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  • richardmitnick 8:37 am on October 19, 2021 Permalink | Reply
    Tags: "An atomic clock measured how general relativity warps time across a millimeter", "Science News (US)", , , , The National Institute of Standards and Technology (US), The University of Colorado-Boulder (US)   

    From JILA – [The Joint Institute for Laboratory Astrophysics] Exploring the Frontiers of Physics (U Colorado and NIST)(US) at University of Colorado-Boulder (US) and National Institute of Standards and Technology (US) via Science News (US) : “An atomic clock measured how general relativity warps time across a millimeter” 

    From JILA – [The Joint Institute for Laboratory Astrophysics] Exploring the Frontiers of Physics (U Colorado and NIST)(US)

    at

    U Colorado

    The University of Colorado-Boulder (US)

    and

    The National Institute of Standards and Technology (US)

    via

    Science News (US)

    October 18, 2021
    Emily Conover

    1
    Clocks at different heights tick at different rates. An atomic clock has now revealed this key feature of the general theory of relativity on a scale of a millimeter. Credit: Hiroshi Watanabe/Getty Images Plus

    A millimeter might not seem like much. But even a distance that small can alter the flow of time.

    According to Einstein’s theory of gravity, general relativity, clocks tick faster the farther they are from Earth or another massive object (SN: 10/4/15). Theoretically, that should hold true even for very small differences in the heights of clocks. Now an incredibly sensitive atomic clock has spotted that speedup across a millimeter-sized sample of atoms, revealing the effect over a smaller height difference than ever before. Time moved slightly faster at the top of that sample than at the bottom, researchers report September 24 [https://arxiv.org/ftp/arxiv/papers/2109/2109.12238.pdf].

    “This is fantastic,” says theoretical physicist Marianna Safronova of The University of Delaware (US), who was not involved with the research. “I thought it would take much longer to get to this point.” The extreme precision of the atomic clock’s measurement suggests the potential to use the sensitive timepieces to test other fundamental concepts in physics.

    An inherent property of atoms allows scientists to use them as timepieces. Atoms exist at different energy levels, and a specific frequency of light makes them jump from one level to another. That frequency — the rate of wiggling of the light’s waves — serves the same purpose as a clock’s regularly ticking second hand. For atoms farther from the ground, time runs faster, so a greater frequency of light will be needed to make the energy jump. Previously, scientists have measured this frequency shift, known as gravitational redshift, across a height difference of 33 centimeters (SN: 9/23/10).

    In the new study, physicist Jun Ye of JILA in Boulder, Colo., and colleagues used a clock made up of roughly 100,000 ultracold strontium atoms. Those atoms were arranged in a lattice, meaning that the atoms sat at a series of different heights as if standing on the rungs of a ladder. Mapping out how the frequency changed over those heights revealed a shift. After correcting for non-gravitational effects that could shift the frequency, the clock’s frequency changed by about a hundredth of a quadrillionth of a percent over a millimeter, just the amount expected according to general relativity.

    1
    Atomic clocks (one shown in a composite image) keep time by measuring the frequency of light that initiates a jump between energy levels in atoms. This atomic clock, located at JILA, is similar to the one used in the new research by Jun Ye and colleagues, and uses laser light to hold strontium atoms in a lattice. Credit: Ye group and Baxley/JILA.

    What’s more, after taking data for about 90 hours, comparing the ticking of upper and lower sections of the clock, the scientists determined their technique could measure the relative ticking rates to a precision of 0.76 millionths of a trillionth of a percent. That makes it a record for the most precise frequency comparison ever performed.

    In a related study, also submitted September 24 , another team of researchers loaded strontium atoms into specific portions of a lattice to create six clocks in one [https://arxiv.org/pdf/2109.12237.pdf]. “It’s very exciting what they did, as well,” Safronova says.

    Shimon Kolkowitz of The University of Wisconsin–Madison (US) and colleagues measured the relative ticking rates of two of the clocks, separated by about six millimeters, to a precision of 8.9 millionths of a trillionth of a percent, which itself would have been a new record had it not been beat by Ye’s group. With that sensitivity, scientists could detect a difference between two clocks ticking at a rate so slightly different that they’d disagree by just one second after about 300 billion years. Ye’s clock could detect an even smaller discrepancy between the two halves of the clock of one second amassed over roughly 4 trillion years. Although Kolkowitz’s team didn’t yet measure gravitational redshift, the setup could be used for that in the future.

    2
    A cloud of strontium atoms (glowing blue dot at center) is trapped inside a vacuum chamber that contains Shimon Kolkowitz and colleagues’ atomic clock. In the experiment, the atoms were shuttled into different parts of a lattice to make multiple atomic clocks in one.Credit: S. Kolkowitz.

    Authors of both studies declined to comment, as the papers have not yet been through the peer-review process.

    The measurements’ precision hints at future possibilities, says theoretical physicist Victor Flambaum of the University of New South Wales in Sydney. For example, “atomic clocks are now so precise that they may be used to search for dark matter,” he says. This stealthy, unidentified substance lurks invisibly in the cosmos; certain hypothesized types of dark matter could alter clocks’ tick-tocks. Scientists could also compare atomic clocks made of different isotopes — atoms with varied numbers of neutrons in their nuclei — which might hint at undiscovered new particles. And atomic clocks can study whether fundamental constants of nature might vary (SN: 11/2/16).

    The ability to precisely compare different clocks is also important for a major goal of timekeeping: updating the definition of a second (SN: 3/24/21). The length of a second is currently defined using an earlier generation of atomic clocks that are not as precise as newer ones like those used in the two new studies (SN: 5/20/19).

    “There is a very bright future for the clocks,” Safronova says.

    See the full article here .

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    NIST Campus, Gaitherberg, MD, USA

    The National Institute of Standards and Technology (US)‘s Mission, Vision, Core Competencies, and Core Values

    Mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.

    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

    Background

    The Articles of Confederation, ratified by the colonies in 1781, contained the clause, “The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States”. Article 1, section 8, of the Constitution of the United States (1789), transferred this power to Congress; “The Congress shall have power…To coin money, regulate the value thereof, and of foreign coin, and fix the standard of weights and measures”.

    In January 1790, President George Washington, in his first annual message to Congress stated that, “Uniformity in the currency, weights, and measures of the United States is an object of great importance, and will, I am persuaded, be duly attended to”, and ordered Secretary of State Thomas Jefferson to prepare a plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States, afterwards referred to as the Jefferson report. On October 25, 1791, Washington appealed a third time to Congress, “A uniformity of the weights and measures of the country is among the important objects submitted to you by the Constitution and if it can be derived from a standard at once invariable and universal, must be no less honorable to the public council than conducive to the public convenience”, but it was not until 1838, that a uniform set of standards was worked out. In 1821, John Quincy Adams had declared “Weights and measures may be ranked among the necessities of life to every individual of human society”.

    From 1830 until 1901, the role of overseeing weights and measures was carried out by the Office of Standard Weights and Measures, which was part of the U.S. Coast and Geodetic Survey in the Department of the Treasury.

    Bureau of Standards

    In 1901 in response to a bill proposed by Congressman James H. Southard (R- Ohio) the National Bureau of Standards was founded with the mandate to provide standard weights and measures and to serve as the national physical laboratory for the United States. (Southard had previously sponsored a bill for metric conversion of the United States.)

    President Theodore Roosevelt appointed Samuel W. Stratton as the first director. The budget for the first year of operation was $40,000. The Bureau took custody of the copies of the kilogram and meter bars that were the standards for US measures, and set up a program to provide metrology services for United States scientific and commercial users. A laboratory site was constructed in Washington DC (US) and instruments were acquired from the national physical laboratories of Europe. In addition to weights and measures the Bureau developed instruments for electrical units and for measurement of light. In 1905 a meeting was called that would be the first National Conference on Weights and Measures.

