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  • richardmitnick 9:17 pm on January 27, 2023 Permalink | Reply
    Tags: , , , , , , Multimessenger Astronomy/Astrophysics, Rochester Institute of Technology scientists reach a milestone in the search for continuous gravitational waves"   

    From The Rochester Institute of Technology: “Rochester Institute of Technology scientists reach a milestone in the search for continuous gravitational waves” 

    From The Rochester Institute of Technology

    Luke Auburn

    Researchers from the LIGO Scientific Collaboration report on a flagship search in Astrophysical Journal Letters

    Artistic representation of a neutron star accreting matter from its companion’s envelope. Credit: Gabriel Pérez Díaz, SMM (IAC)

    Scientists on the hunt for a previously undetected type of gravitational waves believe they are getting close and have refined techniques to use in upcoming observational runs. Researchers from the LIGO-Virgo-KAGRA Collaboration outlined the most sensitive search to date for continuous gravitational waves from a promising source in a paper recently published in the Astrophysical Journal Letters [below].


    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.

    While scientists have been detecting gravitational waves caused by the mergers of black holes and/or neutron stars since 2015, they still have yet to find them from sources that produce continuous gravitational waves, such as single spinning massive objects like neutron stars. Unlike the strong, short gravitational waves produced by mergers, objects like neutron stars that spin hundreds of times per second can produce weaker but regular gravitational waves.

    Using data from LIGO-Virgo-KAGRA’s third observing run, the scientists aimed to detect continuous gravitational waves from Scorpius X-1, a neutron star in a binary orbit with a low-mass star.

    “Scorpius X-1 is one of the most promising sources for detecting these continuous gravitational waves,” said Professor John Whelan from Rochester Institute of Technology’s School of Mathematical Sciences and principal investigator of RIT’s group in the LIGO Scientific Collaboration. “It’s fairly close at only 9,000 light years away and we can see it very brightly in X-rays because the gaseous matter from the companion star is pulled onto the neutron star.”

    While the scientists did not detect continuous gravitational waves from Scorpius X-1 in the study, they have set limits on their possible strength, and reached a sensitivity benchmark that means the search may be able to detect them in future detector runs. LIGO stated the next observing run, O4, is expected to begin in May 2023.

    “This search yielded the best constraint so far on the possible strength of gravitational waves emitted from Scorpius X-1,” said Jared Wofford, an astrophysical sciences and technology Ph.D. candidate whose dissertation focuses on the O3 search. “For the first time, this search is now sensitive to models of the possible torque balance scenario of the system, which states that the torques of the gravitational wave and accretion of matter onto the neutron star are in balance. In the coming years, we expect better sensitivities from more data taken by Advanced LIGO observing runs probing deeper into the torque balance scenario in hopes to make the first continuous wave detection.”

    One of the ways the team refined the search was by improving the way they picked points in the parameter space that they searched. Rather than using a traditional square grid that resembles a chess board, they used a hexagonal pattern analogous to a honeycomb.

    “These changes allowed the search to become the most sensitive to date, as a more efficient lattice on the same computing budget meant that we could actually use a finer grid than before,” said Kate Wagner, an astrophysical sciences and technology Ph.D. student. The lattice configuration was the basis of Wagner’s master’s thesis.

    Additional scientists from RIT’s Center for Computational Relativity and Gravitation who were co-authors on the paper included Elizabeth Champion ’21 (physics); Vera Delfavero ’19 MS, ’22 Ph.D. (astrophysical sciences and technology); astrophysical sciences and technology MS student Jason Hathaway; Research Associate James Healy; Professor Carlos Lousto; Associate Professor Richard O’Shaughnessy; and astrophysical sciences and technology Ph.D. student Anjali Yelikar.

    Astrophysical Journal Letters
    See the science paper for instructive material with images.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Rochester Institute of Technology is a private doctoral university within the town of Henrietta in the Rochester, New York metropolitan area.

    RIT is composed of nine academic colleges, including National Technical Institute for the Deaf(RIT). The Institute is one of only a small number of engineering institutes in the State of New York, including New York Institute of Technology, SUNY Polytechnic Institute, and Rensselaer Polytechnic Institute. It is most widely known for its fine arts, computing, engineering, and imaging science programs; several fine arts programs routinely rank in the national “Top 10” according to US News & World Report.

    The university offers undergraduate and graduate degrees, including doctoral and professional degrees and online masters as well.

    The university was founded in 1829 and is the tenth largest private university in the country in terms of full-time students. It is internationally known for its science; computer; engineering; and art programs as well as for the National Technical Institute for the Deaf- a leading deaf-education institution that provides educational opportunities to more than 1000 deaf and hard-of-hearing students. RIT is known for its Co-op program that gives students professional and industrial experience. It has the fourth oldest and one of the largest Co-op programs in the world. It is classified among “R2: Doctoral Universities – High research activity”.

    RIT’s student population is approximately 19,000 students, about 16,000 undergraduate and 3000 graduate. Demographically, students attend from all 50 states in the United States and from more than 100 countries around the world. The university has more than 4000 active faculty and staff members who engage with the students in a wide range of academic activities and research projects. It also has branches abroad, its global campuses, located in China, Croatia and United Arab Emirates (Dubai).

    Fourteen RIT alumni and faculty members have been recipients of the Pulitzer Prize.


    The university began as a result of an 1891 merger between Rochester Athenæum, a literary society founded in 1829 by Colonel Nathaniel Rochester and associates and The Mechanics Institute- a Rochester school of practical technical training for local residents founded in 1885 by a consortium of local businessmen including Captain Henry Lomb- co-founder of Bausch & Lomb. The name of the merged institution at the time was called Rochester Athenæum and Mechanics Institute (RAMI). The Mechanics Institute however, was considered as the surviving school by taking over The Rochester Athenaeum’s charter. From the time of the merger until 1944 RAMI celebrated The former Mechanics Institute’s 1885 founding charter. In 1944 the school changed its name to Rochester Institute of Technology and re-established The Athenaeum’s 1829 founding charter and became a full-fledged research university.

    The university originally resided within the city of Rochester, New York, proper, on a block bounded by the Erie Canal; South Plymouth Avenue; Spring Street; and South Washington Street (approximately 43.152632°N 77.615157°W). Its art department was originally located in the Bevier Memorial Building. By the middle of the twentieth century, RIT began to outgrow its facilities, and surrounding land was scarce and expensive. Additionally in 1959 the New York Department of Public Works announced a new freeway- the Inner Loop- was to be built through the city along a path that bisected the university’s campus and required demolition of key university buildings. In 1961 an unanticipated donation of $3.27 million ($27,977,071 today) from local Grace Watson (for whom RIT’s dining hall was later named) allowed the university to purchase land for a new 1,300-acre (5.3 km^2) campus several miles south along the east bank of the Genesee River in suburban Henrietta. Upon completion in 1968 the university moved to the new suburban campus, where it resides today.

    In 1966 RIT was selected by the Federal government to be the site of the newly founded National Technical Institute for the Deaf (NTID). NTID admitted its first students in 1968 concurrent with RIT’s transition to the Henrietta campus.

    In 1979 RIT took over Eisenhower College- a liberal arts college located in Seneca Falls, New York. Despite making a 5-year commitment to keep Eisenhower open RIT announced in July 1982 that the college would close immediately. One final year of operation by Eisenhower’s academic program took place in the 1982–83 school year on the Henrietta campus. The final Eisenhower graduation took place in May 1983 back in Seneca Falls.

    In 1990 RIT started its first PhD program in Imaging Science – the first PhD program of its kind in the U.S. RIT subsequently established PhD programs in six other fields: Astrophysical Sciences and Technology; Computing and Information Sciences; Color Science; Microsystems Engineering; Sustainability; and Engineering. In 1996 RIT became the first college in the U.S to offer a Software Engineering degree at the undergraduate level.


    RIT has nine colleges:

    RIT College of Engineering Technology
    Saunders College of Business
    B. Thomas Golisano College of Computing and Information Sciences
    Kate Gleason College of Engineering
    RIT College of Health Sciences and Technology
    College of Art and Design
    RIT College of Liberal Arts
    RIT College of Science
    National Technical Institute for the Deaf

    There are also three smaller academic units that grant degrees but do not have full college faculties:

    RIT Center for Multidisciplinary Studies
    Golisano Institute for Sustainability
    University Studies

    In addition to these colleges, RIT operates three branch campuses in Europe, one in the Middle East and one in East Asia:

    RIT Croatia (formerly the American College of Management and Technology) in Dubrovnik and Zagreb, Croatia
    RIT Kosovo (formerly the American University in Kosovo) in Pristina, Kosovo
    RIT Dubai in Dubai, United Arab Emirates
    RIT China-Weihai Campus

    RIT also has international partnerships with the following schools:

    Yeditepe University İstanbul Eğitim ve Kültür Vakfı] (TR) in Istanbul, Turkey
    Birla Institute of Technology and Science [बिरला इंस्टिट्यूट ऑफ़ टेक्नोलॉजी एंड साइंस] (IN) in India
    Mother and Teacher Pontifical Catholic University [Pontificia Universidad Católica Madre y Maestra] (DO)
    Santo Domingo Institute of Technology[Instituto Tecnológico de Santo Domingo – INTEC] (DO) in Dominican Republic
    Central American Technological University [La universidad global de Honduras] (HN)
    University of the North [Universidad del Norte] (COL)in Colombia
    Peruvian University of Applied Sciences [Universidad Peruana de Ciencias Aplicadas] (PE) (UPC) in Peru

    RIT’s research programs are rapidly expanding. The total value of research grants to university faculty for fiscal year 2007–2008 totaled $48.5 million- an increase of more than twenty-two percent over the grants from the previous year. The university currently offers eight PhD programs: Imaging science; Microsystems Engineering; Computing and Information Sciences; Color science; Astrophysical Sciences and Technology; Sustainability; Engineering; and Mathematical modeling.

    In 1986 RIT founded the Chester F. Carlson Center for Imaging Science and started its first doctoral program in Imaging Science in 1989. The Imaging Science department also offers the only Bachelors (BS) and Masters (MS) degree programs in imaging science in the country. The Carlson Center features a diverse research portfolio; its major research areas include Digital Image Restoration; Remote Sensing; Magnetic Resonance Imaging; Printing Systems Research; Color Science; Nanoimaging; Imaging Detectors; Astronomical Imaging; Visual Perception; and Ultrasonic Imaging.

    The Center for Microelectronic and Computer Engineering was founded by RIT in 1986. The university was the first university to offer a bachelor’s degree in Microelectronic Engineering. The Center’s facilities include 50,000 square feet (4,600 m^2) of building space with 10,000 square feet (930 m^2) of clean room space. The building will undergo an expansion later this year. Its research programs include nano-imaging; nano-lithography; nano-power; micro-optical devices; photonics subsystems integration; high-fidelity modeling and heterogeneous simulation; microelectronic manufacturing; microsystems integration; and micro-optical networks for computational applications.

    The Center for Advancing the Study of CyberInfrastructure (CASCI) is a multidisciplinary center housed in the College of Computing and Information Sciences. The Departments of Computer science; Software Engineering; Information technology; Computer engineering; Imaging Science; and Bioinformatics collaborate in a variety of research programs at this center. RIT was the first university to launch a Bachelor’s program in Information technology in 1991; the first university to launch a Bachelor’s program in Software Engineering in 1996 and was also among the first universities to launch a Computer Science Bachelor’s program in 1972. RIT helped standardize the Forth programming language and developed the CLAWS software package.

    The Center for Computational Relativity and Gravitation was founded in 2007. The CCRG comprises faculty and postdoctoral research associates working in the areas of general relativity; gravitational waves; and galactic dynamics. Computing facilities in the CCRG include gravitySimulator, a novel 32-node supercomputer that uses special-purpose hardware to achieve speeds of 4TFlops in gravitational N-body calculations, and newHorizons [image N/A], a state-of-the art 85-node Linux cluster for numerical relativity simulations.

    Gravity Simulator at the Center for Computational Relativity and Gravitation, RIT, Rochester, New York, USA.

    The Center for Detectors was founded in 2010. The CfD designs; develops; and implements new advanced sensor technologies through collaboration with academic researchers; industry engineers; government scientists; and university/college students. The CfD operates four laboratories and has approximately a dozen funded projects to advance detectors in a broad array of applications, e.g. astrophysics; biomedical imaging; Earth system science; and inter-planetary travel. Center members span eight departments and four colleges.

    RIT has collaborated with many industry players in the field of research as well, including IBM; Xerox; Rochester’s Democrat and Chronicle; Siemens; National Aeronautics Space Agency; and the Defense Advanced Research Projects Agency (DARPA). In 2005, it was announced by Russell W. Bessette- Executive Director New York State Office of Science Technology & Academic Research (NYSTAR), that RIT will lead the SUNY University at Buffalo and Alfred University in an initiative to create key technologies in microsystems; photonics; nanomaterials; and remote sensing systems and to integrate next generation IT systems. In addition, the collaboratory is tasked with helping to facilitate economic development and tech transfer in New York State. More than 35 other notable organizations have joined the collaboratory, including Boeing, Eastman Kodak, IBM, Intel, SEMATECH, ITT, Motorola, Xerox, and several Federal agencies, including as NASA.

