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  • richardmitnick 9:51 am on December 26, 2021 Permalink | Reply
    Tags: "RESEARCH HIGHLIGHT: A new approach to rapidly localise gravitational waves", , , Multimessenger astronomy, ,   

    From The ARC Centres of Excellence for Gravitational Wave Discovery – OzGrav (AU) : “RESEARCH HIGHLIGHT: A new approach to rapidly localise gravitational waves” 

    arc-centers-of-excellence-bloc

    From The ARC Centres of Excellence for Gravitational Wave Discovery – OzGrav (AU)

    1
    Artist’s illustration of a black hole and neutron star orbiting each other and about to merge, by Carl Knox, OzGrav-The Swinburne University of Technology (AU).

    Multimessenger astronomy is an emerging field which aims to study astronomical objects using different ‘messengers’ or sources, like electromagnetic radiation (light), neutrinos and gravitational waves. This field gained enormous recognition after the joint detection of gravitational waves and gamma ray bursts in 2017.
    ________________________________________________________________________________
    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.
    ________________________________________________________________________________

    Gravitational waves can be used to identify the sky direction of an event in space and alert conventional telescopes to follow-up for other sources of radiation. However, following up on prompt emissions would require a rapid and accurate localisation of such events, which will be key for joint observations in the future.

    The conventional method to accurately estimate the sky direction of gravitational waves is tedious—taking a few hours to days—while a faster online version needs only seconds. There is an emerging capacity from the LIGO-Virgo collaboration to detect gravitational waves from electromagnetic-bright binary coalescences, tens of seconds before their final merger, and provide alerts across the world. The goal is to coordinate prompt follow up observations with other telescopes around the globe to capture potential electromagnetic flashes within minutes from the mergers of two neutron stars, or a neutron star with a black hole—this was not possible before. The University of Western Australia (AU)‘s SPIIR team is one of the world leaders in this area of research. Determining sky directions within seconds of a merger event is crucial,as most telescopes need to know where to point in the sky. In our recently accepted paper [Physical Review D], led by three visiting students (undergraduate and Masters by research) at the OzGrav-UWA node, we applied analytical approximations to greatly reduce the computational time of the conventional localisation method while maintaining its accuracy. A similar semi-analytical approach has also been published in another recent study [Physical Review D].

    The results from this work show great potential and will be integrated into the SPIIR online pipeline going forward in the next observing run. We hope that this work complements other methods from the LIGO-Virgo collaboration and that it will be part of some exciting discoveries.

    See the full article here .

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    OzGrav (AU)


    The ARC Centres of Excellence for Gravitational Wave Discovery OzGrav (AU)
    A new window of discovery.
    A new age of gravitational wave astronomy.
    One hundred years ago, Albert Einstein produced one of the greatest intellectual achievements in physics, the theory of general relativity. In general relativity, spacetime is dynamic. It can be warped into a black hole. Accelerating masses create ripples in spacetime known as gravitational waves (GWs) that carry energy away from the source. Recent advances in detector sensitivity led to the first direct detection of gravitational waves in 2015. This was a landmark achievement in human discovery and heralded the birth of the new field of gravitational wave astronomy. This was followed in 2017 by the first observations of the collision of two neutron-stars. The accompanying explosion was subsequently seen in follow-up observations by telescopes across the globe, and ushered in a new era of multi-messenger astronomy.

    The mission of The ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) is to capitalise on the historic first detections of gravitational waves to understand the extreme physics of black holes and warped spacetime, and to inspire the next generation of Australian scientists and engineers through this new window on the Universe.

    OzGrav is funded by the Australian Government through the Australian Research Council Centres of Excellence funding scheme, and is a partnership between Swinburne University of Technology (AU) (host of OzGrav headquarters), the Australian National University (AU), Monash University (AU), University of Adelaide (AU), University of Melbourne (AU), and University of Western Australia (AU), along with other collaborating organisations in Australia and overseas.
    ________________________________________________________

    The objectives for the The ARC Centres of Excellence are 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 10:44 am on December 18, 2021 Permalink | Reply
    Tags: "Gravitational wave scientists set their sights on dark matter", , , , , , , , , Multimessenger astronomy, Scalar field   

    From Cardiff University [Prifysgol Caerdydd] (WLS) : “Gravitational wave scientists set their sights on dark matter” 

    From Cardiff University [Prifysgol Caerdydd] (WLS)

    15 December 2021

    1
    ( H. Lueck. MPG Institute for Gravitational Physics [Max-Planck-Institut für Gravitationsphysik] (Albert Einstein Institute) (DE))

    2
    Fig. 1: A typical amplitude spectrum produced with frequency bins that are tuned to the expected dark matter linewidth using the modified LPSD technique. The black line indicates the amplitude spectrum. The noise spectrum was estimated at each frequency bin from neighboring bins to yield the local noise median (blue) and 95% confidence level (CL, green). Peaks (red) above this confidence level were considered candidates for dark matter signals and analyzed further. Credit: Nature via phys.org .

    The technologies behind one of the biggest scientific breakthroughs of the century – the detection of gravitational waves – are now being used in the long-standing search for Dark Matter.

    Thought to make up roughly 85% of all matter in the Universe, dark matter has never been observed directly and remains one of the biggest unsolved mysteries in modern physics.
    ______________________________________________________
    Dark Matter Background
    Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

    Fritz Zwicky.

    Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.

    In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

    Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

    Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

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

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

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

    Dark Matter Research

    LBNL LZ Dark Matter Experiment (US) xenon detector at Sanford Underground Research Facility(US) Credit: Matt Kapust.

    Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes. Credit: Alex Mittelmann.

    DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

    Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

    DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine

    The LBNL LZ Dark Matter Experiment (US) Dark Matter project at SURF, Lead, SD, USA.

    DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

    DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at the University of Zurich.

    PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

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

    With extremely sensitive detectors now at their disposal, already proven through several outstanding discoveries, scientists believe that existing gravitational wave technology has the true potential to finally discover the exotic material and even find out what it is made of.

    In a study published today in Nature, a team led by scientists from Cardiff University’s Gravity Exploration Institute has taken the first step towards this goal by using the instruments, known as laser interferometers, to look for a new kind of dark matter for the very first time.

    Until recently, it was widely believed that dark matter was composed of heavy elementary particles.

    These were not discovered despite a multitude of efforts, and scientists are now turning to alternative theories to explain dark matter.

    A recent theory says that dark matter is actually something called a scalar field, which would behave as invisible waves bouncing around galaxies, including our own Milky Way.

    “We realised our instruments could be used to hunt for this new kind of dark matter, although they were initially designed for detecting gravitational waves,’’ said Professor Hartmut Grote, from Cardiff University’s Gravity Exploration Institute, who instigated the investigation.

    Within a laser interferometer, two beams of light are bounced between mirrors before meeting up on a detector. From this, scientists can gauge with great accuracy how out of sync the beams of light are with each other, which is itself proxy for any disturbance the beams encounter.

    The Laser Interferometer Gravitational-Wave Observatory (LIGO) consists of two interferometers located in the US, each with two 4 km long arms arranged in the shape of an “L”, which were used to detect gravitational waves for the very first time in 2015, and many times since.
    _____________________________________________________________________________________
    LIGOVIRGOKAGRA

    Caltech /MIT Advanced aLigo

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

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    KAGRA Large-scale Cryogenic Gravitational Wave Telescope Project (JP)
    _____________________________________________________________________________________

    LIGO Virgo Kagra Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University(US)

    The UK/German GEO 600 detector in Germany, where Grote was lead scientist from 2009 to 2017, is another highly sensitive interferometer and was used to develop much of the technology needed to detect gravitational waves.

    3
    GEO600 | Max Planck Institute for Gravitational Physics (Albert Einstein Institute)(DE)

    The GE0600 detector was used, for the very first time, in this study to search specifically for dark matter.

    “Scalar field dark matter waves would pass right through the Earth and our instruments, but as they do so, would cause objects such as mirrors to vibrate ever so slightly,’’ said lead investigator Sander Vermeulen, also from Cardiff University’s Gravity Exploration Institute.

    “Vibrations of mirrors would disturb the beams of light in instruments like GEO600 or the LIGO detectors in a particular way characteristic of dark matter, which is something we should be able to detect, depending on the exact properties of that dark matter.”

    Even though dark matter has never been directly detected, scientists suspect it exists due to its gravitational effect on objects across the Universe. For example, a large amount of unseen matter may explain why galaxies rotate as they do, and how they could have formed in the first place.

