Relativity and Fundamental Physics
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Astrometry for Astrophysics: Methods, Models and Applications William
AstrometryAstrometry forfor Astrophysics:Astrophysics: Methods,Methods, ModelsModels andand ApplicationsApplications William van Altena, editor Yale University 28 chapters - 28 co-authors from 15 countries IAU Beijing, August 2012 Inspiration for Astrometry for Astrophysics • IAU Symposium 248, Shanghai, October 2007 – Jin Wenjing - organizer • Brought together leaders in virtually all fields of modern astrometry. • Most successful astrometric conference in many years. IAU Beijing, August 2012 http://www.astro.yale.edu/vanalten/book.htm IAU Beijing, August 2012 Organization of text • Part I: Astrometry in the twenty-first century (34 pp) • Part II: Foundations of astrometry and celestial mechanics (79 pp) • Part III: Observing through the atmosphere (77 pp) • Part IV: From detected photons to the celestial sphere (120 pp) • Part V: Applications of astrometry to topics in astrophysics (75 pp) – http://www.astro.yale.edu/vanalten/book.htm IAU Beijing, August 2012 Part I: Astrometry in the 21 st Century • Ch 1: Opportunities and challenges for astrometry in the 21 st century – Michael Perryman • Ch 2: Astrometry satellites – Lennart Lindegren • Ch 3: Ground-based opportunities for astrometry – Norbert Zacharias IAU Beijing, August 2012 Part II: Foundations of astrometry and celestial mechanics • Ch 4: Vectors in astrometry, an introduction - Lennart Lindegren • Ch 5: Relativistic foundations of astrometry and celestial mechanics – Sergei Klioner • Ch 6: Celestial mechanics of the N-body problem – Sergei Klioner • Ch 7: Celestial coordinate -
Measurement of the Speed of Gravity
Measurement of the Speed of Gravity Yin Zhu Agriculture Department of Hubei Province, Wuhan, China Abstract From the Liénard-Wiechert potential in both the gravitational field and the electromagnetic field, it is shown that the speed of propagation of the gravitational field (waves) can be tested by comparing the measured speed of gravitational force with the measured speed of Coulomb force. PACS: 04.20.Cv; 04.30.Nk; 04.80.Cc Fomalont and Kopeikin [1] in 2002 claimed that to 20% accuracy they confirmed that the speed of gravity is equal to the speed of light in vacuum. Their work was immediately contradicted by Will [2] and other several physicists. [3-7] Fomalont and Kopeikin [1] accepted that their measurement is not sufficiently accurate to detect terms of order , which can experimentally distinguish Kopeikin interpretation from Will interpretation. Fomalont et al [8] reported their measurements in 2009 and claimed that these measurements are more accurate than the 2002 VLBA experiment [1], but did not point out whether the terms of order have been detected. Within the post-Newtonian framework, several metric theories have studied the radiation and propagation of gravitational waves. [9] For example, in the Rosen bi-metric theory, [10] the difference between the speed of gravity and the speed of light could be tested by comparing the arrival times of a gravitational wave and an electromagnetic wave from the same event: a supernova. Hulse and Taylor [11] showed the indirect evidence for gravitational radiation. However, the gravitational waves themselves have not yet been detected directly. [12] In electrodynamics the speed of electromagnetic waves appears in Maxwell equations as c = √휇0휀0, no such constant appears in any theory of gravity. -
Astrometric Reference Frames in the Solar System and Beyond
Mem. S.A.It. Vol. 83, 1001 c SAIt 2012 Memorie della Astrometric reference frames in the solar system and beyond S. Kopeikin Department of Physics & Astronomy, University of Missouri, 322 Physics Bldg., Columbia, MO 65211, USA Abstract. This presentation discusses the mathematical principles of constructing coordi- nates on curved spacetime manifold in order to build a hierarchy of astrometric frames in the solar system and beyond which can be used in future practical applications as well as for testing the fundamentals of the gravitational physics - general theory of relativity. 