emily Conover

    Two glowing columns hundreds of light-years long extend from the center of the galaxy.

    1
    DOUBLE BUBBLE Two enormous bubbles sandwich the Milky Way and emit gamma rays (illustrated). Two chimneys that glow in X-rays seem to connect these bubbles to the galaxy’s center, scientists report. NASA Goddard Space Flight Center.

    Two towering “chimneys” glowing with X-rays extend from the center of the Milky Way. The newly discovered structures could help explain the source of two even larger features: giant bubbles that emit gamma rays, or high-energy light, found above and below the plane of the galaxy.

    Stretching hundreds of light-years, the X-ray chimneys seem to connect the gamma-ray bubbles to the center of the galaxy, scientists report in the March 21 Nature. “This is really interesting, and it could potentially tell us quite a lot about the origin of the gamma-ray bubbles,” says astrophysicist Tracy Slatyer of MIT. Slatyer was part of the team that discovered the bubbles but was not involved in the new study.

    New observations with the European Space Agency’s XMM-Newton satellite uncovered the chimneys.

    ESA/XMM Newton

    The researchers “have done a fantastic job to demonstrate these very distinct features,” says astronomer Daniel Wang of the University of Massachusetts Amherst. Previously, hints of such structures have been found using Japan’s Suzaku X-ray satellite, he says.

    JAXA/Suzaku satellite

    The chimneys, which are each about 300 light-years wide, could be funneling energy from the galaxy’s center to the gamma-ray bubbles, says astronomer Mark Morris of UCLA, a coauthor of the new study. “One way of looking at it is they are exhaust vents,” through which energy escapes.

    ______________________________________________________
    Colossal chimneys
    Two large gamma-ray bubbles (left) are linked to the galaxy’s heart by chimneys, each hundreds of light-years long (illustrated, center; in X-ray image, right).

    3
    Left two: NASA Goddard from M. Chernyakova/Nature 2019; Right: G. Ponti et al/Nature 2019
    ______________________________________________________

    Each gamma-ray bubble is itself the size of a small galaxy, and the source of the spheres’ energetic light has been a mystery since their discovery in 2010 (SN: 12/4/10, p. 18). Producing gamma rays requires highly energetic particles, which could be belched out by exploding stars, for example, or by the supermassive black hole at the heart of the galaxy as it slurps up matter and rips apart stars.

    The discovery of the chimneys doesn’t definitively pinpoint such a source. But it draws a clearer connection between the galaxy’s center and the bubbles, says astrophysicist Jun-Hui Zhao of the Harvard-Smithsonian Center for Astrophysics. “This is very important to find this piece of the puzzle,” he says.

    See the full article here .


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  • richardmitnick 2:06 pm on March 12, 2019 Permalink | Reply
    Tags: "Nine companies are steering the future of artificial intelligence", , Science News   

    From Science News: “Nine companies are steering the future of artificial intelligence” 

    From Science News

    March 12, 2019
    Maria Temming

    1
    UNDUE INFLUENCE The Big Nine explores how a handful of tech corporations involved in developing artificial intelligence, including Apple, whose headquarters is shown above, play an outsized role in determining the future of society. Uladzik Kryhin/Shutterstock

    1
    The Big Nine
    Amy Webb
    PublicAffairs, $27

    The book highlights warning signs of what happens when we increasingly rely on technology created by corporations that prioritize commercial and political interests over the public. These red flags include mismanagement of users’ personal data (SN Online: 4/15/18) in the United States and a state-sanctioned “social credit” system that monitors people’s behavior in China. Webb generally holds the Big Nine accountable but occasionally pivots to defend the companies, which she believes are led by people with good intentions.

    Readers who aren’t as convinced of the Big Nine’s noble intentions may at least agree with Webb that great power begets great responsibility. The second half of the book details three possible futures through 2069, ranging from a best-case scenario where the Big Nine commit to making user interests the No. 1 priority to a worst-case scenario where the Big Nine continue business as usual.

