Schutz received the 2019 Eddington Medal of the Royal Astronomical Society (RAS) and the 2006 Amaldi Gold Medal from the Italian Society for Gravitation (SIGRAV), shared the 2020 Richard A. Isaacson Award of the American Physical Society (APS), and was awarded an honorary DSc by the University of Glasgow in 2011.[3] In 2011, he was also elected a Fellow of the Learned Society of Wales.[4]
Education and Career Activities
Schutz attended Bethpage High School on Long Island, NY, from 1960-64, and went on to study physics at Clarkson University in Potsdam, NY (at that time named Clarkson College of Technology). He finished his degree in three years and went on to graduate study in physics at the California Institute of Technology in Pasadena, CA. The following year he joined the research group of Kip Thorne, finishing his PhD in 1971 on the theory of fluids in general relativity. A National Science Foundation Fellowship allowed him to spend the year 1971-72 in Cambridge, England, where he divided his time between the research group of Stephen Hawking and the Institute of Astronomy, led by Martin Rees. He then moved to a postdoctoral position at Yale University, in the group of James Bardeen, where he started a fruitful collaboration with fellow postdoc John Friedman.[5]
In 1974, Schutz accepted a position as a Lecturer at Cardiff University in Wales (then called University College Cardiff), joining the newly established astronomy group in the Applied Mathematics department, chaired by Chandra Wickramasinghe. Schutz built up a large research group studying relativistic stars and dynamics. As an outgrowth of his teaching responsibilities, he wrote two well-received textbooks, Geometrical Methods of Mathematical Physics and A First Course in General Relativity (see Bibliography). Schutz became a full professor in 1986, around the time he began re-orienting his research toward gravitational wave detection.
During his time at Cardiff, Schutz organised an irregular series of meetings, the Gregynog Relativity Workshops, held at the Gregynog conference centre in mid-Wales[6].These meetings became a popular way for specialists in relativity in the UK and worldwide to have informal discussions focussed on key research problems. In 1986 and 1987, Schutz organised two international meetings in Cardiff that were aimed at improving coordination and data sharing among gravitational wave detector projects. The second one was sponsored by NATO, and he edited its published proceedings, Gravitational Wave Data Analysis. Schutz served on a number of advisory committees to the UK research councils, and eventually became the first chair of the Astronomy Committee of the newly established Particle Physics and Astronomy Research Council (PPARC), 1994-95.
In 1995 Schutz moved to Germany to join Jürgen Ehlers in founding the Max Planck Institute for Gravitational Physics, commonly known as the Albert Einstein Institute (AEI). This was established in Potsdam, Germany, by the Max Planck Society (MPS) as part of its effort to expand scientific research into areas of former East Germany, following German reunification in 1990. Ehlers led work in mathematical general relativity and Schutz focussed on astrophysical relativity, including numerical simulations of black holes and theoretical studies supporting gravitational wave detectors.[7] With generous funding from MPS, the institute quickly expanded, adding a third Director (Hermann Nicolai, for quantum gravity) in 1997. After Ehlers retired at the end of 1998, Schutz became Managing Director and supervised the establishment a second branch of the AEI in Hannover in 2002.[8] This branch, led by Karsten Danzmann, managed the GEO600 gravitational wave detector and quickly became a major centre for experimental gravitational wave physics, developing key technologies for both the ground-based detectors like GEO600 and LIGO and for the space-based LISA-Pathfinder technology demonstrator mission, the LISA (Laser Interferometer Space Antenna) gravitational wave detector mission, and the space-geodesy mission GRACE Follow-On.[9] Bruce Allen joined the Hannover branch in 2007 as the Director of the new division of Observational Relativity and Cosmology.[10]
After 1995, Schutz served on several committees of the European Space Agency, including chairing its Fundamental Physics Advisory Group from 2004-2008. He served on the LSC’s Executive Committee from 2003 until 2019.
