The Relativistic Geoid: Gravity Potential and Relativistic Effects
arXiv:1912.10159 · doi:10.1103/PhysRevD.101.064032
Abstract
The Earth's geoid is one of the most essential and fundamental concepts to provide a gravity field-related height reference in geodesy and associated sciences. To keep up with the ever-increasing experimental capabilities and to consistently interpret high-precision measurements without any doubt, a relativistic treatment of geodetic notions (including the geoid) within Einstein's theory of General Relativity is inevitable. Building on the theoretical construction of isochronometric surfaces and the so-called redshift potential for clock comparison, we define a relativistic gravity potential as a generalization of (post-)Newtonian notions. This potential exists in any stationary configuration with rigidly co-rotating observers, and it is the same as realized by local plumb lines. In a second step, we employ the gravity potential to define the relativistic geoid in direct analogy to the Newtonian understanding. In the respective limit, the framework allows to recover well-known (post-) Newtonian results. For a better illustration and proper interpretation of the general relativistic gravity potential and geoid, some particular examples are considered. Explicit results are derived for exact vacuum solutions to Einstein's field equation as well as a parametrized post-Newtonian model. Comparing the Earth's Newtonian geoid to its relativistic generalization is a very subtle problem, but of high interest. An isometric embedding into Euclidean three-dimensional space is an appropriate solution and allows a genuinely intrinsic comparison. With this method, the leading-order differences are determined, which are at the mm-level.
arXiv commentfinal version, 16 pages, 5 figures, added journal reference
References in corpus (15)
- The Confrontation between General Relativity and Experiment
- Geodesy and metrology with a transportable optical clock
- A clock network for geodesy and fundamental science
- On orbit performance of the GRACE Follow-On Laser Ranging Interferometer
- Atomic Clocks for Geodesy
- Real-time geopotentiometry with synchronously linked optical lattice clocks
- Test of special relativity using a fiber network of optical clocks
- High Performance Clocks and Gravity Field Determination
- First international comparison of fountain primary frequency standards via a long distance optical fiber link
- Chronometric geodesy: methods and applications
- Towards exact relativistic theory of Earth's geoid undulation
- Definition of the relativistic geoid in terms of isochronometric surfaces
- Relativistic Reference Frames for Astrometry and Navigation in the Solar System
- Geoids in General Relativity: Geoid Quasilocal Frames
- Gravitational clock compass in General Relativity