    Webb’s assessments are based on analyses of patent filings, policy briefings, interviews and other sources. She paints vivid pictures of how AI could benefit the average person, via precision medicine or smarter dating apps, for example, though she primarily focuses on people in the United States. Her forecasts are provocative and unsettlingly plausible.

    Webb closes with a somewhat perfunctory call to action, including predictable steps like reading the G-MAFIA’s terms of service. Unfortunately, The Big Nine may leave many readers feeling less like empowered citizens and more like extras in a film where tech giants and world leaders play the protagonists. But for anyone who wants a preview of how a few tech firms could reshape society in relatively short order, Webb’s account is an accessible, intriguing read.

    See the full article here .


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    • Skyscapes for the Soul 5:13 pm on March 12, 2019 Permalink | Reply

      A couple years ago I met a guy who is the CEO of H2O.ai – which he said was an AI company. I’m surprised they weren’t on the list.

      Like

  • richardmitnick 9:32 am on March 8, 2019 Permalink | Reply
    Tags: , , , Bernhard Kliem of the University of Potsdam in Germany and his colleagues scrutinized a CME recorded on May 13 2013 by NASA’s Solar Dynamics Observatory, But it was unclear how coronal mass ejections or CMEs get started, , , , Over about half an hour the blobs shot upward and merged into a large flux rope which briefly arced over the solar surface before erupting into space., Science News, Solar plasma eruptions are the sum of many parts a new look at a 2013 coronal mass ejection shows, , Solar scientists have long wondered what drives big bursts of plasma called coronal mass ejections. New analysis of an old eruption suggests the driving force might be merging magnetic blobs, That quick growth supports the idea that CMEs grow through magnetic reconnection, That speedy setup might make it more difficult to predict when CMEs are about to occur, The team led by Tingyu Gou and Rui Liu of the University of Science and Technology of China in Hefei, They found that before it erupted a vertical sheet of plasma split into blobs marking breaking and merging magnetic field lines   

    From Science News: “Merging magnetic blobs fuel the sun’s huge plasma eruptions” 

    From Science News

    March 7, 2019
    Lisa Grossman

    Before coronal mass ejections, plasma shoots up, breaks apart and then comes together again.

    1
    BURSTING WITH PLASMA Solar scientists have long wondered what drives big bursts of plasma called coronal mass ejections. New analysis of an old eruption suggests the driving force might be merging magnetic blobs.

    Solar plasma eruptions are the sum of many parts, a new look at a 2013 coronal mass ejection shows.

    These bright, energetic bursts happen when loops of magnetism in the sun’s wispy atmosphere, or corona, suddenly snap and send plasma and charged particles hurtling through space (SN Online: 8/16/17).

    But it was unclear how coronal mass ejections, or CMEs, get started. One theory suggests that a twisted tube of magnetic field lines called a flux rope hangs out on the solar surface for hours or days before a sudden perturbation sends it expanding off the solar surface.

    Another idea is that the sun’s magnetic field lines are forced so close together that the lines break and recombine with each other. The energy of that magnetic reconnection forms a short-lived flux rope that quickly erupts.

    “We do not know which comes first,” the flux rope or the reconnection, says solar physicist Bernhard Kliem of the University of Potsdam in Germany.

    Kliem and his colleagues scrutinized a CME recorded on May 13, 2013, by NASA’s Solar Dynamics Observatory.

    NASA/SDO

    They found that before it erupted, a vertical sheet of plasma split into blobs, marking breaking and merging magnetic field lines. Over about half an hour, the blobs shot upward and merged into a large flux rope, which briefly arced over the solar surface before erupting into space. That quick growth supports the idea that CMEs grow through magnetic reconnection, the team, led by Tingyu Gou and Rui Liu of the University of Science and Technology of China in Hefei, reports March 6 in Science Advances.

    “This was actually surprising, that this reconnection was rather fast,” Kliem says. That speedy setup might make it more difficult to predict when CMEs are about to occur. That’s too bad because, when aimed at Earth, these bursts cause auroras and can knock out power grids and damage satellites.


