1
|
Bahamonde S, Dialektopoulos KF, Escamilla-Rivera C, Farrugia G, Gakis V, Hendry M, Hohmann M, Levi Said J, Mifsud J, Di Valentino E. Teleparallel gravity: from theory to cosmology. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:026901. [PMID: 36279849 DOI: 10.1088/1361-6633/ac9cef] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Teleparallel gravity (TG) has significantly increased in popularity in recent decades, bringing attention to Einstein's other theory of gravity. In this Review, we give a comprehensive introduction to how teleparallel geometry is developed as a gauge theory of translations together with all the other properties of gauge field theory. This relates the geometry to the broader metric-affine approach to forming gravitational theories where we describe a systematic way of constructing consistent teleparallel theories that respect certain physical conditions such as local Lorentz invariance. We first use TG to formulate a teleparallel equivalent of general relativity (GR) which is dynamically equivalent to GR but which may have different behaviors for other scenarios, such as quantum gravity. After setting this foundation, we describe the plethora of modified teleparallel theories of gravity that have been proposed in the literature. We attempt to connect them together into general classes of covariant gravitational theories. Of particular interest, we highlight the recent proposal of a teleparallel analogue of Horndeski gravity which offers the possibility of reviving all of the regular Horndeski contributions. In the second part of the Review, we first survey works in teleparallel astrophysics literature where we focus on the open questions in this regime of physics. We then discuss the cosmological consequences for the various formulations of TG. We do this at background level by exploring works using various approaches ranging from dynamical systems to Noether symmetries, and more. Naturally, we then discuss perturbation theory, firstly by giving a concise approach in which this can be applied in TG theories and then apply it to a number of important theories in the literature. Finally, we examine works in observational and precision cosmology across the plethora of proposal theories. This is done using some of the latest observations and is used to tackle cosmological tensions which may be alleviated in teleparallel cosmology. We also introduce a number of recent works in the application of machine learning to gravity, we do this through deep learning and Gaussian processes, together with discussions about other approaches in the literature.
Collapse
Affiliation(s)
- Sebastian Bahamonde
- Laboratory of Theoretical Physics, Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu, Estonia
- Department of Physics, Tokyo Institute of Technology, 1-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Konstantinos F Dialektopoulos
- Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University, Yangzhou 225009, People's Republic of China
- Laboratory of Physics, Faculty of Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
- Department of Physics, Nazarbayev University, 53 Kabanbay Batyr Avenue, 010000 Astana, Kazakhstan
| | - Celia Escamilla-Rivera
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior C.U., A.P. 70-543, México D.F. 04510, Mexico
| | - Gabriel Farrugia
- Institute of Space Sciences and Astronomy, University of Malta, Msida, Malta
- Department of Physics, University of Malta, Msida, Malta
| | - Viktor Gakis
- Institute of Space Sciences and Astronomy, University of Malta, Msida, Malta
- Department of Physics, University of Malta, Msida, Malta
- Department of Physics, National Technical University of Athens, Zografou Campus GR 157 73, Athens, Greece
| | - Martin Hendry
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Manuel Hohmann
- Laboratory of Theoretical Physics, Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu, Estonia
| | - Jackson Levi Said
- Institute of Space Sciences and Astronomy, University of Malta, Msida, Malta
- Department of Physics, University of Malta, Msida, Malta
| | - Jurgen Mifsud
- Institute of Space Sciences and Astronomy, University of Malta, Msida, Malta
- Department of Physics, University of Malta, Msida, Malta
| | - Eleonora Di Valentino
- Institute for Particle Physics Phenomenology, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| |
Collapse
|
2
|
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. Finally, we move on to a discussion of how the teleparallel perturbations influence the Hawking evaporation in these spacetimes.
Collapse
|
3
|
Yang T, Hu B, Cai RG, Wang B. New Probe of Gravity: Strongly Lensed Gravitational-wave Multimessenger Approach. THE ASTROPHYSICAL JOURNAL 2019; 880:50. [DOI: 10.3847/1538-4357/ab271e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
|
4
|
Casana R, Cavalcante A, Poulis F, Santos E. Exact Schwarzschild-like solution in a bumblebee gravity model. Int J Clin Exp Med 2018. [DOI: 10.1103/physrevd.97.104001] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
5
|
Zakharov A, Jovanović P, Borka D, Jovanović VB. Graviton mass bounds from an analysis of bright star trajectories at the Galactic Center. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201713801010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
6
|
|
7
|
Koyama K. Cosmological tests of modified gravity. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:046902. [PMID: 27007681 DOI: 10.1088/0034-4885/79/4/046902] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.
