arXiv subjects

Kenneth Nordtvedt

Publications and source records attributed to Kenneth Nordtvedt.

5 recordsLinked to original sources

arXiv2015

Constructing metric gravity's N-body non-linear Lagrangian from iterative, linear algebraic scaling equations

A method for constructing metric gravity's N-body Lagrangian is developed which uses iterative, liner algebraic euqations which enforce invariance properties of gravity --- exterior effacement, interior effacement, and the time dilation and Lorentz contraction of matter under boosts. The method is demonstrated by obtaining the full 1/c^4 order Lagrangian, and a combination of exterior and interior effacement enforcement permits construction of the full Schwarzschild temporal and spatial metric potentials.

gr-qc↗

arXiv2003

Lunar Laser Ranging - a comprehensive probe of post-Newtonian gravity

More than 30 years of lunar laser ranging has produced several key tests of gravitational theory, including confirmation that bodies fall in external gravity at rates independent of their internal gravitational binding energy, and that Newton's G is constant to a part in 10^12 per year precision. The fitting of LLR data depends on the entire scope of 1/c^2 order features of the gravitational equation of motion, including non-linearity, gravitomagnetism, and inductive inertial forces.

gr-qc↗

arXiv2002

The special relativistic equivalence principle: gravity theory's foundation

On incorporating special relativity theory into an extended equivalence principle, post-Newtonian gravitational phenomena beyond that originally predicted by Einstein are predicted (required), such as geodetic and gravitomagnetic precessions of local inertial frames, and precession of Mercury's orbital perihelion. Why were not these phenomena predicted in the years 1907-1911? The unique 1/c^2 order dynamical equations for clock rates and motion of both bodies and light in local gravity are derived which guarantee fulfillment of the special relativistic equivalence principle.

gr-qc↗

arXiv2002

Space-Time Variation of Physical Constants and the Equivalence Principle

Location dependence of physical parameters such as the electromagnetic fine structure constant and Newton's G produce body accelerations which violate universality of free fall rates testable with laboratory and space experiments. Theoretically related cosmological time variation of these same parameters are also constrained by experiments such as lunar laser ranging, and these time variations produce accelerations of bodies relative to a preferred cosmological frame.

gr-qc↗

arXiv2002

Gravitational Acceleration of Spinning Bodies From Lunar Laser Ranging Measurements

The Sun's relativistic gravitational gradient accelerations of Earth and Moon, dependent on the motions of the latter bodies, act upon the system's internal angular momentum. This spin-orbit force (which plays a part in determining the gravity wave signal templates for astrophysical sources) slightly accelerates the Earth-Moon system as a whole, but it more robustly perturbs that system's internal dynamics with a 5 cm, synodically oscillating range contribution which is presently measured to 4 mm precision by more than three decades of lunar laser ranging.

gr-qc↗