    A STAR’S CME IS BORN The sun’s coronal mass ejections seem to result from many small plasma blobs combining. In this video, enhanced data from NASA’s Solar Dynamics Observatory shows a vertical sheet of plasma suddenly break into blobs at about 17 seconds. Shortly after, the blobs rearrange themselves into a loop, and the loop bursts off the sun’s surface. At 30 seconds, more distant observations from the SOHO telescope show the CME’s progress. (A second, unrelated CME erupts off the right side of the sun near the video’s end.)

    See the full article here .


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  • richardmitnick 6:42 pm on March 4, 2019 Permalink | Reply
    Tags: "Hidden ancient neutrinos may shape the patterns of galaxies", Although these cosmic relics suffuse the universe the particles have so little energy that they have never been directly spotted., , , , , In the future improved surveys of galaxies might be sensitive enough to reveal unexpected tweaks to the ring patterns which could be caused by the existence of undiscovered phenomena such as hypotheti, , Neutrinos can shift matter around due to the particles’ gravity slightly changing the distribution of matter in the rings, Science News, Shadowy messengers from the Big Bang have seemingly left their mark on ring-shaped patterns imprinted on the sky, Subatomic particles called neutrinos released just one second after the universe’s birth 13.8 billion years ago continually stream through the universe and are exceedingly hard to spot. But circular, This is the first time evidence of the particles’ fingerprints on galaxies has been spotted   

    From Science News: “Hidden ancient neutrinos may shape the patterns of galaxies” 

    From Science News

    March 4, 2019
    Emily Conover

    Subatomic particles born in the universe’s first second may imprint their effects on the sky.

    1
    RUN IN CIRCLES Galaxies in the universe tend to cluster into rings (illustrated), and scientists have found signs that subatomic particles called neutrinos change the way matter is distributed in the circles. Zosia Rostomian/Lawrence Berkeley National Laboratory

    Shadowy messengers from the Big Bang have seemingly left their mark on ring-shaped patterns imprinted on the sky.

    Subatomic particles called neutrinos, released just one second after the universe’s birth 13.8 billion years ago, continually stream through the universe and are exceedingly hard to spot. But circular patterns of galaxies scattered across the sky reveal signs of the shy particles. Those data hint that the neutrinos’ gravity subtly alters the rings, researchers report February 25 in Nature Physics. Since these relic neutrinos were released so early in the universe’s history, scientists hope they can one day use these particles to better understand the cosmos in its first moments.

    The study “is certainly new and interesting in that it shows that we can derive the early universe physics” by observing the recent universe, says cosmologist Hee-Jong Seo of Ohio University in Athens, who wasn’t involved in the research.

    Spotting signs of the ancient particles is no easy feat. All neutrinos are notoriously difficult to detect. They have no electric charge and can pass straight through other matter. With large, highly sensitive detectors, scientists can spot neutrinos produced by everyday processes such as radioactive decay. But neutrinos released from the Big Bang, known collectively as the “cosmic neutrino background,” are much more elusive. Although these cosmic relics suffuse the universe, the particles have so little energy that they have never been directly spotted.

    So rather than trying to observe those relic neutrinos directly, scientists look for their influence on other cosmic signposts. For example: A pattern caused by sound waves in the early universe — known as baryon acoustic oscillations — should be distorted by the neutrinos. Those sound waves spread outward through the universe like circular ripples on a pond, compressing matter into denser pockets. Eventually, that process resulted in galaxies having a tendency to cluster in rings across the sky (SN: 5/5/12, p. 17).

    But neutrinos can shift that matter around due to the particles’ gravity, slightly changing the distribution of matter in the rings. “You’re seeing the pull of the neutrinos,” says cosmologist Daniel Green. Using data from the Baryon Oscillation Spectroscopic Survey, or BOSS, Green and colleagues studied the circular patterns of galaxies and saw evidence that the neutrinos were, in fact, pulling matter around from the inner side of the ring band toward the outer side.

    Scientists have previously spotted signs of the ancient neutrinos in a glow leftover from the Big Bang. The cosmic microwave background [CMB], light that was released when the universe was just 380,000 years old, is also affected by the cosmic neutrino background.

    CMB per ESA/Planck

    But this is the first time evidence of the particles’ fingerprints on galaxies has been spotted.