Collapse
Affiliation(s)
- Kazuya Koyama
- Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX, UK
| |
Collapse
|
8
|
Baker T, Psaltis D, Skordis C. LINKING TESTS OF GRAVITY ON ALL SCALES: FROM THE STRONG-FIELD REGIME TO COSMOLOGY. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/802/1/63] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
9
|
Shabani H, Farhoudi M. Cosmological and solar system consequences off(R,T)gravity models. Int J Clin Exp Med 2014. [DOI: 10.1103/physrevd.90.044031] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
10
|
Will CM. The Confrontation between General Relativity and Experiment. LIVING REVIEWS IN RELATIVITY 2014; 17:4. [PMID: 28179848 PMCID: PMC5255900 DOI: 10.12942/lrr-2014-4] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/06/2014] [Indexed: 05/14/2023]
Abstract
The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eötvös experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.
Collapse
Affiliation(s)
- Clifford M. Will
- Department of Physics, University of Florida, Gainesville, FL 32611 USA
| |
Collapse
|
11
|
Maluf RV, Santos V, Cruz WT, Almeida CAS. Matter-gravity scattering in the presence of spontaneous Lorentz violation. Int J Clin Exp Med 2013. [DOI: 10.1103/physrevd.88.025005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
12
|
Gai M, Vecchiato A, Ligori S, Sozzetti A, Lattanzi MG. Gravitation astrometric measurement experiment. EXPERIMENTAL ASTRONOMY 2012; 34:165-180. [DOI: 10.1007/s10686-012-9304-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
13
|
Uzan JP. Testing general relativity: from local to cosmological scales. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:5042-5057. [PMID: 22084292 DOI: 10.1098/rsta.2011.0293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
I summarize various tests of general relativity on astrophysical scales, based on the large-scale structure of the universe but also on other systems, in particular the constants of physics. I emphasize the importance of hypotheses on the geometric structures of our universe while performing such tests and discuss their complementarity as well as their possible extensions.
Collapse
Affiliation(s)
- Jean-Philippe Uzan
- Institut d'Astrophysique de Paris, UMR-7095 du CNRS, Université Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris, France.
| |
Collapse
|
14
|
Vanderveld RA, Caldwell RR, Rhodes J. Second-order weak lensing from modified gravity. Int J Clin Exp Med 2011. [DOI: 10.1103/physrevd.84.123510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
15
|
March R, Bellettini G, Tauraso R, Dell’Agnello S. Constraining spacetime torsion with the Moon and Mercury. Int J Clin Exp Med 2011. [DOI: 10.1103/physrevd.83.104008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
16
|
On the unreasonable effectiveness of the post-Newtonian approximation in gravitational physics. Proc Natl Acad Sci U S A 2011; 108:5938-45. [PMID: 21447714 DOI: 10.1073/pnas.1103127108] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The post-Newtonian approximation is a method for solving Einstein's field equations for physical systems in which motions are slow compared to the speed of light and where gravitational fields are weak. Yet it has proven to be remarkably effective in describing certain strong-field, fast-motion systems, including binary pulsars containing dense neutron stars and binary black hole systems inspiraling toward a final merger. The reasons for this effectiveness are largely unknown. When carried to high orders in the post-Newtonian sequence, predictions for the gravitational-wave signal from inspiraling compact binaries will play a key role in gravitational-wave detection by laser-interferometric observatories.
Collapse
|
17
|
Uzan JP. Varying Constants, Gravitation and Cosmology. LIVING REVIEWS IN RELATIVITY 2011; 14:2. [PMID: 28179829 PMCID: PMC5256069 DOI: 10.12942/lrr-2011-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/23/2011] [Indexed: 05/27/2023]
Abstract
Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Collapse
Affiliation(s)
- Jean-Philippe Uzan
- Institut d’Astrophysique de Paris, UMR-7095 du CNRS, Université Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris, France
- Department of Mathematics and Applied Mathematics, Cape Town University, Rondebosch, 7701 South Africa
- National Institute for Theoretical Physics (NITheP), Stellenbosch, 7600 South Africa
| |
Collapse
|
18
|
|
19
|
Clifton T, Barrow JD. Observational constraints on the completeness of space near astrophysical objects. Int J Clin Exp Med 2010. [DOI: 10.1103/physrevd.81.063006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
20
|
|
21
|
Deng XM, Xie Y, Huang TY. Modified scalar-tensor-vector gravity theory and the constraint on its parameters. Int J Clin Exp Med 2009. [DOI: 10.1103/physrevd.79.044014] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
22
|
Affiliation(s)
- Gary A Chapman
- Department of Physics and Astronomy, California State University, Northridge, CA 91330, USA.