    RIT has emerged as a national leader in manufacturing research. In 2017, the U.S. Department of Energy selected RIT to lead its Reducing Embodied-Energy and Decreasing Emissions (REMADE) Institute aimed at forging new clean energy measures through the Manufacturing USA initiative. RIT also participates in five other Manufacturing USA research institutes.

  • richardmitnick 1:12 pm on January 23, 2023 Permalink | Reply
    Tags: "Ripples in the fabric of the universe may reveal the start of time", , Better understanding the state of the cosmos shortly after the Big Bang, , , How to use ripples in space-time known as gravitational waves to peer back to the beginning of everything we know., Multimessenger Astronomy/Astrophysics, ,   

    From The DOE’s Princeton Plasma Physics Laboratory: “Ripples in the fabric of the universe may reveal the start of time” 

    From The DOE’s Princeton Plasma Physics Laboratory


    Princeton University

    Princeton University

    Raphael Rosen

    Numerical simulation of the neutron stars merging to form a black hole, with their accretion disks interacting to produce electromagnetic waves. Credit: L. Rezolla (AEI) & M. Koppitz (AEI & Zuse-Institut Berlin)

    Scientists have advanced in discovering how to use ripples in space-time known as gravitational waves to peer back to the beginning of everything we know.

    The researchers say they can better understand the state of the cosmos shortly after the Big Bang by learning how these ripples in the fabric of the universe flow through planets and the gas between the galaxies.

    “We can’t see the early universe directly, but maybe we can see it indirectly if we look at how gravitational waves from that time have affected matter and radiation that we can observe today,” said Deepen Garg, lead author of a paper
    reporting the results in the Journal of Cosmology and Astroparticle Physics [below]. Garg is a graduate student in the Princeton Program in Plasma Physics, which is based at the DOE’s Princeton Plasma Physics Laboratory (PPPL).

    Garg and his advisor Ilya Dodin, who is affiliated with both Princeton University and PPPL, adapted this technique from their research into fusion energy, the process powering the sun and stars that scientists are developing to create electricity on Earth without emitting greenhouse gases or producing long-lived radioactive waste. Fusion scientists calculate how electromagnetic waves move through plasma, the soup of electrons and atomic nuclei that fuels fusion facilities known as tokamaks and stellarators.

    It turns out that this process resembles the movement of gravitational waves through matter. “We basically put plasma wave machinery to work on a gravitational wave problem,” Garg said.

    Gravitational waves, first predicted by Albert Einstein in 1916 as a consequence of his General Theory of Relativity, are disturbances in space-time caused by the movement of very dense objects. They travel at the speed of light and were first detected in 2015 by the Laser Interferometer Gravitational Wave Observatory (LIGO) through detectors in Washington State and Louisiana.

    Garg and Dodin created formulas that could theoretically lead gravitational waves to reveal hidden properties about celestial bodies, like stars that are many light years away. As the waves flow through matter, they create light whose characteristics depend on the matter’s density.

    A physicist could analyze that light and discover properties about a star millions of light years away. This technique could also lead to discoveries about the smashing together of neutron stars and black holes, ultra-dense remnants of star deaths. They could even potentially reveal information about what was happening during the Big Bang and the early moments of our universe.

    The research began without any sense of how important it might become. “I thought this would be a small, six-month project for a graduate student that would involve solving something simple,” Dodin said. “But once we started digging deeper into the topic, we realized that very little was understood about the problem and we could do some very basic theory work here.”

    The scientists now plan to use the technique to analyze data in the near future. “We have some formulas now, but getting meaningful results will take more work,” Garg said.

    Journal of Cosmology and Astroparticle Physics

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit https://energy.gov/science.

    About Princeton: Overview

    Princeton University is a private Ivy League research university in Princeton, New Jersey (US). Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine colonial colleges chartered before the American Revolution. The institution moved to Newark in 1747, then to the current site nine years later. It was renamed Princeton University in 1896.

    Princeton provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences, and engineering. It offers professional degrees through the Princeton School of Public and International Affairs, the School of Engineering and Applied Science, the School of Architecture and the Bendheim Center for Finance. The university also manages the DOE’s Princeton Plasma Physics Laboratory. Princeton has the largest endowment per student in the United States.

    As of October 2020, 69 Nobel laureates, 15 Fields Medalists and 14 Turing Award laureates have been affiliated with Princeton University as alumni, faculty members or researchers. In addition, Princeton has been associated with 21 National Medal of Science winners, 5 Abel Prize winners, 5 National Humanities Medal recipients, 215 Rhodes Scholars, 139 Gates Cambridge Scholars and 137 Marshall Scholars. Two U.S. Presidents, twelve U.S. Supreme Court Justices (three of whom currently serve on the court) and numerous living billionaires and foreign heads of state are all counted among Princeton’s alumni body. Princeton has also graduated many prominent members of the U.S. Congress and the U.S. Cabinet, including eight Secretaries of State, three Secretaries of Defense and the current Chairman of the Joint Chiefs of Staff.

    Princeton University, founded as the College of New Jersey, was considered the successor of the “Log College” founded by the Reverend William Tennent at Neshaminy, PA in about 1726. New Light Presbyterians founded the College of New Jersey in 1746 in Elizabeth, New Jersey. Its purpose was to train ministers. The college was the educational and religious capital of Scottish Presbyterian America. Unlike Harvard University , which was originally “intensely English” with graduates taking the side of the crown during the American Revolution, Princeton was founded to meet the religious needs of the period and many of its graduates took the American side in the war. In 1754, trustees of the College of New Jersey suggested that, in recognition of Governor Jonathan Belcher’s interest, Princeton should be named as Belcher College. Belcher replied: “What a name that would be!” In 1756, the college moved its campus to Princeton, New Jersey. Its home in Princeton was Nassau Hall, named for the royal House of Orange-Nassau of William III of England.

    Following the untimely deaths of Princeton’s first five presidents, John Witherspoon became president in 1768 and remained in that post until his death in 1794. During his presidency, Witherspoon shifted the college’s focus from training ministers to preparing a new generation for secular leadership in the new American nation. To this end, he tightened academic standards and solicited investment in the college. Witherspoon’s presidency constituted a long period of stability for the college, interrupted by the American Revolution and particularly the Battle of Princeton, during which British soldiers briefly occupied Nassau Hall; American forces, led by George Washington, fired cannon on the building to rout them from it.

    In 1812, the eighth president of the College of New Jersey, Ashbel Green (1812–23), helped establish the Princeton Theological Seminary next door. The plan to extend the theological curriculum met with “enthusiastic approval on the part of the authorities at the College of New Jersey.” Today, Princeton University and Princeton Theological Seminary maintain separate institutions with ties that include services such as cross-registration and mutual library access.

    Before the construction of Stanhope Hall in 1803, Nassau Hall was the college’s sole building. The cornerstone of the building was laid on September 17, 1754. During the summer of 1783, the Continental Congress met in Nassau Hall, making Princeton the country’s capital for four months. Over the centuries and through two redesigns following major fires (1802 and 1855), Nassau Hall’s role shifted from an all-purpose building, comprising office, dormitory, library, and classroom space; to classroom space exclusively; to its present role as the administrative center of the University. The class of 1879 donated twin lion sculptures that flanked the entrance until 1911, when that same class replaced them with tigers. Nassau Hall’s bell rang after the hall’s construction; however, the fire of 1802 melted it. The bell was then recast and melted again in the fire of 1855.

    James McCosh became the college’s president in 1868 and lifted the institution out of a low period that had been brought about by the American Civil War. During his two decades of service, he overhauled the curriculum, oversaw an expansion of inquiry into the sciences, and supervised the addition of a number of buildings in the High Victorian Gothic style to the campus. McCosh Hall is named in his honor.

    In 1879, the first thesis for a Doctor of Philosophy (Ph.D.) was submitted by James F. Williamson, Class of 1877.

    In 1896, the college officially changed its name from the College of New Jersey to Princeton University to honor the town in which it resides. During this year, the college also underwent large expansion and officially became a university. In 1900, the Graduate School was established.

    In 1902, Woodrow Wilson, graduate of the Class of 1879, was elected the 13th president of the university. Under Wilson, Princeton introduced the preceptorial system in 1905, a then-unique concept in the United States that augmented the standard lecture method of teaching with a more personal form in which small groups of students, or precepts, could interact with a single instructor, or preceptor, in their field of interest.

    In 1906, the reservoir Carnegie Lake was created by Andrew Carnegie. A collection of historical photographs of the building of the lake is housed at the Seeley G. Mudd Manuscript Library on Princeton’s campus. On October 2, 1913, the Princeton University Graduate College was dedicated. In 1919 the School of Architecture was established. In 1933, Albert Einstein became a lifetime member of the Institute for Advanced Study with an office on the Princeton campus. While always independent of the university, the Institute for Advanced Study occupied offices in Jones Hall for 6 years, from its opening in 1933, until its own campus was finished and opened in 1939.


    In 1969, Princeton University first admitted women as undergraduates. In 1887, the university actually maintained and staffed a sister college, Evelyn College for Women, in the town of Princeton on Evelyn and Nassau streets. It was closed after roughly a decade of operation. After abortive discussions with Sarah Lawrence College to relocate the women’s college to Princeton and merge it with the University in 1967, the administration decided to admit women and turned to the issue of transforming the school’s operations and facilities into a female-friendly campus. The administration had barely finished these plans in April 1969 when the admissions office began mailing out its acceptance letters. Its five-year coeducation plan provided $7.8 million for the development of new facilities that would eventually house and educate 650 women students at Princeton by 1974. Ultimately, 148 women, consisting of 100 freshmen and transfer students of other years, entered Princeton on September 6, 1969 amidst much media attention. Princeton enrolled its first female graduate student, Sabra Follett Meservey, as a PhD candidate in Turkish history in 1961. A handful of undergraduate women had studied at Princeton from 1963 on, spending their junior year there to study “critical languages” in which Princeton’s offerings surpassed those of their home institutions. They were considered regular students for their year on campus, but were not candidates for a Princeton degree.

    As a result of a 1979 lawsuit by Sally Frank, Princeton’s eating clubs were required to go coeducational in 1991, after Tiger Inn’s appeal to the U.S. Supreme Court was denied. In 1987, the university changed the gendered lyrics of “Old Nassau” to reflect the school’s co-educational student body. From 2009 to 2011, Princeton professor Nannerl O. Keohane chaired a committee on undergraduate women’s leadership at the university, appointed by President Shirley M. Tilghman.

    The main campus sits on about 500 acres (2.0 km^2) in Princeton. In 2011, the main campus was named by Travel+Leisure as one of the most beautiful in the United States. The James Forrestal Campus is split between nearby Plainsboro and South Brunswick. The University also owns some property in West Windsor Township. The campuses are situated about one hour from both New York City and Philadelphia.

    The first building on campus was Nassau Hall, completed in 1756 and situated on the northern edge of campus facing Nassau Street. The campus expanded steadily around Nassau Hall during the early and middle 19th century. The McCosh presidency (1868–88) saw the construction of a number of buildings in the High Victorian Gothic and Romanesque Revival styles; many of them are now gone, leaving the remaining few to appear out of place. At the end of the 19th century much of Princeton’s architecture was designed by the Cope and Stewardson firm (same architects who designed a large part of Washington University in St Louis and University of Pennsylvania) resulting in the Collegiate Gothic style for which it is known today. Implemented initially by William Appleton Potter and later enforced by the University’s supervising architect, Ralph Adams Cram, the Collegiate Gothic style remained the standard for all new building on the Princeton campus through 1960. A flurry of construction in the 1960s produced a number of new buildings on the south side of the main campus, many of which have been poorly received. Several prominent architects have contributed some more recent additions, including Frank Gehry (Lewis Library), I. M. Pei (Spelman Halls), Demetri Porphyrios (Whitman College, a Collegiate Gothic project), Robert Venturi and Denise Scott Brown (Frist Campus Center, among several others), and Rafael Viñoly (Carl Icahn Laboratory).

    A group of 20th-century sculptures scattered throughout the campus forms the Putnam Collection of Sculpture. It includes works by Alexander Calder (Five Disks: One Empty), Jacob Epstein (Albert Einstein), Henry Moore (Oval with Points), Isamu Noguchi (White Sun), and Pablo Picasso (Head of a Woman). Richard Serra’s The Hedgehog and The Fox is located between Peyton and Fine halls next to Princeton Stadium and the Lewis Library.

    At the southern edge of the campus is Carnegie Lake, an artificial lake named for Andrew Carnegie. Carnegie financed the lake’s construction in 1906 at the behest of a friend who was a Princeton alumnus. Carnegie hoped the opportunity to take up rowing would inspire Princeton students to forsake football, which he considered “not gentlemanly.” The Shea Rowing Center on the lake’s shore continues to serve as the headquarters for Princeton rowing.

    Cannon Green

    Buried in the ground at the center of the lawn south of Nassau Hall is the “Big Cannon,” which was left in Princeton by British troops as they fled following the Battle of Princeton. It remained in Princeton until the War of 1812, when it was taken to New Brunswick. In 1836 the cannon was returned to Princeton and placed at the eastern end of town. It was removed to the campus under cover of night by Princeton students in 1838 and buried in its current location in 1840.

    A second “Little Cannon” is buried in the lawn in front of nearby Whig Hall. This cannon, which may also have been captured in the Battle of Princeton, was stolen by students of Rutgers University in 1875. The theft ignited the Rutgers-Princeton Cannon War. A compromise between the presidents of Princeton and Rutgers ended the war and forced the return of the Little Cannon to Princeton. The protruding cannons are occasionally painted scarlet by Rutgers students who continue the traditional dispute.