    “It’s another hallmark of the success of standard cosmology,” says cosmologist Kevork Abazajian, who was not involved with the research. Still, the current result is just scratching the surface of this phenomenon, making the measurement a proof of principle rather than a definitive detection, says Abazajian, of the University of California, Irvine.

    In the future, improved surveys of galaxies might be sensitive enough to reveal unexpected tweaks to the ring patterns, which could be caused by the existence of undiscovered phenomena, such as hypothetical new types of neutrinos called sterile neutrinos (SN: 6/23/18, p. 7).

    See the full article here .


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  • richardmitnick 9:18 am on February 28, 2019 Permalink | Reply
    Tags: An element is defined by the number of protons it contains, At the far edge of the periodic table elements decay within instants of their formation offering very little time to study their properties, , , Each element comes in a variety of types known as isotopes distinguished by the number of neutrons in the nucleus, For superheavy atoms chemistry gets weird, , Science News, Scientists are hoping to stretch the periodic table even further beyond tennessine and three other recently discovered elements (113 115 and 118) that completed the table’s seventh row.   

    From Science News: “Extreme elements push the boundaries of the periodic table” 

    From Science News

    February 27, 2019
    Emily Conover

    For superheavy atoms, chemistry gets weird.

    1
    SMASH HIT To create new elements and study the chemistry of the periodic table’s heaviest atoms, researchers at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, use the apparatus above to create beams of ions that scientists then smash into other elements.

    GSI Helmholtz Centre for Heavy Ion Research GmbH, Darmstadt, Germany,

    The rare radioactive substance made its way from the United States to Russia on a commercial flight in June 2009. Customs officers balked at accepting the package, which was ensconced in lead shielding and emblazoned with bold-faced warnings and the ominous trefoil symbols for ionizing radiation. Back it went across the Atlantic.

    U.S. scientists enclosed additional paper work and the parcel took a second trip, only to be rebuffed again. All the while, the precious cargo, 22 milligrams of an element called berkelium created in a nuclear reactor at Oak Ridge National Laboratory in Tennessee, was deteriorating. Day by day, its atoms were decaying. “We were all a little frantic on our end,” says Oak Ridge nuclear engineer Julie Ezold.

    On the third try, the shipment cleared customs. At a laboratory in Dubna, north of Moscow, scientists battered the berkelium with calcium ions to try to create an even rarer substance. After 150 days of pummeling, the researchers spotted six atoms of an element that had never been seen on Earth. In 2015, after other experiments confirmed the discovery, element 117, tennessine, earned a spot on the periodic table (SN: 2/6/16, p. 7).

    2
    Scientists made radioactive berkelium at the High Flux Isotope Reactor at Oak Ridge National Laboratory in Tennessee (shown), and shipped it to Russia to be bombarded with a beam of calcium-48 to yield the superheavy element tennessine. ORNL/Flickr (CC BY 2.0)

    ORNL High Flux Isotope Reactor

    Scientists are hoping to stretch the periodic table even further, beyond tennessine and three other recently discovered elements (113, 115 and 118) that completed the table’s seventh row. Producing the next elements will require finessing new techniques using ultrapowerful beams of ions, electrically charged atoms. Not to mention the stress of shipping more radioactive material across borders.

    But questions circulating around the periodic table’s limits are too tantalizing not to make the effort. It’s been 150 years since Russian chemist Dmitrii Mendeleev created his periodic table. Yet “we still cannot answer the question: Which is the heaviest element that can exist?” says nuclear chemist Christoph Düllmann of the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany.

    At the far edge of the periodic table, elements decay within instants of their formation, offering very little time to study their properties. In fact, scientists still know little about the latest crew of newfound elements. So while some scientists are hunting for never-before-seen elements, others want to learn more about the table’s newcomers and the strange behaviors those superheavy elements may exhibit.

    For such outsized atoms, chemistry can get weird, as atomic nuclei, the hearts at the center of each atom, bulge with hundreds of protons and neutrons. Around them swirl great flocks of electrons, some moving at close to the speed of light. Such extreme conditions might have big consequences — messing with the periodic table’s tidy order, in which elements in each column are close chemical kin that behave in similar ways.

