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  • richardmitnick 12:52 pm on February 8, 2021 Permalink | Reply
    Tags: "The Stars Within Us", , , , , , , Creation of heavier elements requires more extreme environments usually triggered by the end of a star’s life in a supernova., , How the Elements Inside You and Everything Were Forged., Intense heat and pressure fused hydrogen atoms to form helium and lithium., LIGO/VIRGO, , , Within a few hundred million years after the Big Bang clouds of hydrogen gas condensed into the first stars., Within the first three minutes following the Big Bang the fundamental building blocks of matter formed and merged into the first element–hydrogen.   

    From National Science Foundation (US): “The Stars Within Us” 

    From National Science Foundation (US)

    1
    Credit: Nicolle R. Fuller/NSF.

    Humans have always looked to the stars and studied them. Over the past century, science has revealed the fundamental role stars play for nearly everything in existence, including the elements on the Periodic Table.

    Periodic Table from
    International Union of Pure and Applied Chemistry 2019.

    The birth, life and death of every star creates and disseminates the elements of the Periodic Table throughout the universe, a cycle that began nearly 14 billion years ago and repeats continuously today.

    Without it, the Earth and everything on it – air, water, soil, plants, wildlife, and human life – would not exist.


    The Stars Within Us: How the Elements Inside You, and Everything, Were Forged.

    Within the first three minutes following the Big Bang, the fundamental building blocks of matter formed and merged into the first element–hydrogen. Within a few hundred million years after the Big Bang, clouds of hydrogen gas condensed into the first stars. In the cores of those stars, intense heat and pressure fused hydrogen atoms to form helium and lithium.

    Recently, astronomers from several U.S.-based universities detected a signal from the birth of those early stars. Since the stars are too distant to be seen with telescopes, the astronomers searched for indirect evidence, such as a tell-tale change in the background electromagnetic radiation that permeates the universe, called the cosmic microwave background [CMB].

    CMB per ESA/Planck.

    Supported for more than a decade by the U.S. National Science Foundation, researchers placed a radio antenna not much larger than a refrigerator in the Australian desert and found clear evidence of these massive blue stars.

    EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia.

    More chaos, more elements

    The normal functions of a star—those that make it shine brightly and burn at temperatures of thousands of degrees—create the simplest and lightest elements. Creation of heavier elements requires more extreme environments, usually triggered by the end of a star’s life in a supernova.

    After the hydrogen in a star’s core is exhausted, the star fuses helium to form progressively heavier elements, such as carbon and iron. As this fuel runs out, the star either explodes into a supernova, seeding the universe with those elements, or violently collapses, creating neutron stars and black holes. In such violent implosions, star collisions, and the extreme environments around black holes, the heavier elements are forged and then spread far across interstellar space.

    2
    Artist’s now iconic illustration of two merging neutron stars. The beams represent the gamma-ray burst while the rippling space-time grid indicates the isotropic gravitational waves. Credit: A. Simonnet/National Science Foundation/LIGO/Sonoma State University.

    In 2017, for the first time in history, researchers using the twin detectors of NSF’s Laser Interferometer Gravitational-Wave Observatory detected gravitational waves created by the collision of two neutron stars.

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo (IT) came online in August 2018.

    The researchers worked with the Europe-based Virgo gravitational wave detector and some 70 ground- and space-based telescopes across the globe to track and record the gamma radiation, X-rays, light, and radio waves that cascaded from the explosion.

    MIT /Caltech Advanced aLigo at Hanford, WA (US), Livingston, LA, (US) and VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    The observations revealed signatures of recently synthesized elements, including gold and platinum, solving a decades-long mystery of how nearly half of all elements heavier than iron are produced.

    Some of the heaviest elements, such as uranium, are forged near black holes and in the powerful jets that can emanate from them, such as those that surge away from “feeding” black holes, like blazars, an active galactic nucleus with a relativistic jet composed of ionized matter.

    3
    The timeline of the universe, with the first stars emerging by 180 million years after the Big Bang and black holes another 70 millions years after. Photo Credit: N.R.Fuller/National Science Foundation.

    The NSF-supported Event Horizon Telescope presented the first direct visual evidence of a supermassive black hole in 2019, and NSF’s Ice Cube detector has worked with collaborating observatories to trace a cosmic neutrino to its blazar source.

    EHT map.

    Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via JPL/ Event Horizon Telescope Collaboration released on 10 April 2019.

    These extreme environments in space are where the heaviest elements are formed, but because they have such short half-lives, scientists have yet to directly witness their formation, and they have not survived to be found on Earth today.

    This is where researchers in the laboratory have built upon what we have learned from studying the cosmos.

    Filling the Periodic Table

    On Earth, ancient cultures were first to isolate a handful of elements, such as copper and mercury, though in recent centuries, scientists have identified and isolated more than 100 more. They are categorized using the Periodic Table—first published in 1869 by Russian chemist Dmitri Mendeleev. The initial Periodic Table contained 28 elements, and Mendeleev predicted the existence of unidentified elements, leaving gaps for future scientists to fill.

    Laboratory experiments have expanded the Periodic Table to include 118 known elements. For some, particularly the heaviest, they were only discovered when physicists crafted them from the fusion of lighter elements. The heaviest known element is oganesson, which holds 118 protons in its nucleus, although only for fractions of a millisecond.

    Like the stars that constantly recycle and distribute elements throughout space, researchers in all disciplines continue their efforts to expand the Periodic Table and deepen the understanding of the atoms from which we are constructed. This is an ongoing process, and future generations of scientists are just now making their initial observations or conducting their first experiments that will expand the knowledge about the universe and ourselves.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition
    The National Science Foundation (NSF) (US) is an independent federal agency created by Congress in 1950 “to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense…we are the funding source for approximately 24 percent of all federally supported basic research conducted by America’s colleges and universities. In many fields such as mathematics, computer science and the social sciences, NSF is the major source of federal backing.

    We fulfill our mission chiefly by issuing limited-term grants — currently about 12,000 new awards per year, with an average duration of three years — to fund specific research proposals that have been judged the most promising by a rigorous and objective merit-review system. Most of these awards go to individuals or small groups of investigators. Others provide funding for research centers, instruments and facilities that allow scientists, engineers and students to work at the outermost frontiers of knowledge.

    NSF’s goals — discovery, learning, research infrastructure and stewardship — provide an integrated strategy to advance the frontiers of knowledge, cultivate a world-class, broadly inclusive science and engineering workforce and expand the scientific literacy of all citizens, build the nation’s research capability through investments in advanced instrumentation and facilities, and support excellence in science and engineering research and education through a capable and responsive organization. We like to say that NSF is “where discoveries begin.”

    Many of the discoveries and technological advances have been truly revolutionary. In the past few decades, NSF-funded researchers have won some 236 Nobel Prizes as well as other honors too numerous to list. These pioneers have included the scientists or teams that discovered many of the fundamental particles of matter, analyzed the cosmic microwaves left over from the earliest epoch of the universe, developed carbon-14 dating of ancient artifacts, decoded the genetics of viruses, and created an entirely new state of matter called a Bose-Einstein condensate.

    NSF also funds equipment that is needed by scientists and engineers but is often too expensive for any one group or researcher to afford. Examples of such major research equipment include giant optical and radio telescopes, Antarctic research sites, high-end computer facilities and ultra-high-speed connections, ships for ocean research, sensitive detectors of very subtle physical phenomena and gravitational wave observatories.

    Another essential element in NSF’s mission is support for science and engineering education, from pre-K through graduate school and beyond. The research we fund is thoroughly integrated with education to help ensure that there will always be plenty of skilled people available to work in new and emerging scientific, engineering and technological fields, and plenty of capable teachers to educate the next generation.

    No single factor is more important to the intellectual and economic progress of society, and to the enhanced well-being of its citizens, than the continuous acquisition of new knowledge. NSF is proud to be a major part of that process.