    Initially conceived as purely a metrology agency the Bureau of Standards was directed by Herbert Hoover to set up divisions to develop commercial standards for materials and products. Some of these standards were for products intended for government use; but product standards also affected private-sector consumption. Quality standards were developed for products including some types of clothing; automobile brake systems and headlamps; antifreeze; and electrical safety. During World War I, the Bureau worked on multiple problems related to war production even operating its own facility to produce optical glass when European supplies were cut off. Between the wars Harry Diamond of the Bureau developed a blind approach radio aircraft landing system. During World War II military research and development was carried out including development of radio propagation forecast methods; the proximity fuze and the standardized airframe used originally for Project Pigeon; and shortly afterwards the autonomously radar-guided Bat anti-ship guided bomb and the Kingfisher family of torpedo-carrying missiles.

    In 1948, financed by the United States Air Force the Bureau began design and construction of SEAC: the Standards Eastern Automatic Computer. The computer went into operation in May 1950 using a combination of vacuum tubes and solid-state diode logic. About the same time the Standards Western Automatic Computer, was built at the Los Angeles office of the NBS by Harry Huskey and used for research there. A mobile version- DYSEAC- was built for the Signal Corps in 1954.

    Due to a changing mission, the “National Bureau of Standards” became the “ The National Institute of Standards and Technology (US)” in 1988.

    Following September 11, 2001, NIST conducted the official investigation into the collapse of the World Trade Center buildings.

    Organization

    NIST is headquartered in Gaithersburg, Maryland, and operates a facility in Boulder, Colorado, which was dedicated by President Eisenhower in 1954. NIST’s activities are organized into laboratory programs and extramural programs. Effective October 1, 2010, NIST was realigned by reducing the number of NIST laboratory units from ten to six. NIST Laboratories include:

    Communications Technology Laboratory (CTL)
    Engineering Laboratory (EL)
    Information Technology Laboratory (ITL)
    Center for Neutron Research (NCNR)
    Material Measurement Laboratory (MML)
    Physical Measurement Laboratory (PML)

    Extramural programs include:

    Hollings Manufacturing Extension Partnership (MEP), a nationwide network of centers to assist small and mid-sized manufacturers to create and retain jobs, improve efficiencies, and minimize waste through process improvements and to increase market penetration with innovation and growth strategies;
    Technology Innovation Program (TIP), a grant program where NIST and industry partners cost share the early-stage development of innovative but high-risk technologies;
    Baldrige Performance Excellence Program, which administers the Malcolm Baldrige National Quality Award, the nation’s highest award for performance and business excellence.

    NIST’s Boulder laboratories are best known for NIST‑F1 which houses an atomic clock. NIST‑F1 serves as the source of the nation’s official time. From its measurement of the natural resonance frequency of cesium—which defines the second—NIST broadcasts time signals via longwave radio station WWVB near Fort Collins in Colorado, and shortwave radio stations WWV and WWVH, located near Fort Collins and Kekaha in Hawai’i, respectively.

    NIST also operates a neutron science user facility: the NIST Center for Neutron Research (NCNR). The NCNR provides scientists access to a variety of neutron scattering instruments which they use in many research fields (materials science; fuel cells; biotechnology etc.).

    The SURF III Synchrotron Ultraviolet Radiation Facility is a source of synchrotron radiation in continuous operation since 1961. SURF III now serves as the US national standard for source-based radiometry throughout the generalized optical spectrum. All NASA-borne extreme-ultraviolet observation instruments have been calibrated at SURF since the 1970s, and SURF is used for measurement and characterization of systems for extreme ultraviolet lithography.

    The Center for Nanoscale Science and Technology (CNST) performs research in nanotechnology, both through internal research efforts and by running a user-accessible cleanroom nanomanufacturing facility. This “NanoFab” is equipped with tools for lithographic patterning and imaging (e.g., electron microscopes and atomic force microscopes).

    Committees

    NIST has seven standing committees:

    Technical Guidelines Development Committee (TGDC)
    Advisory Committee on Earthquake Hazards Reduction (ACEHR)
    National Construction Safety Team Advisory Committee (NCST Advisory Committee)
    Information Security and Privacy Advisory Board (ISPAB)
    Visiting Committee on Advanced Technology (VCAT)
    Board of Overseers for the Malcolm Baldrige National Quality Award (MBNQA Board of Overseers)
    Manufacturing Extension Partnership National Advisory Board (MEPNAB)

    Measurements and standards

    As part of its mission, NIST supplies industry, academia, government, and other users with over 1,300 Standard Reference Materials (SRMs). These artifacts are certified as having specific characteristics or component content, used as calibration standards for measuring equipment and procedures, quality control benchmarks for industrial processes, and experimental control samples.

    Handbook 44

    NIST publishes the Handbook 44 each year after the annual meeting of the National Conference on Weights and Measures (NCWM). Each edition is developed through cooperation of the Committee on Specifications and Tolerances of the NCWM and the Weights and Measures Division (WMD) of the NIST. The purpose of the book is a partial fulfillment of the statutory responsibility for “cooperation with the states in securing uniformity of weights and measures laws and methods of inspection”.

    NIST has been publishing various forms of what is now the Handbook 44 since 1918 and began publication under the current name in 1949. The 2010 edition conforms to the concept of the primary use of the SI (metric) measurements recommended by the Omnibus Foreign Trade and Competitiveness Act of 1988.

    U Colorado Campus

    As the flagship university of the state of Colorado University of Colorado-Boulder (US), founded in 1876, five months before Colorado became a state. It is a dynamic community of scholars and learners situated on one of the most spectacular college campuses in the country, and is classified as an R1 University, meaning that it engages in a very high level of research activity. As one of 34 U.S. public institutions belonging to the prestigious Association of American Universities (US), a selective group of major research universities in North America, – and the only member in the Rocky Mountain region – we have a proud tradition of academic excellence, with five Nobel laureates and more than 50 members of prestigious academic academies.

    University of Colorado-Boulder (US) has blossomed in size and quality since we opened our doors in 1877 – attracting superb faculty, staff, and students and building strong programs in the sciences, engineering, business, law, arts, humanities, education, music, and many other disciplines.

    Today, with our sights set on becoming the standard for the great comprehensive public research universities of the new century, we strive to serve the people of Colorado and to engage with the world through excellence in our teaching, research, creative work, and service.

    In 2015, the university comprised nine colleges and schools and offered over 150 academic programs and enrolled almost 17,000 students. Five Nobel Laureates, nine MacArthur Fellows, and 20 astronauts have been affiliated with CU Boulder as students; researchers; or faculty members in its history. In 2010, the university received nearly $454 million in sponsored research to fund programs like the Laboratory for Atmospheric and Space Physics and JILA. CU Boulder has been called a Public Ivy, a group of publicly funded universities considered as providing a quality of education comparable to those of the Ivy League.

    The Colorado Buffaloes compete in 17 varsity sports and are members of the NCAA Division I Pac-12 Conference. The Buffaloes have won 28 national championships: 20 in skiing, seven total in men’s and women’s cross country, and one in football. The university has produced a total of ten Olympic medalists. Approximately 900 students participate in 34 intercollegiate club sports annually as well.

    On March 14, 1876, the Colorado territorial legislature passed an amendment to the state constitution that provided money for the establishment of the University of Colorado in Boulder, the Colorado School of Mines(US) in Golden, and the Colorado State University (US) – College of Agricultural Sciences in Fort Collins.

    Two cities competed for the site of the University of Colorado: Boulder and Cañon City. The consolation prize for the losing city was to be home of the new Colorado State Prison. Cañon City was at a disadvantage as it was already the home of the Colorado Territorial Prison. (There are now six prisons in the Cañon City area.)