    3
    In Russia, scientist Vladislav Shchegolev inspects a package of berkelium after its overseas flight in 2009. The material was later used to create element 117, tennessine.
    Courtesy of ORNL.

    Scientists keep pushing these superheavy elements further as part of the search for what’s poetically known as the island of stability. Atoms with certain numbers of protons and neutrons are expected to live longer than their fleeting friends, persisting perhaps for hours rather than fractions of a second. Such an island would give scientists enough time to study those elements more closely and understand their quirks. The first glimpses of that mysterious atoll have been spotted, but it’s not clear how to get a firm footing on its shores.

    Driving all this effort is a deep curiosity about how elements act at the boundaries of the periodic table. “This might sound corny, but it’s really just [about] pure scientific understanding,” says nuclear chemist Dawn Shaughnessy of Lawrence Livermore National Laboratory in California. “We have these things that are really at the extremes of matter and we don’t understand right now how they behave.”

    Assembling atoms

    An element is defined by the number of protons it contains. Create an atom with more protons than ever before, and you’ve got yourself a brand new element. Each element comes in a variety of types, known as isotopes, distinguished by the number of neutrons in the nucleus. Changing the number of neutrons in an atom’s nucleus alters the delicate balance of forces that makes a nucleus stable or that causes it to decay quickly. Different isotopes of an element might have wildly different half-lives, the period of time it takes for half of the atoms in a sample to decay into smaller elements.

    Mendeleev’s periodic table, presented to the Russian Chemical Society on March 6, 1869, contained only 63 elements (SN: 1/19/19, p. 14). At first, scientists added to the periodic table by isolating elements from naturally occurring materials, for example, by scrutinizing minerals and separating them into their constituent parts. But that could take scientists only so far. All the elements beyond uranium (element 92) must be created artificially; they do not exist in significant quantities in nature. Scientists discovered elements beyond uranium by bombarding atoms with neutrons or small atomic nuclei or by sifting through the debris from thermonuclear weapons tests.

    But to make the heaviest elements, researchers adopted a new brute force approach: slamming beams of heavy atoms into a target, a disk that holds atoms of another element. If scientists are lucky, the atoms in the beam and target fuse, creating a new atom with a bigger, bulkier nucleus, perhaps one holding more protons than any other known.

    Researchers are using this strategy to go after elements 119 and 120. Scientists want to create such never-before-seen atoms to test how far the periodic table goes, to satisfy curiosity about the forces that hold atoms together and to understand what bizarre chemistry might occur with these extreme atoms.

    _____________________________________________________________

    How the periodic table went from a sketch to an enduring masterpiece
    150 years ago, Mendeleev perceived the relationships of the chemical elements
    3
    REVOLUTIONARY Russian chemist Dmitrii Mendeleev (shown around 1880) was the first to publish a periodic table, which put the known elements into a logical order and left room for elements not yet discovered. Heritage Image Partnership Ltd/Alamy Stock Photo.

    An ordered vision

    Mendeleev’s periodic table, published in 1869, was a vertical chart that organized 63 known elements by atomic weight. This arrangement placed elements with similar properties into horizontal rows. The title, translated from Russian, reads: “Draft of system of elements: based on their atomic masses and chemical characteristics.”

    4
    _____________________________________________________________
    The periodic table’s lineup

    The search is gearing up for the next superheavy elements, 119 and 120 (red boxes in the table below). Meanwhile, scientists are studying the known superheavy elements (blue) to better understand how such large atoms behave.

    5
    _____________________________________________________________

    Coaxing nuclei to combine into a new element is done only at highly specialized facilities in a few locations across the globe, including labs in Russia and Japan. Researchers carefully choose the makeup of the beam and the target in hopes of producing a designer atom of the element desired. That’s how the four newest elements were created: nihonium (element 113), moscovium (115), tennessine (117) and oganesson (118) (SN Online: 11/30/16).