| |
Collapse
|
23
|
Ahmed M, Magalhães DV, Bebeachibuli A, Müller ST, Alves RF, Ortega TA, Weiner J, Bagnato VS. The Brazilian time and frequency atomic standards program. AN ACAD BRAS CIENC 2008; 80:217-52. [DOI: 10.1590/s0001-37652008000200002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2007] [Accepted: 12/18/2007] [Indexed: 11/22/2022] Open
Abstract
Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. The adoption of optical cooling and trapping techniques, has produced a major advance in atomic clock precision. Cold-atom fountain and compact cold-atom clocks have also been developed. Measurement precision of a few parts in 10(15) has been demonstrated for a cold-atom fountain clock. We present here an overview of the time and frequency metrology program based on cesium atoms under development at USP São Carlos. This activity consists of construction and characterization of atomic-beam, and several variations of cold-atom clocks. We discuss the basic working principles, construction, evaluation, and important applications of atomic clocks in the Brazilian program.
Collapse
|
24
|
Sereno M. Influence of the cosmological constant on gravitational lensing in small systems. Int J Clin Exp Med 2008. [DOI: 10.1103/physrevd.77.043004] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
25
|
Battat JBR, Chandler JF, Stubbs CW. Testing for Lorentz violation: constraints on standard-model-extension parameters via lunar laser ranging. PHYSICAL REVIEW LETTERS 2007; 99:241103. [PMID: 18233436 DOI: 10.1103/physrevlett.99.241103] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Indexed: 05/25/2023]
Abstract
We present constraints on violations of Lorentz invariance based on archival lunar laser-ranging (LLR) data. LLR measures the Earth-Moon separation by timing the round-trip travel of light between the two bodies and is currently accurate to the equivalent of a few centimeters (parts in 10(11) of the total distance). By analyzing this LLR data under the standard-model extension (SME) framework, we derived six observational constraints on dimensionless SME parameters that describe potential Lorentz violation. We found no evidence for Lorentz violation at the 10(-6) to 10(-11) level in these parameters. This work constitutes the first LLR constraints on SME parameters.
Collapse
Affiliation(s)
- James B R Battat
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|
26
|
Will CM. The Confrontation between General Relativity and Experiment. LIVING REVIEWS IN RELATIVITY 2006; 9:3. [PMID: 28179873 PMCID: PMC5256066 DOI: 10.12942/lrr-2006-3] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/27/2006] [Indexed: 05/18/2023]
Abstract
The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eötvös experiment, tests of special relativity, and the gravitational redshift experiment. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and other binary pulsar systems have yielded other tests, especially of strong-field effects. When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.
Collapse
Affiliation(s)
- Clifford M. Will
- McDonnell Center for the Space Sciences Department of Physics, Washington University, St. Louis, MO 63130 USA
| |
Collapse
|
27
|
Keeton CR, Petters AO. Formalism for testing theories of gravity using lensing by compact objects. II. Probing post-post-Newtonian metrics. Int J Clin Exp Med 2006. [DOI: 10.1103/physrevd.73.044024] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
28
|
Keeton CR, Petters AO. Formalism for testing theories of gravity using lensing by compact objects: Static, spherically symmetric case. Int J Clin Exp Med 2005. [DOI: 10.1103/physrevd.72.104006] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
29
|
Williams JG, Turyshev SG, Boggs DH. Progress in lunar laser ranging tests of relativistic gravity. PHYSICAL REVIEW LETTERS 2004; 93:261101. [PMID: 15697965 DOI: 10.1103/physrevlett.93.261101] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Indexed: 05/24/2023]
Abstract
Analyses of laser ranges to the Moon provide increasingly stringent limits on any violation of the equivalence principle (EP); they also enable several very accurate tests of relativistic gravity. These analyses give an EP test of Delta(MG/MI)EP=(-1.0+/-1.4) x 10(-13). This result yields a strong equivalence principle (SEP) test of Delta(MG/MI)SEP=(-2.0+/-2.0) x 10(-13). Also, the corresponding SEP violation parameter eta is (4.4+/-4.5) x 10(-4), where eta=4beta-gamma-3 and both beta and gamma are post-Newtonian parameters. Using the Cassini gamma, the eta result yields beta-1=(1.2+/-1.1) x 10(-4). The geodetic precession test, expressed as a relative deviation from general relativity, is Kgp=-0.0019+/-0.0064. The search for a time variation in the gravitational constant results in G /G=(4+/-9) x 10(-13) yr(-1); consequently there is no evidence for local (approximately 1 AU) scale expansion of the solar system.
Collapse
Affiliation(s)
- James G Williams
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
| | | | | |
Collapse
|