    Specifically, the Foundation’s organic legislation authorizes us to engage in the following activities:

    Initiate and support, through grants and contracts, scientific and engineering research and programs to strengthen scientific and engineering research potential, and education programs at all levels, and appraise the impact of research upon industrial development and the general welfare.
    Award graduate fellowships in the sciences and in engineering.
    Foster the interchange of scientific information among scientists and engineers in the United States and foreign countries.
    Foster and support the development and use of computers and other scientific methods and technologies, primarily for research and education in the sciences.
    Evaluate the status and needs of the various sciences and engineering and take into consideration the results of this evaluation in correlating our research and educational programs with other federal and non-federal programs.
    Provide a central clearinghouse for the collection, interpretation and analysis of data on scientific and technical resources in the United States, and provide a source of information for policy formulation by other federal agencies.
    Determine the total amount of federal money received by universities and appropriate organizations for the conduct of scientific and engineering research, including both basic and applied, and construction of facilities where such research is conducted, but excluding development, and report annually thereon to the President and the Congress.
    Initiate and support specific scientific and engineering activities in connection with matters relating to international cooperation, national security and the effects of scientific and technological applications upon society.
    Initiate and support scientific and engineering research, including applied research, at academic and other nonprofit institutions and, at the direction of the President, support applied research at other organizations.
    Recommend and encourage the pursuit of national policies for the promotion of basic research and education in the sciences and engineering. Strengthen research and education innovation in the sciences and engineering, including independent research by individuals, throughout the United States.
    Support activities designed to increase the participation of women and minorities and others underrepresented in science and technology.

    At present, NSF has a total workforce of about 2,100 at its Alexandria, VA, headquarters, including approximately 1,400 career employees, 200 scientists from research institutions on temporary duty, 450 contract workers and the staff of the NSB office and the Office of the Inspector General.

    NSF is divided into the following seven directorates that support science and engineering research and education: Biological Sciences, Computer and Information Science and Engineering, Engineering, Geosciences, Mathematical and Physical Sciences, Social, Behavioral and Economic Sciences, and Education and Human Resources. Each is headed by an assistant director and each is further subdivided into divisions like materials research, ocean sciences and behavioral and cognitive sciences.

    Within NSF’s Office of the Director, the Office of Integrative Activities also supports research and researchers. Other sections of NSF are devoted to financial management, award processing and monitoring, legal affairs, outreach and other functions. The Office of the Inspector General examines the foundation’s work and reports to the NSB and Congress.

    Each year, NSF supports an average of about 200,000 scientists, engineers, educators and students at universities, laboratories and field sites all over the United States and throughout the world, from Alaska to Alabama to Africa to Antarctica. You could say that NSF support goes “to the ends of the earth” to learn more about the planet and its inhabitants, and to produce fundamental discoveries that further the progress of research and lead to products and services that boost the economy and improve general health and well-being.

    As described in our strategic plan, NSF is the only federal agency whose mission includes support for all fields of fundamental science and engineering, except for medical sciences. NSF is tasked with keeping the United States at the leading edge of discovery in a wide range of scientific areas, from astronomy to geology to zoology. So, in addition to funding research in the traditional academic areas, the agency also supports “high risk, high pay off” ideas, novel collaborations and numerous projects that may seem like science fiction today, but which the public will take for granted tomorrow. And in every case, we ensure that research is fully integrated with education so that today’s revolutionary work will also be training tomorrow’s top scientists and engineers.

    Unlike many other federal agencies, NSF does not hire researchers or directly operate our own laboratories or similar facilities. Instead, we support scientists, engineers and educators directly through their own home institutions (typically universities and colleges). Similarly, we fund facilities and equipment such as telescopes, through cooperative agreements with research consortia that have competed successfully for limited-term management contracts.

    NSF’s job is to determine where the frontiers are, identify the leading U.S. pioneers in these fields and provide money and equipment to help them continue. The results can be transformative. For example, years before most people had heard of “nanotechnology,” NSF was supporting scientists and engineers who were learning how to detect, record and manipulate activity at the scale of individual atoms — the nanoscale. Today, scientists are adept at moving atoms around to create devices and materials with properties that are often more useful than those found in nature.

    Dozens of companies are gearing up to produce nanoscale products. NSF is funding the research projects, state-of-the-art facilities and educational opportunities that will teach new skills to the science and engineering students who will make up the nanotechnology workforce of tomorrow.

    At the same time, we are looking for the next frontier.

    NSF’s task of identifying and funding work at the frontiers of science and engineering is not a “top-down” process. NSF operates from the “bottom up,” keeping close track of research around the United States and the world, maintaining constant contact with the research community to identify ever-moving horizons of inquiry, monitoring which areas are most likely to result in spectacular progress and choosing the most promising people to conduct the research.

    NSF funds research and education in most fields of science and engineering. We do this through grants and cooperative agreements to more than 2,000 colleges, universities, K-12 school systems, businesses, informal science organizations and other research organizations throughout the U.S. The Foundation considers proposals submitted by organizations on behalf of individuals or groups for support in most fields of research. Interdisciplinary proposals also are eligible for consideration. Awardees are chosen from those who send us proposals asking for a specific amount of support for a specific project.

    Proposals may be submitted in response to the various funding opportunities that are announced on the NSF website. These funding opportunities fall into three categories — program descriptions, program announcements and program solicitations — and are the mechanisms NSF uses to generate funding requests. At any time, scientists and engineers are also welcome to send in unsolicited proposals for research and education projects, in any existing or emerging field. The Proposal and Award Policies and Procedures Guide (PAPPG) provides guidance on proposal preparation and submission and award management. At present, NSF receives more than 42,000 proposals per year.

    To ensure that proposals are evaluated in a fair, competitive, transparent and in-depth manner, we use a rigorous system of merit review. Nearly every proposal is evaluated by a minimum of three independent reviewers consisting of scientists, engineers and educators who do not work at NSF or for the institution that employs the proposing researchers. NSF selects the reviewers from among the national pool of experts in each field and their evaluations are confidential. On average, approximately 40,000 experts, knowledgeable about the current state of their field, give their time to serve as reviewers each year.

    The reviewer’s job is to decide which projects are of the very highest caliber. NSF’s merit review process, considered by some to be the “gold standard” of scientific review, ensures that many voices are heard and that only the best projects make it to the funding stage. An enormous amount of research, deliberation, thought and discussion goes into award decisions.

    The NSF program officer reviews the proposal and analyzes the input received from the external reviewers. After scientific, technical and programmatic review and consideration of appropriate factors, the program officer makes an “award” or “decline” recommendation to the division director. Final programmatic approval for a proposal is generally completed at NSF’s division level. A principal investigator (PI) whose proposal for NSF support has been declined will receive information and an explanation of the reason(s) for declination, along with copies of the reviews considered in making the decision. If that explanation does not satisfy the PI, he/she may request additional information from the cognizant NSF program officer or division director.

    If the program officer makes an award recommendation and the division director concurs, the recommendation is submitted to NSF’s Division of Grants and Agreements (DGA) for award processing. A DGA officer reviews the recommendation from the program division/office for business, financial and policy implications, and the processing and issuance of a grant or cooperative agreement. DGA generally makes awards to academic institutions within 30 days after the program division/office makes its recommendation.

     
  • richardmitnick 3:13 pm on December 24, 2020 Permalink | Reply
    Tags: "Ripples in space-time could provide clues to missing components of the universe", , , , , , , LIGO/VIRGO, ,   

    From University of Chicago: “Ripples in space-time could provide clues to missing components of the universe” 

    U Chicago bloc

    From University of Chicago

    Dec 24, 2020
    Louise Lerner

    1
    Credit: Chris Henze/NASA.

    UChicago scientist lays out how LIGO gravitational waves could be scrambled, yielding information.

    There’s something a little off about our theory of the universe. Almost everything fits, but there’s a fly in the cosmic ointment, a particle of sand in the infinite sandwich. Some scientists think the culprit might be gravity—and that subtle ripples in the fabric of space-time could help us find the missing piece.

    A new paper co-authored by a University of Chicago scientist lays out how this might work. Published Dec. 21 in Physical Review D, the method depends on finding such ripples that have been bent by traveling through supermassive black holes or large galaxies on their way to Earth.

    The trouble is that something is making the universe not only expand, but expand faster and faster over time—and no one knows what it is. (The search for the exact rate is an ongoing debate in cosmology).

    Scientists have proposed all kinds of theories for what the missing piece might be. “Many of these rely on changing the way gravity works over large scales,” said paper co-author Jose María Ezquiaga, a NASA Einstein postdoctoral fellow in the Kavli Institute for Cosmological Physics at the UChicago. “So gravitational waves are the perfect messenger to see these possible modifications of gravity, if they exist.”

    Gravitational waves. Credit: MPI for Gravitational Physics/Werner Benger

    Gravitational waves are ripples in the fabric of space-time itself; since 2015, humanity has been able to pick up these ripples using the LIGO observatories.

    MIT /Caltech Advanced aLigo .

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA.

    Caltech/MIT Advanced aLigo detector installation Hanford, WA, USA.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    Whenever two massively heavy objects collide elsewhere in the universe, they create a ripple that travels across space, carrying the signature of whatever made it—perhaps two black holes or two neutron stars colliding.