    In years when the Princeton football team beats the teams of both Harvard University and Yale University in the same season, Princeton celebrates with a bonfire on Cannon Green. This occurred in 2012, ending a five-year drought. The next bonfire happened on November 24, 2013, and was broadcast live over the Internet.


    Princeton’s grounds were designed by Beatrix Farrand between 1912 and 1943. Her contributions were most recently recognized with the naming of a courtyard for her. Subsequent changes to the landscape were introduced by Quennell Rothschild & Partners in 2000. In 2005, Michael Van Valkenburgh was hired as the new consulting landscape architect for the campus. Lynden B. Miller was invited to work with him as Princeton’s consulting gardening architect, focusing on the 17 gardens that are distributed throughout the campus.


    Nassau Hall

    Nassau Hall is the oldest building on campus. Begun in 1754 and completed in 1756, it was the first seat of the New Jersey Legislature in 1776, was involved in the battle of Princeton in 1777, and was the seat of the Congress of the Confederation (and thus capitol of the United States) from June 30, 1783, to November 4, 1783. It now houses the office of the university president and other administrative offices, and remains the symbolic center of the campus. The front entrance is flanked by two bronze tigers, a gift of the Princeton Class of 1879. Commencement is held on the front lawn of Nassau Hall in good weather. In 1966, Nassau Hall was added to the National Register of Historic Places.

    Residential colleges

    Princeton has six undergraduate residential colleges, each housing approximately 500 freshmen, sophomores, some juniors and seniors, and a handful of junior and senior resident advisers. Each college consists of a set of dormitories, a dining hall, a variety of other amenities—such as study spaces, libraries, performance spaces, and darkrooms—and a collection of administrators and associated faculty. Two colleges, First College and Forbes College (formerly Woodrow Wilson College and Princeton Inn College, respectively), date to the 1970s; three others, Rockefeller, Mathey, and Butler Colleges, were created in 1983 following the Committee on Undergraduate Residential Life (CURL) report, which suggested the institution of residential colleges as a solution to an allegedly fragmented campus social life. The construction of Whitman College, the university’s sixth residential college, was completed in 2007.

    Rockefeller and Mathey are located in the northwest corner of the campus; Princeton brochures often feature their Collegiate Gothic architecture. Like most of Princeton’s Gothic buildings, they predate the residential college system and were fashioned into colleges from individual dormitories.

    First and Butler, located south of the center of the campus, were built in the 1960s. First served as an early experiment in the establishment of the residential college system. Butler, like Rockefeller and Mathey, consisted of a collection of ordinary dorms (called the “New New Quad”) before the addition of a dining hall made it a residential college. Widely disliked for their edgy modernist design, including “waffle ceilings,” the dormitories on the Butler Quad were demolished in 2007. Butler is now reopened as a four-year residential college, housing both under- and upperclassmen.

    Forbes is located on the site of the historic Princeton Inn, a gracious hotel overlooking the Princeton golf course. The Princeton Inn, originally constructed in 1924, played regular host to important symposia and gatherings of renowned scholars from both the university and the nearby Institute for Advanced Study for many years. Forbes currently houses nearly 500 undergraduates in its residential halls.

    In 2003, Princeton broke ground for a sixth college named Whitman College after its principal sponsor, Meg Whitman, who graduated from Princeton in 1977. The new dormitories were constructed in the Collegiate Gothic architectural style and were designed by architect Demetri Porphyrios. Construction finished in 2007, and Whitman College was inaugurated as Princeton’s sixth residential college that same year.

    The precursor of the present college system in America was originally proposed by university president Woodrow Wilson in the early 20th century. For over 800 years, however, the collegiate system had already existed in Britain at University of Cambridge (UK) and University of Oxford (UK). Wilson’s model was much closer to Yale University’s present system, which features four-year colleges. Lacking the support of the trustees, the plan languished until 1968. That year, Wilson College was established to cap a series of alternatives to the eating clubs. Fierce debates raged before the present residential college system emerged. The plan was first attempted at Yale, but the administration was initially uninterested; an exasperated alumnus, Edward Harkness, finally paid to have the college system implemented at Harvard in the 1920s, leading to the oft-quoted aphorism that the college system is a Princeton idea that was executed at Harvard with funding from Yale.

    Princeton has one graduate residential college, known simply as the Graduate College, located beyond Forbes College at the outskirts of campus. The far-flung location of the GC was the spoil of a squabble between Woodrow Wilson and then-Graduate School Dean Andrew Fleming West. Wilson preferred a central location for the college; West wanted the graduate students as far as possible from the campus. Ultimately, West prevailed. The Graduate College is composed of a large Collegiate Gothic section crowned by Cleveland Tower, a local landmark that also houses a world-class carillon. The attached New Graduate College provides a modern contrast in architectural style.

    McCarter Theatre

    The Tony-award-winning McCarter Theatre was built by the Princeton Triangle Club, a student performance group, using club profits and a gift from Princeton University alumnus Thomas McCarter. Today, the Triangle Club performs its annual freshmen revue, fall show, and Reunions performances in McCarter. McCarter is also recognized as one of the leading regional theaters in the United States.

    Art Museum

    The Princeton University Art Museum was established in 1882 to give students direct, intimate, and sustained access to original works of art that complement and enrich instruction and research at the university. This continues to be a primary function, along with serving as a community resource and a destination for national and international visitors.

    Numbering over 92,000 objects, the collections range from ancient to contemporary art and concentrate geographically on the Mediterranean regions, Western Europe, China, the United States, and Latin America. There is a collection of Greek and Roman antiquities, including ceramics, marbles, bronzes, and Roman mosaics from faculty excavations in Antioch. Medieval Europe is represented by sculpture, metalwork, and stained glass. The collection of Western European paintings includes examples from the early Renaissance through the 19th century, with masterpieces by Monet, Cézanne, and Van Gogh, and features a growing collection of 20th-century and contemporary art, including iconic paintings such as Andy Warhol’s Blue Marilyn.

    One of the best features of the museums is its collection of Chinese art, with important holdings in bronzes, tomb figurines, painting, and calligraphy. Its collection of pre-Columbian art includes examples of Mayan art, and is commonly considered to be the most important collection of pre-Columbian art outside of Latin America. The museum has collections of old master prints and drawings and a comprehensive collection of over 27,000 original photographs. African art and Northwest Coast Indian art are also represented. The Museum also oversees the outdoor Putnam Collection of Sculpture.

    University Chapel

    The Princeton University Chapel is located on the north side of campus, near Nassau Street. It was built between 1924 and 1928, at a cost of $2.3 million [approximately $34.2 million in 2020 dollars]. Ralph Adams Cram, the University’s supervising architect, designed the chapel, which he viewed as the crown jewel for the Collegiate Gothic motif he had championed for the campus. At the time of its construction, it was the second largest university chapel in the world, after King’s College Chapel, Cambridge. It underwent a two-year, $10 million restoration campaign between 2000 and 2002.

    Measured on the exterior, the chapel is 277 feet (84 m) long, 76 feet (23 m) wide at its transepts, and 121 feet (37 m) high. The exterior is Pennsylvania sandstone, with Indiana limestone used for the trim. The interior is mostly limestone and Aquia Creek sandstone. The design evokes an English church of the Middle Ages. The extensive iconography, in stained glass, stonework, and wood carvings, has the common theme of connecting religion and scholarship.

    The Chapel seats almost 2,000. It hosts weekly ecumenical Christian services, daily Roman Catholic mass, and several annual special events.

    Murray-Dodge Hall

    Murray-Dodge Hall houses the Office of Religious Life (ORL), the Murray Dodge Theater, the Murray-Dodge Café, the Muslim Prayer Room and the Interfaith Prayer Room. The ORL houses the office of the Dean of Religious Life, Alison Boden, and a number of university chaplains, including the country’s first Hindu chaplain, Vineet Chander; and one of the country’s first Muslim chaplains, Sohaib Sultan.


    Published in 2008, Princeton’s Sustainability Plan highlights three priority areas for the University’s Office of Sustainability: reduction of greenhouse gas emissions; conservation of resources; and research, education, and civic engagement. Princeton has committed to reducing its carbon dioxide emissions to 1990 levels by 2020: Energy without the purchase of offsets. The University published its first Sustainability Progress Report in November 2009. The University has adopted a green purchasing policy and recycling program that focuses on paper products, construction materials, lightbulbs, furniture, and electronics. Its dining halls have set a goal to purchase 75% sustainable food products by 2015. The student organization “Greening Princeton” seeks to encourage the University administration to adopt environmentally friendly policies on campus.


    The Trustees of Princeton University, a 40-member board, is responsible for the overall direction of the University. It approves the operating and capital budgets, supervises the investment of the University’s endowment and oversees campus real estate and long-range physical planning. The trustees also exercise prior review and approval concerning changes in major policies, such as those in instructional programs and admission, as well as tuition and fees and the hiring of faculty members.

    With an endowment of $26.1 billion, Princeton University is among the wealthiest universities in the world. Ranked in 2010 as the third largest endowment in the United States, the university had the greatest per-student endowment in the world (over $2 million for undergraduates) in 2011. Such a significant endowment is sustained through the continued donations of its alumni and is maintained by investment advisers. Some of Princeton’s wealth is invested in its art museum, which features works by Claude Monet, Vincent van Gogh, Jackson Pollock, and Andy Warhol among other prominent artists.


    Undergraduates fulfill general education requirements, choose among a wide variety of elective courses, and pursue departmental concentrations and interdisciplinary certificate programs. Required independent work is a hallmark of undergraduate education at Princeton. Students graduate with either the Bachelor of Arts (A.B.) or the Bachelor of Science in Engineering (B.S.E.).

    The graduate school offers advanced degrees spanning the humanities, social sciences, natural sciences, and engineering. Doctoral education is available in most disciplines. It emphasizes original and independent scholarship whereas master’s degree programs in architecture, engineering, finance, and public affairs and public policy prepare candidates for careers in public life and professional practice.

    The university has ties with the Institute for Advanced Study, Princeton Theological Seminary and the Westminster Choir College of Rider University .


    Undergraduate courses in the humanities are traditionally either seminars or lectures held 2 or 3 times a week with an additional discussion seminar that is called a “precept.” To graduate, all A.B. candidates must complete a senior thesis and, in most departments, one or two extensive pieces of independent research that are known as “junior papers.” Juniors in some departments, including architecture and the creative arts, complete independent projects that differ from written research papers. A.B. candidates must also fulfill a three or four semester foreign language requirement and distribution requirements (which include, for example, classes in ethics, literature and the arts, and historical analysis) with a total of 31 classes. B.S.E. candidates follow a parallel track with an emphasis on a rigorous science and math curriculum, a computer science requirement, and at least two semesters of independent research including an optional senior thesis. All B.S.E. students must complete at least 36 classes. A.B. candidates typically have more freedom in course selection than B.S.E. candidates because of the fewer number of required classes. Nonetheless, in the spirit of a liberal arts education, both enjoy a comparatively high degree of latitude in creating a self-structured curriculum.

    Undergraduates agree to adhere to an academic integrity policy called the Honor Code, established in 1893. Under the Honor Code, faculty do not proctor examinations; instead, the students proctor one another and must report any suspected violation to an Honor Committee made up of undergraduates. The Committee investigates reported violations and holds a hearing if it is warranted. An acquittal at such a hearing results in the destruction of all records of the hearing; a conviction results in the student’s suspension or expulsion. The signed pledge required by the Honor Code is so integral to students’ academic experience that the Princeton Triangle Club performs a song about it each fall. Out-of-class exercises fall under the jurisdiction of the Faculty-Student Committee on Discipline. Undergraduates are expected to sign a pledge on their written work affirming that they have not plagiarized the work.


    The Graduate School has about 2,600 students in 42 academic departments and programs in social sciences; engineering; natural sciences; and humanities. These departments include the Department of Psychology; Department of History; and Department of Economics.

    In 2017–2018, it received nearly 11,000 applications for admission and accepted around 1,000 applicants. The University also awarded 319 Ph.D. degrees and 170 final master’s degrees. Princeton has no medical school, law school, business school, or school of education. (A short-lived Princeton Law School folded in 1852.) It offers professional graduate degrees in architecture; engineering; finance and public policy- the last through the Princeton School of Public and International Affairs founded in 1930 as the School of Public and International Affairs and renamed in 1948 after university president (and U.S. president) Woodrow Wilson, and most recently renamed in 2020.


    The Princeton University Library system houses over eleven million holdings including seven million bound volumes. The main university library, Firestone Library, which houses almost four million volumes, is one of the largest university libraries in the world. Additionally, it is among the largest “open stack” libraries in existence. Its collections include the autographed manuscript of F. Scott Fitzgerald’s The Great Gatsby and George F. Kennan’s Long Telegram. In addition to Firestone library, specialized libraries exist for architecture, art and archaeology, East Asian studies, engineering, music, public and international affairs, public policy and university archives, and the sciences. In an effort to expand access, these libraries also subscribe to thousands of electronic resources.


    High Meadows Environmental Institute

    The High Meadows Environmental Institute is an “interdisciplinary center of environmental research, education, and outreach” at the university. The institute was started in 1994. About 90 faculty members at Princeton University are affiliated with it.