    Though the team were unsuccessful in making any sort of detection in this new study, they say they are making important first strides in terms of introducing this technology to dark matter searches and have already made progress in terms of narrowing down certain parameters for future studies.

    “I was surprised by how sensitive an instrument can be for hunting dark matter when it was built for an entirely different purpose originally,” continued Professor Grote.

    “We have definitively ruled out some theories that say dark matter has certain properties, so future searches now have a better idea of what to look for,” said Vermeulen.

    “We believe these new techniques have the true potential to discover dark matter at some point in the future.”

    See the full article here .


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    Cardiff Unversity [Prifysgol Caerdydd] (WLS) is a public research university in Cardiff, Wales. Founded in 1883 as the University College of South Wales and Monmouthshire (University College Cardiff from 1972), it became a founding college of the University of Wales in 1893. It merged with the University of Wales Institute of Science and Technology (UWIST) in 1988 to form the University of Wales College, Cardiff (University of Wales, Cardiff from 1996). In 1997 it received its own degree-awarding powers, but held them in abeyance. The college adopted the public name Cardiff University in 1999; in 2005 this became its legal name, when it became an independent university and began awarding its own degrees.

    Cardiff University is the third oldest university in Wales and contains three colleges: Arts, Humanities and Social Sciences; Biomedical and Life Sciences; and Physical Sciences and Engineering. It is the only Welsh member of the Russell Group of research-intensive British universities. In 2018–2019, Cardiff had a turnover of £537.1 million, including £116.0 million in research grants and contracts. It has an undergraduate enrolment of 23,960 and a total enrolment of 33,190 (according to HESA data for 2018/19) making it one of the ten largest UK universities. The Cardiff University Students’ Union works to promote student interests in the university and further afield.

    Discussions on the founding of a university college in South Wales began in 1879, when a group of Welsh and English MPs urged the government to consider the poor provision of higher and intermediate education in Wales and “the best means of assisting any local effort which may be made for supplying such deficiency.”

    In October 1881, William Gladstone’s government appointed a departmental committee to conduct “an enquiry into the nature and extent of intermediate and higher education in Wales”, chaired by Lord Aberdare and consisting of Viscount Emlyn, Reverend Prebendary H. G. Robinson, Henry Richard, John Rhys and Lewis Morris. The Aberdare Report, as it came to be known, took evidence from a wide range of sources and over 250 witnesses and recommended a college each for North Wales and South Wales, the latter to be located in Glamorgan and the former to be the established University College of Wales in Aberystwyth (now Aberystwyth University). The committee cited the unique Welsh national identity and noted that many students in Wales could not afford to travel to University in England or Scotland. It advocated a national degree-awarding university for Wales, composed of regional colleges, which should be non-sectarian in nature and exclude the teaching of theology.

    After the recommendation was published, Cardiff Corporation sought to secure the location of the college in Cardiff, and on 12 December 1881 formed a University College Committee to aid the matter. There was competition to be the site between Swansea and Cardiff. On 12 March 1883, after arbitration, a decision was made in Cardiff’s favour. This was strengthened by the need to consider the interests of Monmouthshire, at that time not legally incorporated into Wales, and the greater sum received by Cardiff in support of the college, through a public appeal that raised £37,000 and a number of private donations, notably from the Lord Bute and Lord Windsor. In April Lord Aberdare was appointed as the College’s first president. The possible locations considered included Cardiff Arms Park, Cathedral Road, and Moria Terrace, Roath, before the site of the Old Royal Infirmary buildings on Newport Road was chosen.

    The University College of South Wales and Monmouthshire opened on 24 October 1883 with courses in Biology, Chemistry, English, French, German, Greek, History, Latin, Mathematics and Astronomy, Music, Welsh, Logic and Philosophy, and Physics. It was incorporated by Royal Charter the following year, this being the first in Wales to allow the enrollment of women, and specifically forbidding religious tests for entry. John Viriamu Jones was appointed as the University’s first Principal at the age of 27. As Cardiff was not an independent university and could not award its own degrees, it prepared its students for examinations of the University of London or for further study at Oxford or Cambridge.

    In 1888 the University College at Cardiff and that of North Wales (now Bangor University) proposed to the University College Wales at Aberystwyth joint action to gain a university charter for Wales, modelled on that of Victoria University, a confederation of new universities in Northern England. Such a charter was granted to the new University of Wales in 1893, allowing the colleges to award degrees as members. The Chancellor was set ex officio as the Prince of Wales, and the position of operational head would rotate among heads of the colleges.

    In 1885, Aberdare Hall opened as the first hall of residence, allowing women access to the university. This moved to its current site in 1895, but remains a single-sex hall. In 1904 came the appointment of the first female associate professor in the UK, Millicent Mackenzie, who in 1910 became the first female full professor at a fully chartered UK university.

    In 1901 Principal Jones persuaded Cardiff Corporation to give the college a five-acre site in Cathays Park (instead of selling it as they would have done otherwise). Soon after, in 1905, work on a new building commenced under the architect W. D. Caröe. Money ran short for the project, however. Although the side-wings were completed in the 1960s, the planned Great Hall has never been built. Caroe sought to combine the charm and elegance of his former (Trinity College, Cambridge) with the picturesque balance of many Oxford colleges. On 14 October 1909 the “New College” building in Cathays Park (now Main Building) was opened in a ceremony involving a procession from the “Old College” in Newport Road.

    In 1931, the School of Medicine, founded as part of the college in 1893 along with the Departments of Anatomy, Physiology, Pathology, Pharmacology, was split off to form the Welsh National School of Medicine, which was renamed in 1984 the University of Wales College of Medicine.

    In 1972, the institution was renamed University College Cardiff.

     
  • richardmitnick 12:53 pm on December 10, 2021 Permalink | Reply
    Tags: "Gravitational Waves Should Permanently Distort Space-Time", , , , , , , , Multimessenger astronomy,   

    From Quanta Magazine (US) : “Gravitational Waves Should Permanently Distort Space-Time” 

    From Quanta Magazine (US)

    December 8, 2021
    Katie McCormick

    1
    A black hole collision should forever scar space-time. Credit: Alfred Pasieka / Science Source.

    The first detection of gravitational waves in 2016 provided decisive confirmation of Einstein’s general theory of relativity. But another astounding prediction remains unconfirmed: According to general relativity, every gravitational wave should leave an indelible imprint on the structure of space-time. It should permanently strain space, displacing the mirrors of a gravitational wave detector even after the wave has passed.

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

    Since that first detection almost six years ago, physicists have been trying to figure out how to measure this so-called “memory effect.”

    “The memory effect is absolutely a strange, strange phenomenon,” said Paul Lasky, an astrophysicist at Monash University (AU). “It’s really deep stuff.”

    Their goals are broader than just glimpsing the permanent space-time scars left by a passing gravitational wave. By exploring the links between matter, energy and space-time, physicists hope to come to a better understanding of Stephen Hawking’s black hole information paradox, which has been a major focus of theoretical research for going on five decades. “There’s an intimate connection between the memory effect and the symmetry of space-time,” said Kip Thorne, a physicist at The California Institute of Technology (US) whose work on gravitational waves earned him part of the 2017 Nobel Prize in Physics. “It is connected ultimately to the loss of information in black holes, a very deep issue in the structure of space and time.”

    A Scar in Space-Time

    Why would a gravitational wave permanently change space-time’s structure? It comes down to general relativity’s intimate linking of space-time and energy.

    First consider what happens when a gravitational wave passes by a gravitational wave detector. The Laser Interferometer Gravitational-Wave Observatory (LIGO) has two arms positioned in an L shape [see Livingstone, LA installation above]. If you imagine a circle circumscribing the arms, with the center of the circle at the arms’ intersection, a gravitational wave will periodically distort the circle, squeezing it vertically, then horizontally, alternating until the wave has passed. The difference in length between the two arms will oscillate — behavior that reveals the distortion of the circle, and the passing of the gravitational wave.

    According to the memory effect, after the passing of the wave, the circle should remain permanently deformed by a tiny amount. The reason why has to do with the particularities of gravity as described by general relativity.

    The objects that LIGO detects are so far away, their gravitational pull is negligibly weak. But a gravitational wave has a longer reach than the force of gravity. So, too, does the property responsible for the memory effect: the gravitational potential.

    In simple Newtonian terms, a gravitational potential measures how much energy an object would gain if it fell from a certain height. Drop an anvil off a cliff, and the speed of the anvil at the bottom can be used to reconstruct the “potential” energy that falling off the cliff can impart.

    But in general relativity, where space-time is stretched and squashed in different directions depending on the motions of bodies, a potential dictates more than just the potential energy at a location — it dictates the shape of space-time.