    Artist’s iconic conception of two merging black holes similar to those detected by LIGO Credit LIGO-Caltech/MIT/Sonoma State /Aurore Simonnet.

    Gravitational waves are ripples in the fabric of space-time itself; since 2015, humanity has been able to pick up these ripples using the LIGO observatories. Whenever two massively heavy objects collide elsewhere in the universe, they create a ripple that travels across space, carrying the signature of whatever made it—perhaps two black holes or two neutron stars colliding.

    In the paper, Ezquiaga and co-author Miguel Zumalácarregui argue that if such waves hit a supermassive black hole or cluster of galaxies on their way to Earth, the signature of the ripple would change. If there were a difference in gravity compared to Einstein’s theory, the evidence would be embedded in that signature.

    For example, one theory for the missing piece of the universe is the existence of an extra particle. Such a particle would, among other effects, generate a kind of background or “medium” around large objects. If a traveling gravitational wave hit a supermassive black hole, it would generate waves that would get mixed up with the gravitational wave itself. Depending on what it encountered, the gravitational wave signature could carry an “echo,” or show up scrambled.

    “This is a new way to probe scenarios that couldn’t be tested before,” Ezquiaga said.

    Their paper lays out the conditions for how to find such effects in future data. The next LIGO run is scheduled to begin in 2022, with an upgrade to make the detectors even more sensitive than they already are.

    “In our last observing run with LIGO, we were seeing a new gravitational wave reading every six days, which is amazing. But in the entire universe, we think they’re actually happening once every five minutes,” Ezquiaga said. “In the next upgrade, we could see so many of those—hundreds of events per year.”

    The increased numbers, he said, make it more likely that one or more wave will have traveled through a massive object, and that scientists will be able to analyze them for clues to the missing components.

    Zumalácarregui, the other author on the paper, is a scientist at the Max Planck Institute for Gravitational Physics in Germany as well as the Berkeley Center for Cosmological Physics at Lawrence Berkeley National Laboratory and the University of California, Berkeley.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Chicago Campus

    An intellectual destination

    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

    The University of Chicago is an urban research university that has driven new ways of thinking since 1890. Our commitment to free and open inquiry draws inspired scholars to our global campuses, where ideas are born that challenge and change the world.

    We empower individuals to challenge conventional thinking in pursuit of original ideas. Students in the College develop critical, analytic, and writing skills in our rigorous, interdisciplinary core curriculum. Through graduate programs, students test their ideas with UChicago scholars, and become the next generation of leaders in academia, industry, nonprofits, and government.

    UChicago research has led to such breakthroughs as discovering the link between cancer and genetics, establishing revolutionary theories of economics, and developing tools to produce reliably excellent urban schooling. We generate new insights for the benefit of present and future generations with our national and affiliated laboratories: Argonne National Laboratory, Fermi National Accelerator Laboratory, and the Marine Biological Laboratory in Woods Hole, Massachusetts.

    The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

    In all we do, we are driven to dig deeper, push further, and ask bigger questions—and to leverage our knowledge to enrich all human life. Our diverse and creative students and alumni drive innovation, lead international conversations, and make masterpieces. Alumni and faculty, lecturers and postdocs go on to become Nobel laureates, CEOs, university presidents, attorneys general, literary giants, and astronauts.

     
  • richardmitnick 10:45 am on October 13, 2020 Permalink | Reply
    Tags: "New research suggests innovative method to analyse the densest star systems in the Universe", , , , , , LIGO/VIRGO,   

    From ARC Centres of Excellence (AU) via phys.org: “New research suggests innovative method to analyse the densest star systems in the Universe” 

    arc-centers-of-excellence-bloc

    From ARC Centres of Excellence (AU)

    via


    phys.org

    October 13, 2020

    Hubble image – among the largest ever produced with the Earth-orbiting observatory – gives the most detailed view so far of the entire Crab Nebula. The Crab is arguably the single most interesting object, as well as one of the most studied, in all of astronomy. The image is the largest ever taken with Hubble’s WFPC2 workhorse camera. NASA/ESA Hubble.

    In a recently published study [The Astrophysical Journal Letters], a team of researchers led by the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) at Monash university (AU) suggests an innovative method to analyse gravitational waves from neutron star mergers, where two stars are distinguished by type (rather than mass), depending on how fast they’re spinning.

    Neutron stars are extremely dense stellar objects that form when giant stars explode and die—in the explosion, their cores collapse, and the protons and electrons melt into each other to form a remnant neutron star.

    In 2017, the merging of two neutron stars, called GW170817, was first observed by the LIGO and Virgo gravitational-wave detectors.

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo (IT) came online in August 2018.


    MIT /Caltech Advanced aLigo .

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA.

    Caltech/MIT Advanced aLigo detector installation Hanford, WA, USA.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    This merger is well-known because scientists were also able to see light produced from it: high-energy gamma rays, visible light, and microwaves. Since then, an average of three scientific studies on GW170817 have been published every day.

    In January this year, the LIGO and Virgo collaborations announced a second neutron star merger event called GW190425. Although no light was detected, this event is particularly intriguing because the two merging neutron stars are significantly heavier than GW170817, as well as previously known double neutron stars in the Milky Way.

    Scientists use gravitational-wave signals—ripples in the fabric of space and time—to detect pairs of neutron stars and measure their masses. The heavier neutron star of the pair is called the ‘primary’; the lighter one is ‘secondary’.

    The recycled-slow labelling scheme of a binary neutron star system

    A binary neutron star system usually starts with two ordinary stars, each around ten to twenty times more massive than the Sun. When these massive stars age and run out of ‘fuel’, their lives end in supernova explosions that leave behind compact remnants, or neutron stars. Each remnant neutron star weighs around 1.4 times the mass of the Sun, but has a diameter of only 25 kilometres.

    The first-born neutron star usually goes through a ‘recycling’ process: it accumulates matter from its paired star and begins spinning faster. The second-born neutron star doesn’t accumulate matter; its spin speed also slows down rapidly. By the time the two neutron stars merge—millions to billions of years later—it’s predicted that the recycled neutron star may still be spinning rapidly, whereas the other non-recycled neutron star will probably be spinning slowly.

    Another way a binary neutron star system might form is through continuously changing interactions in dense stellar clusters. In this scenario, two unrelated neutron stars, on their own or in other separate star systems, meet each other, pair up and eventually merge like a happy couple due to their gravitational waves. However, current modelling of stellar clusters suggests that this scenario is ineffective in merging the neutron stars.

    OzGrav postdoctoral researcher and lead author of the study Xingjiang Zhu says: ‘The motivation for proposing the recycled-slow labelling scheme of a binary neutron star system is two-fold. First, it’s a generic feature expected for neutron star mergers. Second, it might be inadequate to label two neutron stars as primary and secondary because they’re most likely to be of similar masses and it’s hard to tell which one is heavier.”

    The recent OzGrav study takes a new look at both GW170817 and GW190425 by adopting the recycled-slow scheme. It was found that the recycled neutron star in GW170817 is only mildly or even slowly spinning, whereas that of GW190425 is spinning rapidly, possibly once every 15 milliseconds. It was also found that both merger events are likely to contain two nearly equal-mass neutron stars. Since there is little or no evidence of spin in GW170817, and neutron stars spin down over time, the researchers deduced that the binary probably took billions of years to merge. This agrees well with observations of its host galaxy, called NGC 4993, where little star formation activities are found in the past billions of years.

    OzGrav associate investigator and collaborator Gregory Ashton says: “Our proposed astrophysical framework will allow us to answer important questions about the Universe, such as are there different supernova explosion mechanisms in the formation of binary neutron stars? And to what degree do interactions inside dense star clusters contribute to forming neutron star mergers?”

    The LIGO/Virgo detectors finished their joint third observing run (O3) earlier this year and are currently conducting scheduled maintenance and upgrades. When the fourth run (O4) starts in 2021, scientists will be readily anticipating more discoveries of neutron star mergers. The prospect will be even brighter when the Japanese underground detector KAGRA and the LIGO-India detector join the global network over the coming years.

    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan (JP)

    LIGO-India in the Hingoli district in western India (IN).