    The High Meadows Environmental Institute has the following research centers:

    Carbon Mitigation Initiative (CMI): This is a 15-year-long partnership between PEI and British Petroleum with the goal of finding solutions to problems related to climate change. The Stabilization Wedge Game has been created as part of this initiative.
    Center for BioComplexity (CBC)
    Cooperative Institute for Climate Science (CICS): This is a collaboration with the National Oceanographic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory.
    Energy Systems Analysis Group
    Grand Challenges

    Princeton Plasma Physics Laboratory

    The DOE’s Princeton Plasma Physics Laboratory was founded in 1951 as Project Matterhorn, a top-secret cold war project aimed at achieving controlled nuclear fusion. Princeton astrophysics professor Lyman Spitzer became the first director of the project and remained director until the lab’s declassification in 1961 when it received its current name.
    PPPL currently houses approximately half of the graduate astrophysics department, the Princeton Program in Plasma Physics. The lab is also home to the Harold P. Furth Plasma Physics Library. The library contains all declassified Project Matterhorn documents, included the first design sketch of a stellarator by Lyman Spitzer.

    Princeton is one of five US universities to have and to operate a Department of Energy national laboratory.

    Student life and culture

    University housing is guaranteed to all undergraduates for all four years. More than 98% of students live on campus in dormitories. Freshmen and sophomores must live in residential colleges, while juniors and seniors typically live in designated upperclassman dormitories. The actual dormitories are comparable, but only residential colleges have dining halls. Nonetheless, any undergraduate may purchase a meal plan and eat in a residential college dining hall. Recently, upperclassmen have been given the option of remaining in their college for all four years. Juniors and seniors also have the option of living off-campus, but high rent in the Princeton area encourages almost all students to live in university housing. Undergraduate social life revolves around the residential colleges and a number of coeducational eating clubs, which students may choose to join in the spring of their sophomore year. Eating clubs, which are not officially affiliated with the university, serve as dining halls and communal spaces for their members and also host social events throughout the academic year.

    Princeton’s six residential colleges host a variety of social events and activities, guest speakers, and trips. The residential colleges also sponsor trips to New York for undergraduates to see ballets, operas, Broadway shows, sports events, and other activities. The eating clubs, located on Prospect Avenue, are co-ed organizations for upperclassmen. Most upperclassmen eat their meals at one of the eleven eating clubs. Additionally, the clubs serve as evening and weekend social venues for members and guests. The eleven clubs are Cannon; Cap and Gown; Charter; Cloister; Colonial; Cottage; Ivy; Quadrangle; Terrace; Tiger; and Tower.

    Princeton hosts two Model United Nations conferences, PMUNC in the fall for high school students and PDI in the spring for college students. It also hosts the Princeton Invitational Speech and Debate tournament each year at the end of November. Princeton also runs Princeton Model Congress, an event that is held once a year in mid-November. The four-day conference has high school students from around the country as participants.

    Although the school’s admissions policy is need-blind, Princeton, based on the proportion of students who receive Pell Grants, was ranked as a school with little economic diversity among all national universities ranked by U.S. News & World Report. While Pell figures are widely used as a gauge of the number of low-income undergraduates on a given campus, the rankings article cautions “the proportion of students on Pell Grants isn’t a perfect measure of an institution’s efforts to achieve economic diversity,” but goes on to say that “still, many experts say that Pell figures are the best available gauge of how many low-income undergrads there are on a given campus.”

    TigerTrends is a university-based student run fashion, arts, and lifestyle magazine.


    Princeton has made significant progress in expanding the diversity of its student body in recent years. The 2019 freshman class was one of the most diverse in the school’s history, with 61% of students identifying as students of color. Undergraduate and master’s students were 51% male and 49% female for the 2018–19 academic year.

    The median family income of Princeton students is $186,100, with 57% of students coming from the top 10% highest-earning families and 14% from the bottom 60%.

    In 1999, 10% of the student body was Jewish, a percentage lower than those at other Ivy League schools. Sixteen percent of the student body was Jewish in 1985; the number decreased by 40% from 1985 to 1999. This decline prompted The Daily Princetonian to write a series of articles on the decline and its reasons. Caroline C. Pam of The New York Observer wrote that Princeton was “long dogged by a reputation for anti-Semitism” and that this history as well as Princeton’s elite status caused the university and its community to feel sensitivity towards the decrease of Jewish students. At the time many Jewish students at Princeton dated Jewish students at the University of Pennsylvania in Philadelphia because they perceived Princeton as an environment where it was difficult to find romantic prospects; Pam stated that there was a theory that the dating issues were a cause of the decline in Jewish students.

    In 1981, the population of African Americans at Princeton University made up less than 10%. Bruce M. Wright was admitted into the university in 1936 as the first African American, however, his admission was a mistake and when he got to campus he was asked to leave. Three years later Wright asked the dean for an explanation on his dismissal and the dean suggested to him that “a member of your race might feel very much alone” at Princeton University.


    Princeton enjoys a wide variety of campus traditions, some of which, like the Clapper Theft and Nude Olympics, have faded into history:

    Arch Sings – Late-night concerts that feature one or several of Princeton’s undergraduate a cappella groups, such as the Princeton Nassoons; Princeton Tigertones; Princeton Footnotes; Princeton Roaring 20; and The Princeton Wildcats. The free concerts take place in one of the larger arches on campus. Most are held in Blair Arch or Class of 1879 Arch.

    Bonfire – Ceremonial bonfire that takes place in Cannon Green behind Nassau Hall. It is held only if Princeton beats both Harvard University and Yale University at football in the same season. The most recent bonfire was lighted on November 18, 2018.

    Bicker – Selection process for new members that is employed by selective eating clubs. Prospective members, or bickerees, are required to perform a variety of activities at the request of current members.

    Cane Spree – An athletic competition between freshmen and sophomores that is held in the fall. The event centers on cane wrestling, where a freshman and a sophomore will grapple for control of a cane. This commemorates a time in the 1870s when sophomores, angry with the freshmen who strutted around with fancy canes, stole all of the canes from the freshmen, hitting them with their own canes in the process.

    The Clapper or Clapper Theft – The act of climbing to the top of Nassau Hall to steal the bell clapper, which rings to signal the start of classes on the first day of the school year. For safety reasons, the clapper has been removed permanently.

    Class Jackets (Beer Jackets) – Each graduating class designs a Class Jacket that features its class year. The artwork is almost invariably dominated by the school colors and tiger motifs.

    Communiversity – An annual street fair with performances, arts and crafts, and other activities that attempts to foster interaction between the university community and the residents of Princeton.

    Dean’s Date – The Tuesday at the end of each semester when all written work is due. This day signals the end of reading period and the beginning of final examinations. Traditionally, undergraduates gather outside McCosh Hall before the 5:00 PM deadline to cheer on fellow students who have left their work to the very last minute.

    FitzRandolph Gates – At the end of Princeton’s graduation ceremony, the new graduates process out through the main gate of the university as a symbol of the fact that they are leaving college. According to tradition, anyone who exits campus through the FitzRandolph Gates before his or her own graduation date will not graduate.

    Holder Howl – The midnight before Dean’s Date, students from Holder Hall and elsewhere gather in the Holder courtyard and take part in a minute-long, communal primal scream to vent frustration from studying with impromptu, late night noise making.

    Houseparties – Formal parties that are held simultaneously by all of the eating clubs at the end of the spring term.

    Ivy stones – Class memorial stones placed on the exterior walls of academic buildings around the campus.

    Lawnparties – Parties that feature live bands that are held simultaneously by all of the eating clubs at the start of classes and at the conclusion of the academic year.

    Princeton Locomotive – Traditional cheer in use since the 1890s. It is commonly heard at Opening Exercises in the fall as alumni and current students welcome the freshman class, as well as the P-rade in the spring at Princeton Reunions. The cheer starts slowly and picks up speed, and includes the sounds heard at a fireworks show.

    Hip! Hip!
    Rah, Rah, Rah,
    Tiger, Tiger, Tiger,
    Sis, Sis, Sis,
    Boom, Boom, Boom, Ah!
    Princeton! Princeton! Princeton!

    Or if a class is being celebrated, the last line consists of the class year repeated three times, e.g. “Eighty-eight! Eighty-eight! Eighty-eight!”

    Newman’s Day – Students attempt to drink 24 beers in the 24 hours of April 24. According to The New York Times, “the day got its name from an apocryphal quote attributed to Paul Newman: ’24 beers in a case, 24 hours in a day. Coincidence? I think not.'” Newman had spoken out against the tradition, however.

    Nude Olympics – Annual nude and partially nude frolic in Holder Courtyard that takes place during the first snow of the winter. Started in the early 1970s, the Nude Olympics went co-educational in 1979 and gained much notoriety with the American press. For safety reasons, the administration banned the Olympics in 2000 to the chagrin of students.

    Prospect 11 – The act of drinking a beer at all 11 eating clubs in a single night.

    P-rade – Traditional parade of alumni and their families. They process through campus by class year during Reunions.

    Reunions – Massive annual gathering of alumni held the weekend before graduation.


    Princeton supports organized athletics at three levels: varsity intercollegiate, club intercollegiate, and intramural. It also provides “a variety of physical education and recreational programs” for members of the Princeton community. According to the athletics program’s mission statement, Princeton aims for its students who participate in athletics to be “‘student athletes’ in the fullest sense of the phrase. Most undergraduates participate in athletics at some level.

    Princeton’s colors are orange and black. The school’s athletes are known as Tigers, and the mascot is a tiger. The Princeton administration considered naming the mascot in 2007, but the effort was dropped in the face of alumni opposition.


    Princeton is an NCAA Division I school. Its athletic conference is the Ivy League. Princeton hosts 38 men’s and women’s varsity sports. The largest varsity sport is rowing, with almost 150 athletes.

    Princeton’s football team has a long and storied history. Princeton played against Rutgers University in the first intercollegiate football game in the U.S. on Nov 6, 1869. By a score of 6–4, Rutgers won the game, which was played by rules similar to modern rugby. Today Princeton is a member of the Football Championship Subdivision of NCAA Division I. As of the end of the 2010 season, Princeton had won 26 national football championships, more than any other school.

    Club and intramural

    In addition to varsity sports, Princeton hosts about 35 club sports teams. Princeton’s rugby team is organized as a club sport. Princeton’s sailing team is also a club sport, though it competes at the varsity level in the MAISA conference of the Inter-Collegiate Sailing Association.

    Each year, nearly 300 teams participate in intramural sports at Princeton. Intramurals are open to members of Princeton’s faculty, staff, and students, though a team representing a residential college or eating club must consist only of members of that college or club. Several leagues with differing levels of competitiveness are available.


    Notable among a number of songs commonly played and sung at various events such as commencement, convocation, and athletic games is Princeton Cannon Song, the Princeton University fight song.

    Bob Dylan wrote Day of The Locusts (for his 1970 album New Morning) about his experience of receiving an honorary doctorate from the University. It is a reference to the negative experience he had and it mentions the Brood X cicada infestation Princeton experienced that June 1970.

    “Old Nassau”

    Old Nassau has been Princeton University’s anthem since 1859. Its words were written that year by a freshman, Harlan Page Peck, and published in the March issue of the Nassau Literary Review (the oldest student publication at Princeton and also the second oldest undergraduate literary magazine in the country). The words and music appeared together for the first time in Songs of Old Nassau, published in April 1859. Before the Langlotz tune was written, the song was sung to Auld Lang Syne’s melody, which also fits.

    However, Old Nassau does not only refer to the university’s anthem. It can also refer to Nassau Hall, the building that was built in 1756 and named after William III of the House of Orange-Nassau. When built, it was the largest college building in North America. It served briefly as the capitol of the United States when the Continental Congress convened there in the summer of 1783. By metonymy, the term can refer to the university as a whole. Finally, it can also refer to a chemical reaction that is dubbed “Old Nassau reaction” because the solution turns orange and then black.
    Princeton Shield

  • richardmitnick 9:49 pm on December 17, 2022 Permalink | Reply
    Tags: "Telling apart two types of gravitational-wave signals", , , , , , , Multimessenger Astronomy/Astrophysics, What is needed to distinguish between binary black hole and neutron star black hole mergers?   

    From The MPG Institute for Gravitational Physics [MPG Institut für Gravitationsphysik](Albert Einstein Institut) (DE) : “Telling apart two types of gravitational-wave signals” 

    From The MPG Institute for Gravitational Physics [MPG Institut für Gravitationsphysik](Albert Einstein Institut) (DE)


    Dr. Benjamin Knispel
    Press Officer AEI Hannover
    +49 511 762-19104

    Scientific contacts

    Stephanie Brown
    PhD Student
    +49 511 762-17063

    Dr. Collin Capano
    Senior Scientist
    +49 511 762-17097

    What is needed to distinguish between binary black hole and neutron star black hole mergers?

    Simulation of a neutron-star–black-hole coalescence in which the neutron star is tidally disrupted during the merger. © T. Dietrich (Potsdam University and MPG Institute for Gravitational Physics), N. Fischer, S. Ossokine, H. Pfeiffer (MPG Institute for Gravitational Physics), S.V.Chaurasia (Stockholm University), T. Vu

    As the number of gravitational wave observations increase, many questions arise; one of growing importance is this: when a gravitational-wave from a low mass merger is detected without a concurrent electromagnetic signal how can one distinguish a light weight binary black hole merger from a neutron star black hole merger? Researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute Hannover, AEI), at Leibniz University Hannover, and at Radboud University have used a simulated search for such gravitational-wave signals to answer this question. Their results were now published in The Astrophysical Journal [below]. Third-generation detectors such as Cosmic Explorer and the Einstein Telescope will be able to make a clear-cut distinction under favorable circumstances.

