We point out that extended gravity theories, the Lagrangian of which is an arbitrary function of scalar curvature R, are equivalent to a class of the scalar tensor theories of gravity. The corresponding gravity theory is ω = 0 BransDicke gravity with a potential for the Brans-Dicke scalar field, which is not compatible with solar system experiments if the field is very light: the case when such...

The problem of downward continuation of the gravity field from the Earth’s surface to the reference ellipsoid arises from the fact that the solution to the boundary value problem for geoid determination without applying Stokes formula is sought in terms of the disturbing potential on the ellipsoid but the gravity observations are only available on the Earth’s surface. Downward continuation is a...

There is far less study of the refining effect of super gravity fields on solidification structures of metals than of the effects of electrical currents, magnetic and ultrasonic fields. Moreover, the refining mechanisms of super gravity are far from clear. This study applied a super gravity field to Al-Cu alloys to investigate its effect on refining their structures and the mechanism of interac...

Gravity theory is the basis of modern cosmological models. Thirring-Feynman’s tensor field approach to gravitation is an alternative to General Relativity (GR). Though Field Gravity (FG) approach is still developing subject, it opens new understanding of gravitational interaction, stimulates novel experiments on the nature of gravity and gives possibility to construct new cosmological models in...

In recent twenty years, loop quantum gravity, a background independent approach to unify general relativity and quantum mechanics, has been widely investigated. We consider the quantum dynamics of a real massless scalar field coupled to gravity in this framework. A Hamiltonian operator for the scalar field can be well defined in the coupled diffeomorphism invariant Hilbert space, which is both ...

Using the principle of energy conservation has been considered for gravity field determination from satellite observations since the early satellite era. CHAMP is the first satellite to which the energy balance approach can be usefully applied, now that near-continuous orbit tracking by GPS is available, aided by accelerometry. The feasibility of this approach has recently been demonstrated. Th...

Abstract Satellite missions providing data for a continuous monitoring of the Earth gravity field and its changes are fundamental to study climate changes, hydrology, sea level solid phenomena. GRACE-FO (Gravity Recovery Climate Experiment Follow-On) mission was launched in 2018 NGGM (Next Generation Gravity Mission) studies ongoing long-term time-variable field. In recent years, an innovative ...

We only see a small fraction of the matter in the universe, but the rest gives itself away by the impact of its gravity. The distortions from pure Hubble flow (or peculiar velocities) that this matter creates have the potential to be a powerful cosmological tool, but are also a nuisance for extragalactic astronomers who wish to use redshifts to estimate distances to local galaxies. We provide a...

We have analyzed 3 years of radio tracking data from the MESSENGER spacecraft in orbit around Mercury and determined the gravity field, planetary orientation, and ephemeris of the innermost planet. With improvements in spatial coverage, force modeling, and data weighting, we refined an earlier global gravity field both in quality and resolution, and we present here a spherical harmonic solution...