scholarly journals Gravitational light deflection, time delay and frequency shift in Einstein-Aether theory

2009 ◽  
Vol 5 (S261) ◽  
pp. 140-143
Author(s):  
Kai Tang ◽  
Tian-Yi Huang ◽  
Zheng-Hong Tang
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Time Delay ◽  
Frequency Shift ◽  
Light Propagation ◽  
Gravity Theory ◽  
Light Deflection ◽  
Body Model ◽  
Newtonian Approximation ◽  
Gravity Theories

AbstractEinstein-Aether gravity theory has been proven successful in passing experiments of different scales. Especially its Eddington parameters β and γ have the same numerical values as those in general relativity. Recently Xie and Huang (2008) have advanced this theory to a second post-Newtonian approximation for an N-body model and obtained an explicit metric when the bodies are point-like masses. This research considers light propagation in the above gravitational field, and explores the light deflection, time delay, frequency shift etc. The results will provide for future experiments in testing gravity theories.

The post-Newtonian approximation

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Body Problem ◽  
Equations Of Motion ◽  
Two Body Problem ◽  
Newtonian Approximation ◽  
Actual Motion ◽  
Law Of Attraction ◽  
Universal Law ◽  
Two Bodies

This chapter embarks on a study of the two-body problem in general relativity. In other words, it seeks to describe the motion of two compact, self-gravitating bodies which are far-separated and moving slowly. It limits the discussion to corrections proportional to v2 ~ m/R, the so-called post-Newtonian or 1PN corrections to Newton’s universal law of attraction. The chapter first examines the gravitational field, that is, the metric, created by the two bodies. It then derives the equations of motion, and finally the actual motion, that is, the post-Keplerian trajectories, which generalize the post-Keplerian geodesics obtained earlier in the chapter.

Simulation model for shapiro time delay and light deflection experiments

Open Physics ◽  
2004 ◽  
Vol 2 (4) ◽  
Author(s):  
Abhijit Biswas ◽  
Krishnan Mani
Keyword(s):  
General Relativity ◽  
Time Delay ◽  
Simulation Model ◽  
Time Transformation ◽  
Light Deflection ◽  
Accuracy Level ◽  
Simple Mass ◽  
General Relativistic ◽  
Precise Experiment ◽  
Relativistic Equations

AbstractThe time delay experiment proposed by I.I. Shapiro in 1964 and conducted in the seventies was the most precise experiment of general relativity until that time. Further experimentation has improved the accuracy level of both the time delay and the light deflection experiments. A simulation model is proposed that involves only a simple mass and time transformation factor involving velocity of light. The light deflection and the time delay experiments are numerically simulated using this model that does not use the general relativistic equations. The computed values presented in this paper compare well with recent levels of accuracy of their respective experimental results.

scholarly journals A Priori “Imprinting” of General Relativity Itself on Some Tests of It?

2010 ◽  
Vol 2010 ◽  
pp. 1-5
Author(s):  
Lorenzo Iorio
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Time Delay ◽  
Solar System ◽  
Gravitational Constant ◽  
A Priori ◽  
Astronomical Unit ◽  
Space Curvature ◽  
Order Of Magnitude ◽  
Delay Tests

We investigate the effect of possible a priori “imprinting” effects of general relativity itself on satellite/spacecraft-based tests of it. We deal with some performed or proposed time-delay ranging experiments in the sun's gravitational field. It turns out that the “imprint” of general relativity on the Astronomical Unit and the solar gravitational constant , not solved for in the so far performed spacecraft-based time-delay tests, induces an a priori bias of the order of in typical solar system ranging experiments aimed to measure the space curvature PPN parameter . It is too small by one order of magnitude to be of concern for the performed Cassini experiment, but it would affect future planned or proposed tests aiming to reach a accuracy in determining .

scholarly journals Blackhole in nonlocal gravity: comparing metric from Newmann–Janis algorithm with slowly rotating solution

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Utkarsh Kumar ◽  
Sukanta Panda ◽  
Avani Patel
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Modified Gravity ◽  
Kerr Metric ◽  
Slow Rotation ◽  
Field Equations ◽  
External Region ◽  
Modified Gravity Theories ◽  
Spacetime Metric ◽  
Gravity Theories