Schutz is well-known for his advocacy of open-access scientific publishing. At the AEI, Schutz founded and in 1998 began publishing the open-access online-only review journal Living Reviews in Relativity.[11] It was unique in that its review articles were updated periodically by their authors. This feature proved attractive to readers, and (based on citation counts per article) the journal has for many years had the highest impact factor of any open-access journal worldwide. Its sister journal, Living Reviews in Solar Physics, which began publishing in 2004 from the Max Plank Institute for Solar Physics, is also very highly cited, consistently in the top 100 worldwide.[12] A third journal, Living Reviews in Computational Astrophysics, began publishing in 2015. All three journals are now published by Springer. Schutz was a member of the editorial board of the first OA journal published by the APS, Physical Review X, from its inception in 2011 until 2018.[13] He is currently a member of the editorial board of the Proceedings of the National Academy of Sciences.[14]
The Living Reviews concept was one of the inspirations for the 2003 Berlin Declaration on Open Access,[15] and Schutz helped organize many of the continuing series of Berlin OA Conferences at venues around the world. He hosted the 4th at the AEI.[16] For his contributions to expanding OA, he received the Communitas Award from the Max Planck Society in 2013.[17]
Schutz has long had a strong interest in scientific outreach and education. His book Gravity from the Ground Up[18] provides advanced high-school students and university students with an intuitive introduction to modern gravity using only algebra, thereby avoiding the daunting mathematics of general relativity. Together with Milde Science Communications, Schutz developed the Scienceface website,[19] which offers original interviews and short videos of scientists working on black holes and gravitational waves. Again with help of Milde Science Communications and also Exozet Potsdam, Schutz developed a multimedia popular lecture on gravitational waves called Music of the Spheres, which he presented in many locations around the world, leading up to the first detection in 2015.[20]
In 2014 Schutz retired from the AEI and became an Emeritus Director, and he returned to Cardiff University for a part-time professorship. His first activity there was to help set up and then to become the first director of the Data Innovation Research Institute, which assists research groups in the university who are dealing with issues of big data.[21] After stepping down from this, Schutz returned to research and teaching in general relativity and gravitational waves at Cardiff.[22] In 2015 he became an adjunct professor of physics at the Georgia Institute of Technology.[23]
Research
In his PhD thesis in 1971, Schutz reformulated the relativistic equations of fluid dynamics in terms of scalar velocity potentials,[1] an approach that has since had many applications in field theory and cosmology. He used this reformulation in his thesis to develop a framework for studying the pulsation and stability of stars in general relativity.
This early work led, in collaboration with John Friedman during the 1970s, to the elucidation of the unexpected gravitational-wave driven instability of rotating stars, first noticed by Chandrasekhar in the simple model of uniform-density stars.[24][25] In what is now called the Chandrasekhar-Friedman-Schutz (CFS) instability, gravitational wave emission taps into the rotational energy of the star in such a way that a small initial perturbation will grow exponentially fast unless it is sufficiently strongly damped by some other effect, like viscosity. It is a generic instability, potentially present in all rotating stars. A member of the CFS class is the r-mode instability discovered by Nils Andersson, which is thought to limit the rotation rate of neutron stars.[26]
Working with Toshifume Futamase, Schutz developed a new way of approaching what is called the post-Newtonian limit of general relativity, in which general relativity makes small corrections to Newtonian gravity. The Futamase-Schutz method[27] is free of the point-mass singularities used in most other approaches to this problem, and it is based on initial data, so it is mathematically fully consistent and convergent. They then used it to prove rigorously that the standard “quadrupole formula” for the emission of gravitational waves applies even if the sources are orbiting black holes, which are of course not small corrections to Newtonian objects.[28]
In 1986, now focussing more on gravitational wave detection, Schutz showed that the gravitational waves emitted by a binary system contain information from which it is possible to deduce the distance to the source, something that is normally very difficult to do in astronomy.[29] This possibility arises from the special scale-free nature of gravity in general relativity. Because the distance information is encoded in the phase evolution of the emitted waves and in their polarization, a network of at least three interferometric gravitational wave detectors is necessary in order to extract this information from the data. These systems were christened “standard sirens” by Daniel Holz and Scott Hughes.[30] Knowing the distance to the source is important for extracting almost all the physical information that comes from gravitational wave observations of merging binary systems: the masses and spins of the component objects, statistical measures of the rate of such events per unit spatial volume, and estimates of how the formation rate of such systems has evolved over time since the Big Bang.
Besides showing how to measure distances, in his 1986 paper Schutz showed how a number of detections of such binaries could be used to measure the value of the Hubble Constant H0, which represents the expansion rate of the Universe. He showed how this would be possible even if the emitting binary systems could not be individually identified though optical or other astronomical observations. Because of the importance of H0 and because of the difficulty of measuring it accurately with other astronomical methods, this became a principal part of the scientific case for building LIGO and other detectors, which were being proposed in the late 1980s. The first gravitational-wave measurement of H0 was eventually performed in 2017 with the data from GW170817, the first detected merger of two neutron stars. As future observations by LIGO, Virgo, and KAGRA accumulate more and more statistics, this method is expected in the long run to provide the most accurate way of measuring H0.