    ‘We are in a golden era of studying binary neutron stars with highly-sensitive gravitational-wave detectors that will deliver dozens of discoveries in the next few years,’ adds Zhu.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The objectives for the ARC Centres of Excellence (AU) are to to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
    develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
    offer Australian researchers opportunities to work on large-scale problems over long periods of time
    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

     
  • richardmitnick 8:47 am on July 26, 2020 Permalink | Reply
    Tags: , , LIGO/VIRGO, , , Quantum gravity-seek to unify Albert Einstein’s general theory of relativity with quantum mechanics.,   

    From WIRED: “Looking for Gravitons? Check for the ‘Buzz’” 


    From WIRED

    07.26.2020
    Thomas Lewton


    If gravity plays by the rules of quantum mechanics, particles called gravitons should gingerly jostle ordinary objects.Video: Alexander Dracott/Quanta Magazine

    MANY PHYSICISTS ASSUME that gravitons exist, but few think that we will ever see them. These hypothetical elementary particles are a cornerstone of theories of quantum gravity, which seek to unify Albert Einstein’s general theory of relativity with quantum mechanics. But they are notoriously hard—perhaps impossible—to observe in nature.

    The world of gravitons only becomes apparent when you zoom in to the fabric of space-time at the smallest possible scales, which requires a device that can harness truly extreme amounts of energy. Unfortunately, any measuring device capable of directly probing down to this “Planck length” would necessarily be so massive that it would collapse into a black hole. “It appears that Nature conspires to forbid any measurement of distance with error smaller than the Planck length,” said Freeman Dyson, the celebrated theoretical physicist, in a 2013 talk presenting a back-of-the-envelope calculation of this limit.

    And so gravitons, according to conventional thinking, might only reveal themselves in the universe’s most extreme places: around the time of the Big Bang, or in the heart of black holes. “The problem with black holes is that they’re black, and so nothing comes out,” said Daniel Holz, an astrophysicist at the University of Chicago. “And the quantum gravity stuff is happening right at the center of this—so that’s too bad.”

    But recently published papers challenge this view, suggesting that gravitons may create observable “noise” in gravitational wave detectors such as LIGO, the Laser Interferometer Gravitational-Wave Observatory.

    MIT /Caltech Advanced aLigo

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    “We’ve found that the quantum fuzziness of space-time is imprinted on matter as a kind of jitter,” said Maulik Parikh, a cosmologist at Arizona State University and a coauthor of one of the papers.

    And while it’s still unclear if existing or even future gravitational wave observatories have the sensitivity needed to detect this noise, these calculations have made the near-impossible at least plausible. By considering how gravitons interact with a detector en masse, they have given a solid theoretical footing to the idea of graviton noise—and taken physicists one step closer to an experimental proof that deep down, gravity plays by the rules of quantum mechanics.

    The Jitter of the Wave

    Dyson’s 2013 calculation convinced many people that gravitational wave detectors were, at best, impractical probes for learning about quantum gravity.

    “There’s a kind of default consensus that it’s a waste of time to think about quantum effects and gravitational radiation,” said Frank Wilczek, a Nobel Prize-winning physicist at MIT who was a coauthor with Parikh on the new paper. Indeed, neither Wilczek, Parikh, nor George Zahariade, a cosmologist at Arizona State and the third coauthor, took the possibility seriously until after the 2015 discovery of gravitational waves by LIGO [Physical Review Letters]. “There’s nothing like actual experimental results to focus the attention,” said Wilczek.

    1
    Maulik Parikh, Frank Wilczek and George Zahariade (from left) calculated how gravitational wave detectors could find evidence for gravitons.Courtesy of Maulik Parikh; Katherine Taylor for Quanta Magazine; Ryan Rahn.

    Gravitons are thought to carry the force of gravity in a way that’s similar to how photons carry the electromagnetic force. Just as light rays can be pictured as a well-behaved collection of photons, gravitational waves—ripples in space-time created by violent cosmic processes—are thought to be made up of gravitons. With this in mind, the authors asked whether gravitational wave detectors are, in principle, sensitive enough to see gravitons. “That’s like asking, how can a surfer on a wave tell just from the motion that the wave is made up of droplets of water?” said Parikh.

    Unlike Dyson, whose broad-brush calculation focused on a single graviton, they considered the effects of many gravitons. “We were always inspired by Brownian motion,” said Parikh, referring to the random jiggle and shake of microscopic particles in a fluid. Einstein used Brownian motion to deduce the existence of atoms, which bombard the microscopic particles. In the same way, the collective behavior of many gravitons might subtly reshape a gravitational wave.

    Gravitational wave detectors can, at their simplest, be thought of as two masses separated by some distance. When a gravitational wave passes by, this distance will increase and decrease as the wave stretches and squashes the space between the masses. Add gravitons into the mix, however, and you add a new motion on top of the usual ripples in space-time. As the detector absorbs and emits gravitons, the masses randomly jitter. This is graviton noise. How big the jitter is, and thus whether it can be detected, ultimately depends on the type of gravitational wave hitting the detector.

    Gravitational fields exist in different “quantum states,” depending on how they were created. Most often, a gravitational wave is produced in a “coherent state,” which is akin to ripples on a pond. Detectors like LIGO are tuned to search for these conventional gravitational waves, which are emitted from black holes and neutron stars as they spiral around each other and collide.

    3
    Next-generation gravitational wave detectors could be made of fleets of spacecraft. The LISA Pathfinder mission, shown here being prepared for its December 2015 launch, successfully tested the technologies that would be needed for these next-gen detectors.Photograph: P. BAUDON/ESA-CNES-Arianespace/Optique Vidéo du CSG.

    ESA/LISA Pathfinder

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/NASA eLISA space based, the future of gravitational wave research

    Even coherent gravitational waves produce graviton noise, but—as Dyson also found—it’s far too small to ever measure. This is because the jitter created as the detector absorbs gravitons is “exquisitely balanced” with the jitter created when it emits gravitons, said Wilczek, who had hoped that their calculation would lead to a bigger noise for coherent states. “It was a little disappointing,” he said.

    Undeterred, Parikh, Wilczek and Zahariade examined several other types of gravitational waves that Dyson did not consider. They found that one quantum state in particular, called a squeezed state, produces a much more pronounced graviton noise. In fact, Parikh, Wilczek and Zahariade found that the noise increases exponentially the more the gravitons are squeezed.

    Their theoretical exploration suggested—against prevailing wisdom—that graviton noise is in principle observable. Moreover, detecting this noise would tell physicists about the exotic sources that might create squeezed gravitational waves. “They are thinking about it in a very serious way, and they’re approaching it in a precise language,” said Erik Verlinde, a theoretical physicist at the University of Amsterdam.

    “We always had this image that gravitons would bombard detectors in some way, and so there would be a little bit of jitter,” said Parikh. “But,” Zahariade added, “when we understood how this graviton noise term arises mathematically, it was a beautiful moment.”

    5
    Erik Verlinde has co-authored a proposal to look for graviton noise directly in the bubbling vacuum of space-time.Photograph: Ilvy Njiokiktjien/Quanta Magazine.

    The calculations were worked out over three years and are summarized in a recent paper [The Noise of Gravitons]. The paper describing the complete set of calculations is currently under peer review.

    Yet while squeezed light is routinely made in the lab—including at LIGO—it’s still unknown whether squeezed gravitational waves exist. Wilczek suspects that the final stages of black hole mergers, where gravitational fields are very strong and changing rapidly, could produce this squeezing effect. Inflation—a period in the early universe when space-time expanded very rapidly—could also lead to squeezing. The authors now plan to build precise models of these cosmological events and the gravitational waves they emit.

    “This opens the door to very difficult calculations that are going to be a challenge to carry through to the end,” said Wilczek. “But the good news is that it gets really interesting and potentially realistic as an experimental target.”

    A Hologram Shake

    Rather than looking to quantum sources in the cosmos, other physicists hope to see graviton noise directly in the bubbling vacuum of space-time, where particles fleetingly pop into existence and then disappear. As they appear, these virtual particles cause space-time to gently warp around them, creating random fluctuations known as space-time foam.

    This quantum world might seem inaccessible to experiment. But it’s not—if the universe obeys the “holographic principle,” in which the fabric of space-time emerges in the same way that a 3D hologram pops out of a 2D pattern. If the holographic principle is true, quantum particles like the graviton live on the lower-dimensional surface and encode the familiar force of gravity in higher-dimensional space-time.

    In such a scenario, the effects of quantum gravity can be amplified into the everyday world of experiments like LIGO. Recent work by Verlinde and Kathryn Zurek, a theoretical physicist at the California Institute of Technology, proposes using LIGO or another sensitive interferometer to observe the bubbling vacuum that surrounds the instrument.

    In a holographic universe, the interferometer sits in higher-dimensional space-time, which is closely wrapped in a lower-dimensional quantum surface. Adding up the tiny fluctuations across the surface creates a noise that is big enough to be detected by the interferometer. “We’ve shown that the effects due to quantum gravity are not just determined by the Planck scale, but also by [the interferometer’s] scale,” said Verlinde.