1. Introduction equations in order to find out the metric tensor corresponding to the coordinate charts cover- Fundamental astrometry is an essential ingre- ing either a local domain or the entire space- dient of modern gravitational physics. It mea- time manifold. sures positions and proper motions of vari- ous celestial objects and establishes a corre- The standard theory adopted by the spondence between theory and observations. International Astronomical Union (IAU) pos- Theoretical foundation of astrometry is general tulates that spacetime is asymptotically-flat theory of relativity which operates on curved and the only source of gravitational field is the spacetime manifold covered by a set of local matter of the solar system (Soffel et al. 2003; coordinates which are used to identify posi- Kopeikin 2007). This approach completely ig- tions and to parametrize the motion of celestial nores the presence of the huge distribution of objects and observer. The set of the local co- mass in our own galaxy – the Milky Way, the ordinates is structured in accordance with the local cluster of galaxies, and the other visi- hierarchical clustering of the gravitating bod- ble matter of the entire universe. -
File Reference: 208737
Institute of Physics Publishing Journal of Physics: Conference Series 32 (2006) 154–160 doi:10.1088/1742-6596/32/1/024 Sixth Edoardo Amaldi Conference on Gravitational Waves ASTROD and ASTROD I: Progress Report Wei-Tou Ni1,2,3, Henrique Araújo4, Gang Bao1, Hansjörg Dittus5,TianyiHuang6, Sergei Klioner7, Sergei Kopeikin8, George Krasinsky9, Claus Lämmerzahl5, Guangyu Li1,2, Hongying Li1,LeiLiu1,Yu-XinNie10, Antonio Pulido Patón1, Achim Peters11, Elena Pitjeva9, Albrecht Rüdiger12, Étienne Samain13,Diana Shaul4, Stephan Schiller14, Jianchun Shi1, Sachie Shiomi3,M.H.Soffel7,Timothy Sumner4, Stephan Theil5,PierreTouboul15, Patrick Vrancken13, Feng Wang1, Haitao Wang16, Zhiyi Wei10, Andreas Wicht14,Xue-JunWu1,17, Yan Xia1, Yaoheng Xiong18, Chongming Xu1,17,JunYan1,2, Hsien-Chi Yeh19, Yuan-Zhong Zhang20, Cheng Zhao1, and Ze-Bing Zhou21 1 Center for Gravitation and Cosmology, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, 210008 China E-mail: [email protected] 2 National Astronomical Observatories, CAS, Beijing, 100012 China 3 Center for Gravitation and Cosmology, Department of Physics, Tsing Hua University, Hsinchu, Taiwan 30013 4 Department of Physics, Imperial College of Science, Technology and Medicine, London, SW7 2BW, UK 5 ZARM, University of Bremen, 28359 Bremen, Germany 6 Department of Astronomy, Nanjing University, Nanjing, 210093 China 7 Lohrmann-Observatorium, Institut für Planetare Geodäsie, Technische Universität Dresden, 01062 Dresden, Germany 8 Department of Physics and Astronomy, University of Missouri-Columbia, -
Recent VLBA/VERA/IVS Tests of General Relativity
Relativity in Fundamental Astronomy Proceedings IAU Symposium No. 261, 2009 c International Astronomical Union 2010 S. A. Klioner, P. K. Seidelman & M. H. Soffel, eds. doi:10.1017/S1743921309990536 Recent VLBA/VERA/IVS tests of general relativity Ed Fomalont1, Sergei Kopeikin2,DaytonJones3, Mareki Honma4 & Oleg Titov5 1 National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA email: [email protected] 2 Dept. of Physics & Astronomy, University of Missouri-Columbia, 223 Physics Bldg., Columbia, MO 65211, USA email: [email protected] 3 Jet Propulsion Laboratory, 4800 Oak Grove Ave, Pasadena, CA 91109, USA email: [email protected] 4 VERA Project Office, Mizusawa VLBI Observatory, NAOJ, 181-8588, Tokyo, Japan email: [email protected] 5 Geoscience, Australia, GPO Box 378, Canberra, ACT 2601, Australia email: [email protected] Abstract. We report on recent VLBA/VERA/IVS observational tests of General Relativity. First, we will summarize the results from the 2005 VLBA experiment that determined gamma with an accuracy of 0.0003 by measuring the deflection of four compact radio sources by the solar gravitational field. We discuss the limits of precision that can be obtained with VLBA experiments in the future. We describe recent experiments using the three global arrays to measure the aberration of gravity when Jupiter and Saturn passed within a few arcmin of bright radio sources. These reductions are still in progress, but the anticipated positional accuracy of the VLBA experiment may be about 0.01 mas. Keywords. gravitation—quasars: individual (3C279)—relativity techniques: interferometric 1. The VLBA 2005 Solar-Bending Experiment The history of the experiments to measured the deflection of light by the solar gravi- tational field is well-known. -