Abstract The strong gravitational field near massive blackhole is an interesting regime to test General Relativity (GR) and modified gravity theories. The knowledge of spacetime metric around a blackhole is a primary step for such tests. Solving field equations for rotating blackhole is extremely challenging task for the most modified gravity theories. Though the derivation of Kerr metric of GR is also demanding job, the magical Newmann–Janis algorithm does it without actually solving Einstein equation for rotating blackhole. Due to this notable success of Newmann–Janis algorithm in the case of Kerr metric, it has been being used to obtain rotating blackhole solution in modified gravity theories. In this work, we derive the spacetime metric for the external region of a rotating blackhole in a nonlocal gravity theory using Newmann–Janis algorithm. We also derive metric for a slowly rotating blackhole by perturbatively solving field equations of the theory. We discuss the applicability of Newmann–Janis algorithm to nonlocal gravity by comparing slow rotation limit of the metric obtained through Newmann–Janis algorithm with slowly rotating solution of the field equation.

scholarly journals GALILEAN COVARIANCE AND THE GRAVITATIONAL FIELD

2009 ◽  
Vol 24 (28n29) ◽  
pp. 5287-5297 ◽  
Author(s):  
SÉRGIO C. ULHOA ◽  
FAQIR C. KHANNA ◽  
ADEMIR E. SANTANA
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
Gravitational Field ◽  
Relativistic Theory ◽  
Galilei Group ◽  
Newtonian Approximation ◽  
Covariant Version ◽  
Galilean Covariance

This paper is concerned with the development of a gravitational field theory having locally a covariant version of the Galilei group. We show that this Galilean gravity can be used to study the advance of perihelion of a planet, following in parallel with the result of the (relativistic) theory of general relativity in the post-Newtonian approximation.

scholarly journals Gravity, Where Does It Come From?

2021 ◽  
Author(s):  
Ahmed Isam
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Kinetic Energy ◽  
Light Propagation ◽  
Spherically Symmetric ◽  
Rest Energy ◽  
Strong Gravity ◽  
Massive Object ◽  
New Form

Einstein’s theory of general relativity describes the gravitational field around massive objects ( like Earth) as a curvature in the spacetime. But it leaves the following question unanswered; why is the spacetime curved by a mass? Through a theory that has been introduced recently, regarding a medium for a light propagation, a simple answer is introduced. It depends on redefining the rest energy for a massive object ( like a planet) as new form of kinetic energy. For a static and spherically symmetric object, with a specific radius(

scholarly journals Do solar system experiments constrain scalar–tensor gravity?

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Valerio Faraoni ◽  
Jeremy Côté ◽  
Andrea Giusti
Keyword(s):  
General Relativity ◽  
Time Delay ◽  
Solar System ◽  
Experimental Tests ◽  
Higher Order ◽  
Common Belief ◽  
Light Deflection ◽  
Higher Order Terms ◽  
The One ◽  
Weak Gravity

Abstract It is now established that, contrary to common belief, (electro-)vacuum Brans–Dicke gravity does not reduce to general relativity (GR) for large values of the Brans–Dicke coupling $$\omega $$ω. Since the essence of experimental tests of scalar–tensor gravity consists of providing lower bounds on $$\omega $$ω, in light of the misguided assumption of the equivalence between the limit $$\omega \rightarrow \infty $$ω→∞ and the GR limit of Brans–Dicke gravity, the parametrized post-Newtonian (PPN) formalism on which these tests are based could be in jeopardy. We show that, in the linearized approximation used by the PPN formalism, the anomaly in the limit to general relativity disappears. However, it survives to second (and higher) order and in strong gravity. In other words, while the weak gravity regime cannot tell apart GR and $$\omega \rightarrow \infty $$ω→∞ Brans–Dicke gravity, when higher order terms in the PPN analysis of Brans–Dicke gravity are included, the latter never reduces to the one of GR in this limit. This fact is relevant for experiments aiming to test second order light deflection and Shapiro time delay.

scholarly journals "IMPRINTING" IN GENERAL RELATIVITY TESTS?

2011 ◽  
Vol 20 (10) ◽  
pp. 1945-1948
Author(s):  
LORENZO IORIO
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Time Delay ◽  
Solar System ◽  
Gravitational Constant ◽  
A Priori ◽  
Astronomical Unit ◽  
Delay Test ◽  
Space Curvature ◽  
Order Of Magnitude

We investigate possible a priori "imprinting" of general relativity itself on spaceraft-based tests of it. We deal with some performed or proposed time-delay ranging experiments in the Sun's gravitational field. The "imprint" of general relativity on the Astronomical Unit and the solar gravitational constant GM⊙, not solved for in the spacecraft-based time-delay test performed so far, may induce an a priori bias of the order of 10-6 in typical solar system ranging experiments aimed to measuring the space curvature PPN parameter γ. It is too small by one order of magnitude to be of concern for the performed Cassini experiment, but it would affect future planned or proposed tests aiming to reach a 10-7–10-9 accuracy in determining γ.

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