    6
    Kathryn Zurek emphasizes that it’s important for theoretical physicists to think outside the narrow range of what is conventional and acceptable, especially when unorthodox ideas can be connected to experiment. “The principles of quantum mechanics are kind of crazy when you think about it,” she said, “but it’s based on a postulate that gives rise to consequences, and so you can go and see if it describes nature.” Courtesy of Caltech.

    If their assumptions about the holographic principle hold true, graviton noise will become an experimental target for LIGO, or even for a tabletop experiment. In 2015 at the Fermi National Accelerator Laboratory, a tabletop experiment called the Holometer looked for evidence that the universe is holographic—and was found wanting. “The theoretical ideas at that time were very primitive,” said Verlinde, noting that the calculations in his paper with Zurek are grounded on the more in-depth holographic methods developed since then. If the calculations enable researchers to precisely predict what this graviton noise looks like, he thinks their odds of discovery are better—although still rather unlikely.

    Zurek and Verlinde’s approach will only work if our universe is holographic—a conjecture that is far from established. Describing their attitude as “more of a wild west mentality,” Zurek said, “It’s high risk and unlikely to succeed, but what the heck, we don’t understand quantum gravity.”

    Uncharted Territory

    By contrast, Parikh, Wilczek and Zahariade’s calculation is built on physics that few would disagree with. “We did a very conservative calculation, which is almost certainly correct,” said Parikh. “It essentially just assumes there exists something called the graviton and that gravity can be quantized.”

    But the trio acknowledge that more theoretical legwork must be done before it’s known whether current or planned gravitational wave detectors can discover graviton noise. “It would require several lucky breaks,” said Parikh. Not only must the universe harbor exotic sources that create squeezed gravitational waves, but the graviton noise must be distinguishable from the many other sources of noise that LIGO is already subject to.

    “So far, LIGO hasn’t shown any signs of physics that breaks with the predictions of Einstein’s general relativity,” said Holz, who is a member of the LIGO collaboration. “That’s where you start: General relativity is amazing.” Still, he acknowledges that gravitational wave detectors are our best hope for making new fundamental discoveries about the universe, because the terrain is “completely uncharted.”

    Wilczek argues that if researchers develop an understanding of what graviton noise might look like, gravitational wave detectors can be adjusted to improve the chances of finding it. “Naturally, people have been focusing on trying to fish out signals, and not worrying about the interesting properties of the noise,” said Wilczek. “But if you have that in mind, you would maybe design something different.” (Holz clarified that LIGO researchers have already studied some possible cosmic noise signals [Nature].)

    Despite the challenges ahead, Wilczek said he is “guardedly optimistic” that their work will lead to predictions that can be probed experimentally. In any case, he hopes the paper will spur other theorists to study graviton noise.

    “Fundamental physics is a hard business. You can famously write the whole thing on a T-shirt, and it’s hard to make additions or changes to that,” Wilczek said. “I don’t see how this is going to lead there directly, but it opens a new window on the world.

    “And then we’ll see what we see.”

    See the full article here .

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    Please help promote STEM in your local schools.

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  • richardmitnick 10:34 am on July 11, 2020 Permalink | Reply
    Tags: "Milky Way neutron star pair illuminates cosmic cataclysms", , , , , , , LIGO/VIRGO, , , The binary neutron star named PSR J1913+1102, The fast-spinning binary neutron star was discovered in 2012 by the Pulsar Arecibo L-band Feed Array (PALFA) survey at the radio telescope at Arecibo Observatory Puerto Rico.   

    From Cornell Chronicle: “Milky Way neutron star pair illuminates cosmic cataclysms” 

    From Cornell Chronicle

    July 10, 2020
    Blaine Friedlander
    bpf2@cornell.edu

    1
    A pair of binary neutron stars in the Milky Way galaxy in this illustration may give researchers insight into cataclysmic mergers. William Gonzalez/Arecibo Observatory


    NAIC Arecibo Observatory operated by University of Central Florida, Yang Enterprises and UMET, Altitude 497 m (1,631 ft).

    A pair of binary neutron stars in the Milky Way galaxy – discovered eight years ago by a pulsar survey developed at Cornell – is giving researchers a front-row seat at what they believe will be the stars’ eventual cataclysmic merger.

    Two Cornell astronomers with an international team of scientists have found that the masses of the neutron stars orbiting each other are strikingly different – so that when they eventually merge, their two masses will produce more ejecta than otherwise expected.

    The merger will be similar to the famous 2017 neutron star event, named GW170817, that produced the first observed gravitational waves and light – and featured a flurry of electromagnetic phenomena.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    “The connection is that we’re getting a chance to see this kind of binary in its baby stages,” said James Cordes, the George Feldstein Professor of Astronomy in the College of Arts and Sciences and co-author of a study on the discovery. “Observe locally and understand from afar.”

    The team’s work was published July 8 in Nature.

    In the study, radio astronomers measured the masses of the two neutron stars in the binary neutron star, named PSR J1913+1102, and concluded that they were asymmetric, Cordes said.

    As a result, the astronomers believe that when this binary neutron star merges in about a half-billion years, violent tidal forces will shred the neutron stars and eject a lot of material as it emits gravitational waves.

    They’re basing that hypothesis on the August 2017 event, when the LIGO and Virgo detectors observed gravitational waves visually and by radio telescope that were 130 million light-years away. In the final throes of merging, two neutron stars had emitted copious gravitation waves.

    “That merger event detected in 2017 was a Rosetta stone for ‘multi-messenger’ astronomy, which includes standard observations in the gamma rays, X-rays, and optical and radio bands combined with gravitational waves,” said Cordes. “The cataclysmic event featured more ejecta than expected, allowing the detailed study.”

    For radio astronomers, examining the binary neutron star is a professional treat.

    “We’re watching the whole binary evolution process long before the merger happens,” said co-author Shami Chatterjee, senior research associate in astronomy. “This gives us a front-row seat right in our own Milky Way neighborhood.”

    The fast-spinning binary neutron star was discovered in 2012 by the Pulsar Arecibo L-band Feed Array (PALFA), survey at the radio telescope at Arecibo Observatory, Puerto Rico. Cordes started PALFA in 2004, and Cornell manages the PALFA data through the university’s Center for Advanced Computing.

    The larger neutron star is 1.62 times the mass of our own sun, but all that mass fits tightly into a ball the size of a city, according to the astronomers. The smaller star is about 1.27 times the mass of the sun.

    “Seeing PSR J1913+1102 allows astronomers to calculate what neutron star mergers should look like if the masses are asymmetrical,” Chatterjee said. “We can detect the gravitational waves, spot the neutron stars and know what we’re looking for in other galaxies.”

    The lead authors of the paper, “Asymmetric Mass Ratios for Bright Double Neutron-Star Mergers,” are Robert. D. Ferdman, University of East Anglia, Norwich, England; Paulo Freire, Max Planck Institute for Radio Astronomy, Bonn, Germany; Benetge Perera, Arecibo Observatory; and Nihan Pol from West Virginia University.

    The National Science Foundation funded the Cornell portion of the research.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

    Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

    On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

     
  • richardmitnick 11:36 am on July 1, 2020 Permalink | Reply
    Tags: "Researchers find the origin and the maximum mass of massive black holes observed by gravitational wave detectors", , , , , Kavli IMPU, LIGO/VIRGO, Through simulations of a dying star a team of theoretical physics researchers have found the evolutionary origin and the maximum mass of black holes.   

    From Kavli IMPU: “Researchers find the origin and the maximum mass of massive black holes observed by gravitational wave detectors” 

    KavliFoundation

    From The Kavli Institute for the Physics and Mathematics of the Universe – Tokyo

    Kavli IPMU
    From Kavli IMPU

    June 25, 2020
    Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)

    Research contact
    Ken’ichi Nomoto
    Senior Scientist
    Kavli Institute for the Physics and Mathematics for the Universe,
    University of Tokyo
    E-mail: nomoto@astron.s.u-tokyo.ac.jp
    Phone: +81-4-7136-5940

    Media Contact
    John Amari
    Press officer
    Kavli Institute for the Physics and Mathematics of the Universe
    The University of Tokyo
    E-mail: press@ipmu.jp

    TEL: 080-4056- 2767

    Through simulations of a dying star, a team of theoretical physics researchers have found the evolutionary origin and the maximum mass of black holes which are discovered by the detection of gravitational waves as shown in Figure 1.

