arXiv subjects

John D. Anderson

Publications and source records attributed to John D. Anderson.

41 records · Page 3Linked to original sources

arXiv1996

Relativistic Gravity Theory And Related Tests With A Mercury Orbiter Mission

Due to its relatively large eccentricity and proximity to the Sun, Mercury's orbital motion provides one of the best solar-system tests of relativistic gravity. We emphasize the number of feasible relativistic gravity tests that can be performed within the context of the parameterized weak field and slow motion approximation - a usefulframework for testing modern gravitational theories in the solar system. We discuss a new approximation method, which includes two Eddington parameters $(γ,β)$, proposed for construction of the relativistic equations of motion of extended bodies. Within the present accuracy of radio measurements, we discuss the generalized Fermi-normal-like proper reference frame which is defined in the immediate vicinity of the extended compact bodies. Based on the Hermean-centric equations of motion of the spacecraft around the planet Mercury, we suggest a new test of the Strong Equivalence Principle. The corresponding experiment could be performed with the future {\it Mercury Orbiter} mission scheduled by the European Space Agency ({\small ESA}) for launch between 2006 and 2016. We discuss other relativistic effects including the perihelion advance, redshift and geodetic precession of the orbiter's orbital plane about Mercury.

gr-qc↗

arXiv1995

Testing the Strong Equivalence Principle with Mars Ranging Data

The year 1996 will mark the initiation of a number of new space missions to the planet Mars from which we expect to obtain a rich set of data, including spacecraft radio tracking data. Anticipating these events, we have analyzed the feasibility of testing a violation of the strong equivalence principle (SEP) with Earth-Mars ranging. Using analytic and numerical methods, we have demonstrated that ranging data can provide a useful estimate of the SEP parameter $η$. Two estimates of the predicted accuracy are quoted, one based on conventional covariance analysis, and the other based on ``modified worst case'' analysis, which assumes that systematic errors dominate the experiment. If future Mars missions provide ranging measurements with an accuracy of $σ$ meters, after ten years of ranging the expected accuracy for the parameter $η$ will be of order $σ_η\approx (1-12)\times 10^{-4}σ$. In addition, these ranging measurements will provide a significantly improved determination of the mass of the Jupiter system, independent of the test of the {\small SEP} polarization effect.

astro-ph↗

arXiv1995

The Solar Test of the Equivalence Principle

The Earth, Mars, Sun, Jupiter system allows for a sensitive test of the strong equivalence principle (SEP) which is qualitatively different from that provided by Lunar Laser Ranging. Using analytic and numerical methods we demonstrate that Earth-Mars ranging can provide a useful estimate of the SEP parameter $η$. Two estimates of the predicted accuracy are derived and quoted, one based on conventional covariance analysis, and another (called ``modified worst case'' analysis) which assumes that systematic errors dominate the experiment. If future Mars missions provide ranging measurements with an accuracy of $σ$ meters, after ten years of ranging the expected accuracy for the SEP parameter $η$ will be of order $(1-12)\times 10^{-4}σ$. These ranging measurements will also provide the most accurate determination of the mass of Jupiter, independent of the SEP effect test.

gr-qc↗

arXiv1995

Improved bounds on non-luminous matter in solar orbit

We improve, using a larger set of observations including Voyager 2 Neptune flyby data, previous bounds on the amount of dark matter (DM) trapped in a spherically symmetric distribution about the sun. We bound DM by noting that such a distribution would increase the effective mass of the sun as seen by the outer planets and by finding the uncertainty in that effective mass for Uranus and Neptune in fits to the JPL Developmental Ephermeris residuals, including optical data and those two planets' Voyager 2 flybys. We extend our previous procedure by fitting more parameters of the developmental ephemerides. Additionally, we present here the values for Pioneer 10 and 11 and Voyager 1 and 2 Jupiter ranging normal points (and incorporate these data as well). Our principal result is to limit DM in spherically symmetric distributions in orbit about the sun interior to Neptune's orbit to less than an earth mass and interior to Uranus' orbit to about 1/6 of an earth's mass.

hep-ph↗

arXiv1994

Theoretical Motivation for Gravitation Experiments on Ultra-Low Energy Antiprotons and Antihydrogen

We know that the generally accepted theories of gravity and quantum mechanics are fundamentally incompatible. Thus, when we try to combine these theories, we must beware of physical pitfalls. Modern theories of quantum gravity are trying to overcome these problems. Any ideas must confront the present agreement with general relativity, but yet be free to wonder about not understood phenomena, such as the dark matter problem and the anomalous spacecraft data which we announce here. This all has led some ``intrepid" theorists to consider a new gravitational regime, that of antimatter. Even more ``daring" experimentalists are attempting, or considering attempting, the measurement of the gravitational force on antimatter, including low-energy antiprotons and, perhaps most enticing, antihydrogen.

hep-ph↗