    “The memory is nothing but the change in the gravitational potential,” said Thorne, “but it’s a relativistic gravitational potential.” The energy of a passing gravitational wave creates a change in the gravitational potential; that change in potential distorts space-time, even after the wave has passed.

    How, exactly, will a passing wave distort space-time? The possibilities are literally infinite, and, puzzlingly, these possibilities are also equivalent to one another. In this manner, space-time is like an infinite game of Boggle. The classic Boggle game has 16 six-sided dice arranged in a four-by-four grid, with a letter on each side of each die. Each time a player shakes the grid, the dice clatter around and settle into a new arrangement of letters. Most configurations are distinguishable from one another, but all are equivalent in a larger sense. They are all at rest in the lowest-energy state that the dice could possibly be in. When a gravitational wave passes through, it shakes the cosmic Boggle board, changing space-time from one wonky configuration to another. But space-time remains in its lowest-energy state.

    Super Symmetries

    That characteristic — that you can change the board, but in the end things fundamentally stay the same — suggests the presence of hidden symmetries in the structure of space-time. Within the past decade, physicists have explicitly made this connection.

    The story starts back in the 1960s, when four physicists wanted to better understand general relativity. They wondered what would happen in a hypothetical region infinitely far from all mass and energy in the universe, where gravity’s pull can be neglected, but gravitational radiation cannot. They started by looking at the symmetries this region obeyed.

    They already knew the symmetries of the world according to special relativity, where space-time is flat and featureless. In such a smooth world, everything looks the same regardless of where you are, which direction you’re facing, and the speed at which you’re moving. These properties correspond to the translational, rotational and boost symmetries, respectively. The physicists expected that infinitely far from all the matter in the universe, in a region referred to as “asymptotically flat,” these simple symmetries would reemerge.

    To their surprise, they found an infinite set of symmetries in addition to the expected ones. The new “supertranslation” symmetries indicated that individual sections of space-time could be stretched, squeezed and sheared, and the behavior in this infinitely distant region would remain the same.

    In the 1980s, Abhay Ashtekar, a physicist at The Pennsylvania State University (US), discovered that the memory effect was the physical manifestation of these symmetries. In other words, a supertranslation was exactly what would cause the Boggle universe to pick a new but equivalent way to warp space-time.

    His work connected these abstract symmetries in a hypothetical region of the universe to real effects. “To me that’s the exciting thing about measuring the memory effect — it’s just proving these symmetries are really physical,” said Laura Donnay, a physicist at The Vienna University of Technology (TU Wien)[Technische Universität Wien](AT). “Even very good physicists don’t quite grasp that they act in a nontrivial way and give you physical effects. And the memory effect is one of them.”

    Probing a Paradox

    The point of the Boggle game is to search the seemingly random arrangement of letters on the grid to find words. Each new configuration hides new words, and hence new information.

    Like Boggle, space-time has the potential to store information, which could be the key to solving the infamous black hole information paradox. Briefly, the paradox is this: Information cannot be created or destroyed. So where does the information about particles go after they fall into a black hole and are re-emitted as information-less Hawking radiation?

    In 2016, Andrew Strominger, a physicist at Harvard University (US), along with Stephen Hawking [The University of Cambridge (UK)] and Malcolm Perry [The University of Cambridge (UK) and Queen Mary University of London (UK)] realized that the horizon of a black hole has the same supertranslation symmetries as those in asymptotically flat space. And by the same logic as before, there would be an accompanying memory effect. This meant the infalling particles could alter space-time near the black hole, thereby changing its information content. This offered a possible solution to the information paradox. Knowledge of the particles’ properties wasn’t lost — it was permanently encoded in the fabric of space-time.

    “The fact that you can say something interesting about black hole evaporation is pretty cool,” said Sabrina Pasterski, a theoretical physicist at Princeton University (US). “The starting point of the framework has already had interesting results. And now we’re pushing the framework even further.”

    Pasterski and others have launched a new research program relating statements about gravity and other areas of physics to these infinite symmetries. In chasing the connections, they’ve discovered new, exotic memory effects. Pasterski established a connection between a different set of symmetries and a spin memory effect, where space-time becomes gnarled and twisted from gravitational waves that carry angular momentum.

    A Ghost in the Machine

    Alas, LIGO scientists haven’t yet seen evidence of the memory effect. The change in the distance between LIGO’s mirrors from a gravitational wave is minuscule — about one-thousandth the width of a proton — and the memory effect is predicted to be 20 times smaller.

    LIGO’s placement on our noisy planet worsens matters. Low-frequency seismic noise mimics the memory effect’s long-term changes in the mirror positions, so disentangling the signal from noise is tricky business.

    Earth’s gravitational pull also tends to restore LIGO’s mirrors to their original position, erasing its memory. So even though the kinks in space-time are permanent, the changes in the mirror position — which enables us to measure the kinks — are not. Researchers will need to measure the displacement of the mirrors caused by the memory effect before gravity has time to pull them back down.

    While detecting the memory effect caused by a single gravitational wave is infeasible with current technology, astrophysicists like Lasky and Patricia Schmidt of The University of Birmingham (UK) have thought up clever workarounds. “What you can do is effectively stack up the signal from multiple mergers,” said Lasky, “accumulating evidence in a very statistically rigorous way.”

    Lasky and Schmidt have independently predicted that they’ll need over 1,000 gravitational wave events to accumulate enough statistics to confirm they’ve seen the memory effect. With ongoing improvements to LIGO, as well as contributions from the VIRGO detector in Italy and KAGRA in Japan, Lasky thinks reaching 1,000 detections is a few short years away.

    _____________________________________________________________________________________
    LIGOVIRGOKAGRA

    Caltech /MIT Advanced aLigo.

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

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    KAGRA Large-scale Cryogenic Gravitational Wave Telescope Project (JP).
    _____________________________________________________________________________________

    LIGO Virgo Kagra Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University(US).

    “It is such a special prediction,” said Schmidt. “It’s quite exciting to see if it’s actually true.”

    Correction: December 9, 2021
    The original version of this article attributed the original discovery of the connection between supertranslation symmetries and the memory effect to Andrew Strominger in 2014. In fact, that connection had previously been known. The 2014 discovery by Strominger was between supertranslation symmetries, the memory effect and a third topic.

    See the full article here .


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    Formerly known as Simons Science News, Quanta Magazine (US) is an editorially independent online publication launched by the Simons Foundation to enhance public understanding of science. Why Quanta? Albert Einstein called photons “quanta of light.” Our goal is to “illuminate science.” At Quanta Magazine, scientific accuracy is every bit as important as telling a good story. All of our articles are meticulously researched, reported, edited, copy-edited and fact-checked.

     
  • richardmitnick 1:15 pm on November 15, 2021 Permalink | Reply
    Tags: , "Study shows what happens to apparent horizons when binary black holes merge", , , , Binary black hole mergers are fascinating cosmological events., , , Multimessenger astronomy   

    From phys.org : “Study shows what happens to apparent horizons when binary black holes merge” 

    From phys.org

    November 15, 2021
    Ingrid Fadelli

    1
    Figure showing sections through marginal surfaces in a ‘snapshot’ of the researchers’ simulation. The apparent horizons are the three dark lines (the newly formed one is outside and contains the two original ones), while unstable marginal surfaces are lighter colored. Some of the unstable surfaces evolve to merge and annihilate with the two original (inner) apparent horizons. Credit: Pook-Kolb, Hennigar & Booth.

    Binary black hole mergers are fascinating cosmological events, which have been theorized to be the among the strongest sources of gravitational waves in the universe. While astrophysicists have carried out extensive research focusing on these events, many questions remain unanswered.

    Researchers at The MPG Institute for Gravitational Physics[MPG Institut für Gravitationsphysik] [Albert Einstein Institute] (DE) and The Memorial University of Newfoundland and Labrador’s University (CA) have recently carried out a study exploring what happens to the original apparent horizons during a merger between two non-spinning black holes. Their paper, published in Physical Review Letters, suggests that when binary black holes merge, apparent horizons vanish by merging with other horizon-like structures.

    Apparent horizons are boundaries delineating the edge of a black hole. In their previous works, two of the researchers involved in the recent study had been trying to develop new ways to identify apparent horizons in spacetimes simple enough that their metrics could be written down on paper. Using the methods they developed, they were able to identify several new horizon-like surfaces that had been overlooked by previous works.