    The cornerstone of the building that became Old Main was laid on September 20, 1875. The doors of the university opened on September 5, 1877. At the time, there were few high schools in the state that could adequately prepare students for university work, so in addition to the University, a preparatory school was formed on campus. In the fall of 1877, the student body consisted of 15 students in the college proper and 50 students in the preparatory school. There were 38 men and 27 women, and their ages ranged from 12–23 years.

    During World War II, Colorado was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a navy commission.

    University of Colorado-Boulder (US) hired its first female professor, Mary Rippon, in 1878. It hired its first African-American professor, Charles H. Nilon, in 1956, and its first African-American librarian, Mildred Nilon, in 1962. Its first African American female graduate, Lucile Berkeley Buchanan, received her degree in 1918.

    Research institutes

    University of Colorado-Boulder’s (US) research mission is supported by eleven research institutes within the university. Each research institute supports faculty from multiple academic departments, allowing institutes to conduct truly multidisciplinary research.

    The Institute for Behavioral Genetics (IBG) is a research institute within the Graduate School dedicated to conducting and facilitating research on the genetic and environmental bases of individual differences in behavior. After its founding in 1967 IBG led the resurging interest in genetic influences on behavior. IBG was the first post-World War II research institute dedicated to research in behavioral genetics. IBG remains one of the top research facilities for research in behavioral genetics, including human behavioral genetics, psychiatric genetics, quantitative genetics, statistical genetics, and animal behavioral genetics.

    The Institute of Cognitive Science (ICS) at CU Boulder promotes interdisciplinary research and training in cognitive science. ICS is highly interdisciplinary; its research focuses on education, language processing, emotion, and higher level cognition using experimental methods. It is home to a state of the art fMRI system used to collect neuroimaging data.

    ATLAS Institute is a center for interdisciplinary research and academic study, where engineering, computer science and robotics are blended with design-oriented topics. Part of CU Boulder’s College of Engineering and Applied Science, the institute offers academic programs at the undergraduate, master’s and doctoral levels, and administers research labs, hacker and makerspaces, and a black box experimental performance studio. At the beginning of the 2018–2019 academic year, approximately 1,200 students were enrolled in ATLAS academic programs and the institute sponsored six research labs.[64]

    In addition to IBG, ICS and ATLAS, the university’s other institutes include Biofrontiers Institute, Cooperative Institute for Research in Environmental Sciences, Institute of Arctic & Alpine Research (INSTAAR), Institute of Behavioral Science (IBS), JILA, Laboratory for Atmospheric & Space Physics (LASP), Renewable & Sustainable Energy Institute (RASEI), and the University of Colorado Museum of Natural History.

     
  • richardmitnick 10:07 am on October 7, 2021 Permalink | Reply
    Tags: "An easier and greener way to build molecules wins the chemistry Nobel Prize", "Science News (US)", , Asymmetric organocatalysis,   

    From Science News (US) : “An easier and greener way to build molecules wins the chemistry Nobel Prize” 

    From Science News (US)

    10.6.21

    Jonathan Lambert

    1
    Many chemical reactions produce two versions of a molecule that are mirror, or asymmetrical, images of one another, such as these illustrations of a molecule called limonene. Often, chemists want to make just one.
    ©Johan Jarnestad/The Royal Swedish Academy of Sciences.

    Making molecules is hard work. Atoms must be stitched together into specific arrangements through a series of chemical reactions that are often slow, convoluted and wasteful. The 2021 Nobel Prize in chemistry recognizes two scientists who developed a tool at the turn of the century that revolutionized how chemists construct new molecules, making the process faster and more environmentally friendly.

    Chemists Benjamin List of the MPG Institute for Coal Research [MPG Institut für Kohlenforschung](DE)in Mülheim an der Ruhr, Germany and David MacMillan of Princeton University(US) were awarded the prize for independently developing organic catalysts that speed up chemical reactions necessary for constructing specific molecules, a process called asymmetric organocatalysis. The two will share the prize of 10 million Swedish kroner (more than $1.1 million), the Royal Swedish Academy of Sciences (SE) announced October 6 in a news conference in Stockholm.

    “This is a fitting recognition of very important work,” says H.N. Cheng, president of The American Chemical Society (US).

    “We can think of chemists as magicians having magic wands in the lab,” Cheng says. “We wave the wand and a reaction goes on.” These Nobel laureates gave chemists “a new wand,” that’s drastically more efficient and less wasteful, he says.

    Making new drugs or designing novel materials often requires building new molecules from simpler chemical building blocks. But these chemical building blocks can’t just be thrown together. Instead, they must be carefully combined in precise arrangements through a series of chemical reactions. Many chemical reactions produce two versions of a molecule that are mirror images of one another, and often those two versions can have very different effects. For example, thalidomide, a drug prescribed in the 1950s and ‘60s for morning sickness, caused birth defects in more than 10,000 babies because of one mirror image of this molecule (SN: 12/24/94). Consequently, building these asymmetric molecules and controlling which version of a molecule gets produced is extremely important, especially for drug development.

    Chemical reactions can be coaxed along by catalysts — molecular workhorses that accelerate chemical reactions without being transformed by them. Historically, chemists have known about two kinds of catalysts: enzymes and metal complexes. Enzymes are big, clunky proteins that have been honed by evolution to perform very specific chemical actions in the body, but they can be difficult to use on a large scale in the lab. Metals, such as platinum or cobalt, can kick-start some reactions too, but many only work in airless, waterless environments that are difficult to achieve in manufacturing contexts (SN: 2/21/17). Additionally, many metal catalysts are also toxic to the environment and expensive to procure.

    For much of the history of chemistry, these were the only tools available to chemists who wanted to make new molecules. “But in the year 2000, everything changed,” Pernilla Wittung-Stafshede, a chemist at Chalmers University of Technology in Gothenburg, Sweden and a member of the Nobel Committee for Chemistry, said during the news conference.

    Benjamin List, then at The Scripps Research Institute (US) in La Jolla, Calif., was studying the aldol reaction, which links two molecules together through carbon bonds. In organisms, such reactions are crucial for converting food into energy, and depend on a large and complex enzyme called aldolase A. Only a small part of the enzyme actually catalyzes the reaction, however, and List discovered that a single amino acid — proline — could do the work of this big clunky protein while also producing one version of the final product much more often than the other.

    “When I did this experiment, I didn’t know what would happen and I thought maybe it’s a stupid idea,” List said during the news conference. “When I saw it work, I did feel it could be something big.”

    Unbeknown to List, MacMillan was also looking for alternative organic catalysts around the same time. MacMillan, then at The University of California-Berkeley (US), focused on another chemical reaction, the Diels-Alder reaction, which forms rings of carbon atoms (SN: 11/18/50). It’s an important reaction, used today to make products as different as rubber and pharmaceuticals, but was very slow and relied on finicky metal catalysts that wouldn’t work when wet. MacMillan designed small organic molecules that mimicked the catalytic action of metals in a simpler way, while also favoring the production of one of two possible mirror images of the final product. He coined this new kind of catalysis “asymmetric organocatalysis.”

    List’s and MacMillan’s discoveries set off an explosion of research into finding more organocatalysts over the next two decades, work that’s aided drug discovery among other uses.

    About 35 percent of the world’s gross domestic product depends on catalysis, Peter Somfai, a chemist at Lund University in Sweden and a member of the Nobel Committee for Chemistry, said during the news conference. “We now have a new powerful tool available for making organic molecules,” one that can be drastically more efficient and greener than previous methods.