    The exciting detection of gravitational waves with LIGO (laser interferometer gravitational-wave observatory) and VIRGO (Virgo interferometric gravitational-wave antenna) have shown the presence of merging black holes in close binary systems.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    1
    Figure 1: Schematic diagram of the binary black hole formation path for GW170729. A star below 80 solar mass evolves and develops into a core-collapse supernova. The star does not experience pair-instability, so there is no significant mass ejection by pulsation. After the star forms a massive iron core, it collapses by its own gravity and forms a black hole with a mass below 38 solar mass. A star between 80 and 140 solar mass evolves and develops into a pulsational pair-instability supernova. After the star forms a massive carbon-oxygen core, the core experiences catastrophic electron-positron pair-creation. This excites strong pulsation and partial ejection of the stellar materials. The ejected materials form the circumstellar matter surrounding the star. After that, the star continues to evolve and forms a massive iron core, which collapses in a fashion similar to the ordinary core-collapse supernova, but with a higher final black hole mass between 38 – 52 solar mass. These two paths could explain the origin of the detected binary black hole masses of the gravitational wave event GW170729. (Credit:Shing-Chi Leung et al./Kavli IPMU)

    The masses of the observed black holes before merging have been measured and turned out to have a much larger than previously expected mass of about 10 times the mass of the Sun (solar mass). In one of such event, GW170729, the observed mass of a black hole before merging is actually as large as about 50 solar mass. But it is not clear which star can form such a massive black hole, or what the maximum of black holes which will be observed by the gravitational wave detectors is.

    To answer this question, a research team at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) consisting of Project Researcher at the time Shing-Chi Leung (currently at the California Institute of Technology), Senior Scientist Ken’ichi Nomoto, and Visiting Senior Scientist Sergei Blinnikov (professor at the Institute for Theoretical and Experimental Physics in Mosow) have investigated the final stage of the evolution of very massive stars, in particular 80 to 130 solar mass stars in close binary systems. Their finding are shown in Illustrations (a – e) and Figures (1 – 4).

    In close binary systems, initially 80 to 130 solar mass stars lose their hydrogen-rich envelope and become helium stars of 40 to 65 solar mass. When the initially 80 to 130 solar mass stars form oxygen-rich cores, the stars undergo dynamical pulsation (Illustrations a – b and Figure 2), because the temperature in the stellar interior becomes high enough for photons to be converted into electron-positron pairs. Such “pair-creation” makes the core unstable and accelerates contraction to collapse (Illustration b).

    2
    Simulation: Pulsational pair-instability supernova evolutionary process. (Credit: Shing-Chi Leung et al.)

    In the over-compressed star, oxygen burns explosively. This triggers a bounce of collapse and then rapid expansion of the star. A part of the stellar outer layer is ejected, while the inner part cools down and collapses again (Illustration c). The pulsation (collapse and expansion) repeats until oxygen is exhausted (Illustration d). This process is called “pulsational pair-instability”(PPI). The star forms an iron core and finally collapses into a black hole, which would trigger the supernova explosion (Illustration e), being called PPI-supernova (PPISN).

    3
    Figure 2: The red line shows the time evolution of the temperature and density at the center of the initially 120 solar mass star (PPISN: pulsational pair-instability supernova). The arrows show the direction of time. The star pulsates (i.e., contraction and expansion twice) by making bounces at #1 and #2 and finally collapses along a line similar to that of a 25 solar mass star (thin blue line: CCSN (core-collapse supernova)). The thick blue line shows the contraction and final expansion of the 200 solar mass star which is disrupted completely with no black hole left behind (PISN: pair-instability supernova). Top left area enclosed by the black solid line is the region where a star is dynamically unstable. (Credit:Shing-Chi Leung et al.)

    By calculating several such pulsations and associated mass ejection until the star collapses to form a black hole, the team found that the maximum mass of the black hole formed from pulsational pair-instability supernova is 52 solar mass (Figure 3).

    Stars initially more massive than 130 solar mass (which form helium stars more massive than 65 solar mass) undergo “pair instability supernova” due to explosive oxygen burning, which disrupts the star completely with no black hole remnant. Stars above 300 solar mass collapse and may form a black hole more massive than about 150 solar mass.

    The above results predict that there exists a “mass-gap” in the black hole mass between 52 and about 150 solar mass. The results mean that the 50 solar mass black hole in GW170729 is most likely a remnant of a pulsational pair-instability supernova as shown in Figures 3 and 4.

    4
    Figure 3: The red line (that connects the red simulation points) shows the mass of the black hole left after the pulsational pair-instability supernova (PPISN) against the initial stellar mass. The red and black dashed lines show the mass of the helium core left in the binary system. The red line is lower than the dashed line because some amount of mass is lost from the core by pulsational mass loss. (Pair-instability supernova, PISN, explodes completely with no remnant left.) The peak of the red line gives the maximum mass, 52 solar mass, of the black hole to be observed by gravitational waves. (Credit:Shing-Chi Leung et al.)

    5
    Figure 4: The masses of a pair of the black holes (indicated by the same color) whose merging produced gravitational waves (GW) detected by advanced LIGO and VIRGO (merger event names GW150914 to GW170823 indicate year-month-day). The box enclosed by 38 – 52 solar mass is the remnant mass range produced by PPISNe. Black hole masses falling inside this box must have an origin of PPISN before collapse. Below 38 solar mass is the black hole formed by a massive star undergoing CCSN. In addition to GW170729, GW170823 is a candidate of a PPISN in the lower mass limit side. (Credit:Shing-Chi Leung et al.)

    The result also predicts that a massive circumstellar medium is formed by the pulsational mass loss, so that the supernova explosion associated with the black hole formation will induce collision of the ejected material with the circumstellar matter to become a super-luminous supernovae. Future gravitational wave signals will provide a base upon which their theoretical prediction will be tested.

    Paper details:
    Pulsational Pair-instability Supernovae. I. Pre-collapse Evolution and Pulsational Mass Ejection
    The Astrophysical Journal

    See the full article here .

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    Stem Education Coalition

    Kavli IPMU (Kavli Institute for the Physics and Mathematics of the Universe -Tokyo) is an international research institute with English as its official language. The goal of the institute is to discover the fundamental laws of nature and to understand the Universe from the synergistic perspectives of mathematics, astronomy, and theoretical and experimental physics. The Institute for the Physics and Mathematics of the Universe (IPMU) was established in October 2007 under the World Premier International Research Center Initiative (WPI) of the Ministry of Education, Sports, Science and Technology in Japan with the University of Tokyo as the host institution. IPMU was designated as the first research institute within the University of Tokyo Institutes for Advanced Study (UTIAS) in January 2011. It received an endowment from The Kavli Foundation and was renamed the “Kavli Institute for the Physics and Mathematics of the Universe” in April 2012. Kavli IPMU is located on the Kashiwa campus of the University of Tokyo, and more than half of its full-time scientific members come from outside Japan. http://www.ipmu.jp/

    The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

     
  • richardmitnick 4:54 pm on June 18, 2020 Permalink | Reply
    Tags: "Scientists reveal a lost eight billion light years of universe evolution", , It's likely there are another 2 million gravitational wave events from merging black holes., LIGO/VIRGO, , , , The further away we see the gravitational waves from these mergers the younger the Universe was when they formed., We may be able to look more than 8 billion light years further than we are currently observing.   

    From ARC Centres of Excellence via phys.org: “Scientists reveal a lost eight billion light years of universe evolution” 

    arc-centers-of-excellence-bloc

    From ARC Centres of Excellence

    via
    phys.org

    1
    Artistic impression of the background hum of gravitational waves permeating the Universe. Credit: Carl Knox, OzGrav/Swinburne University of Technology

    Last year, the Advanced LIGO-VIRGO gravitational-wave detector network recorded data from 35 merging black holes and neutron stars.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    A great result—but what did they miss? According to Dr. Rory Smith from the ARC Centre of Excellence in Gravitational Wave Discovery at Monash University in Australia—it’s likely there are another 2 million gravitational wave events from merging black holes, “a pair of merging black holes every 200 seconds and a pair of merging neutron stars every 15 seconds” that scientists are not picking up.

    Dr. Smith and his colleagues, also at Monash University, have developed a method to detect the presence of these weak or “background” events that to date have gone unnoticed, without having to detect each one individually.The method—which is currently being test driven by the LIGO community—”means that we may be able to look more than 8 billion light years further than we are currently observing,” Dr. Smith said.

    “This will give us a snapshot of what the early universe looked like while providing insights into the evolution of the universe.”