10. Scientific Programme 10.1
10. SCIENTIFIC PROGRAMME 10.1. OVERVIEW (a) Invited Discourses Plenary Hall B 18:00-19:30 ID1 “The Zoo of Galaxies” Karen Masters, University of Portsmouth, UK Monday, 20 August ID2 “Supernovae, the Accelerating Cosmos, and Dark Energy” Brian Schmidt, ANU, Australia Wednesday, 22 August ID3 “The Herschel View of Star Formation” Philippe André, CEA Saclay, France Wednesday, 29 August ID4 “Past, Present and Future of Chinese Astronomy” Cheng Fang, Nanjing University, China Nanjing Thursday, 30 August (b) Plenary Symposium Review Talks Plenary Hall B (B) 8:30-10:00 Or Rooms 309A+B (3) IAUS 288 Astrophysics from Antarctica John Storey (3) Mon. 20 IAUS 289 The Cosmic Distance Scale: Past, Present and Future Wendy Freedman (3) Mon. 27 IAUS 290 Probing General Relativity using Accreting Black Holes Andy Fabian (B) Wed. 22 IAUS 291 Pulsars are Cool – seriously Scott Ransom (3) Thu. 23 Magnetars: neutron stars with magnetic storms Nanda Rea (3) Thu. 23 Probing Gravitation with Pulsars Michael Kremer (3) Thu. 23 IAUS 292 From Gas to Stars over Cosmic Time Mordacai-Mark Mac Low (B) Tue. 21 IAUS 293 The Kepler Mission: NASA’s ExoEarth Census Natalie Batalha (3) Tue. 28 IAUS 294 The Origin and Evolution of Cosmic Magnetism Bryan Gaensler (B) Wed. 29 IAUS 295 Black Holes in Galaxies John Kormendy (B) Thu. 30 (c) Symposia - Week 1 IAUS 288 Astrophysics from Antartica IAUS 290 Accretion on all scales IAUS 291 Neutron Stars and Pulsars IAUS 292 Molecular gas, Dust, and Star Formation in Galaxies (d) Symposia –Week 2 IAUS 289 Advancing the Physics of Cosmic -
Arxiv:Gr-Qc/0507001V3 16 Oct 2005
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Missouri: MOspace February 7, 2008 3:29 WSPC/INSTRUCTION FILE ijmp˙october12 International Journal of Modern Physics D c World Scientific Publishing Company Gravitomagnetism and the Speed of Gravity Sergei M. Kopeikin Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, Missouri 65211, USA [email protected] Experimental discovery of the gravitomagnetic fields generated by translational and/or rotational currents of matter is one of primary goals of modern gravitational physics. The rotational (intrinsic) gravitomagnetic field of the Earth is currently measured by the Gravity Probe B. The present paper makes use of a parametrized post-Newtonian (PN) expansion of the Einstein equations to demonstrate how the extrinsic gravitomag- netic field generated by the translational current of matter can be measured by observing the relativistic time delay caused by a moving gravitational lens. We prove that mea- suring the extrinsic gravitomagnetic field is equivalent to testing relativistic effect of the aberration of gravity caused by the Lorentz transformation of the gravitational field. We unfold that the recent Jovian deflection experiment is a null-type experiment testing the Lorentz invariance of the gravitational field (aberration of gravity), thus, confirming existence of the extrinsic gravitomagnetic field associated with orbital motion of Jupiter with accuracy 20%. We comment on erroneous interpretations of the Jovian deflection experiment given by a number of researchers who are not familiar with modern VLBI technique and subtleties of JPL ephemeris. We propose to measure the aberration of gravity effect more accurately by observing gravitational deflection of light by the Sun and processing VLBI observations in the geocentric frame with respect to which the Sun arXiv:gr-qc/0507001v3 16 Oct 2005 is moving with velocity ∼ 30 km/s. -
New Experiments in Gravitational Physics