    Somfai highlighted this leap forward in efficiency using the neurotoxin strychnine. The molecule itself isn’t useful for chemists, but its complicated structure makes it a good benchmark for comparing different synthesis methodologies. Previously, chemists relied on an extremely wasteful process of 29 different reactions where just 0.0009 percent of the initial material became strychnine. Using organocatalysis, strychnine can now be synthesized in just 12 steps, and the whole process is 7,000 times more efficient, Somfai said. And because this extra efficiency is gained without using toxic metals, organocatalysis is a more environmentally friendly way of synthesizing chemicals.

    If building new molecules is like playing chess, organocatalysis has “completely changed the game,” Somfai said. “It’s like adding a new chess piece that can move in different ways.”

    See the full article here .


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    Please help promote STEM in your local schools.


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  • richardmitnick 10:45 am on October 5, 2021 Permalink | Reply
    Tags: "Science News (US)", "Scientists are one step closer to error-correcting quantum computers"   

    From Science News (US) : “Scientists are one step closer to error-correcting quantum computers” 

    From Science News (US)

    October 4, 2021
    Emily Conover

    1
    Scientists used a chip (shown) to trap ytterbium ions that serve as the quantum bits for a quantum computer.
    Kai Hudek/Joint Quantum Institute (US).

    Mistakes happen — especially in quantum computers. The fragile quantum bits, or qubits, that make up the machines are notoriously error-prone, but now scientists have shown that they can fix the flubs.

    Computers that harness the rules of quantum mechanics show promise for making calculations far out of reach for standard computers (SN: 6/29/17). But without a mechanism for fixing the computers’ mistakes, the answers that a quantum computer spits out could be gobbledygook (SN: 6/22/20).

    Combining the power of multiple qubits into one can solve the error woes, researchers report October 4 in Nature. Scientists used nine qubits to make a single, improved qubit called a logical qubit, which, unlike the individual qubits from which it was made, can be probed to check for mistakes.

    “This is a key demonstration on the path to build a large-scale quantum computer,” says quantum physicist Winfried Hensinger of The University of Sussex (UK) who was not involved in the new study.

    Still, that path remains a long one, Hensinger says. To do complex calculations, scientists will have to dramatically scale up the number of qubits in the machines. But now that scientists have shown that they can keep errors under control, he says, “there’s nothing fundamentally stopping us to build a useful quantum computer.”

    In a logical qubit, information is stored redundantly. That allows researchers to check and fix mistakes in the data. “If a piece of it goes missing, you can reconstruct it from the other pieces, like Voldemort,” says quantum physicist David Schuster of The University of Chicago (US), who was not involved with the new research. (The Harry Potter villain kept his soul safe by concealing it in multiple objects called Horcruxes.)

    In the new study, four additional, auxiliary qubits interfaced with the logical qubit, in order to identify errors in its data. Future quantum computers could make calculations using logical qubits in place of the original, faulty qubits, repeatedly checking and fixing any errors that crop up.

    To make their logical qubit, the researchers used a technique called a Bacon-Shor code, applying it to qubits made of ytterbium ions hovering above an ion-trapping chip inside a vacuum, which are manipulated with lasers. The researchers also designed sequences of operations so that errors don’t multiply uncontrollably, what’s known as “fault tolerance.”

    Thanks to those efforts, the new logical qubit had a lower error rate than that of the most flawed components that made it up, says quantum physicist Christopher Monroe of The University of Maryland (US) and Duke University (US).

    However, the team didn’t quite complete the full process envisioned for error correction. While the computer detected the errors that arose, the researchers didn’t correct the mistakes and continue on with computation. Instead, they fixed errors after the computer was finished. In a full-fledged example, scientists would detect and correct errors multiple times on the fly.

    Demonstrating quantum error correction is a necessity for building useful quantum computers. “It’s like achieving criticality with [nuclear] fission,” Schuster says. Once that nuclear science barrier was passed in 1942, it led to technologies like nuclear power and atomic bombs (SN: 11/29/17).

    As quantum computers gradually draw closer to practical usefulness, companies are investing in the devices. Technology companies such as IBM, Google and Intel host major quantum computing endeavors. On October 1, a quantum computing company cofounded by Monroe, called IonQ, went public; Monroe spoke to Science News while on a road trip to ring the opening bell at the New York Stock Exchange.

    The new result suggests that full-fledged quantum error correction is almost here, says coauthor Kenneth Brown, a quantum engineer also at Duke University. “It really shows that we can get all the pieces together and do all the steps.”

    See the full article here .


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  • richardmitnick 11:46 am on September 26, 2021 Permalink | Reply
    Tags: "One of nature’s key constants is much larger in a quantum material", "Science News (US)", "Spinons", , If the fine-structure constant throughout the cosmos were as large as the one in quantum spin ices “the periodic table would only have 10 elements., , , Quantum spin ices are a class of substances in which particles can’t agree., , The fine-structure constant is about 10 times its normal value in a type of material called quantum spin ice., The impasse occurs because of the materials’ geometry: The particles are located at the corners of an array of pyramids that are connected at the corners., Unfortunately scientists haven’t yet found a material that definitively qualifies as quantum spin ice.   

    From “Science News (US) : “One of nature’s key constants is much larger in a quantum material” 

    From “Science News (US)

    September 21, 2021
    Emily Conover

    1
    Particles with the quantum property called spin, illustrated by the blue arrow, can’t agree on an orientation in a type of material called quantum spin ice. Credit: ELLA MARU STUDIO/Science Source.

    The fine-structure constant is about 10 times its normal value in a type of material called quantum spin ice, physicists calculate in the Sept. 10 Physical Review Letters. The new calculation hints that quantum spin ice could give a glimpse at physics within an alternate universe where the constant is much larger.

    With an influence that permeates physics and chemistry, the fine-structure constant sets the strength of interactions between electrically charged particles. Its value, about 1/137, consternates physicists because they can’t explain why it has that value, even though it is necessary for the complex chemistry that is the basis of life (SN: 11/2/16).

    If the fine-structure constant throughout the cosmos were as large as the one in quantum spin ices “the periodic table would only have 10 elements,” says theoretical physicist Christopher Laumann of Boston University (US). “And it probably would be hard to make people; there wouldn’t be enough richness to chemistry.”

    Quantum spin ices are a class of substances in which particles can’t agree. The materials are made up of particles with spin, a quantum version of angular momentum, which makes them magnetic. In a normal material, particles would come to a consensus below a certain temperature, with the magnetic poles lining up in either the same direction or in alternating directions. But in quantum spin ices, the particles are arranged in such a way that the magnetic poles, or equivalently the spins, can’t agree even at a temperature of absolute zero (SN: 2/13/11).

    The impasse occurs because of the materials’ geometry: The particles are located at the corners of an array of pyramids that are connected at the corners. Conflicts between multiple sets of neighbors mean that the closest these particles can get to harmony is arranging themselves so that two spins face out from each pyramid, and two face in.

    2
    In quantum spin ices, particles (black dots) are located at the corners of an array of pyramids (red). Normally, the spins of the particles (green arrows) arrange so that two are pointing into the pyramid and two out. If that rule is broken, as illustrated, quasiparticles called spinons (orange and blue) form.S.D. Pace et al/PRL 2021.

    This uneasy truce can give rise to disturbances that behave like particles within the material, or quasiparticles (SN: 10/3/14). Flip particles’ spins around and you can get what are called spinons, quasiparticles that can move through the material and interact with other spinons in a manner akin to electrons and other charged particles found in the world outside the material. The material re-creates the theory of quantum electrodynamics, the piece of particles physics’ standard model that hashes out how electrically charged particles do their thing. But the specifics, including the fine-structure constant, don’t necessarily match those in the wider universe.