    The paper, recently published in the MNRAS, details how researchers will measure the properties of a background of gravitational waves from the millions of unresolved black hole mergers.

    Binary black hole mergers release huge amounts of energy in the form of gravitational waves and are now routinely being detected by the Advanced LIGO-Virgo detector network. According to co-author, Eric Thrane from OzGrav-Monash, these gravitational waves generated by individual binary mergers “carry information about spacetime and nuclear matter in the most extreme environments in the Universe. Individual observations of gravitational waves trace the evolution of stars, star clusters, and galaxies,” he said.

    1
    Artistic impression of the background hum of gravitational waves permeating the Universe. Credit: Carl Knox, OzGrav/Swinburne University of Technology.

    “By piecing together information from many merger events, we can begin to understand the environments in which stars live and evolve, and what causes their eventual fate as black holes. The further away we see the gravitational waves from these mergers, the younger the Universe was when they formed. We can trace the evolution of stars and galaxies throughout cosmic time, back to when the Universe was a fraction of its current age.”

    The researchers measure population properties of binary black hole mergers, such as the distribution of black hole masses. The vast majority of compact binary mergers produce gravitational waves that are too weak to yield unambiguous detections—so vast amounts of information is currently missed by our observatories.

    “Moreover, inferences made about the black hole population may be susceptible to a ‘selection bias’ due to the fact that we only see a handful of the loudest, most nearby systems. Selection bias means we might only be getting a snapshot of black holes, rather than the full picture,” Dr. Smith warned.

    The analysis developed by Smith and Thrane is being tested using real world observations from the LIGO-VIRGO detectors with the program expected to be fully operational within a few years, according to Dr. Smith.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The objectives for the ARC Centres of Excellence are to to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
    develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
    offer Australian researchers opportunities to work on large-scale problems over long periods of time
    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

     
  • richardmitnick 11:37 am on March 27, 2020 Permalink | Reply
    Tags: , , , , , , , , LIGO/VIRGO   

    From AAS NOVA: ” Signals from Neutron Star Binaries” 

    AASNOVA

    From AAS NOVA

    27 March 2020
    Tarini Konchady

    1
    Artist’s illustration of a binary star system consisting of two highly magnetized neutron stars. [John Rowe Animations]

    Fast radio bursts (FRBs) are brief radio signals that last on the order of milliseconds. They appear to be extragalactic, coming from small, point-like areas on the sky. Some FRBs are one-off events, while others are periodic or “repeating”. The sources of FRBs are still unknown, but binary neutron star systems might be a piece of the puzzle.

    Wanted: A Reliable Source of Repeating Fast Radio Bursts

    Any proposed model for a repeating FRB must explain a number of observed behaviors. Among them are the following:

    Repeating bursts from a given FRB source are consistent in frequency and overall intensity on the timescale of years.
    Bursts exhibit small-scale variations in measures of the source’s magnetic environment.
    FRBs seem to be preferentially hosted in massive, Milky-Way-like galaxies.

    2
    Example of an FRB from a repeating source, showing the intensity and various frequencies contained in a single burst (darker means more intense, lighter means less intense). The red lines just below and above 550 MHz and those near 450 MHz and 650 MHz indicate frequencies that were unused due to other radio signals interfering [adapted from the CHIME/FRB Collaboration, Andersen et al. 2019].

    CHIME Canadian Hydrogen Intensity Mapping Experiment -A partnership between the University of British Columbia, the University of Toronto, McGill University, Yale and the National Research Council in British Columbia, at the Dominion Radio Astrophysical Observatory in Penticton, British Columbia, CA Altitude 545 m (1,788 ft)

    Binary neutron stars (BNSs) have been considered as possible solutions to the repeating FRB puzzle. Specifically, binary neutron star mergers might produce FRBs, along with gamma-ray bursts and gravitational waves. But how could BNSs produce repeating, consistent FRBs?

    In a recent study, Bing Zhang (University of Nevada Las Vegas; Kyoto University, Japan) attempts to explain repeating FRBs using BNSs in a novel way. Instead of considering the neutron-star merger itself, Zhang examined whether the years leading up to the merger could produce repeating FRBs.

    A Magnetic Dance

    Repeating FRBs put out an enormous amount of energy over a few milliseconds — at least as much energy as the Sun puts out over three days. To put constraints on the average FRB-producing BNS, Zhang used the double-pulsar system PSR J0737-3039A/B (pulsars are fast-rotating neutron stars with strong magnetic fields), which is very well characterized in terms of its component stars and overall structure.

    Aside from having enormous amounts of rotational energy intrinsically and in their orbits, BNSs also have strong magnetic fields. These magnetic fields are key to the production of FRBs in Zhang’s scenario — as the neutron stars orbit each other, their magnetic fields interact, possibly triggering a flow of particles that would produce FRBs.

    On the scale of centuries or even decades pre-merger, these triggers could occur repeatedly and consistently, satisfying a key requirement for repeating FRBs. This picture of interacting magnetic fields would also explain the small-scale variations in the magnetic environment measures, and there is an overlap between the sorts of galaxies that host FRBs and those that host the gamma-ray bursts that could be associated with BNS mergers.

    By Way of Gravitational Waves

    An observational test for this scenario is the detection of gravitational waves from an FRB source. Space-based gravitational wave detectors, such as the Laser Interferometer Space Antenna, would be well-suited for this.

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/NASA eLISA space based, the future of gravitational wave research

    Ground-based detectors would also play a role, picking up waves from the BNSs actually merging.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    And of course, the more FRBs we observe, the more we can narrow down their properties and sources. Fortunately, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is predicted to detect 2 to 50 FRBs per day, and other radio telescopes are hard at work as well. So maybe this FRB mystery will be solved sooner than we think!

    Citation

    “Fast Radio Bursts from Interacting Binary Neutron Star Systems,” Bing Zhang 2020 ApJL 890 L24.

    https://iopscience.iop.org/article/10.3847/2041-8213/ab7244

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 9:51 am on October 1, 2019 Permalink | Reply
    Tags: "Here's How Gravitational Wave Detectors Might Be Able to Detect Dark Matter Particles", , , , LIGO/VIRGO   

    From Curiosity: “Here’s How Gravitational Wave Detectors Might Be Able to Detect Dark Matter Particles” 

    Curiosity Makes You Smarter

    From From Curiosity

    September 27, 2019
    Matt Williams

    The field of astronomy has been revolutionized thanks to the first-ever detection of gravitational waves (GWs). Since the initial detection was made in February of 2016 by scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO), multiple events have been detected. These have provided insight into a phenomenon that was predicted over a century ago by Albert Einstein.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    As it turns out, the infrastructure that is used to detect GWs could also help crack another astronomical mystery: dark matter! According to a new study by a team of Japanese researchers, laser interferometers could be used to look for weakly interacting massive particles (WIMPs), a major candidate particle in the hunt for dark matter.

    To recap, WIMPS are a theoretical elementary particle that interacts with normal matter (baryonic) only through weak interaction. As with other elementary particles that are part of the Standard Model (of which WIMPS are not), they would have been created during the early universe when the cosmos was extremely hot.

    WIMPs are essentially the microscopic candidate particle, which puts them at the opposite end of the spectrum from the other major candidate — the macroscopic Massive Compact Halo Objects (MACHOs). So far, multiple experiments have been conducted to find these particles — ranging from particle collisions and indirect detections to more direct methods — but the results have been largely inconclusive.

    As Dr. Satoshi Tsuchida, a postdoctoral physics researcher at Osaka City University and the lead author of the study (which recently appeared online [above]), told Universe Today via email:

    “Most MACHOs are believed to consist of baryonic matter, but baryons account for only 5 percent of the universe. Thus, we cannot explain the structure of the present universe if all of dark matter consists of MACHOs. On the other hand, WIMPs are non-baryonic matter and we have no reason to exclude [them] from dark matter… Therefore, WIMPs can be promising dark matter candidates.”

    For the sake of their study, the research team (which includes members hail Osaka University’s Nambu Yoichiro Institute of Theoretical and Experimental Physics and Ritsumeikan University) propose a new search method that takes advantage of recent advances in gravity wave detection. Using the same method to detect ripples in spacetime, they argue that WIMPs could also be detected for the first time.

    This would constitute a “direct detection” approach using laser interferometers, a method that has been proposed in the past. However, this method has not yet been tested, in part because scientists have not yet calculated what kinds of signals will be caused by direct interactions between WIMPs and nucleons in a laser interferometer’s mirror.