St. John Fisher College Fisher Digital Publications Physics Faculty/Staff Publications Physics 2014 New Experiments in Gravitational Physics Munawar Karim St. John Fisher College, [email protected] Ashfaque H. Bokhari King Fahd University of Petroleum and Minerals Follow this and additional works at: https://fisherpub.sjfc.edu/physics_facpub Part of the Physics Commons How has open access to Fisher Digital Publications benefited ou?y Publication Information Karim, Munawar and Bokhari, Ashfaque H. (2014). "New Experiments in Gravitational Physics." EPJ Web of Conferences 75, 05001-05001-p.10. Please note that the Publication Information provides general citation information and may not be appropriate for your discipline. To receive help in creating a citation based on your discipline, please visit http://libguides.sjfc.edu/citations. This document is posted at https://fisherpub.sjfc.edu/physics_facpub/29 and is brought to you for free and open access by Fisher Digital Publications at St. John Fisher College. For more information, please contact [email protected]. New Experiments in Gravitational Physics Abstract We propose experiments to examine and extend interpretations of the Einstein field equations. Experiments encompass the fields of astrophysics, quantum properties of the gravity field, gravitational effects on quantum electrodynamic phenomena and coupling of spinors to gravity. As an outcome of this work we were able to derive the temperature of the solar corona. Disciplines Physics Comments Proceedings from the Fifth International Symposium on Experimental Gravitation in Nanchang, China, July 8-13, 2013. Copyright is owned by the authors, published by EDP Sciences in EPJ Web of Conferences in 2014. Article is available at: http://dx.doi.org/10.1051/epjconf/20147405001. -
Effect of the Earth's Time-Retarded Transverse Gravitational Field On
-1- Effect of the Earth’s Time-Retarded Transverse Gravitational Field on Spacecraft Flybys (Version 3) J. C. Hafele1 ______________________________________________________________________________ In 2008 a group of NASA scientists reported an anomalous change in the speed of six spacecraft flybys of the Earth. The reported speed change for the NEAR spacecraft flyby is 13.460.01 mm/s. It is known that general relativity theory reduces to classical time-retarded electromagnetic field theory in the linearized approximation. This report shows that time-retarded field theory applied to the Earth’s transverse gravitational field gives rise to a small change in the speed of a spacecraft during a flyby. The speed change depends on the time dependence of the transverse gravitational field, which generates an induction field that is proportional to the time derivative of the transverse field. If the corresponding speed for the induction field is set equal to (4.1300.003) times the Earth’s equatorial rotational surface speed, and the speed of the Earth’s gravitational field is set equal to (1.0600.001) times the vacuum speed of light, the calculated value for the speed change for the NEAR flyby agrees exactly with the observed value. Similar results are found for the remaining five flybys. ______________________________________________________________________________ Key Words: time-retarded gravity; transverse gravity; speed of gravity; flyby anomaly 1. INTRODUCTION It has long been known that electromagnetic fields propagate at the speed of light. The actual speed of light depends on whether the field is propagating in a vacuum or in a material medium. In either case, to calculate the electromagnetic fields of a moving point-charge, the concept of “time retardation” must be used.(1) Time retardation is necessary because it takes a certain amount of time for causal physical fields to propagate from a moving point-source to a distant field point. -
Research.Pdf (342.4Kb)
General Relativistic Theory of Light Propagation in the Field of Gravitational Multipoles A Dissertation presented to the Faculty of the Graduate School University of Missouri-Columbia In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Pavel Korobkov Dr. Sergei Kopeikin, Dissertation Supervisor AUGUST 2007 The undersigned, appointed by the Dean of the Graduate School, have ex- amined the dissertation entitled: General Relativistic Theory of Light Propagation in the Field of Gravitational Multipoles presented by Pavel Korobkov a candidate for the degree of Doctor of Philosophy and hereby certify that in their opinion it is worthy of acceptance. Dr. Sergei Kopeikin Dr. Bahram Mashhoon Dr. Adam Helfer Dr. Giovanni Vignale Dr. Aigen Li ACKNOWLEDGMENTS I would like to thank my advisor Dr. Sergei Kopeikin for guidance, Dr. Bahram Mashhoon, Dr. Adam Helfer, Dr. Giovanni Vignale, and Dr. Aigen Li for taking the time to be on the committee and for warm, supportive attitude. I am indebted to my family, friends, and to many people who in different ways supported and helped me during the time in graduate school. ii Contents ACKNOWLEDGEMENTS ii LIST OF FIGURES iv CHAPTER 1 Introduction 1 1 Historical Background and Statement of the Problem. 