    “Part of the original inspiration for that study was understanding self-intersecting apparent horizons that had recently been identified during black hole mergers by Daniel and his collaborators,” Daniel Pook-Kolb, Robie A. Hennigar and Ivan Booth, the researchers who carried out the study, told Phys.org, via email. “Then, Ivan was asked to be an examiner for Daniel’s Ph.D. thesis and, while writing his report, realized that the simple methods could also be applied in Daniel’s much more complicated numerically generated merger spacetimes. After the thesis was published, we started collaborating.”

    Initially, Pook-Kolb analyzed data from the full numerical simulations he produced as part of his thesis. Almost immediately, he identified a series of new structures that matched the team’s theoretical predictions.

    One of the primary objectives of the new study was to gain a better understanding of how two black holes can merge and become one. As the researchers continued their analyses, they became more confident that they would be able to answer this unanswered question.

    “For many years, it has been known how the event horizon looks during a merger; that’s the famous pair of pants diagram, but that does not tell us much about the dynamics, especially how the spacetime evolves inside the black holes,” Pook-Kolb, Hennigar and Booth explained. “To get more insight, we look instead at apparent horizons, which are ubiquitous in the numerical relativity community.”

    Approximately 50 years ago, Stephen Hawking and George Ellis speculated briefly about what happens to the apparent horizons of binary black holes when they merge, in their book The Large Scale Structure of Space-Time. Since then, however, researchers have been unable to paint a full and consistent picture of this phenomenon.

    “For a long time, this has been a fairly academic question, as black holes were elusive objects that had never been directly observed individually, let alone witnessing two of them merge,” Pook-Kolb, Hennigar and Booth said. “This has changed dramatically since the first gravitational wave signatures of mergers were detected in 2015.

    Caltech /MIT Advanced aLigo

    Merger observations are now almost routine. We therefore think that gaining an understanding of all their aspects is interesting in itself.”

    In their paper, Pook-Kolb, Hennigar and Booth specifically examined black hole configurations with a certain symmetry, where the whole system remains unchanged after rotations occur around one axis. The method they used to carry out their analysis has three key components.

    Firstly, the researchers employed a highly accurate technique for simulating spacetimes, including spacetimes inside a black hole. Secondly, they used a numerical method that allowed them to resolve the horizons, even in instances when they become very distorted.

    “The third ‘ingredient’ of our method is a conceptually simple way to find all the possible horizons: The equations for finding apparent horizons are rewritten from complicated equations for surfaces to relatively simple ones for curves,” Pook-Kolb, Hennigar and Booth said. “Once one finds one of these curves, it can be rotated to obtain the full surface. Then the search for horizons becomes a one-dimensional search, which is easy to tackle with today’s computers. To the best of our knowledge, no one fully worked out the mathematics for that before, yet it is what finally enabled us to uncover the structure in the interior of the newly formed black hole.”

    Over the past few decades, astrophysicists were able to paint a clear picture of what happens in the exterior spacetime of black holes during binary black hole mergers. In addition, the gravitational waves that were predicted to be associated with these events are now consistently detected.

    What happens in the interior spacetime, however, so far remained unclear. The recent work by Pook-Kolb, Hennigar, and Booth sheds some light on what could happen inside binary black holes when they merge.

    “The most important result of our study is that it unveiled the fate of the original two horizons,” Pook-Kolb, Hennigar and Booth said. “They both eventually vanish, but they don’t just disappear. Instead, they smoothly annihilate with other horizon-like structures. One might go as far as saying ‘they turn around in time,” and in doing so, they become what we call unstable.”

    A further achievement of this recent study is that it introduces a method to easily differentiate between generic marginal surfaces, also known as MOTSs, and MOTSs that can be regarded as physically meaningful black hole boundaries (i.e., horizons). In the future, this method could also be used by other research teams to study horizons in black holes.

    “By computing a MOTS’s stability properties, we can immediately tell if it belongs to a physically behaving horizon or if it is just an unstable marginal surface,” Pook-Kolb, Hennigar and Booth explained. “This criterion establishes something very important to us: Despite the sheer number of marginal surfaces we found, we find a very clear and simple structure when we include the stability properties.”

    In their recent study, Pook-Kolb, Hennigar and Booth report valuable new insight about what could happen to apparent horizons when two black holes merge into one. So far, their analyses considered non-spinning binary black holes, but they plan to eventually conduct further studies focusing on rotating black holes.

    “Obviously, there are still many questions to address,” Pook-Kolb, Hennigar and Booth said. “Probably the most important one will be to extend our study to fully generic mergers of rotating black holes. While we do think that very similar structures should exist, we have been surprised often enough to remain extremely curious.”

    See the full article here .

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    About Science X in 100 words
    Science X™ is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004 (Physorg.com), Science X’s readership has grown steadily to include 5 million scientists, researchers, and engineers every month. Science X publishes approximately 200 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Science X community members enjoy access to many personalized features such as social networking, a personal home page set-up, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.
    Mission 12 reasons for reading daily news on Science X Organization Key editors and writers include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 10:11 pm on November 9, 2021 Permalink | Reply
    Tags: "LLNL-led team uses machine learning to derive black hole motion from gravitational waves", , , , Multimessenger astronomy   

    From DOE’s Lawrence Livermore National Laboratory (US) : “LLNL-led team uses machine learning to derive black hole motion from gravitational waves” 

    From DOE’s Lawrence Livermore National Laboratory (US)

    11.9.21

    Jeremy Thomas
    thomas244@llnl.gov
    925-422-5539

    1
    A multidisciplinary team including an LLNL mathematician has discovered a machine learning-based technique capable of automatically deriving a mathematical model for the motion of binary black holes from raw gravitational wave data. Gravitational waves are produced by cataclysmic events such as the merger of two black holes, which ripple outward as the black holes spiral toward each other and can be detected by installations such as the Laser Interferometer Gravitational-wave Observatory (LIGO). Image credit: T. Pyle/LIGO.

    The announcement that the Laser Interferometer Gravitational-wave Observatory (LIGO) had detected gravitational waves during the merger of two black holes sent ripples throughout the scientific community in 2016. The earthshaking news not only confirmed one of Albert Einstein’s key predictions in his general theory of relativity, but also opened a door to a better understanding of the motion of black holes and other spacetime-warping phenomena.

    Cataclysmic events such as the collision of black holes or neutron stars produce the largest gravitational waves. Binary black holes orbit around each other for billions of years before eventually colliding to form a single massive black hole. During the final moments as they merge, their mass is converted to a gigantic burst of energy — per Einstein’s equation e=mc2 — which can then be detected in the form of gravitational waves.

    To understand the motion of binary black holes, researchers have traditionally simplified Einstein’s field equations and solved them to calculate the emitted gravitational waves. The approach is complex and requires expensive, time-consuming simulations on supercomputers or approximation techniques that can lead to errors or break down when applied to more complicated black hole systems.

    Along with collaborators at The University of Massachusetts (US), Dartmouth College (US) and The University of Mississippi (US), a Lawrence Livermore National Laboratory (LLNL) mathematician has discovered an inverse approach to the problem, a machine learning-based technique capable of automatically deriving a mathematical model for the motion of binary black holes from raw gravitational wave data, requiring only the computing power of a laptop. The work appears online in the journal Physical Review Research.

    Working backward using gravitational wave data from numerical relativity simulations, the team designed an algorithm that could learn the differential equations describing the dynamics of merging black holes for a range of cases. The waveform inversion strategy can quickly output a simple equation with the same accuracy as equations that have taken humans years to develop or models that take weeks to run on supercomputers.

    “We have all this data that relates to more complicated black hole systems, and we don’t have complete models to describe the full range of these systems, even after decades of work,” said lead author Brendan Keith, a postdoctoral researcher in LLNL’s Center for Applied Scientific Computing. “Machine learning will tell us what the equations are automatically. It will take in your data, and it will output an equation in a few minutes to an hour, and that equation might be as accurate as something a person had been working on for 10-20 years.”

    Keith and the other two members of the multidisciplinary team met at a computational relativity workshop at the Institute for Computational and Experimental Research in Mathematics at Brown University (US). They wanted to test ideas from recent papers describing a similar type of machine learning problem — one that derived equations based on trajectories of a dynamical system — on lower-dimensional data, like that of gravitational waves.

    Keith, a computational scientist in addition to being a mathematician, wrote the inverse problem and the computer code, while his academic partners helped him obtain the data, and added the physics needed to scale from one-dimensional data to a multi-dimensional system of equations and interpret the model.

    “We had some confidence that if we went from one dimension to one dimension, it would work — that’s what the earlier papers had done — but a gravitational wave is lower-dimensional data than the trajectory of a black hole,” Keith said. “It was a big, exciting moment when we found out it does work.”