    So Laumann and colleagues set out to calculate the fine-structure constant in quantum spin ices for the first time. The team pegged the number at about 1/10, instead of 1/137. What’s more, the researchers found that they could change the value of the fine-structure constant by tweaking the properties of the theoretical material. That could help scientists study the effects of altering the fine-structure constant — a test that’s well out of reach in our own universe, where the fine-structure constant is fixed.

    Unfortunately scientists haven’t yet found a material that definitively qualifies as quantum spin ice. But one much-studied prospect is a group of minerals called pyrochlores, which have magnetic ions, or electrically charged atoms, arranged in the appropriate pyramid configuration. Scientists might also be able to study the materials using a quantum computer or another quantum device designed to simulate quantum spin ices (SN: 6/29/17).

    If scientists succeed in creating quantum spin ice, the materials could reveal how quantum electrodynamics and the standard model would work in a universe with a much larger fine-structure constant. “That would be the hope,” says condensed matter theorist Shivaji Sondhi of the University of Oxford, who was not involved with the research. “It’s interesting to be able to make a fake standard model … and ask what would happen.”

    See the full article here .


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  • richardmitnick 11:58 am on September 7, 2021 Permalink | Reply
    Tags: , , "Science News (US)", "New ‘vortex beams’ of atoms and molecules are the first of their kind"   

    From “Science News (US) : “New ‘vortex beams’ of atoms and molecules are the first of their kind” 

    From “Science News (US)

    September 2, 2021
    Emily Conover

    1
    Scientists made spiraling beams of atoms and molecules, known as vortex beams, for the first time. Credit: zf L/Moment/Getty Images Plus.

    Scientists previously made twisted beams of light and electrons.

    Scientists already knew how to dish up spiraling beams of light or electrons, known as vortex beams (SN: 1/14/11). Now, the first vortex beams of atoms and molecules are on the menu, researchers report in the Sept. 3 Science.

    Vortex beams made of light or electrons have shown promise for making special types of microscope images and for transmitting information using quantum physics (SN: 8/5/15). But vortex beams of larger particles such as atoms or molecules are so new that the possible applications aren’t yet clear, says physicist Sonja Franke-Arnold of the University of Glasgow (SCT) , who was not involved with the research. “It’s maybe too early to really know what we can do with it.”

    In quantum physics, particles are described by a wave function, a wavelike pattern that allows scientists to calculate the probability of finding a particle in a particular place (SN: 6/8/11). But vortex beams’ waves don’t slosh up and down like ripples on water. Instead, the beams’ particles have wave functions that move in a corkscrewing motion as a beam travels through space. That means the beam carries a rotational oomph known as orbital angular momentum. “This is something really very strange, very nonintuitive,” says physicist Edvardas Narevicius of the Weizmann Institute of Science (IL).

    Narevicius and colleagues created the new beams by passing helium atoms through a grid of specially shaped slit patterns, each just 600 nanometers wide. The team detected a hallmark of vortex beams: a row of doughnut-shaped rings imprinted on a detector by the atoms, in which each doughnut corresponds to a beam with a different orbital angular momentum.

    Another set of doughnuts revealed the presence of vortex beams of helium excimers, molecules created when a helium atom in an excited, or energized, state pairs up with another helium atom.

    2
    A pattern of rings reveals the presence of vortex beams of atoms and molecules. Each doughnut shape corresponds to a beam of helium atoms with a different angular momentum. Two hard-to-see circles from helium molecules sit in between the center dot and the first two doughnuts left and right of the center. Credit: A. Luski et al/Science 2021.

    Next, scientists might investigate what happens when vortex beams of molecules or atoms collide with light, electrons or other atoms or molecules. Such collisions are well-understood for normal particle beams, but not for those with orbital angular momentum. Similar vortex beams made with protons might also serve as a method for probing the subatomic particle’s mysterious innards (SN: 4/18/17).

    In physics, “most important things are achieved when we are revisiting known phenomena with a fresh perspective,” says physicist Ivan Madan of EPFL (Swiss Federal Institute of Technology in Lausanne) [École polytechnique fédérale de Lausanne](CH), who was not involved with the research. “And, for sure, this experiment allows us to do that.”

    See the full article here .


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  • richardmitnick 7:23 pm on September 2, 2021 Permalink | Reply
    Tags: "How radio astronomy put new eyes on the cosmos", "Science News (US)", Dame Susan Jocelyn Bell Burnell discovered pulsars with radio astronomy but typically for women she was denied the Nobel just like Vera Rubin who worked on Dark Matter., Green Bank Observatory in West Virginia, Grote Reber built the world’s first dedicated radio telescope., In 1967 Dame Jocelyn Bell Burnell noticed that the radio antenna array she helped build was picking up a steady beep … beep … beep from deep space every 1.3 seconds., Karl Jansky stumbled on a radio hiss coming from the direction of the center of the galaxy marking the beginnings of radio astronomy., More than 100 radio telescopes-from spidery antennas hunkered low to the ground to supersized versions of Reber’s dish that span hundreds of meters-dot the globe., Radio telescopes also turned up objects previously unimagined: quasars-the blazing cores of remote galaxies powered by behemoth black holes; pulsars-the ultradense spinning cores of dead stars., The basic discovery that there was radio radiation coming from interstellar space confounded theory., The Karl V. Jansky Very Large Array is a network of twenty-eight 25-meter radio dishes in New Mexico., The Karl V. Jansky Very Large Array was featured in the 1997 movie "Contact".   

    From “Science News (US) : “How radio astronomy put new eyes on the cosmos” 

    From “Science News (US)

    August 31, 2021
    Christopher Crockett

    1

    The Karl V Jansky Very Large Array, a network of radio dishes in New Mexico, was featured in the 1997 movie Contact. Astronomers have used it to study black holes and the regions around young stars where planets form. Credit: Jeff Hellerman/National Radio Astronomy Observatory (US)/Associated Universities Inc (US)/The National Science Foundation (US).

    Radio telescopes have uncovered quasars and pulsars, and offered up the first pic of a black hole.

    One can only imagine what Grote Reber’s neighbors thought when, in 1937, the amateur radio enthusiast erected in his yard a nearly 10-meter-wide shallow bowl of sheet metal, perched atop an adjustable scaffold and topped by an open pyramid of gangly towers. Little could his neighbors have known that they were witnessing the birth of a new way of looking at the cosmos.

    Reber was building the world’s first dedicated radio telescope. Unlike traditional telescopes, which use lenses or mirrors to focus visible light, this contraption used metal and circuitry to collect interstellar radio waves, low frequency ripples of electromagnetic radiation. With his homemade device, Reber made the first map of the sky as seen with radio-sensitive eyes and kicked off the field of radio astronomy.

    “Radio astronomy is as fundamental to our understanding of the universe as … optical astronomy,” says Karen O’Neil, site director at Green Bank Observatory in West Virginia.

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    _____________________________________________________________________________________

    “If we want to understand the universe, we really need to make sure we have as many different types of eyes on the universe as we possibly can.”

    When astronomers talk about radio waves from space, they aren’t (necessarily) referring to alien broadcasts. More often, they are interested in low-energy light that can emerge when molecules change up their rotation, for example, or when electrons twirl within a magnetic field. Tuning in to interstellar radio waves for the first time was akin to Galileo pointing a modified spyglass at the stars centuries earlier — we could see things in the sky we’d never seen before.

    Today radio astronomy is a global enterprise. More than 100 radio telescopes-from spidery antennas hunkered low to the ground to supersized versions of Reber’s dish that span hundreds of meters-dot the globe. These eyes on the sky have been so game-changing that they’ve been at the center of no fewer than three Nobel Prizes.

    Not bad for a field that got started by accident.

    In the early 1930s, an engineer at Bell Telephone Laboratories named Karl Jansky was tracking down sources of radio waves that interfered with wireless communication. He stumbled upon a hiss coming from somewhere in the constellation Sagittarius, in the direction of the center of the galaxy.

