The three-fold theoretical basis of the Gravity Probe B gyro precession calculation

Abstract

The Gravity Probe B (GP-B) experiment is complete and the results are in agreement with the predictions of general relativity (GR) for both the geodetic precession, 6.6 arcsec/yr to about 0.3%, and the Lense-Thirring precession, 39 marcsec to about 19%. This note is concerned with the theoretical basis for the predictions. The predictions depend on three elements of gravity theory, firstly that macroscopic gravity is described by a metric theory such as general relativity, secondly that the Lense-Thirring metric provides an approximate description of the gravitational field of the spinning earth, and thirdly that the spin axis of a gyroscope is parallel displaced in spacetime, which gives its equation of motion. We look at each of these three elements to show how each is solidly based on previous experiments and well-tested theory. The agreement of GP-B with theory strengthens our belief that all three elements are correct and increases our confidence in applying GR to astrophysical phenomena. Conversely, if GP-B had not verified the predictions a major theoretical quandary would have occurred.

To appear as one of 21 articles in a special issue of Classical and Quantum Gravity devoted to the GP-B experiment. 16 pages, 1 figure

References in corpus (5)

• Gravity Probe B: Final Results of a Space Experiment to Test General Relativity
• Test of the Equivalence Principle Using a Rotating Torsion Balance
• Testing General Relativity with Atom Interferometry
• Motion of spinning test bodies in Kerr spacetime
• Gauge Gravity: a forward-looking introduction

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• Relativistic effects due to gravimagnetic moment of a rotating body
• Spacetime, Spin and Gravity Probe B
• Coulomb problem for classical spinning particle
• On the world sheet of continuous helicity particle
• Gravitational orbital Hall effect of vortex light in Lense-Thirring metric
• Static and stationary dark fluid universes: A gravitoelectromagnetic perspective
• Geometrical model of massive spinning particle in four-dimensional Minkowski space