Spacetime Symmetries and Kepler's Third Law
Feb, 2012Citations per year
Abstract: (arXiv)
The curved spacetime geometry of a system of two point masses moving on a circular orbit has a helical symmetry. We show how Kepler's third law for circular motion, and its generalization in post-Newtonian theory, can be recovered from a simple, covariant condition on the norm of the associated helical Killing vector field. This unusual derivation can be used to illustrate some concepts of prime importance in a general relativity course, including those of Killing field, covariance, coordinate dependence, and gravitational redshift.Note:
- 11 pages, 3 figures; minor changes and text improvements; matches version to appear in Class. Quant. Grav
- vector: Killing
- symmetry: space-time
- gravitation: redshift
- field theory: vector
- space-time: geometry
- general relativity
- covariance
- orbit
- curvature
- gravitation: weak field
References(28)
Figures(3)
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