    This shows that new instruments will be needed for precise gravitational-wave astrophysics.

    Gravitational-wave signals are like fingerprints. They allow astrophysicists to find the culprit for a signal they detect. Moreover, the researchers can infer many properties of the source that emitted the signal. All signals observed so far by LIGO and Virgo came from collisions of compact objects, such as black holes and neutron stars. Their masses and spins and the nature of the merging objects can be extracted from the gravitational wave.


    Caltech /MIT Advanced aLigo.

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

    Caltech/MIT Advanced aLigo Hanford, WA. installation.

    VIRGO Gravitational Wave interferometer installation, near Pisa (IT).

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



    Gravitational-wave look-alikes

    Some types of signals can be harder to tell apart than others. “If you only consider the masses of the objects, a binary black hole merger where one black hole is very small can be difficult, if not impossible, to distinguish from a neutron star black hole merger. We don’t know with certainty the maximum mass of a neutron star or the minimum mass of a black hole,” says Stephanie Brown, a PhD student at the MPG Institute for Gravitational Physics and at Leibniz University-Hannover, lead author of the study published now in The Astrophysical Journal [below].

    If mass alone is not sufficient to unambiguously distinguish the two merger types, then what is? Neutron stars – unlike black holes – consist of matter. Therefore, there are two ways in which the presence of a neutron star in the merger can be determined: the presence of an electromagnetic counterpart or the imprint of matter effects on the gravitational wave itself.

    If there is an electromagnetic signal such as a flash of gamma-rays associated to the event, there must be matter in the system, and one of the two merging compact objects must be a neutron star. In most cases, it is unlikely that electromagnetic radiation will be detected for such events: perhaps because the distance is large and the light is too faint or because it is not directed at Earth at all.

    The fingerprints of deformed neutron stars

    “Independent of their elusive light show, neutron stars leave behind other traces in the gravitational-wave signal. They will be deformed by the enormous gravitational pull from their black hole partners well before the merger,” says Collin Capano, a researcher at AEI Hannover, and co-author of the study. “These ‘tidal effects’ – similar to the tides induced by the Moon on Earth – leave characteristic, yet faint, fingerprints in the gravitational-wave signal. Black holes on the other hand have no tidal effects,” Capano adds.

    Simulation of a black-hole–neutron-star merger (GW200115). © T. Dietrich (Potsdam University and Max Planck Institute for Gravitational Physics), N. Fischer, S. Ossokine, H. Pfeiffer (Max Planck Institute for Gravitational Physics), S.V.Chaurasia (Stockholm University). The movie represents a system compatible to GW200115, i.e., the black hole mass was chosen to be 6.1 solar masses and the neutron star mass was set to 1.4 solar masses. Both objects were non-spinning.

    So far it has been impossible to unambiguously detect the tidal effects from neutron star deformation in any of the observed LIGO-Virgo signals. The international team led by Stephanie Brown estimated just how difficult this task is. They simulated gravitational-wave signals from neutron star black hole mergers at different distances to Earth for both current and future detector configurations. Building on their earlier work, they predicted the amount a companion black hole will tidally deform a neutron star by using nuclear physics models that describe the behavior of the matter inside the star.

    They considered the present LIGO and Virgo detectors at their design sensitivities, their near term upgrades (LIGO A+ and LIGO Voyager), and also Cosmic Explorer, a third generation detector. They identified those cases in which the data analysis of their simulated search was able to provide decisive evidence for the presence of tidal effects.

    Third-generation detectors are required

    Artist’s impression of the underground Einstein Telescope, a planned third-generation gravitational-wave detector. © National Institute for Subatomic Physics (NL).

    Their results: Only when the black hole was relatively light-weight (about 4 times the mass of the neutron star, equivalent to five times the mass of our Sun) was there a chance of clearly observing tidal effects in the gravitational-wave signal. This is because the tidal effects are stronger if the black hole’s mass is more similar to the neutron star’s mass. Even at design sensitivity the current detector network, LIGO A+, and even LIGO Voyager will not be able to distinguish between the two types of merger signals based on the detection or non-detection of tidal effects.

    According to the study, only the third-generation detector Cosmic Explorer would be able to tell apart the two types of signals, but even this much more sensitive detector will likely need an event to take place very close to Earth (130 million light-years, as close as GW170817, the first binary neutron star merger observed by LIGO and Virgo).

    “We find that third-generation detectors like Cosmic Explorer can detect tidal effects and can use that to distinguish between binary black hole mergers and neutron star black hole mergers,” says Brown. “This underlines the necessity of third generation detectors for precise gravitational-wave astronomy and astrophysics.”

    Science paper:
    The Astrophysical Journal
    See the science paper for instructive material with images.

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The MPG Institute for Gravitational Physics [MPG Institut für Gravitationsphysik] (Albert Einstein Institut)(DE) is the largest research institute in the world specializing in General Relativity and beyond. The institute is located in Potsdam-Golm and in Hannover where it is closely related to the Leibniz Universität Hannover.

    The MPG Institute for Gravitational Physics (Albert Einstein Institute) is a Max Planck Institute whose research is aimed at investigating Albert Einstein’s Theory of General Relativity and beyond: Mathematics; quantum gravity; astrophysical relativity; and gravitational-wave astronomy. The Institute was founded in 1995 and is located in the Potsdam Science Park in Golm, Potsdam and in Hannover where it is closely related to the Leibniz University Hannover [Gottfried Wilhelm Leibniz Universität Hannover](DE). The Potsdam part of the institute is organized in three research departments, while the Hannover part has two departments. Both parts of the institute host a number of independent research groups.

    The institute conducts fundamental research in Mathematics; data analysis; Astrophysics and Theoretical Physics; as well as research in Laser Physics; vacuum technology; vibration isolation; and Classical and Quantum Optics.

    When the Caltech MIT Advanced aLIGO Scientific Collaboration announced the first detection of gravitational waves, researchers of the Institute were involved in modeling, detecting, analyzing and characterizing the signals. The Institute is part of a number of collaborations and projects: it is a main partner in the gravitational-wave detector GEO600. Institute scientists are developing waveform-models that are applied in the gravitational-wave detectors for detecting and characterizing gravitational waves. They are developing detector technology and are also analyzing data from the detectors of the LIGO Scientific Collaboration, the VIRGO European Gravitational Observatory(IT) and the KAGRA Large-scale Cryogenic Gravitional wave Telescope Project(JP).

    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.
    They also play a leading role in planning and preparing the space-based detector
    European Space Agency(EU)/National Aeronautics and Space AgencyLISA Next Gravitational Wave Observatory; Einstein Telescope » APPEC(EU); and the Cosmic Explorer.

    The Institute is also a major player in the Einstein@Home(DE) and PyCBC projects.

    From 1998 to 2015, the institute has published the open access review journal Living Reviews in Relativity.


    The newly founded institute started its work in April 1995 and has been located in Potsdam-Golm since 1999.

    In 2002 the Institute opened a branch at the Leibniz University Hannover [Gottfried Wilhelm Leibniz Universität Hannover](DE) with a focus on data analysis and the development and operation of gravitational-wave detectors on Earth and in space. The Hannover institute originated from the Institute for Atom and Molecule Physics (AMP) of the Universität Hannover, which was established in 1979 by the Department of Physics.


    The research focus of the Institute is in the field of General Relativity. It covers Theoretical and Experimental Gravitational Physics; quantum gravity; Multi-messenger Astrophysics and Cosmology. The Institute has a strong research focus on Gravitational-wave Astronomy: four out of five departments are working on different aspects of this research field. Central research topics are:

    Source modeling (binary neutron stars, binary black holes, mixed binaries, stellar core collapse).
    Experimental work on gravitational-wave detectors – both on Earth and in space.
    Solving the Two-Body problem in General Relativity.
    Analytical and numerical solutions of Einstein’s equations.
    Development and implementation of data analysis algorithms for gravitational-wave searches.
    Follow-up analyses to infer properties of the gravitational-wave sources.

    All these efforts enable a new kind of Astronomy, which began with the first direct detection of gravitational waves on Earth.

    Scientists of the Institute also work towards the unification of the fundamental theories of PhysicsGeneral Relativity and Quantum Mechanics – into a theory of Quantum Gravity.

    Max Planck Partner Groups

    Max Planck Partner Groups carry out research in fields overlapping with those of the former host Max Planck institute. They are established to support junior scientists returning to their home country after a research stay at a Max Planck Institute.

    The Max Planck Institute for Gravitational Physics has five Max Planck Partner Groups:

    at the Institute of Theoretical Physics, Chinese Academy of Sciences [中国科学院](CN), collaborating with the “Quantum Gravity and Unified Theories” department.
    at the Chennai Mathematical Institute(IN), collaborating with “Quantum Gravity and Unified Theories” department.
    at the Indian Institute of Technology Kanpur(IN), collaborating with the “Quantum Gravity and Unified Theories” department.
    at Jilin University [吉林大学](CN) collaborating with the “Quantum Gravity and Unified Theories” department.
    at the Tata Institute of Fundamental Research(IN), collaborating with the “Observational Relativity and Cosmology” department.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the MPG Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) MPG Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The MPG Institutes focus on excellence in research. The MPG Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the MPG institutes fifth worldwide in terms of research published in Nature journals (after Harvard University, The Massachusetts Institute of Technology, Stanford University and The National Institutes of Health). In terms of total research volume, the Max Planck Society is only outranked by The Chinese Academy of Sciences [中国科学院](CN), The Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the MPG Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

    The MPG Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.


    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.

    The MPG Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the MPG Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and The DOE’s Argonne National Laboratory.

    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.

    MPG Institutes and research groups

    The MPG Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University focusing on neuroscience.

    The MPG Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.

    Internally, MPG Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.

    In addition, there are several associated institutes:

    International Max Planck Research Schools

    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:

    • Cologne Graduate School of Ageing Research, Cologne
    • International Max Planck Research School for Intelligent Systems, at the Max Planck Institute for Intelligent Systems located in Tübingen and Stuttgart
    • International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    • International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    • International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPI for Astronomy
    • International Max Planck Research School for Astrophysics, Garching at the MPI for Astrophysics
    • International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    • International Max Planck Research School for Computer Science, Saarbrücken
    • International Max Planck Research School for Earth System Modeling, Hamburg
    • International Max Planck Research School for Elementary Particle Physics, Munich, at the MPI for Physics
    • International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the Max Planck Institute for Terrestrial Microbiology
    • International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    • International Max Planck Research School “From Molecules to Organisms”, Tübingen at the Max Planck Institute for Developmental Biology
    • International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    • International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPI for Gravitational Physics
    • International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the Max Planck Institute for Heart and Lung Research
    • International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    • International Max Planck Research School for Language Sciences, Nijmegen
    • International Max Planck Research School for Neurosciences, Göttingen
    • International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    • International Max Planck Research School for Marine Microbiology (MarMic), joint program of the Max Planck Institute for Marine Microbiology in Bremen, the University of Bremen, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    • International Max Planck Research School for Maritime Affairs, Hamburg
    • International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    • International Max Planck Research School for Molecular and Cellular Life Sciences, Munich
    • International Max Planck Research School for Molecular Biology, Göttingen
    • International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    • International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster and the Max Planck Institute for Molecular Biomedicine
    • International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    • International Max Planck Research School for Organismal Biology, at the University of Konstanz and the Max Planck Institute for Ornithology
    • International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion
    • International Max Planck Research School for Science and Technology of Nano-Systems, Halle at Max Planck Institute of Microstructure Physics
    • International Max Planck Research School for Solar System Science at the University of Göttingen hosted by MPI for Solar System Research
    • International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPI for Radio Astronomy (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    • International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    • International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at Max Planck Institute for Iron Research GmbH
    • International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

    Max Planck Schools

    • Max Planck School of Cognition
    • Max Planck School Matter to Life
    • Max Planck School of Photonics

    Max Planck Center

    • The Max Planck Centre for Attosecond Science (MPC-AS), POSTECH Pohang
    • The Max Planck POSTECH Center for Complex Phase Materials, POSTECH Pohang

    Max Planck Institutes

    Among others:
    • Max Planck Institute for Neurobiology of Behavior – caesar, Bonn
    • Max Planck Institute for Aeronomics in Katlenburg-Lindau was renamed to Max Planck Institute for Solar System Research in 2004;
    • Max Planck Institute for Biology in Tübingen was closed in 2005;
    • Max Planck Institute for Cell Biology in Ladenburg b. Heidelberg was closed in 2003;
    • Max Planck Institute for Economics in Jena was renamed to the Max Planck Institute for the Science of Human History in 2014;
    • Max Planck Institute for Ionospheric Research in Katlenburg-Lindau was renamed to Max Planck Institute for Aeronomics in 1958;
    • Max Planck Institute for Metals Research, Stuttgart
    • Max Planck Institute of Oceanic Biology in Wilhelmshaven was renamed to Max Planck Institute of Cell Biology in 1968 and moved to Ladenburg 1977;
    • Max Planck Institute for Psychological Research in Munich merged into the Max Planck Institute for Human Cognitive and Brain Sciences in 2004;
    • Max Planck Institute for Protein and Leather Research in Regensburg moved to Munich 1957 and was united with the Max Planck Institute for Biochemistry in 1977;
    • Max Planck Institute for Virus Research in Tübingen was renamed as Max Planck Institute for Developmental Biology in 1985;
    • Max Planck Institute for the Study of the Scientific-Technical World in Starnberg (from 1970 until 1981 (closed)) directed by Carl Friedrich von Weizsäcker and Jürgen Habermas.
    • Max Planck Institute for Behavioral Physiology
    • Max Planck Institute of Experimental Endocrinology
    • Max Planck Institute for Foreign and International Social Law
    • Max Planck Institute for Physics and Astrophysics
    • Max Planck Research Unit for Enzymology of Protein Folding
    • Max Planck Institute for Biology of Ageing

  • richardmitnick 10:46 am on December 17, 2022 Permalink | Reply
    Tags: , "Team of physicists suggests LIGO could be used to detect giant alien spacecraft", , , , Multimessenger Astronomy/Astrophysics   

    From The LIGO Scientific Collaboration Via “phys.org” : “Team of physicists suggests LIGO could be used to detect giant alien spacecraft” 

    From The LIGO Scientific Collaboration



    A team of physicists affiliated with several institutions in the U.S. has collaborated on a paper that discusses the possibility of using the Laser Interferometer Gravitational Wave Observatory (LIGO) to search for evidence of aliens piloting huge spacecraft around the Milky Way. The group has posted their paper for MNRAS [below].

