Gravitomagnetic time delay

G_{\mu \nu} + \Lambda g_{\mu \nu}= {8\pi G\over c^4} T_{\mu \nu}

Fundamental concepts

Phenomena

Spacetime
Kepler problem Gravitational lensing Gravitational waves Frame-dragging Geodetic effect Event horizon Singularity Black hole
Spacetime diagrams Minkowski spacetime Einstein–Rosen bridge

Equations
Formalisms

Equations
Linearized gravity Einstein field equations Friedmann Geodesics Mathisson–Papapetrou–Dixon Hamilton–Jacobi–Einstein
Formalisms
ADM BSSN Post-Newtonian
Advanced theory
Kaluza–Klein theory Quantum gravity

Solutions

Scientists

In according to general relativity, a branch of physics, a massive spinning body endowed with angular momentum S will alter the space-time fabric around it in such a way that several effects on moving test particles and propagating electromagnetic waves occur.^[1]

In particular, the direction of motion with respect to the sense of rotation of the central body is relevant because co-and counter-propagating waves carry a "gravitomagnetic" time delay Δt_GM which could be, in principle, be measured^[2]^[3] if S is known.

On the contrary, if the validity of general relativity is assumed, it is possible to use Δt_GM to measure S. Such effect must not be confused with the much larger Shapiro time delay^[4] Δt_GE induced by the "gravitoelectric" Schwarzschild-like component of the gravitational field of a planet of mass M considered non-rotating. Unlike the small Δt_GM, the Shapiro time delay has been accurately measured in several radar-ranging experiments with solar system interplanetary spacecraft.

References

↑ G.W. Richter, R.A. Matzner (1983). "Second-order contributions to gravitational deflection of light in the parametrized post-Newtonian formalism". Phys. Rev. D 26 (Austin, Texas). doi:10.1103/PhysRevD.26.1219.
↑ A. Tartaglia, M.L. Ruggiero (2004). "Gravitomagnetic Measurement of the Angular Momentum of Celestial Bodies". General Relativity and Gravitation 36 (Kluwer Academic Publishers-Plenum). doi:10.1023/B:GERG.0000010476.58203.b6.
↑ A. Tartaglia, M.L. Ruggiero (2002). "Angular Momentum Effects in Michelson–Morley Type Experiments". General Relativity and Gravitation 34 (Kluwer Academic Publishers-Plenum). doi:10.1023/A:1020022717216.
↑ I.I. Shapiro (1964). "Fourth Test of General Relativity". Phys. Rev. Lett. 13 (Lexington, Massachusetts). doi:10.1103/PhysRevLett.13.789.

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Gravitomagnetic time delay

See also

References