    The approach doesn’t require complicated general relativity theory, only the application of Kepler’s laws of planetary motion and the math needed to solve an inverse problem. Starting with just a basic Newtonian, non-relativistic model (like the moon orbiting around the Earth) and a system of differential equations parameterized by neural networks, the team discovered the algorithm could learn from the differences between the basic model and one that behaved much differently (like two orbiting black holes) to fill in the missing relativistic physics.

    “This is a completely new way to approach the problem,” said co-author Scott Field, an assistant professor in mathematics and gravitational wave data scientist at The University of Massachusetts-Dartmouth (US). “The gravitational-wave modeling community has been moving towards a more data-driven approach, and our paper is the most extreme version of this, whereby we rely almost exclusively on data and sophisticated machine learning tools.”

    Applying the methodology to a range of binary black hole systems, the team showed that the resulting differential equations automatically accounted for relativistic effects in black holes such as perihelion precession, radiation reaction and orbital plunge. In a side-by-side comparison with state-of-the-art orbital dynamics models that the scientific community has used for decades, the team discovered their machine learning model was equally accurate and could be applied to more complex black hole systems, including situations with higher dimension data but a limited number of observations.

    “The most surprising part of the results was how well the model could extrapolate outside of the training set,” said co-author Akshay Khadse, a Ph.D. student in physics at the University of Mississippi. “This could be used for generating information in the regime where the gravitational wave detectors are not very sensitive or if we have a limited amount of gravitational wave signal.”

    The researchers will need to perform more mathematical analysis and compare their predictions to more numerical relativity data before the method is ready to use with current gravitational data collected from the LIGO installations, the team said. They hope to devise a Bayesian inversion approach to quantify uncertainties and apply the technique to more complicated systems and orbital scenarios, as well as use it to better calibrate traditional gravitational-wave models.

    LIGO Virgo Kagra Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University(US)

    The work was performed with a grant from The National Science Foundation (US) and funding from LLNL.

    See the full article here .


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    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration

    DOE’s Lawrence Livermore National Laboratory (LLNL) (US) is an American federal research facility in Livermore, California, United States, founded by the University of California-Berkeley (US) in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System (US). In 2012, the laboratory had the synthetic chemical element livermorium named after it.

    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km^2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence, director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

    Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the DOE’s Los Alamos National Laboratory(US) and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

    Historically, the DOE’s Lawrence Berkeley National Laboratory (US) and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.

    The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.” The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS. The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.

    On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km^2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

    [NIF National Ignition Facility located at the DOE’s Lawrence Livermore National Laboratory in Livermore, California.


    NNSA

     
  • richardmitnick 11:01 am on November 8, 2021 Permalink | Reply
    Tags: "Scientists detect a "tsunami" of gravitational waves", , , Multimessenger astronomy, OzGrav-ARC CENTRE OF EXCELLENCE FOR GRAVITATIONAL WAVE DISCOVERY (AU), ,   

    From The Australian National University (AU) : “Scientists detect a “tsunami” of gravitational waves” 

    ANU Australian National University Bloc

    From The Australian National University (AU)

    8 November 2021
    James Giggacher
    +61 2 6125 7979
    media@anu.edu.au

    1
    Black Holes to merge. Credit: The National Aeronautics and Space Agency (US).
    Artist’s by now iconic conception of two merging black holes similar to those detected by LIGO. Credit: Aurore Simonnet /Caltech MIT Advanced aLIGO(US)/Sonoma State University (US).

    3
    Graphic by Carl Knox, OzGrav-ARC CENTRE OF EXCELLENCE FOR GRAVITATIONAL WAVE DISCOVERY (AU)The Swinburne University of Technology (AU), 90 detections!

    A team of international scientists, including researchers from The Australian National University (ANU), and researchers from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) have unveiled the largest number of gravitational waves ever detected.

    The discoveries will help solve some of the most complex mysteries of the Universe, including the building blocks of matter and the workings of space and time.

    The global team’s study, published today on Physical Review X, made 35 new detections of gravitational waves caused by pairs of black holes merging or neutron stars and black holes smashing together, using the LIGO and Virgo observatories between November 2019 and March 2020.

    _____________________________________________________________________________________
    LIGOVIRGOKAGRA

    Caltech /MIT Advanced aLigo

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

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    KAGRA Large-scale Cryogenic Gravitational Wave Telescope Project (JP)
    _____________________________________________________________________________________

    LIGO Virgo Kagra Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University(US)

    This brings the total number of detections to 90 after three observing runs between 2015 and 2020.

    The new detections are from massive cosmic events, most of them billions of light years away, which hurl ripples through space-time. They include 32 black hole pairs merging, and likely three collisions between neutron stars and black holes.

    ANU is one of the key players in the international team making the observations and developing the sophisticated technology to hunt down elusive gravitational waves across the vast expanse of the Universe.

    Distinguished Professor Susan Scott, from the ANU Centre for Gravitational Astrophysics, said the latest discoveries represented “a tsunami” and were a “major leap forward in our quest to unlock the secrets of the Universe’s evolution”.

    “These discoveries represent a tenfold increase in the number of gravitational waves detected by LIGO and Virgo since they started observing,” Distinguished Professor Scott said.

    “We’ve detected 35 events. That’s massive! In contrast, we made three detections in our first observing run, which lasted four months in 2015-16.

    “This really is a new era for gravitational wave detections and the growing population of discoveries is revealing so much information about the life and death of stars throughout the Universe.

    “Looking at the masses and spins of the black holes in these binary systems indicates how these systems got together in the first place.

    “It also raises some really fascinating questions. For example, did the system originally form with two stars that went through their life cycles together and eventually became black holes? Or were the two black holes thrust together in a very dense dynamical environment such as at the centre of a galaxy?”

    Distinguished Professor Scott, who is also a Chief Investigator of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), said the continual improvement of gravitational wave detector sensitivity was helping drive an increase in detections.

    “This new technology is allowing us to observe more gravitational waves than ever before,” she said.

    “We are also probing the two black hole mass gap regions and providing more tests of Einstein’s theory of general relativity.

    “The other really exciting thing about the constant improvement of the sensitivity of the gravitational wave detectors is that this will then bring into play a whole new range of sources of gravitational waves, some of which will be unexpected.”

    See the full article here .

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    ANU Campus

    The Australian National University (AU) is a world-leading university in Australia’s capital city, Canberra. Our location points to our unique history, ties to the Australian Government and special standing as a resource for the Australian people.

    Our focus on research as an asset, and an approach to education, ensures our graduates are in demand the world-over for their abilities to understand, and apply vision and creativity to addressing complex contemporary challenges.

    Australian National University is regarded as one of the world’s leading research universities, and is ranked as the number one university in Australia and the Southern Hemisphere by the 2021 QS World University Rankings. It is ranked 31st in the world by the 2021 QS World University Rankings, and 59th in the world (third in Australia) by the 2021 Times Higher Education.

    In the 2020 Times Higher Education Global Employability University Ranking, an annual ranking of university graduates’ employability, Australian National University was ranked 15th in the world (first in Australia). According to the 2020 QS World University by Subject, the university was also ranked among the top 10 in the world for Anthropology, Earth and Marine Sciences, Geography, Geology, Philosophy, Politics, and Sociology.

    Established in 1946, Australian National University is the only university to have been created by the Parliament of Australia. It traces its origins to Canberra University College, which was established in 1929 and was integrated into Australian National University in 1960. Australian National University enrolls 10,052 undergraduate and 10,840 postgraduate students and employs 3,753 staff. The university’s endowment stood at A$1.8 billion as of 2018.

    Australian National University counts six Nobel laureates and 49 Rhodes scholars among its faculty and alumni. The university has educated two prime ministers, 30 current Australian ambassadors and more than a dozen current heads of government departments of Australia. The latest releases of ANU’s scholarly publications are held through ANU Press online.

     
  • richardmitnick 3:31 pm on November 3, 2021 Permalink | Reply
    Tags: "cosmological coupling", "New study proposes expansion of the universe directly impacts black hole growth", , , , Multimessenger astronomy,   

    From The University of Hawai’i-Manoa (US) via phys.org : “New study proposes expansion of the universe directly impacts black hole growth” 

    From The University of Hawai’i-Manoa (US)

    via

    phys.org

    November 3, 2021

    1
    The first rendered image of a black hole, illuminated by infalling matter. In this study, researchers have proposed a model where these objects can gain mass without the addition of matter: they can cosmologically couple to the growth of the universe itself. Image Credit: Jean-Pierre Luminet, “Image of a Spherical Black Hole with Thin Accretion Disk,” Astronomy and Astrophysics 75 (1979): 228–35.

