scholarly journals Gravity between Newton and Einstein

2019 ◽  
Vol 28 (14) ◽  
pp. 1944010 ◽  
Author(s):  
Dennis Hansen ◽  
Jelle Hartong ◽  
Niels A. Obers
Keyword(s):  
General Relativity ◽  
Causal Structure ◽  
Relativistic Effects ◽  
Newtonian Gravity ◽  
Speed Of Light ◽  
Perihelion Precession ◽  
Tests Of General Relativity ◽  
Deflection Of Light ◽  
Weak Fields ◽  
Large Speed

Statements about relativistic effects are often subtle. In this essay we will demonstrate that the three classical tests of general relativity, namely perihelion precession, deflection of light and gravitational redshift, are passed perfectly by an extension of Newtonian gravity that includes gravitational time dilation effects while retaining a non-relativistic causal structure. This non-relativistic gravity theory arises from a covariant large speed of light expansion of Einstein’s theory of gravity that does not assume weak fields and which admits an action principle.

On claims that general relativity differs from Newtonian physics for self-gravitating dusts in the low velocity, weak field limit

2015 ◽  
Vol 24 (08) ◽  
pp. 1550065 ◽  
Author(s):  
David R. Rowland
Keyword(s):  
General Relativity ◽  
Solar System ◽  
Relativistic Effects ◽  
Weak Field ◽  
Newtonian Gravity ◽  
Galactic Rotation ◽  
Low Velocity ◽  
Rotation Curves ◽  
Newtonian Physics ◽  
General Relativistic

Galaxy rotation curves are generally analyzed theoretically using Newtonian physics; however, two groups of authors have claimed that for self-gravitating dusts, general relativity (GR) makes significantly different predictions to Newtonian physics, even in the weak field, low velocity limit. One group has even gone so far as to claim that nonlinear general relativistic effects can explain flat galactic rotation curves without the need for cold dark matter. These claims seem to contradict the well-known fact that the weak field, low velocity, low pressure correspondence limit of GR is Newtonian gravity, as evidenced by solar system tests. Both groups of authors claim that their conclusions do not contradict this fact, with Cooperstock and Tieu arguing that the reason is that for the solar system, we have test particles orbiting a central gravitating body, whereas for a galaxy, each star is both an orbiting body and a contributor to the net gravitational field, and this supposedly makes a difference due to nonlinear general relativistic effects. Given the significance of these claims for analyses of the flat galactic rotation curve problem, this article compares the predictions of GR and Newtonian gravity for three cases of self-gravitating dusts for which the exact general relativistic solutions are known. These investigations reveal that GR and Newtonian gravity are in excellent agreement in the appropriate limits, thus supporting the conventional use of Newtonian physics to analyze galactic rotation curves. These analyses also reveal some sources of error in the referred to works.

scholarly journals Astronomical Measurements and Coordinate Conditions in Relativistic Celestial Mechanics

1979 ◽  
Vol 81 ◽  
pp. 95-95
Author(s):  
V. A. Brumberg
Keyword(s):  
General Relativity ◽  
Celestial Mechanics ◽  
Relativistic Effects ◽  
Newtonian Theory ◽  
Deflection Of Light ◽  
Radar Reflection ◽  
Light Beams ◽  
Coordinate Conditions

The differences between the Newtonian theory and the general relativity appear both in the “relativistic effects,” such as the advance of perihelion, and in the deflection of light beams that modifies the astronomic observations and the radar reflection measurements.

Particle Theory: A New Theory That May Reconcile General Relativity and Quantum Theory

2021 ◽  
pp. 1-12
Author(s):  
Dino Martinez
Keyword(s):  
General Relativity ◽  
Quantum Mechanics ◽  
Atomic System ◽  
Relativistic Effects ◽  
Speed Of Light ◽  
Particle Theory ◽  
Atomic Particle ◽  
Screening Effect ◽  
Central Potential ◽  
System Of Particles

In an attempt to reconcile General Relativity and Quantum Mechanics, Particle Theory is a concept that may try to address this issue. This theory explains the effects accurately calculated by General Relativity in an alternate and real, physical way, and is therefore an alternative to GR. The theory states that indivisible atomic particles are instead divided into even smaller particles (called “EM particles”) held together by a central potential, the speed of light being the limit to their velocities. The “shedding” of these particles are responsible for the static and magnetic fields we observe. This also creates a “screening” effect that, for an atomic particle at rest, blocks about half of what this theory defines as the “true gravitational potential”, which is just twice the Newtonian value (mediated by what this theory defines as “gravity particles”). When an atomic system of particles starts moving in a certain direction, the act of shedding and the internal movement decreases as the particles orient themselves in the direction of the velocity, which reduces the screening effect, where we start to observe the relativistic effects of General (and Special) Relativity.