    2
    Karl Jansky, shown here with his rotating radio antenna, stumbled on a radio hiss coming from the direction of the center of the galaxy marking the beginnings of radio astronomy.Credit: Jeff Hellerman/NRAO/AUI/NSF.

    “The basic discovery that there was radio radiation coming from interstellar space confounded theory,” says astronomer Jay Lockman, also of Green Bank. “There was no known way of getting that.”

    Bell Labs moved Jansky on to other, more Earthly pursuits. But Reber, a fan of all things radio, read about Jansky’s discovery and wanted to know more. No one had ever built a radio telescope before, so Reber figured it out himself, basing his design on principles used to focus visible light in optical scopes. He improved upon Jansky’s antenna — a bunch of metal tubes held up by a pivoting wooden trestle — and fashioned a parabolic metal dish for focusing incoming radio waves to a point, where an amplifier boosted the feeble signal. The whole contraption sat atop a tilting wooden base that let him scan the sky by swinging the telescope up and down. The same basic design is used today for radio telescopes around the world.

    For nearly a decade — thanks partly to the Great Depression and World War II — Reber was largely alone. The field didn’t flourish until after the war, with a crop of scientists brimming with new radio expertise from designing radar systems. Surprises have been coming ever since.

    3
    Grote Reber erected the world’s first dedicated radio telescope – shown here – in his yard in Wheaton, Ill. Credit: GBO/NSF/AUI.

    “The discovery of interstellar molecules, that’s a big one,” says Lisa Young, an astronomer at The New Mexico Institute of Mining and Technology (US) in Socorro. Radio telescopes are well suited to peering into the dense, cold clouds where molecules reside and sensing radiation emitted when they lose rotational energy. Today, the list of identified interstellar molecules includes many complex organics, including some thought to be precursors for life.

    Radio telescopes also turned up objects previously unimagined. Quasars-the blazing cores of remote galaxies powered by behemoth black holes, first showed up in detailed radio maps from the late 1950s. Pulsars-the ultradense spinning cores of dead stars, made themselves known in 1967 when Jocelyn Bell Burnell noticed that the radio antenna array she helped build was picking up a steady beep … beep … beep from deep space every 1.3 seconds.

    (She was passed over when the 1974 Nobel Prize in physics honored this discovery — her adviser got the recognition. But an accolade came in 2018, when she was awarded a Special Breakthrough Prize in Fundamental Physics.)

    [Ed.: Since Jocelyn Bell Burnell is still alive she could still get the Nobel Prize due to her.]

    Pulsars are “not only interesting for being a discovery in themselves,” Lockman says. They “are being used now to make tests of general relativity and detect gravitational waves.” That’s because anything that nudges a pulsar — say, a passing ripple in spacetime — alters when its ultraprecise radio beats arrive at Earth. In the early 1990s, such timing variations from one pulsar led to the first confirmed discovery of planets outside the solar system.

    More recently, brief blasts of radio energy primarily from other galaxies have captured astronomers’ attention. Discovered in 2007, the causes of these “fast radio bursts” are still unknown. But they are already useful probes of the stuff between galaxies. The light from these eruptions encodes signatures of the atoms encountered while en route to Earth, allowing astronomers to track down lots of matter they thought should be out in the cosmos but hadn’t found yet. “That was the thing that allowed us to weigh the universe and understand where the missing matter is,” says Dan Werthimer, an astronomer at The University of California- Berkeley (US).

    And it was a radio antenna that, in 1964, gave the biggest boost to the then-fledgling Big Bang theory. Arno Penzias and Robert Wilson, engineers at Bell Labs, were stymied by a persistent hiss in the house-sized, horn-like antenna they were repurposing for radio astronomy.

    The culprit was radiation that permeates all of space, left behind from a time when the universe was much hotter and denser than it is today. This “cosmic microwave background,” named for the relatively high frequencies at which it is strongest, is still the clearest window that astronomers have into the very early universe.

    Radio telescopes have another superpower. Multiple radio dishes linked together across continents can act as one enormous observatory, with the ability to see details much finer than any of those dishes acting alone. Building a radio eye as wide as the planet — the Event Horizon Telescope — led to the first picture of a [event horizon of a ] black hole.

    “Not that anybody needed proof of the existence [of black holes],” Young says, “but there’s something so marvelous about actually being able to see it.”

    The list of discoveries goes on: Galaxies from the early universe that are completely shrouded in dust and so emit no starlight still glow bright in radio images. Rings of gas and dust encircling young stars are providing details about planet formation. Intel on asteroids and planets in our solar system can be gleaned by bouncing radio waves off their surfaces.

    And, of course, there’s the search for extraterrestrial intelligence, or SETI.

    “Radio is probably the most likely place where we will answer the question: ‘Are we alone?’” Werthimer says.

    That sentiment goes back more than a century. In 1899, inventor Nikola Tesla picked up radio signals that he thought were coming from folks on another planet. And for 36 hours in August 1924, the United States ordered all radio transmitters silent for five minutes every hour to listen for transmissions from Mars as Earth lapped the Red Planet at a relatively close distance. The field got a more official kickoff in 1960 when astronomer Frank Drake pointed Green Bank’s original radio telescope at the stars Tau Ceti and Epsilon Eridani, just in case anyone there was broadcasting.

    While SETI has had its ups and downs, “there’s kind of a renaissance,” Werthimer says. “There’s a lot of new, young people going into SETI … and there’s new money.” In 2015, entrepreneur Yuri Milner pledged $100 million over 10 years to the search for other residents of our universe.

    _____________________________________________________________________________________
    Breakthrough Listen Project

    1


    _____________________________________________________________________________________

    Though the collapse of the giant Arecibo Observatory in 2020 — at 305 meters across, it was the largest single dish radio telescope for most of its lifetime — was tragic and unexpected, radio astronomers have new facilities in the works.

    The Square Kilometer Array, which will link up small radio dishes and antennas across Australia and South Africa when complete in the late 2020s, will probe the acceleration of the universe’s expansion, seek out signs of life and explore conditions from cosmic dawn.

    “We’ll see the signatures of the first structures in the universe forming the first galaxies and stars,” Werthimer says.

    But if the history of radio astronomy is any guide, the most remarkable discoveries yet to come will be the things no one has thought to look for. So much about the field is marked by serendipity, Werthimer notes. Even radio astronomy as a field started serendipitously. “If you just build something to look at some place that nobody’s looked before,” he says, “you’ll make interesting discoveries.”

    See the full article here .


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  • richardmitnick 7:47 am on August 26, 2021 Permalink | Reply
    Tags: "Physicists caught protons ‘surfing’ on shock waves", "Science News (US)", ,   

    From “Science News (US) : “Physicists caught protons ‘surfing’ on shock waves” 

    From “Science News (US)

    8.26.21
    Emily Conover

    A laser experiment could help scientists understand how the subatomic particles reach high energies.

    Protons can surf some truly gnarly waves.

    A new experiment suggests that the subatomic particles can be accelerated by a process akin to surfers catching waves. The protons get a speed boost not from ocean swells, but from shock waves within plasma, a mixture of electrically charged particles. Such shock waves are sonic boom–like disturbances marked by an abrupt increase in density, temperature and pressure.

    The research could help scientists better understand some of the high-energy particles that zip through the cosmos. Shock waves in space are thought to propel charged particles, but it’s still not fully understood how particles get their pep (SN: 11/12/20).

    In the experiment, which mimicked certain types of cosmic shock waves, protons reached energies up to 80,000 electron volts, physicists report August 19 in Nature Physics. In space, similar shock waves occur where the outflow of charged particles from the sun meets the Earth’s magnetic field, for example, and also where those particles slow down dramatically as they approach the edge of the solar system, at what’s called the termination shock (SN: 10/4/13).