    Over the past 6 years, gravitational wave observatories have been detecting black hole mergers, verifying a major prediction of Albert Einstein’s theory of gravity.

    But there is a problem—many of these black holes are unexpectedly large. Now, a team of researchers from the University of Hawaiʻi at Mānoa, The University of Chicago (US), and The University of Michigan (US) have proposed a novel solution to this problem: Black holes grow along with the expansion of the universe.

    Since the first observation of merging black holes by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2015, astronomers have been repeatedly surprised by their large masses.

    Though they emit no light, black hole mergers are observed through their emission of gravitational waves—-ripples in the fabric of spacetime that were predicted by Einstein’s theory of general relativity.

    Gravitational waves. Credit: W.Benger-Zib. MPG Institute for Gravitational Physics [MPG für Gravitationsphysik] (Albert Einstein Institute) (DE)

    Physicists originally expected that black holes would have masses less than about 40 times that of the Sun, because merging black holes arise from massive stars, which can’t hold themselves together if they get too big.

    The LIGO and Virgo observatories, however, have found many black holes with masses greater than that of 50 suns, with some as massive as 100 suns.

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

    Numerous formation scenarios have been proposed to produce such large black holes, but no single scenario has been able to explain the diversity of black hole mergers observed so far, and there is no agreement on which combination of formation scenarios is physically viable. This new study, published in The Astrophysical Journal Letters, is the first to show that both large and small black hole masses can result from a single pathway, wherein the black holes gain mass from the expansion of the universe itself.

    Astronomers typically model black holes inside a universe that cannot expand. “It’s an assumption that simplifies Einstein’s equations because a universe that doesn’t grow has much less to keep track of,” said Kevin Croker, a professor at the UH Mānoa Department of Physics and Astronomy. “There is a trade-off though: Predictions may only be reasonable for a limited amount of time.”

    Because the individual events detectable by LIGO—Virgo only last a few seconds, when analyzing any single event, this simplification is sensible. But these same mergers are potentially billions of years in the making. During the time between the formation of a pair of black holes and their eventual merger, the universe grows profoundly. If the more subtle aspects of Einstein’s theory are carefully considered, then a startling possibility emerges: The masses of black holes could grow in lockstep with the universe, a phenomenon that Croker and his team call cosmological coupling.

    The most well-known example of cosmologically-coupled material is light itself, which loses energy as the universe grows. “We thought to consider the opposite effect,” said research co-author and UH Mānoa Physics and Astronomy Professor Duncan Farrah. “What would LIGO—Virgo observe if black holes were cosmologically coupled and gained energy without needing to consume other stars or gas?”

    To investigate this hypothesis, the researchers simulated the birth, life, and death of millions of pairs of large stars. Any pairs where both stars died to form black holes were then linked to the size of the universe, starting at the time of their death. As the universe continued to grow, the masses of these black holes grew as they spiraled toward each other. The result was not only more massive black holes when they merged, but also many more mergers. When the researchers compared the LIGO—Virgo data to their predictions, they agreed reasonably well. “I have to say I didn’t know what to think at first,”‘ said research co-author and University of Michigan Professor Gregory Tarlé. “It was a such a simple idea, I was surprised it worked so well.”

    According to the researchers, this new model is important because it doesn’t require any changes to our current understanding of stellar formation, evolution, or death. The agreement between the new model and our current data comes from simply acknowledging that realistic black holes don’t exist in a static universe. The researchers were careful to stress, however, that the mystery of LIGO—Virgo’s massive black holes is far from solved.

    “Many aspects of merging black holes are not known in detail, such as the dominant formation environments and the intricate physical processes that persist throughout their lives,” said research co-author and NASA Hubble Fellow Dr. Michael Zevin. “While we used a simulated stellar population that reflects the data we currently have, there’s a lot of wiggle room. We can see that cosmological coupling is a useful idea, but we can’t yet measure the strength of this coupling.”

    Research co-author and UH Mānoa Physics and Astronomy Professor Kurtis Nishimura expressed his optimism for future tests of this novel idea, “As gravitational-wave observatories continue to improve sensitivities over the next decade, the increased quantity and quality of data will enable new analysis techniques. This will be measured soon enough.”

    Gravity is talking. Lisa will listen. Dialogos of Eide.

    European Space Agency(EU)/National Aeronautics and Space Administration (US) eLISA space based, the future of gravitational wave research.

    See the full article here .

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    System Overview

    The The University of Hawai‘I (US) includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

    The University of Hawaiʻi system, formally the University of Hawaiʻi (US) is a public college and university system that confers associate, bachelor’s, master’s, and doctoral degrees through three university campuses, seven community college campuses, an employment training center, three university centers, four education centers and various other research facilities distributed across six islands throughout the state of Hawaii in the United States. All schools of the University of Hawaiʻi system are accredited by the Western Association of Schools and Colleges. The U.H. system’s main administrative offices are located on the property of the University of Hawaiʻi at Mānoa in Honolulu CDP.

    The University of Hawaiʻi-Mānoa is the flagship institution of the University of Hawaiʻi system. It was founded as a land-grant college under the terms of the Morrill Acts of 1862 and 1890. Programs include Hawaiian/Pacific Studies, Astronomy, East Asian Languages and Literature, Asian Studies, Comparative Philosophy, Marine Science, Second Language Studies, along with Botany, Engineering, Ethnomusicology, Geophysics, Law, Business, Linguistics, Mathematics, and Medicine. The second-largest institution is the University of Hawaiʻi at Hilo on the “Big Island” of Hawaiʻi, with over 3,000 students. The University of Hawaiʻi-West Oʻahu in Kapolei primarily serves students who reside in Honolulu’s western and central suburban communities. The University of Hawaiʻi Community College system comprises four community colleges island campuses on O’ahu and one each on Maui, Kauaʻi, and Hawaiʻi. The schools were created to improve accessibility of courses to more Hawaiʻi residents and provide an affordable means of easing the transition from secondary school/high school to college for many students. University of Hawaiʻi education centers are located in more remote areas of the State and its several islands, supporting rural communities via distance education.

    Research facilities

    Center for Philippine Studies
    Cancer Research Center of Hawaiʻi
    East-West Center
    Haleakalā Observatory
    Hawaiʻi Natural Energy Institute
    Institute for Astronomy
    Institute of Geophysics and Planetology
    Institute of Marine Biology
    Lyon Arboretum
    Mauna Kea Observatory
    W. M. Keck Observatory
    Waikīkī Aquarium

    U Hawaii 2.2 meter telescope, Mauna Kea, Hawai’I (US)
    University of Hawaii 2.2 meter telescope.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth.

    W.M. Keck Observatory two ten meter telescopes operated by California Institute of Technology(US) and the University of California(US) Maunakea Hawaii USA, altitude 4,207 m (13,802 ft). Credit: Caltech.

    The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the island of Hawai’i feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

    Pann-STARS 1 Telescope, U Hawaii, situated at Haleakala Observatories near the summit of Haleakala in Hawaii, USA, altitude 3,052 m (10,013 ft).

     
  • richardmitnick 1:35 pm on October 25, 2021 Permalink | Reply
    Tags: "Neutron star collisions are a “goldmine” of heavy elements study finds", Collisions between two neutron stars, , Multimessenger astronomy,   

    From The Massachusetts Institute of Technology (US) : “Neutron star collisions are a “goldmine” of heavy elements study finds” 

    MIT News

    From The Massachusetts Institute of Technology (US)

    October 25, 2021
    Jennifer Chu

    1
    New research suggests binary neutron stars are a likely cosmic source for the gold, platinum, and other heavy metals we see today.
    Credits: A. Simonnet National Science Foundation (US)/Caltech/ MIT Advanced aLIGO (US)/Sonoma State University (US)/, edited by MIT News.

    Most elements lighter than iron are forged in the cores of stars. A star’s white-hot center fuels the fusion of protons, squeezing them together to build progressively heavier elements. But beyond iron, scientists have puzzled over what could give rise to gold, platinum, and the rest of the universe’s heavy elements, whose formation requires more energy than a star can muster.

    A new study by researchers at MIT and the University of New Hampshire finds that of two long-suspected sources of heavy metals, one is more of a goldmine than the other.

    The study, published today in The Astrophysical Journal Letters, reports that in the last 2.5 billion years, more heavy metals were produced in binary neutron star mergers, or collisions between two neutron stars, than in mergers between a neutron star and a black hole.