    However, the research team argues that the motions of a pendulum and mirror in a GW detector will become excited due to a collision. The research team analyzed these motions and estimated how detectable they would be to a system of highly sophisticated sensors, like those used by LIGO and other GW detectors.

    From this, the team was able to provide a framework which could come in handy for future research. “Thus, our method might [provide] some new knowledge for dark matter [research],” said Dr. Satoshi. “The next-generation GW detectors have better sensitivity than current-generation ones, so the signal to noise ratio would be improved by some orders of magnitude.”

    “If we can establish a method to extract the dark matter signals on GW detector, the method could play [an] important role to elucidate the nature of WIMPs by [an] independent approach,” he added. “Thus, our study might help in revealing the structure of the universe not only at present, but also in the past and future.”

    These include the Kamioka Gravitational wave detector, Large-scale Cryogenic Gravitational wave Telescope (KAGRA) in Japan — which is currently being upgraded — and the Einstein Telescope (ET), a third-generation European detector that is still in the design phase.


    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan

    Depiction of the ASPERA Albert Einstein Telescope, Albert Einstein Institute Hannover and Max Planck Institute for Gravitational Physics and Leibniz Universitat Hannover

    When these come online and join LIGO and the Virgo observatory (in Italy), they will allow for an unprecedented rate of detection.

    This is not the first time that scientists have suggested other applications for GW research. For instance, an international team of scientists recently proposed that GWs could be used to study dwarf galaxies, in the hopes of seeing how they are dominated by dark matter. Another proposal is using GWs to measure the expansion rate of the universe — a method that could tell us a great deal about the nature and influence of dark energy!

    A mysterious astronomical force, one which was only recently confirmed, that could lead to a new understanding about two of the greatest cosmological mysteries! What a time to be alive!

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 11:04 am on September 30, 2019 Permalink | Reply
    Tags: "Stanford experiment harnesses atoms to detect gravitational waves", An atom interferometer a custom-built device designed to study the wave nature of atoms, ‘Tabletop’ experiments, , Detecting gravitational waves, , LIGO/VIRGO, MAGIS-100,   

    From Stanford University: “Stanford experiment harnesses atoms to detect gravitational waves” 

    Stanford University Name
    From Stanford University

    September 25, 2019
    Erin I. Garcia De Jesus

    Hidden deep in a basement at Stanford stands a 10-meter-tall tube, wrapped in a metal cage and draped in wires. A barrier separates it from the main room, beyond which the cylinder spans three stories to an apparatus holding ultra-cold atoms ready to shoot upward. Tables stocked with lasers to fire at the atoms – and analyze how they respond to forces such as gravity – fill the rest of the laboratory.

    The tube is an atom interferometer, a custom-built device designed to study the wave nature of atoms. According to quantum mechanics, atoms exist simultaneously as particles and waves. The Stanford instrument represents a model for an ambitious new instrument ten times its size that could be deployed to detect gravitational waves – minute ripples in spacetime created by energy dissipating from moving astronomical objects. The instrument also could shed light on another mystery of the universe: dark matter.

    Stanford experimental physicists Jason Hogan and Mark Kasevich never intended for their device to be implemented this way. When Hogan began his graduate studies in Kasevich’s lab, he focused instead on testing gravity’s effects on atoms. But conversations with theoretical physicist Savas Dimopoulos, a professor of physics, and his graduate students – often lured downstairs by an espresso machine housed directly across the hall from Kasevich’s office – led them to start thinking about its utility as a highly sensitive detector.

    “We were just talking physics, as physicists often do,” says Kasevich, a professor of physics and applied physics at Stanford’s School of Humanities and Sciences. One thing led to another and the group landed on a bold plan for creating an atom interferometer capable of detecting gravitational waves that no one has seen before.

    Their idea fits into another wave sweeping through physics, one that involves co-opting exquisitely sensitive instruments developed for other purposes to answer fundamental questions about nature.

    1
    Physicists Jason Hogan and Mark Kasevich are developing a smaller-scale technique for measuring gravitational waves. (Image credit: L.A. Cicero)

    A new detection method

    In 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a brief signal from a 1.3 billion-year-old collision between two supermassive black holes. Since then, LIGO has catalogued more gravitational waves passing through Earth, providing astronomers with a powerful new lens with which to study the universe.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Gravitational waves are ripples in space-time, much like ocean waves – except they distort space, not water. In theory, any accelerating mass, whether a waving hand or an orbiting planet, produces gravitational waves. These movements, however, occur at levels far below our ability to detect them. Only gravitational waves from immense astronomical phenomena cause large enough shifts in space-time that they can be recognized by sensors on Earth.

    Just as different frequencies make up the electromagnetic spectrum, gravitational waves also vary. LIGO and other current gravitational wave detectors sense a very narrow range – high-frequency waves such as those from the moment two black holes collide – but other parts of the gravitational wave spectrum remain unexplored. And just as astronomers can learn new things about a star by studying its ultraviolet light versus its visible light, analyzing data from other gravitational wave frequencies could help solve mysteries of space that are currently out of reach, including those about the early universe.

    “We identified a region of the spectrum that wasn’t well-covered by any other detector, and it happened to be a match for the methods that we were already developing,” said Hogan, an assistant professor of physics in the School of Humanities and Sciences.

    During Hogan’s graduate studies, he and his colleagues constructed the 10-meter-tall atom interferometer to test some of their ideas. However, in order to increase the sensitivity of the device – necessary to detect space-time wiggles smaller than the width of a proton – they need a bigger detector. And thus the 100-meter Matter-wave Atomic Gradiometer Interferometric Sensor, or MAGIS-100, experiment was born.

    2

    With help from a $9.8 million grant from the Gordon and Betty Moore Foundation, scientists plan to make an existing underground shaft at Fermilab, a Department of Energy National Laboratory in Illinois, MAGIS-100’s new home.

    “You can find holes in the ground, but it’s kind of hard to find a hole in the ground with a lab attached to it,” said Rob Plunkett, a senior scientist at Fermilab involved with the project.

    Conceptually, MAGIS-100 will work similar to LIGO. Both experiments harness light to measure the distance between two test masses, much like radar ranging. But while LIGO has mirrors, MAGIS-100 favors atoms.

    “The atom turns out to be an amazing test mass for these purposes,” said Hogan. “We have very powerful techniques for manipulating it and allowing it to be insensitive to all the background sources of noise.”

    LIGO’s mirrors hang on glass threads, meaning that an earthquake could set off its sensors. MAGIS-100, on the other hand, has measures in places to prevent such sources of extraneous noise from affecting its data.

    After being cooled to a fraction of a degree above absolute zero, the atoms are dropped vertically into the shaft like dripping water droplets from a faucet. The frigid temperature puts the atoms into a state of rest, so they remain still as they fall, and because the shaft is a vacuum, the atoms plummet without risk of veering off course. The shaft’s vertical orientation also ensures that a shaking Earth won’t affect the measurements.

    Lasers then manipulate the falling atoms and the team can measure how long they are in an excited state. Hogan and Kasevich hope to employ strontium as their test mass – the same element used in atomic clocks – to determine whether there are any time delays when light excites atoms. A delay would suggest a gravitational wave passed through.

    In addition, MAGIS-100 scientists can use the atomic data to test predictions made by dark matter models. According to some models, the presence of dark matter could lead to variations in atomic energy levels. The supersensitive laser technology allows Plunkett and collaborators to look for these variations.

    Looking toward space

    MAGIS-100 is a prototype, another step toward building an even larger device that would be many times more sensitive. Hogan and Kasevich said they envision one day building something on the scale of LIGO, which is 4-kilometers long.

    Because a future full-scale MAGIS-100 should detect low-frequency gravitational waves around 1 Hertz, such as those emitting from two black holes orbiting around each other, it could identify the same events that LIGO has already seen, but before the masses actually collide. The two experiments could thus complement one another.

    “We could make a detector that could see the same system, but much, much younger,” said Hogan.

    Advanced MAGIS-style detectors might also find sources of gravitational waves that fly under LIGO’s radar. Primordial gravitational waves, for example, produced moments after the Big Bang.

    “Detecting gravitational waves that originated from the early universe can shed light on what actually happened,” said Kasevich.

    No one knows the frequencies of these primordial gravitational waves or whether the future large-scale detector can pick them up. Hogan said that he believes as many detectors as possible should be built in order to cover a broad range of frequencies and simply see what is out there.

    “The known sources that are exciting are these LIGO-like sources,” said Hogan. “Then there are the unknown, which we should be open to as well.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    Stanford University campus. No image credit

    Stanford University

    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

    Stanford University Seal

     
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