Solar system tests in Rastall gravity

2019 ◽  
Vol 35 (07) ◽  
pp. 2050034 ◽  
Author(s):  
Tuhina Manna ◽  
Farook Rahaman ◽  
Monimala Mondal
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Time Delay ◽  
Solar System ◽  
Astrophysical Object ◽  
Tests Of General Relativity ◽  
Deflection Of Light

In this paper, we have investigated the classical tests of General Relativity like precession of perihelion, deflection of light and time delay by considering a phenomenological astrophysical object like Sun, as a neutral regular Hayward black hole in Rastall gravity. We have tabulated all our results for some appropriate values of the parameter [Formula: see text]. We have compared our values with [Formula: see text], which corresponds to the Schwarzschild case. Also the value of [Formula: see text] is of particular interest as it gives some promising results.

scholarly journals Testing general relativity with geodetic VLBI

2018 ◽  
Vol 618 ◽  
pp. A8 ◽  
Author(s):  
O. Titov ◽  
A. Girdiuk ◽  
S. B. Lambert ◽  
J. Lovell ◽  
J. McCallum ◽  
...  
Keyword(s):  
General Relativity ◽  
Solar Corona ◽  
Radio Sources ◽  
The Sun ◽  
Dual Frequency ◽  
Single Session ◽  
Tests Of General Relativity ◽  
Geodetic Vlbi ◽  
Deflection Of Light ◽  
Group Delays

Context. We highlight the capabilities of geodetic VLBI technique to test general relativity in the classical astrometric style, i.e. measuring the deflection of light in the vicinity of the Sun.Aims. In previous studies, the parameterγwas estimated by global analyses of thousands of geodetic VLBI sessions. Here we estimateγfrom a single session where the Sun has approached two strong reference radio sources, 0229+131 and 0235+164, at an elongation angle of 1–3°.Methods. The AUA020 VLBI session of 1 May 2017 was designed to obtain more than 1000 group delays from the two radio sources. The solar corona effect was effectively calibrated with the dual-frequency observations even at small elongation.Results. We obtainedγwith a greater precision (0.9 × 10−4) than has been obtained through global analyses of thousands of standard geodetic sessions over decades. Current results demonstrate that the modern VLBI technology is capable of establishing new limits on observational tests of general relativity.

scholarly journals Reference Frame/Coordinate System in General Relativity

1986 ◽  
Vol 7 ◽  
pp. 113-116
Author(s):  
Toshio Fukushima
Keyword(s):  
General Relativity ◽  
Coordinate System ◽  
Reference Frame ◽  
Relativistic Effects ◽  
Speed Of Light ◽  
The Earth ◽  
Order Of Magnitude

The order of magnitude of relativistic effects is expressed as the power of v/c where v is a typical speed of objects and c is the speed of light in vacuum. In the neighbourhood of the Earth, v ≅ 30 km/s. Then the magnitudes of the relativistic effects are ordered as follows:

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

Discreteness of Space and Its Consequences

2021 ◽  
pp. 132-141
Author(s):  
Аnatoly М. Shutyi ◽  
Keyword(s):  
Spatial Configuration ◽  
Relativistic Effects ◽  
Space Time ◽  
Maximum Speed ◽  
Speed Of Light ◽  
Quantum Uncertainty ◽  
Proposed Model ◽  
Spatial Configurations ◽  
New Interpretation ◽  
Component Particle