    The study is the first to compare the two merger types in terms of their heavy metal output, and suggests that binary neutron stars are a likely cosmic source for the gold, platinum, and other heavy metals we see today. The findings could also help scientists determine the rate at which heavy metals are produced across the universe.

    “What we find exciting about our result is that to some level of confidence we can say binary neutron stars are probably more of a goldmine than neutron star-black hole mergers,” says lead author Hsin-Yu Chen, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research (US).

    Chen’s co-authors are Salvatore Vitale, assistant professor of physics at MIT, and Francois Foucart of The University of New Hampshire (US).

    An efficient flash

    As stars undergo nuclear fusion, they require energy to fuse protons to form heavier elements. Stars are efficient in churning out lighter elements, from hydrogen to iron. Fusing more than the 26 protons in iron, however, becomes energetically inefficient.

    “If you want to go past iron and build heavier elements like gold and platinum, you need some other way to throw protons together,” Vitale says.

    Scientists have suspected supernovae might be an answer. When a massive star collapses in a supernova, the iron at its center could conceivably combine with lighter elements in the extreme fallout to generate heavier elements.

    In 2017, however, a promising candidate was confirmed, in the form a binary neutron star merger, detected for the first time by LIGO and Virgo, the gravitational-wave observatories in the United States and in Italy, respectively.

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

    The detectors picked up gravitational waves, or ripples through space-time, that originated 130 million light years from Earth, from a collision between two neutron stars — collapsed cores of massive stars, that are packed with neutrons and are among the densest objects in the universe.

    The cosmic merger emitted a flash of light, which contained signatures of heavy metals.

    “The magnitude of gold produced in the merger was equivalent to several times the mass of the Earth,” Chen says. “That entirely changed the picture. The math showed that binary neutron stars were a more efficient way to create heavy elements, compared to supernovae.”

    UCSC All the Gold in the Universe.

    A binary goldmine

    Chen and her colleagues wondered: How might neutron star mergers compare to collisions between a neutron star and a black hole? This is another merger type that has been detected by LIGO and Virgo and could potentially be a heavy metal factory. Under certain conditions, scientists suspect, a black hole could disrupt a neutron star such that it would spark and spew heavy metals before the black hole completely swallowed the star.

    The team set out to determine the amount of gold and other heavy metals each type of merger could typically produce. For their analysis, they focused on LIGO and Virgo’s detections to date of two binary neutron star mergers and two neutron star – black hole mergers.

    The researchers first estimated the mass of each object in each merger, as well as the rotational speed of each black hole, reasoning that if a black hole is too massive or slow, it would swallow a neutron star before it had a chance to produce heavy elements. They also determined each neutron star’s resistance to being disrupted. The more resistant a star, the less likely it is to churn out heavy elements. They also estimated how often one merger occurs compared to the other, based on observations by LIGO, Virgo, and other observatories.

    Finally, the team used numerical simulations developed by Foucart, to calculate the average amount of gold and other heavy metals each merger would produce, given varying combinations of the objects’ mass, rotation, degree of disruption, and rate of occurrence.

    On average, the researchers found that binary neutron star mergers could generate two to 100 times more heavy metals than mergers between neutron stars and black holes. The four mergers on which they based their analysis are estimated to have occurred within the last 2.5 billion years. They conclude then, that during this period, at least, more heavy elements were produced by binary neutron star mergers than by collisions between neutron stars and black holes.

    The scales could tip in favor of neutron star-black hole mergers if the black holes had high spins, and low masses. However, scientists have not yet observed these kinds of black holes in the two mergers detected to date.

    Chen and her colleagues hope that, as LIGO and Virgo resume observations next year, more detections will improve the team’s estimates for the rate at which each merger produces heavy elements. These rates, in turn, may help scientists determine the age of distant galaxies, based on the abundance of their various elements.

    “You can use heavy metals the same way we use carbon to date dinosaur remains,” Vitale says. “Because all these phenomena have different intrinsic rates and yields of heavy elements, that will affect how you attach a time stamp to a galaxy. So, this kind of study can improve those analyses.”

    This research was funded, in part, by NASA, the National Science Foundation, and the LIGO Laboratory.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    The Massachusetts Institute of Technology (US) is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory (US), the MIT Bates Research and Engineering Center (US), and the Haystack Observatory (US), as well as affiliated laboratories such as the Broad Institute of MIT and Harvard(US) and Whitehead Institute (US).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology (US) adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology (US) . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology (US) is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia (US), wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after Massachusetts Institute of Technology (US) was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst (US)). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    Massachusetts Institute of Technology (US) was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology (US) faculty and alumni rebuffed Harvard University (US) president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, the Massachusetts Institute of Technology (US) administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology (US) catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities (US)in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at Massachusetts Institute of Technology (US) that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    Massachusetts Institute of Technology (US)‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology (US)’s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, Massachusetts Institute of Technology (US) became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected Massachusetts Institute of Technology (US) profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of Massachusetts Institute of Technology (US) between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, Massachusetts Institute of Technology (US) no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and Massachusetts Institute of Technology (US)’s defense research. In this period Massachusetts Institute of Technology (US)’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. Massachusetts Institute of Technology (US) ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT (US) Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology (US) students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at Massachusetts Institute of Technology (US) over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, Massachusetts Institute of Technology (US)’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    Massachusetts Institute of Technology (US) has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology (US) classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    Massachusetts Institute of Technology (US) was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, Massachusetts Institute of Technology (US) launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, Massachusetts Institute of Technology (US) announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology (US) faculty adopted an open-access policy to make its scholarship publicly accessible online.

    Massachusetts Institute of Technology (US) has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology (US) community with thousands of police officers from the New England region and Canada. On November 25, 2013, Massachusetts Institute of Technology (US) announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of the Massachusetts Institute of Technology (US) community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO (US) was designed and constructed by a team of scientists from California Institute of Technology (US), Massachusetts Institute of Technology (US), and industrial contractors, and funded by the National Science Foundation (US) .

    MIT/Caltech Advanced aLigo .

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology (US) physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also an Massachusetts Institute of Technology (US) graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of Massachusetts Institute of Technology (US) is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
    • MIKE EYE 1:53 pm on October 25, 2021 Permalink | Reply

      Fellow Allstonian from across the River; just was wondering what the people who put on the time travelers convention @MIT think about the upcoming 2023 Third Phase of Montauk & Phi-Ex: what will happen that permenalty changes time forever??

      Like

  • richardmitnick 12:50 pm on October 11, 2021 Permalink | Reply
    Tags: , , , Multimessenger astronomy,   

    From AAS NOVA : ” Merging Black Holes vs. Gas and Stars” 

    AASNOVA

    From AAS NOVA

    11 October 2021
    Kerry Hensley

    1
    This simulated image shows a massive black hole at the center of a galaxy. Some massive black holes may be the result of mergers between the black holes hosted by two or more galaxies. Credit: D. Coe, J. Anderson,The National Aeronautics and Space Agency (US), The European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), and and R. van der Marel (Space Telescope Science Institute (US))]

    When galaxies merge, what happens to the massive black holes at their centers? Today’s article explores the math behind the merger.

    2
    When galaxies merge, it shakes up star formation and sets the stage for a massive black hole merger. [NASA, ESA, the Hubble Heritage (STScI/The Association of Universities for Research in Astronomy (AURA)(US))-ESA/Hubble Collaboration, and A. Evans (The University of Virginia (US), Charlottesville/National Radio Astronomy Observatory (US)/Stony Brook University-SUNY (US))]

    An Emerging Question

    Two galaxies, adrift in the universe, pass near one another. If they become gravitationally entangled, the billion-year process of merging begins as they gradually coalesce into a single galaxy. As part of this process, the massive black holes at the centers of the colliding galaxies undergo a merger of their own.

    As these massive black holes begin their death spiral, they encounter other galactic material like stars and gas. While simulations have shown that interacting with nearby stars causes the black-hole binary to spiral inward more quickly, the results aren’t as clear when it comes to gaseous material. Some studies have found that the presence of gas hastens the merger, while others suggest that it delays the merger instead.

    The rate at which massive black holes merge has implications for upcoming gravitational-wave observatories, like the Laser Interferometer Space Antenna (LISA).

    Massive black-hole mergers at the centers of colliding galaxies are expected to be the loudest source of low-frequency gravitational waves in upcoming surveys — but if some process prevents these mergers, there may be nothing to listen to.

    Black Holes on Paper

    Elisa Bortolas (The University of Milano-Bicocca [Università degli Studi di Milano-Bicocca](IT)) and collaborators used a mathematical model of a black-hole merger to understand how interactions with stars and the presence of gas affect the inspiraling of the binary. Unlike most previous work, the set of differential equations developed by Bortolas and coauthors allowed for the effects of stars and gas to be considered simultaneously rather than separately.

