Related papers: Gravitomagnetism, Frame-Dragging and Lunar Laser R…
Laser pulses fired at retroreflectors on the Moon provide very accurate ranges. Analysis yields information on Earth, Moon, and orbit. The highly accurate retroreflector positions have uncertainties less than a meter. Tides on the Moon show…
Among the effects predicted by the General Theory of Relativity for the orbital motion of a test particle, the post-Newtonian gravitomagnetic Lense-Thirring effect is very interesting and, up to now, there is not yet an undisputable…
The Lunar Laser Ranging (LLR) experiment has accumulated 50 years of range data of improving accuracy from ground stations to the laser retroreflector arrays (LRAs) on the lunar surface. The upcoming decade offers several opportunities to…
The Gravity Probe B (GP-B) satellite experiment will measure the precession of on-board gyroscopes to extraordinary accuracy. Such precessions are predicted by General Relativity (GR), and one component of this precession is the…
We apply the Kolmogorov statistic to analyse the residual data of two LAGEOS satellites on General Relativistic Lense-Thirring effect, and show that it reveals a tiny difference in the properties of the satellites, possibly related to…
In this brief note some comments about the observable used in a recently published paper on the measurement of the general relativistic Lense-Thirring in the gravitational field of the Earth are presented. It turns out that, among other…
Total precession (geodetic precession and frame dragging) depends on the velocity of each source of gravitation, which means that it depends on the choice of the coordinate system. We consider the latter as an anomaly specifically in the…
We present the first constraints on pure-gravity sector Standard-Model Extension (SME) parameters using Lunar Laser Ranging (LLR). LLR measures the round trip travel time of light between the Earth and the Moon. With 34+ years of LLR data,…
A decreasing gravitational constant, G, coupled with angular momentum conservation is expected to increrase a planetary semimajor axis, a, as \dot a/a=-\dot G/G. Analysis of lunar laser ranging data strongly limits such temporal variations…
We introduce a linearized bi-metric theory of gravity with two metrics. The metric g_{ab} describes null hypersurfaces of the gravitational field while light moves on null hypersurfaces of the optical metric \bar{g}_{ab}. Bi-metrism…
Violations of Lorentz Invariance, a cornerstone of modern physics, are predicted by theories of quantum gravity and by extensions of General Relativity involving new vector or tensor fields. In the weak-field limit, such a violation would…
Mass currents in astrophysics generate gravitomagnetic fields of enormous complexity. Gravitomagnetic helicity, in direct analogy with magnetic helicity, is a measure of entwining of the gravitomagnetic field lines. We discuss…
The LAGEOS 3 (today LARES 2) space experiment was proposed in the eighties by the Physics Department and by the Center of Space Research (CSR) of the University of Texas (UT) at Austin and by the Italian Space Agency (ASI) to test and…
We present new constraints on Lorentz symmetry (LS) violations with lunar laser ranging (LLR). Those constraints are derived in the standard-model extension (SME) framework aiming at parameterizing any LS deviations in all sectors of…
We consider a nearly free falling Earth satellite where atomic wave interferometers are tied to a telescope pointing towards a faraway star. They measure the acceleration and the rotation relatively to the local inertial frame. We calculate…
The main theoretical aspects of gravitoelectromagnetism ("GEM") are presented. Two basic approaches to this subject are described and the role of the gravitational Larmor theorem is emphasized. Some of the consequences of GEM are briefly…
Strong theoretical arguments suggest that a breakdown of Lorentz Invariance could arise under some very particular conditions. From an experimental point of view, it is important to test the Local Lorentz Invariance with ever greater…
The gravitomagnetic field generated by a rotating sphere is usually calculated from the ideal dipole model. However, for a sphere with a homogeneous mass density, this model is not generally valid. Trying to obtain a more accurate value of…
The detection of some tiny gravitomagnetic effects in the field of the Earth by means of artificial satellites is a very demanding task because of the various other perturbing forces of gravitational and non-gravitational origin acting upon…
We reexamine non-Einsteinian effects observable in the orbital motion of low-orbit artificial Earth satellites. The motivations for doing so are twofold: (i) recent theoretical studies suggest that the correct theory of gravity might…