Based on the general principle of the unity of the nature of interacting entities and the principle of the relativity of motion, as well as following the requirement of an indissoluble and conditioning connection of space and time, the model of a discrete space-time consisting of identical interacting particles is proposed as the most acceptable one. We consider the consequences of the discreteness of space, such as: the occurrence of time quanta, the limiting speed of signal propa­gation, and the constancy of this speed, regardless of the motion of the reference frame. Regularly performed acts of particles of space-time (PST) interaction en­sure the connectivity of space, set the quantum of time and the maximum speed – the speed of light. In the process of PST communication, their mixing occurs, which ensures the relativity of inertial motion, and can also underlie quantum uncertainty. In this case, elementary particles are spatial configurations of an excited “lattice” of PST, and particles with mass must contain loop struc­tures in their configuration. A new interpretation of quantum mechanics is pro­posed, according to which the wave function determines the probability of de­struction of a spatial configuration (representing a quantum object) in its corresponding region, which leads to the contraction of the entire structure to a given, detectable component. Particle entanglement is explained by the appear­ance of additional links between the PST – the appearance of a local coordinate along which the distance between entangled objects does not increase. It is shown that the movement of a body should lead to an asymmetry of the tension of the bonds between the PST – to the asymmetry of its effective gravity, the es­tablishment of which is one of the possibilities for experimental verification of the proposed model. It is shown that the constancy of the speed of light in a vac­uum and the appearance of relativistic effects are based on ensuring the connec­tivity of space-time, i.e. striving to prevent its rupture.

The precise calculations of the constant terms in the equations of motions of planets and photons of general relativity

2021 ◽  
Vol 34 (2) ◽  
pp. 183-192
Author(s):  
Mei Xiaochun
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Deflection Angle ◽  
Constant Term ◽  
Equation Of Motion ◽  
Time Dependent ◽  
Newtonian Gravity ◽  
Newtonian Theory ◽  
The Deflection Angle ◽  
Equations Of Motions

In general relativity, the values of constant terms in the equations of motions of planets and light have not been seriously discussed. Based on the Schwarzschild metric and the geodesic equations of the Riemann geometry, it is proved in this paper that the constant term in the time-dependent equation of motion of planet in general relativity must be equal to zero. Otherwise, when the correction term of general relativity is ignored, the resulting Newtonian gravity formula would change its basic form. Due to the absence of this constant term, the equation of motion cannot describe the elliptical and the hyperbolic orbital motions of celestial bodies in the solar gravitational field. It can only describe the parabolic orbital motion (with minor corrections). Therefore, it becomes meaningless to use general relativity calculating the precession of Mercury's perihelion. It is also proved that the time-dependent orbital equation of light in general relativity is contradictory to the time-independent equation of light. Using the time-independent orbital equation to do calculation, the deflection angle of light in the solar gravitational field is <mml:math display="inline"> <mml:mrow> <mml:mn>1.7</mml:mn> <mml:msup> <mml:mn>5</mml:mn> <mml:mo>″</mml:mo> </mml:msup> </mml:mrow> </mml:math> . But using the time-dependent equation to do calculation, the deflection angle of light is only a small correction of the prediction value <mml:math display="inline"> <mml:mrow> <mml:mn>0.87</mml:mn> <mml:msup> <mml:mn>5</mml:mn> <mml:mo>″</mml:mo> </mml:msup> </mml:mrow> </mml:math> of the Newtonian gravity theory with a magnitude order of <mml:math display="inline"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . The reason causing this inconsistency was the Einstein's assumption that the motion of light satisfied the condition <mml:math display="inline"> <mml:mrow> <mml:mi>d</mml:mi> <mml:mi>s</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> in gravitational field. It leads to the absence of constant term in the time-independent equation of motion of light and destroys the uniqueness of geodesic in curved space-time. Meanwhile, light is subjected to repulsive forces in the gravitational field, rather than attractive forces. The direction of deflection of light is opposite, inconsistent with the predictions of present general relativity and the Newtonian theory of gravity. Observing on the earth surface, the wavelength of light emitted by the sun is violet shifted. This prediction is obviously not true. Practical observation is red shift. Finally, the practical significance of the calculation of the Mercury perihelion's precession and the existing problems of the light's deflection experiments of general relativity are briefly discussed. The conclusion of this paper is that general relativity cannot have consistence with the Newtonian theory of gravity for the descriptions of motions of planets and light in the solar system. The theory itself is not self-consistent too.

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