    To create tennessine, for example, scientists combined beams of calcium with a target made of berkelium — once the berkelium finally made it through customs in Russia. The union makes sense when you consider the number of protons in each nucleus. Calcium has 20 protons and berkelium has 97, making for 117 protons total, the number found in tennessine’s nucleus. Combine calcium with the next element down the table, californium, and you get element 118, oganesson.

    Using calcium beams — specifically a stable calcium isotope with a combined total of 48 protons and neutrons known as calcium-48 — has been highly successful. But to create bigger nuclei would take increasingly exotic materials. The californium and berkelium used in previous efforts are so rare that the target materials had to be made at Oak Ridge, where researchers stew materials in a nuclear reactor for months and carefully process the highly radioactive product that comes out. All that work might produce just milligrams of the material.

    To discover element 119 using a calcium-48 beam, researchers would need a target made of einsteinium (element 99) which is even rarer than californium and berkelium. “We can’t make enough einsteinium,” says Oak Ridge physicist James Roberto. Scientists need a new approach. They’ve switched to relatively untested techniques relying on different beams of particles.

    _____________________________________________________________
    Decay parade

    To discover oganesson-294 (with 294 protons and neutrons), scientists slammed calcium ions into a californium target and observed the chain of radioactive decays initiated by the new element.

    6

    _____________________________________________________________

    But any new approach would have to produce new elements often enough to be worthwhile. It took almost nine years for a Japanese experiment to prove the existence of nihonium. In that time, researchers spotted the element only three times.

    To avoid such long waits, scientists are carefully choosing their tactics and revving up improved machines to quicken the search.

    A team at the RIKEN Nishina Center for Accelerator-Based Science near Tokyo uses beams of vanadium (element 23), rather than calcium, slamming them into curium (element 96) in the quest to grab elemental glory and find element 119. The group is starting with an existing accelerator and will soon switch to an accelerator upgraded to pump out ion beams that pack more punch. That revamped accelerator could be ready within a year, says RIKEN nuclear chemist Hiromitsu Haba.

    Meanwhile, a new laboratory at the Joint Institute for Nuclear Research, or JINR, in Dubna called the Superheavy Element Factory boasts an accelerator that will crank out ion beams that pummel the target at 10 times the rate of its predecessor. In an upcoming experiment, scientists plan to crash beams of titanium (element 22) into berkelium and californium targets to attempt to produce elements 119 and 120.

    Once JINR’s new experiment is up and running, 119 might be discovered after a couple of years, says JINR nuclear physicist Yuri Oganessian, for whom oganesson, one of several elements discovered there, was named.

    7
    Scientists in Russia have built a new accelerator facility, the Superheavy Element Factory, to search for elements 119 and 120. JINR.

    Relativity rules

    Simply detecting an element, however, doesn’t mean scientists know much about it. “How would one kilogram of flerovium behave, if I had it?” Düllmann asks, referring to element 114. “It would be unlike any other material.”

    The known superheavy elements — those beyond number 103 on the table — are too short-lived to create a chunk big enough to hold in the palm of your hand. So scientists are limited to studying individual atoms, getting to know each new element by analyzing its properties, including how easily it reacts with other substances.

    One big question is whether the periodicity the table is named for applies to superheavy elements. In the table, elements are ordered according to their number of protons, arranged so that the elements in each column have similar properties. Lithium, sodium and others in the first column react violently with water, for example. Elements in the last column, known as noble gases, are famously inert (SN: 1/19/19, p. 18). But for the newest, heaviest elements at the periodic table’s outer reaches, that long-standing rule of chemistry may unravel; some superheavy elements may behave differently from neighbors sitting above them in the table.

    For nuclei crammed with 100-plus protons, a special type of physics takes center stage. Electrons zip around these giant nuclei, sometimes surpassing 80 percent the speed of light. According to Einstein’s special theory of relativity, when particles move that fast, they seem to gain mass. That property changes how closely the electrons hug the nucleus, and as a result, how easily the atoms share electrons to produce chemical reactions. In such atoms, “relativity rules, and standard common wisdom breaks down,” says nuclear physicist Witold Nazarewicz of Michigan State University in East Lansing. “We have to write new textbooks on those atoms.”