    Credit: Pixabay/CC0 Public Domain

    Over the past several decades, astrophysicists and sci-fi enthusiasts alike have grown increasingly frustrated with mankind’s inability to detect the presence of life anywhere in the universe other than planet Earth. Scientists have noted that based on the billions of planets that have been found in habitable zones around the universe, and the fact that life does exist in one place, on Earth, there should be life somewhere else, too.

    The problem, now referred to as the “Fermi paradox”, is that scientists have yet to find even the tiniest shred of evidence for it. Prominent scientists have increasingly begun calling for new and more exotic ways to search.

    In this new effort, the researchers note that science has advanced to the point that gravity waves can be detected by technology such as LIGO. They further suggest that it is not beyond the realm of possibility that aliens piloting spacecraft could leave gravity waves in their wake that could be detected here on Earth using such technology.

    Intrigued by their own idea, the researchers imagined the factors that might be involved for such a scenario to unfold. First, they factored the size of such a craft. They found it would have to be really big to generate gravity waves strong enough to reach Earth—perhaps the size of Jupiter.

    It would also have to be moving really fast—their calculations showed approximately 1/10 the speed of light. And it would have to be reasonably close—say about 326,000 light-years from Earth. They note that under such conditions, if they were to arise, researchers at LIGO should be able to spot the gravity waves generated.

    The researchers also note that if aliens are using warp drives, scientists on Earth should be able to spot them, too, using the same technology, because such a craft would also generate gravity waves.

    Science paper:
    See the science paper for instructive material with images and pertinent mathematics.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    About the LSC

    The The LIGO Scientific Collaboration is a group of scientists seeking to detect gravitational waves, use them to explore the fundamental physics of gravity, and develop the emerging field of gravitational wave science as a tool of astronomical discovery. The LSC works toward this goal through research on, and development of techniques for, gravitational wave detection; and the development, commissioning and exploitation of gravitational wave detectors.

    The LSC carries out the science of the LIGO Observatories, located in Hanford, Wa and Livingston, LA as well as that of the GEO600 detector in Hannover (DE). Our collaboration is organized around three general areas of research: analysis of LIGO and GEO data searching for gravitational waves from astrophysical sources, detector operations and characterization, and development of future large scale gravitational wave detectors.

    Founded in 1997, the LSC is currently made up of more than 1000 scientists from dozens of institutions and 15 countries worldwide. A list of the participating universities.

  • richardmitnick 3:23 pm on November 25, 2022 Permalink | Reply
    Tags: "Two Black Holes Met by Chance And It Created Something Never Seen Before", , , , , , Detected in May 2019 GW19052 emitted space-time ripples like no other., , Gravitational waves encode information about black holes., , Multimessenger Astronomy/Astrophysics, , The National Institution for Nuclear Physics (IT), The ripples in space-time generated by colliding black holes have taught us a lot about these enigmatic objects., University of Jena   

    From “Science Alert (AU)” : “Two Black Holes Met by Chance And It Created Something Never Seen Before” 


    From “Science Alert (AU)”

    Michelle Starr

    A numerical simulation of the curvature of space-time during the merger that produced GW190521. (AG Bernuzzi/University of Jena)

    The ripples in space-time generated by colliding black holes have taught us a lot about these enigmatic objects.

    These gravitational waves encode information about black holes: their masses, the shape of their inward spiral towards each other, their spins, and their orientations.

    From this, scientists ascertained that most of the collisions we’ve seen have been between black holes in binary systems. The two black holes started as a binary of massive stars that turned into black holes together, then spiraled in and merged.

    Of the 90 or so mergers detected so far, however, one stands out as very peculiar. Detected in May 2019, GW19052 emitted space-time ripples like no other.

    “Its morphology and explosion-like structure are very different from previous observations,” says astrophysicist Rossella Gamba of the University of Jena in Germany.

    She adds, “GW190521 was initially analyzed as the merger of two rapidly rotating heavy black holes approaching each other along almost circular orbits, but its special features led us to propose other possible interpretations.”


    In particular, the short, sharp duration of the gravitational wave signal was challenging to explain.

    Gravitational waves are generated by the actual merger of two black holes, like ripples from a rock dropped into a pond. But they’re also generated by the binary inspiral, and the intense gravitational interaction sends out weaker ripples as two black holes move inexorably closer.

    Gravitational waves from the first detection of a neutron star – black hole merger (GW200105)

    “The shape and brevity – less than a tenth of a second – of the signal associated with the event lead us to hypothesize an instantaneous merger between two black holes, which occurred in the absence of a spiraling phase,” explains astronomer Alessandro Nagar of The National Institution for Nuclear Physics in Italy.

    There’s more than one way to end up with a pair of black holes gravitationally interacting.

    The first is that the two were together for a long time, perhaps even from the formation of baby stars from the same piece of molecular cloud in space.

    The other is when two objects moving through space pass each other closely enough to get snagged gravitationally in what is known as a dynamical encounter.

    This is what Gamba and her colleagues thought might have happened with GW190521, so they designed simulations to test their hypothesis. They smashed together pairs of black holes, tweaking parameters such as trajectory, spin, and mass, to try to reproduce the weird gravitational wave signal detected in 2019.

    Their results suggest that the two black holes did not start out in a binary but were caught in each other’s gravitational web, tumbling past each other twice on a wild, eccentric loop before slamming together to form one larger black hole. And neither of the black holes in this scenario was spinning.

    “By developing precise models using a combination of state-of-the-art analytical methods and numerical simulations, we found that a highly eccentric merger in this case explains the observation better than any other hypothesis previously put forward,” says astronomer Matteo Breschi of the University of Jena.

    “The probability of error is 1:4,300!”

    This scenario, the team says, is more likely in a densely populated region of space, such as a star cluster, where such gravitational interactions are more likely.

    This tracks with previous discoveries about GW190521. One of the black holes in the merger was measured at around 85 times the mass of the Sun.

    According to our current models, black holes over 65 solar masses can’t form from a single star; the only way we know a black hole of that mass can form is through mergers between two lower-mass objects.

    The work of Gamba and her colleagues found that the masses of the two black holes in the collision sit at around 81 and 52 solar masses; that’s slightly lower than previous estimates, but one of the black holes is still outside the single star core collapse formation pathway.

    It’s still unclear if our models need tweaking, but hierarchical mergers – whereby larger structures form through the continuous merging of smaller objects – are more likely in a cluster environment with a large population of dense objects.

    Dynamic encounters between black holes are considered pretty rare, and the gravitational wave data collected by LIGO and Virgo to date would seem to support this. However, rare doesn’t mean impossible, and the new work suggests that GW190521 may be the first we’ve detected.

    And a first means that there could be more in the years ahead. The gravitational wave observatories are currently being upgraded and maintained but will come online again in March 2023 for a new observing run. This time, LIGO’s two detectors in the US and the Virgo detector in Italy will be joined by KAGRA in Japan for even more observing power.


    Caltech /MIT Advanced aLigo.

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

    Caltech/MIT Advanced aLigo Hanford, WA. installation.

    VIRGO Gravitational Wave interferometer installation, near Pisa (IT).

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


    More detections like GW190521 would be amazing.

    The research has been published in Nature Astronomy.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.

  • richardmitnick 1:01 pm on November 12, 2022 Permalink | Reply
    Tags: "Magnetars making waves", , , , , , , LIGO–Virgo–KAGRA-GEO600, Magnetars are extreme objects in our universe — highly magnetized neutron stars with magnetic fields on the order of 10^15 Gauss., Multimessenger Astronomy/Astrophysics   

    From Astrobites : “Magnetars making waves” 

    Astrobites bloc

    From Astrobites

    Jessie Thwaites

    Paper Title: Search for gravitational-wave transients associated with magnetar bursts in Advanced LIGO and Advanced Virgo data from the third observing run

    Authors: The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration

    Status: ArXiv open access

    Credit: NASA’s Goddard Space Flight Center


    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 GEO600 Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University.

    Magnetars are extreme objects in our universe — highly magnetized neutron stars with magnetic fields on the order of 10^15 Gauss. For reference, our Sun’s magnetic field is about 1 Gauss — this means that a magnetar magnetic field is an almost unimaginable thousand trillion times stronger than our Sun!

    Magnetars emit in a number of different wavelengths, most notably in soft gamma-rays (which is the origin of many magnetars having the designation “SGR”, for soft gamma repeater), and in radio (they are the leading progenitor model for Fast Radio Bursts). They can also have extremely bright bursting periods, which look similar to (and are often categorized as) short Gamma Ray Bursts (GRBs). These bursts are called giant flares, which release a massive amount of energy in under a second! One such burst, GRB 200415A, which was from a magnetar in the galaxy NGC 253 released an energy equivalent to the amount emitted by our Sun over 100,000 years in only 0.016 seconds. The mechanisms for this emission are not yet clear, although there are some models which may give us insight.

    But what about in messengers other than photons? In some models, the aforementioned giant flares are the result of oscillations in the core or crust of the magnetar, which could mean that they produce gravitational waves in addition to photons. Today’s authors, members of the LIGO–Virgo–KAGRA (LVK) Collaborations, set out to see if we can detect gravitational wave counterparts to these energetic bursts.

    What would the gravitational wave emission we expect to see from magnetar giant flares look like?

    These authors focus on 2 known magnetars, with 12 giant flares between them. The first is SGR 1935+2154, which has also been associated with an FRB, and Swift J1818.0-1607, which, in addition to being a magnetar, is also a radio pulsar. They also include 3 additional bursts, which have the same characteristics of the other giant flares that aren’t well localized, but the authors attribute to another magnetar within the localization regions, 1 RXS J170849. This gives a total of 15 giant flares in the search, attributed to 3 sources. Each flare is chosen so that at least 2 detectors from LVK are in operating mode at the time of the burst.

    These giant flares are thought to excite two different types of oscillations – the fundamental (f-mode) and quasi-periodic oscillations (QPOs). The f-mode is thought to be excited when the magnetar’s internal magnetic field rearranges itself. QPOs, on the other hand, are other excited oscillation modes, which are longer-lived than the f-mode and can be seen in the tails of the flaring activity.

    These authors search for both types with specialized searches. They search for f-mode oscillations in a short duration search, of 8 seconds centered on the burst. This short time scale allows them to optimize the sensitivity of the detectors by looking at the most probable time when the emission could occur. They also search the 500 seconds just after this window to check for any short-duration signals following the burst.

    The long duration search covers the same time window, but extends out longer after the two short searches, up to 1400s (about 23 minutes) after the burst. This search targets the QPOs that occur in the tails of the giant flare.

    Results and outlook to the future

    Spoiler alert – these searches, though well motivated by the theory, don’t yet show any evidence of gravitational waves observed in the detectors. There are two bursts identified as the most significant in the short time window search, but both seem to be instrument artifacts. But, that doesn’t mean the story is over yet!

    Using the distance to each magnetar, they are able to set constraints on the amount of energy emitted in gravitational waves during the burst. These upper limits can be seen in Figure 1. These upper limits show how much the current detectors can constrain the emission from magnetar giant flares; the amount of energy released from the giant flares must be less than these upper limits.

    Fig 1: Upper limits set in the searches, compared to the LVK sensitivities from the O3 observing run. The y-axis here is strain, which here is essentially a measure of the gravitational wave signal seen in the detectors. The blue and orange curves show the sensitivity for each of the LIGO and the Virgo detectors from this run, while the solid gray curve below these shows the Advanced LIGO design, with improvements that will be made during the next observing run, O4. The yellow and red lines and markers show upper limits set for the emission from the tests performed in this paper. Fig 5 in the paper.

    These upper limits represent a significant improvement over previous searches – they are more than 10 times better than previous searches in the short duration search, and 1000 times better in the long duration search. Although there is no detection reported in this paper, these improvements give great insight into constraints on models for emission of both f-mode and QPO gravitational waves from magnetar giant flares. These constraints are important to improving our understanding of the dynamics of the magnetic fields in magnetars.