Schutz oriented most of the effort of his research group in Cardiff after 1986 to the development of methods of data analysis, not just to detect binary system mergers, but also to search for spinning neutron stars, for a random cosmological background of gravitational waves, and for unexpected signals. In 1990 his group began the analysis of data from the “100-Hour Run”, which was the first extended joint data-taking exercise between two interferometers, the prototypes in Glasgow and in Garching, Germany. This data run and analysis had been requested by the funding providers of both the UK and Germany, as part of their evaluation of the joint UK-German proposal for a 3-km gravitational wave interferometer to be built in Germany. Although the proposal was not funded (in part because German reunification in 1990 forced a redirection of government funding away from pure science and into the rebuilding of the former East Germany), Schutz’s group did the data analysis and set upper limits on possible signals.[31] The exercise allowed the group to create the first working versions of algorithms that still lie at the heart of the LIGO-Virgo-KAGRA data analysis today.
Also in the late 1980s, Schutz began working with Chris Clarke and John Stewart to develop methods to program supercomputers to solve Einstein’s equations, with the aim of studying the mergers of binary black holes. His PhD student Gabrielle Allen and postdoc Miguel Alcubierre have gone on to establish themselves as leading experts in this field.
In the 1990s, Kostas Kokkotas and Schutz[32] discovered a new family of neutron-star vibration modes that do not exist in Newtonian gravity, in which the relativistic gravitational field around the star is the principal dynamical element. Dubbed w-modes, these are stellar analogues of the quasi-normal vibration modes of black holes.
When he moved to the AEI in 1995, Schutz was able to build a bigger group in numerical relativity, bringing Ed Seidel from NCSA in the US to lead it. Supplied with leading-edge in-house computing systems, this group was for many years the largest in the world devoted to numerical relativity, and made fundamental contributions that underlie much of the current software in this field. In particular the open Einstein Toolkit has roots in software created at the AEI in this period. Schutz himself focussed more on preparing for gravitational wave data analysis. He helped develop the F-Statistic,[33] which is the optimal frequentist statistical measure of the significance of a possible detection of a nearly periodic signal from a spinning neutron star. Working with M.-A. Papa and other collaborators,[34] Schutz helped develop the Hough Transform technique for efficient hierarchical searches for such signals in months-long stretches of data, a method that is still a key tool for LIGO-Virgo-KAGRA analysis.
Awards
Academies:
Fellow, Royal Society of London (elected 2021)[35]
Member, National Academy of Sciences, USA (elected 2019)[36]
Fellow, Learned Society of Wales (elected 2011)[37]
Member, Deutsche Akademie der Naturforscher Leopoldina (elected 2006)[38]
Member, Royal Academy of Arts and Sciences, Uppsala, Sweden (elected 2005)
Medals and other awards from societies:
Richard A. Isaacson Award in Gravitational-Wave Science, American Physical Society, jointly with Bruce Allen (2020)[39]
Eddington Medal of the Royal Astronomical Society (2019)[40]
General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever present matter and radiation. The relation is specified by the Einstein field equations, a system of second-order partial differential equations.
In theories of quantum gravity, the graviton is the hypothetical quantum of gravity, an elementary particle that mediates the force of gravitational interaction. There is no complete quantum field theory of gravitons due to an outstanding mathematical problem with renormalization in general relativity. In string theory, believed by some to be a consistent theory of quantum gravity, the graviton is a massless state of a fundamental string.
In physics, gravity (from Latin gravitas 'weight') is a fundamental interaction primarily observed as mutual attraction between all things that have mass. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force and 1029 times weaker than the weak interaction. As a result, it has no significant influence at the level of subatomic particles. However, gravity is the most significant interaction between objects at the macroscopic scale, and it determines the motion of planets, stars, galaxies, and even light.
The following is a timeline of gravitational physics and general relativity.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool. Two large observatories were built in the United States with the aim of detecting gravitational waves by laser interferometry. These observatories use mirrors spaced four kilometers apart to measure changes in length—over an effective span of 1120 km—of less than one ten-thousandth the charge diameter of a proton.
Einstein@Home is a volunteer computing project that searches for signals from spinning neutron stars in data from gravitational-wave detectors, from large radio telescopes, and from a gamma-ray telescope. Neutron stars are detected by their pulsed radio and gamma-ray emission as radio and/or gamma-ray pulsars. They also might be observable as continuous gravitational wave sources if they are rapidly spinning and non-axisymmetrically deformed. The project was officially launched on 19 February 2005 as part of the American Physical Society's contribution to the World Year of Physics 2005 event.
General relativity is a theory of gravitation developed by Albert Einstein between 1907 and 1915. The theory of general relativity says that the observed gravitational effect between masses results from their warping of spacetime.