    _____________________________________________________________
    Getting heavy

    The nucleus of superheavy oganesson has 118 protons and many neutrons (blue and red). Its 118 electrons (green) surround the nucleus. Carbon, which is much lighter, contains just six protons and six electrons (not to scale).

    8
    T. Tibbitts
    _____________________________________________________________

    Some of the periodic table’s more familiar elements are already affected by special relativity. The theory explains why gold has a yellowish hue and why mercury is liquid at room temperature (SN: 2/18/17, p. 11). “Without relativity, a car would not start,” says theoretical chemist Pekka Pyykkö of the University of Helsinki. The reactions that power a car battery depend on special relativity.

    Relativity’s influence may surge as scientists progress along the periodic table. In 2018 in Physical Review Letters, Nazarewicz and colleagues reported that oganesson could be utterly bizarre (SN Online: 2/12/18). The table’s heaviest element, oganesson sits among the reclusive noble gases that shun reactions with other elements. But oganesson bucks the trend, theoretical calculations suggest, and may instead be reactive.

    Oganesson’s chemistry is a hot topic, but scientists haven’t yet been able to directly probe its properties with experiments because oganesson is too rare and fleeting. “All the theoreticians are now running around this element trying to make spectacular predictions,” says theoretical chemist Valeria Pershina of GSI. Similarly, some calculations suggest that flerovium might lean in the opposite direction, being relatively inert, even though it inhabits the same column as more reactive elements such as lead.

    Chemists are striving to test such calculations about how superheavy elements behave. But there is nothing traditional about these chemistry experiments. There are no scientists in white coats wielding flasks and Bunsen burners. “Because we make these things one atom at a time, we can’t do what most people think of as chemistry,” Lawrence Livermore’s Shaughnessy says.

    The experiments can run for months with only a few atoms to show for it. Scientists put those atoms in contact with other elements to see if the two react. At GSI, Düllmann and colleagues are looking at whether flerovium sticks to gold surfaces. Likewise, Shaughnessy and colleagues are testing whether flerovium will glom on to ring-shaped molecules, chosen so that the heavy element could fit inside the molecule’s ring. These studies will test how easily flerovium bonds with other elements, revealing whether it behaves as expected based on its place on the periodic table.

    It’s not just chemical reactions that can get wacky for superheavy elements. Atomic nuclei can be warped into various shapes when packed with protons. Oganesson may have a “bubble” in its nucleus, with fewer protons in its center than at its edges (SN: 11/26/16, p. 11). Still more extreme nuclei may be doughnut-shaped, Nazarewicz says.

    Even the most basic properties of these elements, such as their mass, need to be measured. While scientists had estimated the mass of the various isotopes of the latest new elements using indirect measurements, the arguments supporting those mass estimates weren’t airtight, says Jacklyn Gates of Lawrence Berkeley National Laboratory in California. “They hinge on physics not throwing you a curveball.”

    9
    Jacklyn Gates and Ken Gregorich of the FIONA experiment at Lawrence Berkeley National Laboratory made the first measurements of the masses of recently discovered elements 113 and 115.
    Marilyn Chung/Berkeley Lab

    So Gates and colleagues directly measured the masses of isotopes of nihonium and moscovium using an accelerator at Lawrence Berkeley. An apparatus called FIONA helped researchers measure the masses, thanks to electromagnetic fields that steered an ion of each element onto a detector. The location where each ion hit indicated how massive it was.

    The nihonium isotope the researchers detected had a mass number of 284, meaning its nucleus had a combined total of 284 protons and neutrons. Moscovium had a mass number of 288. Those masses were as predicted, the scientists reported in November in Physical Review Letters. It took about a month just to find one atom of each element.
    Island views

    If researchers could coax these fleeting elements to live longer, studying their properties might be easier. Scientists have caught enticing visions of increasing life spans lying just out of reach — the fabled island of stability (SN: 6/5/10, p. 26). Scientists hope that the isotopes on that island, which would be packed with lots of neutrons, may live long enough that their chemistry can be studied in detail.