    There are now 30 known magnetars [1] and with the next LVK data run (observing run O4), planned to start in March of 2023, more data will be available both on the electromagnetic and gravitational wave sides of the equation. This search was limited in the number of bursts (only 15 bursts from 3 magnetars) due to the requirement that LVK has at least 2 detectors operating during the burst and a limited number of giant flares that have been identified. More data available, and more sensitive detectors, would allow for more sources and bursts to be analyzed, which would give a higher chance for a significant detection!

    [1] The Astrophysical Journal Supplement Series

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.

    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

  • richardmitnick 10:38 am on November 1, 2022 Permalink | Reply
    Tags: "How to maintain a physics experiment in a desert", , Extreme swings in temperature make it difficult to maintain the temperature inside the large vacuum equipment areas of LIGO which must be kept right around 67 degrees Fahrenheit., , Multimessenger Astronomy/Astrophysics, , Ravens ripped seals out of windows on brand-new buildings and even caused glitches in the detector one hot summer. They pecked on the ice that builds up on the liquid nitrogen tubes., , The holes the ravens created let rainwater leak through., The project also has to contend with the desert’s animal inhabitants. There are many different creatures roaming the grounds of the Observatory. Some do no harm. Others cause trouble., The project maintenance people have removed venomous scorpions and spiders from buildings and repaired rabbit-chewed wires. They have evicted porcupines., Tumbleweed walls-as much as 10 feet high-clog the 2.5-mile-long roads that run along the arms completely blocking the detector., Tumbleweeds are a problem. They are plants that have evolved detach from their root system and spread their seeds. Desert winds blow these desiccated plant balls into the detector.   

    From “Symmetry”: “How to maintain a physics experiment in a desert” 

    Symmetry Mag

    From “Symmetry”

    Chris Patrick

    Threats of scorching heat, walls of tumbleweed, and countless critters mean innovation is a must for the facilities manager for LIGO Hanford Observatory.

    Glynn “Bubba” Gateley is not a physicist. And yet, the first thing he does upon waking is check on a physics experiment. The tablet he takes home from work provides constant updates about the HVAC system at the Laser Interferometer Gravitational-wave Observatory, or LIGO Hanford Observatory, in Richland, Washington.

    Before heading to work, Gateley checks his phone to make sure he hasn’t missed any calls about tumbleweeds, porcupines, ravens, or any other desert-dwellers that cause trouble for the LIGO facility.

    Along with its twin site in Livingston, Louisiana, LIGO Hanford Observatory—funded by the National Science Foundation—detects gravitational waves.

    In fact, in 2015 this pair of identical detectors were the first to confirm the existence of these ripples in spacetime caused by cataclysmic astronomical events billions of light-years away.

    The detectors at both LIGO locations are L-shaped structures with two 2.5-mile-long arms. Minute movements of sensitive instruments inside of these arms indicate the arrival of gravitational waves, which carry information about the events that created them, such as exploding supernovae, merging black holes, and colliding neutron stars.

    LIGO Hanford Observatory lives in a unique environment. The low seismic activity of Richland makes it a quiet place optimal for detecting weak signals. But a trifecta of vacillating temperatures, persistent flora and resourceful fauna make it a challenge to maintain the delicate equipment scientists use to do it.

    As the observatory’s facilities manager since 2014, Gateley is one of the people that must face this challenge. With his small staff of six, he is responsible for most of the facility’s logistics, including water, electricity, roadways, cleaning, and the aforementioned HVAC system.

    “I keep the facility functional and operational for pretty much everything but the instrument itself,” he says. “There’s definitely some interesting situations out here, to say the least.”

    Beating the heat (and the cold)

    Richland is situated east of Washington’s Cascade Mountains, in an arid shrub steppe ecosystem.

    “Usually when people think of Washington, they think of the rainforests of the Pacific Northwest, right in Seattle. That’s not the case in Richland,” says Michael Landry, head of LIGO Hanford Observatory and a physicist at the California Institute of Technology. “It’s starkly beautiful.”

    Of course, deserts mean hot temperatures. In the summer, many days in Richland are over 100 degrees Fahrenheit, sometimes reaching 118. But at night, the temperature can drop significantly. And in colder months of the year, it can plummet to zero. There are even snow days.

    These extreme swings in temperature outside make it difficult to maintain the temperature inside the large vacuum equipment areas of LIGO, which must be kept right around 67 degrees Fahrenheit.

    “If the temperature starts varying too much in the vacuum equipment areas, then the optics for the instrument start changing drastically and the scientists get upset,” Gateley says. “And then I get a lot of calls.”

    To keep the temperature steady, he does a lot of monitoring, fine-tuning, and finessing of the HVAC system. That’s why every day starts with Gateley checking its status.

    Tumbling a wall of weeds

    While temperature control is a 24/7 concern, Gateley also regularly grapples with another hallmark of the desert, tumbleweeds.

    A single tumbleweed may look innocuous enough, but at LIGO Hanford Observatory, these dust bunnies of the wild west are a nuisance. “Tumbleweeds are one of our biggest natural challenges,” Gateley says.

    Tumbleweeds are actually plants that have evolved to dry out, detach from their root system and spread their seeds as they roll along. Strong desert winds blow these desiccated plant balls into the arms of the observatory’s detector, where they get stuck. They build up quickly, forming walls that can be 10 feet tall.

    These tumble-walls clog the 2.5-mile-long roads that run along the arms, completely blocking the detector.

    However, the tanks along the detector’s arms need to be accessed on a weekly basis. The tanks hold liquid nitrogen running minus 320 degrees Fahrenheit, which the detector needs to ensure its arms are under vacuum.

    To clear these roads for the semitruck delivering liquid nitrogen, the observatory’s maintenance staff used to bale these tumbleweeds like hay, feeding the baler by hand. “It was a very slow process,” Gateley says. “I got to thinking and thinking, trying to figure out some way to expedite that.”

    Eventually, he thought of farm equipment. Specifically, a harvester, which drives through fields of corn or wheat and pulls up stalks.

    But if you drive a harvester into a tumbleweed, it just pushes it forward. So five years ago, Gateley purchased a harvester and added a modified hay reel to the front, creating the LIGO Franken-harvester.

    Its tined wheel grabs tumbleweeds and pulls them into the threshing cylinder, which grinds them up and shoots them out. “With the harvester we can drive down the road ten times faster than the baler ever could,” Gateley says.

    Cohabitating with critters

    Plants aren’t the only organisms that have required Gateley to get innovative with his job. In addition to being an HVAC expert, tumbleweed destroyer, and general handyman, Gateley also has to contend with the desert’s animal inhabitants. There are many different creatures roaming the grounds of LIGO Hanford Observatory. Some of these, like coyotes and deer, do no harm. Others cause trouble.

    Gateley has removed venomous scorpions and spiders from buildings. He has repaired rabbit-chewed wires. And he has evicted porcupines who took to snoozing on top of a trellis next to a building on the observatory’s campus.

    Porcupines would climb the wisteria vines threaded through the trellis and fall asleep at the top. Although the animals are nocturnal, when daytime public tours departed from the building it sometimes woke the porcupines up, at which point they relieved themselves before settling back to sleep.

    Luckily, Gateley noticed incriminating stains on the concrete before any passers-by received an unpleasant surprise from above.

    At first, he just tried to shoo the porcupines away, but they returned undeterred. So, again, Gateley turned to another field for a solution. This time, it was shipping.

    Workers attach disks to ropes that tie boats to docks to prevent rats from using them to board. “I made some of those and clamped them around the wisteria vines so the porcupines couldn’t climb up there,” Gateley says.

    Problem solved.

    Another animal, however, has proved more bothersome. Ravens have ripped seals out of windows on brand-new buildings, and even caused glitches in the detector during one hot summer when they pecked on the ice that builds up on the liquid nitrogen tubes.

    The birds also started pecking out the caulk that joins the concrete sections enclosing the detector arms. The holes they created let rainwater leak through. “It doesn’t rain much here, but we don’t like any moisture to get under there because it could eventually create issues,” Gateley says.

    A biologist helped him figure out what the ravens were trying to do: reach mice underneath the concrete enclosure. So Gateley covered the caulk with thin aluminum metal strips.

    “It deterred them somewhat,” he says. “I hesitate to say it stopped them completely.”

    Despite all of the trouble it creates for him, Gateley says he much prefers the desert to the climate of Louisiana, home of the other LIGO detector, where he coincidentally grew up.

    “I do not miss the humidity,” he says. “And the desert is intriguing.”

    Although he’s lived near Richland for over 40 years now, Gateley says he never knows what the desert will throw at him next. History suggests he’ll be able to figure out a solution anyway.

    “It’s one of the most challenging jobs I’ve ever had,” he says. “But definitely the most interesting. I enjoy it immensely.”

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 9:36 am on October 18, 2022 Permalink | Reply
    Tags: , "f2": “peak spectral frequency”, , , , , Multimessenger Astronomy/Astrophysics, ,   

    From The Institute for Advanced Study: “New Tool Allows Scientists to Peer Inside Neutron Stars” 

    From The Institute for Advanced Study

    Lee Sandberg
    (609) 455-4398

    Imagine taking a star twice the mass of the Sun and crushing it to the size of Manhattan. The result would be a neutron star—one of the densest objects found anywhere in the Universe, exceeding the density of any material found naturally on Earth by a factor of tens of trillions. Neutron stars are extraordinary astrophysical objects in their own right, but their extreme densities might also allow them to function as laboratories for studying fundamental questions of nuclear physics, under conditions that could never be reproduced on Earth.

    Because of these exotic conditions, scientists still do not understand what exactly neutron stars themselves are made from, their so-called “equation of state” (EoS). Determining this is a major goal of modern astrophysics research. A new piece of the puzzle, constraining the range of possibilities, has been discovered by a pair of scholars at IAS: Carolyn Raithel, John N. Bahcall Fellow in the School of Natural Sciences; and Elias Most, Member in the School and John A. Wheeler Fellow at Princeton University. Their work was recently published in The Astrophysical Journal Letters [below].

    Neutron star merger and the gravity waves it produces. Credit: NASA/Goddard Space Flight Center.

    Ideally, scientists would like to peek inside these exotic objects, but they are too small and distant to be imaged with standard telescopes. Scientists rely instead on indirect properties that they can measure—like the mass and radius of a neutron star—to calculate the EoS, the same way that one might use the length of two sides of a right-angled triangle to work out its hypotenuse. However, the radius of a neutron star is very difficult to measure precisely. One promising alternative for future observations is to instead use a quantity called the “peak spectral frequency” (or f2) in its place.

    But how is f2 measured? Collisions between neutron stars, which are governed by the laws of Albert Einstein’s Theory of Relativity, lead to strong bursts of gravitational wave emission. In 2017, scientists directly measured such emissions for the first time.

    The collision of two neutron stars, seen in an artist’s rendering, created both gravitational waves and gamma rays. Researchers used those signals to locate the event with optical telescopes.
    Robin Dienel/Carnegie Institution for Science.

    “At least in principle, the peak spectral frequency can be calculated from the gravitational wave signal emitted by the wobbling remnant of two merged neutron stars,” says Most.

    It was previously expected that f2 would be a reasonable proxy for radius, since—until now—researchers believed that a direct, or “quasi-universal,” correspondence existed between them. However, Raithel and Most have demonstrated that this is not always true. They have shown that determining the EoS is not like solving a simple hypotenuse problem. Instead, it is more akin to calculating the longest side of an irregular triangle, where one also needs a third piece of information: the angle between the two shorter sides. For Raithel and Most, this third piece of information is the “slope of the mass-radius relation,” which encodes information about the EoS at higher densities (and thus more extreme conditions) than the radius alone.

    This new finding will allow researchers working with the next generation of gravitational wave observatories (the successors to the currently operating LIGO) to better utilize the data obtained following neutron star mergers.


    Caltech /MIT Advanced aLigo.

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

    Caltech/MIT Advanced aLigo Hanford, WA. installation.

    VIRGO Gravitational Wave interferometer installation, near Pisa (IT).

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


    According to Raithel, this data could reveal the fundamental constituents of neutron star matter. “Some theoretical predictions suggest that within neutron star cores, phase transitions could be dissolving the neutrons into sub-atomic particles called quarks,” stated Raithel. “This would mean that the stars contain a sea of free quark matter in their interiors. Our work may help tomorrow’s researchers determine whether such phase transitions actually occur.”

    The Astrophysical Journal Letters
    See the science paper for detailed material with images.

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Institute for Advanced Study, located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholars, including J. Robert Oppenheimer, Albert Einstein, Hermann Weyl, John von Neumann, and Kurt Gödel, many of whom had emigrated from Europe to the United States.

    It was founded in 1930 by American educator Abraham Flexner, together with philanthropists Louis Bamberger and Caroline Bamberger Fuld. Although it is close to and collaborates with Princeton University, Rutgers University, and other nearby institutions, it is independent and does not charge tuition or fees.

    Flexner’s guiding principle in founding the institute was the pursuit of knowledge for its own sake. The faculty have no classes to teach. There are no degree programs or experimental facilities at the institute. Research is never contracted or directed. It is left to each individual researcher to pursue their own goals. Established during the rise of fascism in Europe, the institute played a key role in the transfer of intellectual capital from Europe to America. It quickly earned its reputation as the pinnacle of academic and scientific life—a reputation it has retained.