1 2 Notations and Conventions . 7 2 Metric Tensor and Coordinate Systems 12 1 Metric Tensor . 12 2 The Harmonic Coordinate System . 14 3 The Arnowitt-Deser-Misner Coordinate System . 15 3 Equations for Propagation of Electromagnetic Signals 18 1 Geometrical Optics in Curved Spacetime . 18 2 Equations for Trajectory of a Photon . 20 3 Equations for Propagation of Polarization Properties . -
New Varying Speed of Light Theories
New varying speed of light theories Jo˜ao Magueijo The Blackett Laboratory,Imperial College of Science, Technology and Medicine South Kensington, London SW7 2BZ, UK ABSTRACT We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying c, dispelling the myth that the constancy of c is a matter of logical consistency. We then summarize the main VSL mechanisms proposed so far: hard breaking of Lorentz invariance; bimetric theories (where the speeds of gravity and light are not the same); locally Lorentz invariant VSL theories; theories exhibiting a color dependent speed of light; varying c induced by extra dimensions (e.g. in the brane-world scenario); and field theories where VSL results from vacuum polarization or CPT violation. We show how VSL scenarios may solve the cosmological problems usually tackled by inflation, and also how they may produce a scale-invariant spectrum of Gaussian fluctuations, capable of explaining the WMAP data. We then review the connection between VSL and theories of quantum gravity, showing how “doubly special” relativity has emerged as a VSL effective model of quantum space-time, with observational implications for ultra high energy cosmic rays and gamma ray bursts. Some recent work on the physics of “black” holes and other compact objects in VSL theories is also described, highlighting phenomena associated with spatial (as opposed to temporal) variations in c. Finally we describe the observational status of the theory. The evidence is slim – redshift dependence in alpha, ultra high energy cosmic rays, and (to a much lesser extent) the acceleration of the universe and the WMAP data. -
Static Spherically Symmetric Black Holes in Weak F(T)-Gravity
universe Article Static Spherically Symmetric Black Holes in Weak f (T)-Gravity Christian Pfeifer 1,*,† and Sebastian Schuster 2,† 1 Center of Applied Space Technology and Microgravity—ZARM, University of Bremen, Am Fallturm 2, 28359 Bremen, Germany 2 Ústav Teoretické Fyziky, Matematicko-Fyzikální Fakulta, Univerzita Karlova, V Holešoviˇckách2, 180 00 Praha 8, Czech Republic; [email protected] * Correspondence: [email protected] † These authors contributed equally to this work. Abstract: With the advent of gravitational wave astronomy and first pictures of the “shadow” of the central black hole of our milky way, theoretical analyses of black holes (and compact objects mimicking them sufficiently closely) have become more important than ever. The near future promises more and more detailed information about the observable black holes and black hole candidates. This information could lead to important advances on constraints on or evidence for modifications of general relativity. More precisely, we are studying the influence of weak teleparallel perturbations on general relativistic vacuum spacetime geometries in spherical symmetry. We find the most general family of spherically symmetric, static vacuum solutions of the theory, which are candidates for describing teleparallel black holes which emerge as perturbations to the Schwarzschild black hole. We compare our findings to results on black hole or static, spherically symmetric solutions in teleparallel gravity discussed in the literature, by comparing the predictions for classical observables such as the photon sphere, the perihelion shift, the light deflection, and the Shapiro delay. On the basis of these observables, we demonstrate that among the solutions we found, there exist spacetime geometries that lead to much weaker bounds on teleparallel gravity than those found earlier.