Tests of general relativity serve to establish observational evidence for the theory of general relativity. The first three tests, proposed by Albert Einstein in 1915, concerned the "anomalous" precession of the perihelion of Mercury, the bending of light in gravitational fields, and the gravitational redshift. The precession of Mercury was already known; experiments showing light bending in accordance with the predictions of general relativity were performed in 1919, with increasingly precise measurements made in subsequent tests; and scientists claimed to have measured the gravitational redshift in 1925, although measurements sensitive enough to actually confirm the theory were not made until 1954. A more accurate program starting in 1959 tested general relativity in the weak gravitational field limit, severely limiting possible deviations from the theory.
The Max Planck Institute for Gravitational Physics is a Max Planck Institute whose research is aimed at investigating Einstein's theory of 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 closely collaborates with the Leibniz University Hannover. Both the Potsdam and the Hannover parts of the institute are organized in three research departments and host a number of independent research groups.
GEO600 is a gravitational wave detector located near Sarstedt, a town 20 kilometres (12 mi) to the south of Hanover, Germany. It is designed and operated by scientists from the Max Planck Institute for Gravitational Physics, Max Planck Institute of Quantum Optics and the Leibniz Universität Hannover, along with University of Glasgow, University of Birmingham and Cardiff University in the United Kingdom, and is funded by the Max Planck Society and the Science and Technology Facilities Council (STFC).
The Virgo interferometer is a large Michelson interferometer designed to detect the gravitational waves predicted by general relativity. It is in Santo Stefano a Macerata, near the city of Pisa, Italy. The instrument has two arms that are three kilometres long and contain its mirrors and instrumentation in an ultra-high vacuum.
Gravitational waves are transient displacements in a gravitational field – generated by the relative motion of gravitating masses – that radiate outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as the gravitational equivalent of electromagnetic waves. In 1916, Albert Einstein demonstrated that gravitational waves result from his general theory of relativity as ripples in spacetime.
A gravitational-wave detector is any device designed to measure tiny distortions of spacetime called gravitational waves. Since the 1960s, various kinds of gravitational-wave detectors have been built and constantly improved. The present-day generation of laser interferometers has reached the necessary sensitivity to detect gravitational waves from astronomical sources, thus forming the primary tool of gravitational-wave astronomy.
Gravitational-wave astronomy is a subfield of astronomy concerned with the detection and study of gravitational waves emitted by astrophysical sources.
Jürgen Ehlers was a German physicist who contributed to the understanding of Albert Einstein's theory of general relativity. From graduate and postgraduate work in Pascual Jordan's relativity research group at Hamburg University, he held various posts as a lecturer and, later, as a professor before joining the Max Planck Institute for Astrophysics in Munich as a director. In 1995, he became the founding director of the newly created Max Planck Institute for Gravitational Physics in Potsdam, Germany.
Einstein Telescope (ET) or Einstein Observatory, is a proposed third-generation ground-based gravitational wave detector, currently under study by some institutions in the European Union. It will be able to test Einstein's general theory of relativity in strong field conditions and realize precision gravitational wave astronomy.
Alessandra Buonanno is an Italian-American theoretical physicist and director at the Max Planck Institute for Gravitational Physics in Potsdam. She is the head of the "Astrophysical and Cosmological Relativity" department. She holds a research professorship at the University of Maryland, College Park, and honorary professorships at the Humboldt University in Berlin, and the University of Potsdam. She is a leading member of the LIGO Scientific Collaboration, which observed gravitational waves from a binary black-hole merger in 2015.
In astrophysics, the chirp mass of a compact binary system determines the leading-order orbital evolution of the system as a result of energy loss from emitting gravitational waves. Because the gravitational wave frequency is determined by orbital frequency, the chirp mass also determines the frequency evolution of the gravitational wave signal emitted during a binary's inspiral phase. In gravitational wave data analysis, it is easier to measure the chirp mass than the two component masses alone.
The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of two black holes and the subsequent ringdown of a single, 62 M☉ black hole remnant. The signal was named GW150914. It was also the first observation of a binary black hole merger, demonstrating both the existence of binary stellar-mass black hole systems and the fact that such mergers could occur within the current age of the universe.
↑ Physics, Professor Bernard Schutz Gravity Exploration Institute School of. "Professor Bernard Schutz". Cardiff University. Retrieved November 22, 2021.
↑ Wales, The Learned Society of. "Bernard Schutz". The Learned Society of Wales. Retrieved August 31, 2023.
↑ Physics, Professor Bernard Schutz Gravity Exploration Institute School of. "Professor Bernard Schutz". Cardiff University. Retrieved January 14, 2022.
↑ Schutz, Bernard F.; Papa, M. Alessandra (May 6, 1999). "End-to-end algorithm for hierarchical area searches for long-duration GW sources for GEO 600". arXiv:gr-qc/9905018.
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