    The institute consists of four schools: Historical Studies, Mathematics, Natural Sciences, and Social Sciences. The institute also has a program in Systems Biology.

    It is supported entirely by endowments, grants, and gifts. It is one of eight American mathematics institutes funded by the National Science Foundation. It is the model for the other eight members of the consortium Some Institutes for Advanced Study.

  • richardmitnick 8:05 pm on October 12, 2022 Permalink | Reply
    Tags: "Hubble Spots Ultra-Speedy Jet Blasting from Star Crash", , , , , GW170817 Neutron Star Merger, , Multimessenger Astronomy/Astrophysics,   

    From Hubblesite: “Hubble Spots Ultra-Speedy Jet Blasting from Star Crash” 

    From Hubblesite



    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland


    Kunal P. Mooley
    California Institute of Technology, Pasadena, California

    About This Image

    This is an artist’s impression of two neutron stars colliding. The smashup between two dense stellar remnants unleashes the energy of 1,000 standard stellar nova explosions. In the aftermath of the collision a blowtorch jet of radiation is ejected at nearly the speed of light. The jet is directed along a narrow beam confined by powerful magnetic fields. The roaring jet plowed into and swept up material in the surrounding interstellar medium.

    ARTWORK: Elizabeth Wheatley (STScI)


    Titanic Stellar Collision Rattles Space and Time

    Neutron stars are the “trash-compacted” surviving cores of massive stars that exploded. Weighing more than our Sun, they would fit inside New York City. At this unimaginable density, one teaspoon of surface material would weigh at least 4 billion tons on Earth.

    If that doesn’t stagger the imagination, just think of what happens when two of these cannon balls collide head-on. They ripple the very fabric of time and space in a phenomenon called gravitational waves, which can be measured by detectors on the ground.

    The explosive event, named GW170817, was observed in August 2017. The blast released the energy comparable to that of a supernova explosion. It was the first combined detection of gravitational waves and gamma radiation from a neutron star merger.

    In the aftermath of the smashup a blowtorch jet of radiation was ejected at nearly the speed of light, slamming into material surrounding the obliterated pair. Hubble was on the scene of the explosion just two days after the collision. Astronomers used Hubble to measure the motion of a blob of material the jet slammed into. As the jet rocketed away from the site of the explosion, the blob moved outward like a leaf caught on a stream of water from a garden hose. The incredible precision, gleaned from Hubble and radio telescopes, needed to measure the blob’s trajectory, was equivalent to measuring the diameter of a 12-inch-diameter pizza placed on the Moon as seen from Earth. This was a major watershed in the ongoing investigation of neutron star collisions that keep ringing throughout the universe.
    Astronomers using NASA’s Hubble Space Telescope have made a unique measurement that indicates a jet, plowing through space at speeds greater than 99.97% the speed of light, was propelled by the titanic collision between two neutron stars.

    The explosive event, named GW170817, was observed in August 2017 [above]. The blast released the energy comparable to that of a supernova explosion. It was the first combined detection of gravitational waves and gamma radiation from a binary neutron star merger.

    This was a major watershed in the ongoing investigation of these extraordinary collisions. The aftermath of this merger was collectively seen by 70 observatories around the globe and in space, across a broad swath of the electromagnetic spectrum in addition to the gravitational wave detection. This heralded a significant breakthrough for the emerging field of Time Domain and Multi-Messenger Astrophysics, the use of multiple “messengers” like light and gravitational waves to study the universe as it changes over time.

    Scientists quickly aimed Hubble at the site of the explosion just two days later. The neutron stars collapsed into a black hole whose powerful gravity began pulling material toward it. That material formed a rapidly-spinning disk that generated jets moving outward from its poles. The roaring jet smashed into and swept up material in the expanding shell of explosion debris. This included a blob of material through which a jet emerged.

    While the event took place in 2017, it has taken several years for scientists to come up with a way to analyze the Hubble data and data from other telescopes to paint this full picture.

    The Hubble observation was combined with observations from multiple National Science Foundation radio telescopes working together for very long baseline interferometry (VLBI). The radio data were taken 75 days and 230 days after the explosion.

    “I’m amazed that Hubble could give us such a precise measurement, which rivals the precision achieved by powerful radio VLBI telescopes spread across the globe,” said Kunal P. Mooley of Caltech in Pasadena, California and lead author of a paper being published in the October 13 journal of Nature magazine [below].

    The authors used Hubble data together with data from ESA’s (the European Space Agency) Gaia satellite, in addition to VLBI, to achieve extreme precision. “It took months of careful analysis of the data to make this measurement,” said Jay Anderson of the Space Telescope Science Institute in Baltimore, Maryland.

    By combining the different observations, they were able to pinpoint the explosion site. The Hubble measurement showed the jet was moving at an apparent velocity of seven times the speed of light. The radio observations show the jet later had decelerated to an apparent speed of four times faster than the speed of light.

    In reality, nothing can exceed the speed of light, so this “superluminal” motion is an illusion. Because the jet is approaching Earth at nearly the speed of light, the light it emits at a later time has a shorter distance to go. In essence the jet is chasing its own light. In actuality more time has passed between the jet’s emission of the light than the observer thinks. This causes the object’s velocity to be overestimated — in this case seemingly exceeding the speed of light.

    “Our result indicates that the jet was moving at least at 99.97% the speed of light when it was launched,” said Wenbin Lu of the University of California, Berkeley.

    The Hubble measurements, combined with the VLBI measurements, announced in 2018, greatly strengthen the long-presumed connection between neutron star mergers and short-duration gamma-ray bursts. That connection requires a fast-moving jet to emerge, which has now been measured in GW170817.

    This work paves the way for more precision studies of neutron star mergers, detected by the LIGO, Virgo and KAGRA gravitational wave observatories. With a large enough sample over the coming years, relativistic jet observations might provide another line of inquiry into measuring the universe’s expansion rate, associated with a number known as the Hubble constant.

    At present there is a discrepancy between Hubble constant values as estimated for the early universe and nearby universe — one of the biggest mysteries in astrophysics today. The differing values are based on extremely precise measurements of Type Ia supernovae by Hubble and other observatories, and Cosmic Microwave Background measurements by ESA’s Planck satellite. More views of relativistic jets could add information for astronomers trying to solve the puzzle.

    Science paper:

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Space Telescope Science Institute (STScI) is the science operations center for the Hubble Space Telescope (HST) and mission operations for the James Webb Space Telescope (JWST).

    The Hubble telescope was built by the United States space agency National Aeronautics Space Agency with contributions from the The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU). The Space Telescope Science Institute (STScI) selects Hubble’s targets and processes the resulting data, while the NASA Goddard Space Flight Center controls the spacecraft.

    STScI is located on The Johns Hopkins University Homewood Campus in Baltimore, Maryland and was established in 1981 as a community-based science center that is operated for National Aeronautics Space Agency by The Assocation of Universities for Research in Astronomy (AURA). In addition to performing continuing science operations of HST and preparing for scientific exploration with JWST, STScI manages and operates the NASA Mikulski Archive for Space Telescopes, the Kepler Mission Data Resources in the Exoplanet Archive – NASA and a number of other activities benefiting from its expertise in and infrastructure for supporting the operations of space-based astronomical observatories. Most of the funding for STScI activities comes from contracts with NASA’s Goddard Space Flight Center but there are smaller activities funded by NASA’s Ames Research Center, NASA’s Jet Propulsion Laboratory, and The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU). The staff at STScI consists of scientists (mostly astronomers and astrophysicists), spacecraft engineers, software engineers, data management personnel, education and public outreach experts, and administrative and business support personnel. There are approximately 100 Ph.D. scientists working at STScI, 15 of which are ESA staff who are on assignment to the HST project. The total STScI staff consists of about 850 people as of 2021.

    STScI operates its missions on behalf of NASA, the worldwide astronomy community, and to the benefit of the public. The science operations activities directly serve the astronomy community, primarily in the form of HST, and eventually JWST observations and grants, but also include distributing data from other NASA missions, such as the FUSE: Far Ultraviolet Spectroscopic Explorer – NASA, Galaxy Evolution Explorer – Universe Missions – NASA JPL-Caltech and ground-based sky surveys.

    The ground system development activities create and maintain the software systems that are needed to provide these services to the astronomy community. STScI’s public outreach activities provide a wide range of information, on-line media, and programs for formal educators, planetariums and science museums, and the general public. STScI also serves as a source of guidance to NASA on a range of optical and UV space astrophysics issues.

    The STScI staff interacts and communicates with the professional astronomy community through a number of channels, including participation at the bi-annual meetings of the American Astronomical Society, publication of quarterly STScI newsletters and the STScI website, hosting user committees and science working groups, and holding several scientific and technical symposia and workshops each year. These activities enable STScI to disseminate information to the telescope user community as well as enabling the STScI staff to maximize the scientific productivity of the facilities they operate by responding to the needs of the community and of NASA.

  • richardmitnick 3:10 pm on August 2, 2022 Permalink | Reply
    Tags: "Calibrating the Universe:: Behind the Scenes-NIST Scientists Play a Critical Role in Improving Gravitational Wave Measurements", , LIGO–Virgo–KAGRA-GEO600-eLISA, Multimessenger Astronomy/Astrophysics,   

    From The National Institute of Standards and Technology: “Calibrating the Universe:: Behind the Scenes-NIST Scientists Play a Critical Role in Improving Gravitational Wave Measurements” 

    From The National Institute of Standards and Technology


    Technical Contact

    Matthew Spidell
    (303) 497-5796

    Michelle Stephens
    (303) 497-3742

    Space-time ripples, exploding stars, colliding black holes …. and the National Institute of Standards and Technology? NIST doesn’t exactly come to mind when thinking about cataclysmic events in the cosmos. But behind the scenes, NIST played an essential supporting role in the Nobel Prize-winning discovery of ripples in spacetime — gravitational waves — which scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) announced in 2015. NIST researchers helped calibrate the gravitational-wave detector system, ensuring that the LIGO team accurately measured the historic event.

    Now, the NIST scientists have more than doubled the accuracy of those calibrations. When LIGO resumes observations in mid-December, the new calibrations will enable astronomers to more accurately pinpoint the origin and nature of future space-time disturbances.


    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 GEO600 Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University.

    Front side of the radiometer developed at NIST (left) and view inside the vacuum chamber (right). The radiometer helps calibrate the power of infrared lasers used at LIGO to ever so slightly nudge the detector’s mirrored test masses, simulating the passage of a gravitational wave. Credit: NIST.

    The first ripple ever directly detected arrived at LIGO’s twin sites in Louisiana and Washington state on Sept. 14, 2015. Generated by the collision of two black holes, the wave had journeyed 1.3 billion light-years to reach Earth.

    The detection provided stunning confirmation of Albert Einstein’s century-old prediction that massive bodies undergoing acceleration not only distort but actually shake spacetime.

    The discovery was also a technological feat. Each LIGO observatory features two L-shaped, 4-kilometer-long arms that form an exquisitely sensitive interferometer, a device that uses light to measure distance. When a gravitational wave passes by, it alternately compresses one arm while stretching the other by an amount much less than the diameter of a single proton. This alters the relative separation between sets of mirrored test masses, suspended within each arm.

    The size of the displacement induced by the wave and the frequency at which the wave oscillates encode information that cosmologists have sought for decades about some of the most violent events in the universe. The data include the location in the sky, the exact distance from Earth, and the mass and identity of the cosmic participants in these massive collisions. To accurately determine these properties, LIGO researchers must measure the displacement imparted by a gravitational wave to better than one ten-thousandth the diameter of a proton. Even then, scientists can’t reliably determine the force and other features of the gravitational wave unless they can compare the tiny displacement it imparts to the same displacement imparted by a well-calibrated force.

    One of LIGO’s test masses, a 40-kilogram mirror that reflects laser beams along the length of one of the two detector arms. A tiny displacement of the mass—much less than the diameter of a single proton—could signal the passage of a gravitational wave. Credit: Caltech/MIT/LIGO Lab.

    The power carried by a ray of light can be equated to the force it imparts to objects it strikes. The force is tiny, but if the power is accurately measured, that tiny force can be, too. LIGO scientists use a low-power infrared laser to produce the force. The laser light bouncing off the mirrored mass nudges the body ever so slightly, simulating the action of a gravitational wave. To ensure accuracy, that power must be precisely calibrated. And that’s where the expertise of scientists at NIST comes in.

    Meeting the needs of U.S. industry, defense and academic research, NIST calibrates laser power ranging from the output of single photons (less than a billionth of a watt) to more than 10,000 watts, and across wavelengths from the ultraviolet to far infrared. To perform these calibrations, NIST researchers over the past four decades have developed and employed two types of devices — calorimeters, which measure the total energy generated by a system, and radiometers, which measure the intensity of radiation. These instruments, now operated by a NIST team led by Matthew Spidell, measure optical power and energy without having to compare those quantities to those measured by another instrument. Instead, the instruments enable researchers to directly link optical power and energy to the fundamental physical constants, which by definition do not vary and require no calibration.

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD.

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


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

    NIST’s vision

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

    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

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

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


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

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

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

    Bureau of Standards

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

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

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

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

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

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


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

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

    Extramural programs include:

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

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

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

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

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


    NIST has seven standing committees:

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

    Measurements and standards

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

    Handbook 44

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

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

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