    When the idea of an island of stability was proposed in the 1960s, scientists had suggested that the isotopes on its shores might live millions of years. Advances in theoretical physics have since knocked that time frame down, Nazarewicz says. Instead, nuclear physicists now expect the island’s inhabitants to stick around for minutes, hours or maybe even a day — a pleasant eternity for superheavy elements.

    To reach the island of stability, scientists must create new isotopes of known elements. Researchers already know which direction they need to row: They must cram more neutrons into the nuclei of the superheavy elements that have already been discovered. Currently, scientists can’t make atoms with enough neutrons to reach the island’s center, where isotopes are expected to be most stable. But the signs of this island’s existence are already clear. The half-lives of superheavy elements tend to shoot up as scientists pack more neutrons into each nucleus, approaching the island. Flerovium’s half-life increases by almost a factor of 700 as five more neutrons are added, from three milliseconds to two seconds.

    _____________________________________________________________
    Long life

    Each row below is an element, and each column a different isotope. Atoms are expected to be more stable on the island of stability (predicted location shown). As isotopes of elements (gray squares) approach the island, they tend to live longer, as more neutrons fill the nucleus. Flerovium’s half-life, for example, increases from 0.003 to two seconds.

    9
    T. Tibbitts

    Sources: S. Hofmann et al/Pure and Applied Chemistry 2018; W. Nazarewicz; Y. Oganessian
    _____________________________________________________________

    Reaching this island “is our big dream,” Haba says. “Unfortunately, we don’t have a very good method to reach the island.” That island is thought to be centered around isotopes that bulge with around 184 neutrons and something like 110 protons. Making such neutron-rich nuclei would demand new, difficult techniques, such as using beams of radioactive particles instead of stable ones. Although radioactive beams can be produced at RIKEN, Haba says, the beams aren’t intense enough to produce new elements at a reasonable rate.

    Still, superheavy element sleuths are keeping at it to learn how these weird atoms behave.

    End of the line

    To fully grasp nature’s extremes, scientists want to know where the periodic table ends.

    “Everybody knows at some point there will be an end,” Düllmann says. “There will be a heaviest element, ultimately.” The table will be finished when we’ve discovered all elements with isotopes that live at least a hundredth of a trillionth of a second. That’s the limit for what qualifies as an element, according to the standards set by the International Union of Pure and Applied Chemistry. More ephemeral nuclei wouldn’t have enough time to gather a crew of electrons. Since the give-and-take of electrons is the basis of chemical reactions, lone nuclei wouldn’t exhibit chemistry at all, and therefore don’t deserve a spot on the table.

    “Where it will exactly end is difficult to say,” Nazarewicz says. Calculations of how quickly a nucleus will decay by fission, or splitting in two, are uncertain, which makes it hard to estimate how long elements might live without actually creating them.

    10
    The linear accelerator at RIKEN in Japan, used to discover element 113*, is being refurbished to probe for element 119. RIKEN

    *According to a statement via email from LLNL, 113, was first found at LLNL; but on 113, Riken published first and so got the credit.

    And the final table may contain holes or other odd features. That could happen if, within a row of elements, there’s one spot for which no isotope persists long enough to qualify as an element.

    Another idiosyncrasy: Elements may not be arranged in sequential order by the number of protons they contain, according to calculations in a 2011 paper by Pyykkö in Physical Chemistry Chemical Physics. Element 139, for example, might sit to the right of element 164 — if such heavy elements indeed exist. That’s because special relativity alters the normal order in which electrons slot themselves into shells, arrangements that define how the electrons swirl about the atom. That pattern of shell filling is what gives the periodic table its shape, and the unusual filling may mean scientists decide to assign elements to spots out of order.

    But additions to the table could dry up before that happens if scientists reach the limit of their ability to create heavier elements. When elements live minuscule fractions of a second, even the atom’s trip to a detector may take too long; the element would decay before it ever had a chance to be spotted.

    In reality, there’s no clear idea of how to search for elements beyond 119 and 120. But the picture has seemed bleak before.

    “We should not underestimate the next generation. They may have smart ideas. They will have new technologies,” Düllmann says. “The next element is always the hardest. But it’s probably not the last one.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
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