    The authors find that stars and gas tend to compete with one another as the black holes merge. If the black-hole pair accretes only a little mass from the surrounding material, gravitational interactions with nearby stars cause the black-hole pair to tighten inward. If the accretion rate is higher, the presence of a gaseous disk works to expand the binary pair, delaying the merger. Eventually, though, the stars win out, and the binary pair draws close enough to shed massive amounts of energy in the form of gravitational waves, sending the black holes on a collision course.

    Looking Ahead to Future Detections

    The results from Bortolas and coauthors showed that while the presence of gas can delay a merger, it won’t prevent it altogether. Under the conditions the authors explored, the presence of gas increased the time to the merger by a factor of a few, but all mergers occurred within a few hundred million years.

    This is good news for LISA and other gravitational-wave detectors, and there are implications for the non-gravitational-wave detections of these events as well; the presence of gas in the black holes’ surroundings seems to make them pause with just a few light-years between them, increasing the chance that a survey might detect them in this phase.

    Citation

    “The Competing Effect of Gas and Stars in the Evolution of Massive Black Hole Binaries,” Elisa Bortolas et al 2021 ApJL 918 L15.

    https://iopscience.iop.org/article/10.3847/2041-8213/ac1c0c

    See the full article here .


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

    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

    The society was founded in 1899 through the efforts of George Ellery Hale. The constitution of the group was written by Hale, George Comstock, Edward Morley, Simon Newcomb and Edward Charles Pickering. These men, plus four others, were the first Executive Council of the society; Newcomb was the first president. The initial membership was 114. The AAS name of the society was not finally decided until 1915, previously it was the “Astronomical and Astrophysical Society of America”. One proposed name that preceded this interim name was “American Astrophysical Society”.

    The AAS today has over 7,000 members and six divisions – the Division for Planetary Sciences (1968); the Division on Dynamical Astronomy (1969); the High Energy Astrophysics Division (1969); the Solar Physics Division (1969); the Historical Astronomy Division (1980); and the Laboratory Astrophysics Division (2012). The membership includes physicists, mathematicians, geologists, engineers and others whose research interests lie within the broad spectrum of subjects now comprising contemporary astronomy.

    In 2019 three AAS members were selected into the tenth anniversary class of TED Fellows.

    The AAS established the AAS Fellows program in 2019 to “confer recognition upon AAS members for achievement and extraordinary service to the field of astronomy and the American Astronomical Society.” The inaugural class was designated by the AAS Board of Trustees and includes an initial group of 232 Legacy Fellows.

     
  • richardmitnick 1:32 pm on September 14, 2021 Permalink | Reply
    Tags: "NASA Provides Laser for LISA Mission", , , LISA: Laser Interferometer Space Antenna, Multimessenger astronomy,   

    From NASA Goddard Space Flight Center (US) : “NASA Provides Laser for LISA Mission” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center (US)

    By Karl B. Hille
    NASA’s Goddard Space Flight Center in Greenbelt, Md.

    Media contact:
    Claire Andreoli
    claire.andreoli@nasa.gov
    (301) 286-1940

    Finding the biggest collisions in the universe takes time, patience, and super steady lasers.

    In May, NASA specialists working with industry partners delivered the first prototype laser for the The European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU)-led Laser Interferometer Space Antenna, or LISA, mission.

    1
    The first prototype of a laser sits on a testbed at the Swiss Center for Electronics and Microtechnology (CSEM), headquartered in Neuchâtel, Switzerland. CSEM will test and characterize the laser, which will be used to conduct gravitational wave experiments in space for the LISA mission.Credits: European Space Agency/CSEM

    This unique laser instrument is designed to detect the telltale ripples in gravitational fields caused by the mergers of neutron stars, black holes, and supermassive black holes in space.

    Anthony Yu at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, leads the laser transmitter development for LISA.

    “We’re developing a highly stable and robust laser for the LISA observatory,” Yu said. “We’ve leveraged lessons learned from previous missions and the latest technologies in photonics packaging and reliability engineering. Now, to meet the challenging LISA requirements, NASA has developed a system that produces a laser transmitter by using a low-power laser enhanced by a fiber-optic amplifier.”

    The team is building upon the laser technology used in NASA’s GRACE mission. “We developed a more compact version as a master oscillator,” Yu said. “It has much smaller size, weight, and power consumption to allow for a fully redundant master oscillator for long-duration lifetime requirements.”

    The LISA laser prototype is a 2-watt laser operating in the near-infrared part of the spectrum. “Our laser is about 400 times more powerful than the typical laser pointer that puts out about 5 milliwatts or less,” Yu said. “The laser module size, not including the electronics, is about half the volume of a typical shoe box.”

    The Swiss Center for Electronics and Microtechnology (CSEM), headquartered in Neuchâtel, Switzerland, confirmed receipt of the lasers and will begin testing them for stability.

    LISA will consist of three spacecraft following Earth in its orbit around the Sun and flying in a precision formation, with 1.5 million miles (2.5 million kilometers) separating each one. Each spacecraft will continuously point two lasers at its counterparts. The laser receiver must be sensitive to a few hundreds of picowatts of signal strength, as the laser beam will spread to about 12 miles (20 kilometers) by the time it reaches its target spacecraft. A time-code signal embedded in the beams allows LISA to measure the slightest interference in these transmissions.

    Ripples in the fabric of space-time as small as a picometer – 50 times smaller than a hydrogen atom – will produce a detectable change in the distances between the spacecraft. Measuring these changes will give scientists the general scale of what collided to produce these ripples and an idea of where in the sky to aim other observatories looking for secondary effects.

    These gravitational wave fluctuations are so small they would be obscured by external forces such as dust impacts and the radiation pressure of sunlight on the spacecraft. To mitigate this, the drag-free control concept – demonstrated on the LISA Pathfinder mission in 2015 – uses free-floating test masses sheltered inside each spacecraft as reference points for the measurement.

    LISA expands on work by the National Science Foundation’s (US)3 Laser Interferometer Gravitational-Wave Observatory (LIGO), which captured its first recording of gravitational waves in 2015.

    Since then, the pair of ground-based observatories in Hanford, Washington, and Livingston, Louisiana, have captured four dozen mergers.

    Thomas Hams, program scientist for LISA at NASA Headquarters in Washington, said the precision laser measurements will allow us to zoom in on the gravitational wave signatures of these mergers and enable other observatories to focus on the right part of the sky to capture these events in the electromagnetic spectrum.

    NASA’s Fermi Gamma-ray Space Telescope picked up the first such multimessenger observation just seconds after LIGO detected a merger of two neutron stars through gravitational waves.

    “With LISA, the hope is you will be able to see these things develop before the merger actually happens,” Hams said. “There will be an indicator that something is coming.”

    Industry Partnership

    To achieve the required stability, the team brought Fibertek Inc. in Herndon, Virginia, and Avo Photonics Inc. in Horsham, Pennsylvania, to develop the laser, oscillator, and power amplifier, and an independent optical engineer in San Jose, California.

    Avo Photonics built the laser for the observatory.

    “Here you have the challenges of spaceborne ruggedness needs, on top of submicron-level optical alignment tolerance requirements. These really push your optical, thermal, and mechanical design chops,” Avo Photonics President Joseph L. Dallas said. “In addition, the narrow linewidth, low noise, and overall stability needed for this mission is unprecedented.”

    Photonics pioneer Tom Kane invented the monolithic laser oscillator technology that Goddard used to stabilize the frequency of the laser light. “Your average laser can be very messy,” Kane said. “They can wander all around their target frequency. You need a ‘quiet’ laser that’s exactly one wavelength and a perfect beam out to 15 decimal places of accuracy.”

    His oscillator technology uses feedback loops to keep the laser burning at such precision. “The wavelength ends up becoming the ruler for these incredible distances,” Kane said.

    The high-power, low-noise amplifier came from Fibertek.

    Fibertek also contributed to NASA’s Ice Cloud and Land Elevation Satellite (ICESat) 2 and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), which has been operating a laser pointed at Earth for 15 years.

    Including time for testing on the ground and potential mission extensions, LISA’s lasers must operate without skipping a hertz for up to 16 years, Goddard’s Yu said.

    “Once launched, they will need to be in 24/7 operation for five years for the initial mission, with a possible six to seven years of extended mission after that,” Yu explained. “We need them to be stable and quiet.”

    See the full article here.


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    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
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