    The scientists used powerful lasers to re-create the physics of such cosmic shock waves on a smaller scale. In the experiment, a laser blast vaporized a target, sending a burst of plasma careening into a cloud of hydrogen gas. As the plasma plowed through the gas, a shock wave formed, and protons from the gas sped up, measurements indicated.

    Scientists had predicted that protons could be accelerated by a process called the shock surfing acceleration, which happens in the presence of a magnetic field. A particle is pushed along by the shock wave’s electric field, and the magnetic field helps the particle stay on course. If the particle glides away from the shock wave, the magnetic field twists the particle’s trajectory to return it to the wave, so the proton can surf again.

    Of course, there’s no such automatic return for human surfers, says Julien Fuchs of National Centre for Scientific Research [Centre national de la recherche scientifique, [CNRS] (FR) and the Laboratory for the User of Intense Lasers [Laboratoire pour l’Utilisation des Lasers Intenses] (FR), in Palaiseau, France. It’s too bad, he muses: “I think they would like that.”

    Still, the measurements alone didn’t pinpoint if shock surfing was responsible for the protons’ speedup. “The challenge is always in the interpretation, so what exactly caused that acceleration,” says plasma physicist Frederico Fiuza of DOE’s SLAC National Accelerator Laboratory (US) in Menlo Park, Calif., who was not involved with the research.

    So Fuchs and colleagues created computer simulations of the experiment. Comparing the simulations and the real data suggests that the protons were surfing the shock wave.

    “This is definitely an exciting result,” says plasma physicist Carolyn Kuranz of The University of Michigan (US) in Ann Arbor. She says she hopes that further research would be able to uncover more direct evidence that doesn’t rely on computer simulations. “It’s very promising for future work.”

    See the full article here .


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  • richardmitnick 9:35 am on August 17, 2021 Permalink | Reply
    Tags: "Science News (US)", "Vera Rubin’s work on dark matter led to a paradigm shift in cosmology", , , , , ,   

    From “Science News (US) : “Vera Rubin’s work on dark matter led to a paradigm shift in cosmology” 

    From “Science News (US)

    8.17.21
    Maria Temming

    1
    Bright Galaxies, Dark Matter, and Beyond
    Ashley Jean Yeager
    MIT Press, $24.95

    Vera Rubin’s research forced cosmologists to radically reimagine the cosmos.

    In the 1960s and ’70s, Rubin’s observations of stars whirling around within galaxies revealed the gravitational tug of invisible “dark matter.” Although astronomers had detected hints of this enigmatic substance for decades, Rubin’s data helped finally convince a skeptical scientific community that dark matter exists (SN: 1/10/20).

    “Her work was pivotal to redefining the composition of our cosmos,” Ashley Yeager, Science News’ associate news editor, writes in her new book. Bright Galaxies, Dark Matter, and Beyond follows Rubin’s journey from stargazing child to preeminent astronomer and fierce advocate for women in science.

    That journey, Yeager shows, was rife with obstacles. When Rubin was a young astronomer in the 1950s and ’60s, many observatories were closed to women, and more established scientists often brushed her off. Much of her early work was met with intense skepticism, but that only made Rubin, who died in 2016 at age 88, a more dogged data collector.

    On graphs plotting the speeds of stars swirling around galaxies, Rubin showed that stars farther from galactic centers orbited just as fast as inner stars. That is, the galaxies’ rotation curves were flat. Such speedy outer stars must be pulled along by the gravitational grip of dark matter.

    Science News staff writer Maria Temming spoke with Yeager about Rubin’s legacy and what, beyond her pioneering research, made Rubin remarkable. The following discussion has been edited for clarity and brevity.

    Temming: What inspired you to tell Rubin’s story?

    Yeager: It all started when I was working at the National Air and Space Museum in Washington, D.C., in 2007. I was walking around the “Explore the Universe” exhibit and noticed there weren’t many women featured. But then there was this picture of a woman with big glasses and cropped hair, and I thought, “Who is this?” It was Vera Rubin.

    My supervisor was a curator of oral histories. He was working on Rubin’s, so I asked him about her. He said, “I have one more oral history interview to do with her. Would you like to come?” So I got to interview her. She was charismatic, kind and curious — not a person who was all about herself, but wanted to know about you. That stuck with me.

    Temming: You spend much of the book describing evidence for dark matter besides Rubin’s research. Why?

    Yeager: I wanted to make sure I didn’t portray Rubin as this lone person who discovered dark matter, because there were a lot of different moving pieces in astronomy and physics that came together in the ’70s and early ’80s for the scientific community to say, “OK, we really have to take dark matter seriously.”

    Temming: What made Rubin’s work a linchpin for confirming dark matter?

    Yeager: She really went after nailing down that flat rotation curve in all types of galaxies. Mainly because she did get a lot of pushback, continually, that said, “Oh, that’s just a special case in that galaxy, or that’s just for those types of galaxies.” She studied hundreds of galaxies to double-check that, yes, in fact, the rotation curves are flat. People saying, “We don’t believe you,” didn’t ever really knock her down. She just came back swinging harder.

    It helped that she did the work in visible wavelengths of light. There had been a lot of radio astronomy data to suggest flat rotation curves, but because radio astronomy was very new, it was really only once you saw it with the eye that the astronomy community was convinced.

    Temming: Do you have a favorite anecdote about Rubin?

    Yeager: The one that comes to mind is how much she loved flowers. She told me about how on drives from Lowell Observatory to Kitt Peak National Observatory in Arizona, she and her colleague Kent Ford would always stop and buy wildflowers. The fact that picking these wildflowers stuck with her, I thought, was just representative of who she was. Her favorite moments weren’t necessarily these big discoveries she’d made, but stopping to pick some flowers and enjoy their beauty.

    2
    Author Ashley Yeager (left) interviewed Vera Rubin (right) in 2007 as part of an oral history project with Smithsonian’s National Air and Space Museum. Smithsonian National Air and Space Museum (NASM 9A16674).

    Temming: Did you learn anything in your research that surprised you?

    Yeager: I didn’t initially grasp how many different types of projects she had. She did a lot with looking for larger-scale structure [in the universe] and looking at the Hubble constant [which describes how fast the universe is expanding] (SN: 4/21/21). She had a very diverse set of questions that she wanted to answer, well into her 70s.

    Temming: I was surprised by her decision to get out of the rat-race of hunting for quasars, when that area of research heated up in the 1960s.

    Yeager: She very much didn’t like to be in pressure situations where she could be wrong. She liked to go and collect so much data that no one could [dispute it]. With quasar research, it was just too fast, and she wanted to be methodical about it.

    Temming: Why is Rubin’s story important to tell now?

    Yeager: Unfortunately for women and minorities in science, it’s still very relevant, in that there are a lot of challenges to pursuing a career in STEM. Her story demonstrates that you have to surround yourself with people who are willing to help you and get away from the people who want to keep you down. Plus her story is also very encouraging: Your curiosity can keep you going and can fuel something way bigger than yourself.

    Temming: How did she advocate for women in astronomy?

    Yeager: She was very outspoken about it. At National Academy of Sciences meetings, the organizers always dreaded her standing up, because she would say, “What are we doing about women in science? We’re not doing enough.” She was constantly pushing for women to be recognized with awards. She kept tabs on the number of women who had earned Ph.D.s and who had gotten staff positions — and their salaries. She was very data-driven. She’d cull that information and use it to advocate for better representation and recognition of women in astronomy.

    Temming: How would you describe Rubin to someone who hasn’t met her?

    Yeager: She was one of the most persistent, gracious and nurturing people that I’ve ever met. You could strip away all that she did in astronomy and she would still be this incredible figure — the way she carried herself, the way she treated people. Just a beautiful human being.
    ______________________________________________________________________________________________________________

    Dark Matter Background
    Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com.


    Coma cluster via NASA/ESA Hubble.


    In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.
    Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.
    Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

    Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).


    Vera Rubin measuring spectra, worked on Dark Matter (Emilio Segre Visual Archives AIP SPL).


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970

    Dark Matter Research

    Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.
    ______________________________________________________________________________________________________________

    See the full article here .


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  • richardmitnick 8:48 am on August 12, 2021 Permalink | Reply
    Tags: "Science News (US)", "The new UN climate change report shows there’s no time for denial or delay", , , , , IPCC Sixth Assessment Report   

    From “Science News (US) : “The new UN climate change report shows there’s no time for denial or delay” 

    From “Science News (US)

    August 9, 2021
    Carolyn Gramling

    The science is unequivocal: Humans are dramatically overhauling Earth’s climate. The effects of climate change are now found everywhere around the globe IPCC Sixth Assessment Report and are intensifying rapidly, states a sweeping new analysis released August 9 by the United Nations’ Intergovernmental Panel on Climate Change, or IPCC. And the window to reverse some of these effects is closing.

    1
    Torrential rains flooded Xinxiang in China’s Henan province in mid-July 2021, leading to dramatic rescues like this one. A new U.N. report finds that human-caused climate change is linked to extreme weather events all around the globe. Credit: Cui Nan/China News Service (CN) via Getty Images.

    “There is no room for doubt any longer” about humans’ responsibility for current climate change, says Kim Cobb, a climate scientist at Georgia Tech in Atlanta and an author on the first chapter of the report. “And now we can say quite definitely that a whole class of extreme [events]” is linked to human-caused climate change.

    Climate change is already affecting every region on Earth in multiple ways, from drought and fire conditions in the U.S. West to heat waves in Europe and flooding in Asia, the report notes (SN: 7/7/21). Each of the past four decades has been the warmest on record since preindustrial times (SN: 5/26/21).

    The study also looks at several different scenarios of greenhouse gas warming, including perhaps the most hopeful scenarios in which by 2050 the world achieves “net zero” carbon emissions, where emitted gases are balanced by carbon removal from the atmosphere.

    If the world gets down to net-zero emissions, the decades afterward hold “hints of light,” says Baylor Fox-Kemper, an oceanographer at Brown University (US) in Providence, R.I., and the coordinating lead author of the new report’s chapter on oceans and Earth’s icy regions. “Temperatures come back down a little — not all the way back to preindustrial times, but there’s a little recovery.”

    But other changes are irreversible on near-future timescales — that is, the next century or more, Fox-Kemper says. Even in those mid-century net-zero emissions scenarios, “it’s still pretty bad,” he says. Sea levels, for example, will continue to rise until about the year 2300, driven in part by the juggernaut of Greenland’s melting ice sheet (SN: 9/30/20). “We may have already crossed [the] threshold beyond which Greenland’s melting could be stopped,” he says. Still, swift and deep emissions reductions would significantly slow how much sea levels will rise by the end of the century, the report finds.

    The new analysis is the sixth in a series of massive assessment reports undertaken by the IPCC since 1990. In each report, hundreds of scientists from around the world analyze the findings of thousands of studies to form a consensus picture of how Earth’s climate is changing and what role people play in those changes.

    “The key message [of this report] is still the same as was first published in 1990 … human-induced emissions of greenhouse gases pose a threat for humans’ well-being and the biosphere,” said Petteri Taalas, Secretary-General of the World Meteorological Organization, at an event announcing the report’s release August 9.

    But researchers understand climate change far better now than they did in 1990, when the first assessment report was released. In the last three decades, new findings have poured in from tens of thousands more observing stations, from a wealth of satellite instruments, and from dramatically improved climate simulations (SN: 1/7/20).

    The IPCC’s fifth assessment report, released in several parts during 2013 and 2014, was itself a game changer. It was the first to state that greenhouse gas emissions from human activities are driving climate change — a conclusion that set the stage for 195 nations to agree in Paris in 2015 to curb those emissions (SN: 4/13/14; SN: 12/12/15).

    The Paris Agreement set a target of limiting the global average temperature to 2 degrees Celsius above preindustrial times. But many island nations and others most threatened by climate change feared that this target wasn’t stringent enough. So in an unprecedented step, the U.N. commissioned a report by the IPCC to compare how a future Earth might look if warming were limited to just 1.5 degrees Celsius instead.

    That special report, released in 2018, revealed in fine detail how just half a degree of extra warming by 2100 could matter, from the increased likelihood of heat waves to higher sea levels (SN: 12/17/18). The one-two punch of those concrete findings and scorching temperatures in 2019 grabbed the attention of public and policy makers alike.

    Scientists were surprised by how hard the 1.5 degree report landed. “Even for me,” says Ko Barrett, vice chair of the IPCC and a senior advisor for climate at the U.S. National Oceanic and Atmospheric Administration, “a person who has dedicated my entire professional career to addressing climate change, the report caused me to rethink my personal contribution to the climate problem. Climate change was not some distant temperature target to be hit in the ethereal future. It was close; it was now.”

    IPCC scientists hope the new report, with its powerful emphasis on the regional and local effects of climate change — fully a third of the report is devoted to outlining those — will have a similar impact. And its timing is significant. Beginning October 31, heads of state from around the world are scheduled to meet in Glasgow, Scotland, to discuss updated — and hopefully increasingly ambitious — plans to reduce emissions to meet the targets of the 2015 Paris Agreement.

    With previous reports, “the world listened, but it didn’t hear. Or the world listened, but it didn’t act strongly enough,” said Inger Andersen, executive director of the U.N. Environment Programme, at the Aug. 9 event for the report’s release. “We certainly urge them … to listen to the facts on the table now.”

    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 11:41 am on August 5, 2021 Permalink | Reply
    Tags: "A bounty of potential gravitational wave events hints at exciting possibilities", "Science News (US)", ,   

    From “Science News (US) : “A bounty of potential gravitational wave events hints at exciting possibilities” 

    From “Science News (US)

    August 4, 2021
    Emily Conover

    1
    One way that gravitational waves (shown in this illustration) are stirred up is when two black holes spiral around one another and collide. Credit: MARK GARLICK/
    SCIENCE PHOTO LIBRARY (UK)

    A new crew of potential ripples in spacetime has just debuted — emphasis on the word “potential.”

    By loosening the criteria for what qualifies as evidence for gravitational waves, physicists identified 1,201 possible tremors. Most are probably fakes, spurious jitters in the data that can mimic the cosmic vibrations, the team reports August 2 at arXiv.org. But by allowing in more false alarms, the new tally may also include some weak but genuine signals that would otherwise be missed, potentially revealing exciting new information about the sources of gravitational waves.

    Scientists can now look for signs that may corroborate some of the uncertain detections, such as flashes of light in the sky that flared from the cosmic smashups that set off the ripples. Gravitational waves are typically spawned by collisions of dense, massive objects, such as black holes or neutron stars, the remnants of dead stars (SN: 1/21/21).

    To come up with the new census, physicists reanalyzed six months of data from the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, and Virgo gravitational wave observatories. Scientists had already identified 39 of the events as likely gravitational waves in earlier analyses.

    Eight events that hadn’t been previously identified stand a solid chance of being legitimate — with greater than a 50 percent probability of coming from an actual collision.

    The physicists analyzed the data from those eight events to see how they might have occurred. In one, two black holes may have slammed together, melding into a whopper black hole with about 180 times the mass of the sun, which would make it the biggest black hole merger seen yet (SN: 9/2/20). Another event could be a rare sighting of a black hole swallowing a neutron star (SN: 6/29/21).

    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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