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where = is the gravitational redshift, is the optical clock transition frequency, = is the difference in gravitational potential, and denotes the violation from general relativity. By Ramsey spectroscopy of the strontium-87 optical clock transition (429 THz, 698 nm) the group determined the gravitational redshift between the two optical clocks ...
The Center for Astrophysics (CfA) Redshift Survey was the first attempt to map the large-scale structure of the universe.. The first survey began in 1977 with the objective of calculating the velocities of the brighter galaxies in the nearby universe by measuring their redshifts at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts.
[36] [37] The first accurate measurement of the gravitational redshift of a white dwarf was done by Popper in 1954, measuring a 21 km/s gravitational redshift of 40 Eridani B. [37] The redshift of Sirius B was finally measured by Greenstein et al. in 1971, obtaining the value for the gravitational redshift of 89 ± 16 km/s , with more accurate ...
Gravitational time dilation is closely related to gravitational redshift, [4] in which the closer a body emitting light of constant frequency is to a gravitating body, the more its time is slowed by gravitational time dilation, and the lower (more "redshifted") would seem to be the frequency of the emitted light, as measured by a fixed observer.
Gravitational redshift has been measured in the laboratory [65] and using astronomical observations. [66] Gravitational time dilation in the Earth's gravitational field has been measured numerous times using atomic clocks , [ 67 ] while ongoing validation is provided as a side effect of the operation of the Global Positioning System (GPS). [ 68 ]
Other high-redshift events predicted by physics but not presently observable are the cosmic neutrino background from about two seconds after the Big Bang (and a redshift in excess of z > 10 10) [83] and the cosmic gravitational wave background emitted directly from inflation at a redshift in excess of z > 10 25.
The Kerr metric or Kerr geometry describes the geometry of empty spacetime around a rotating uncharged axially symmetric black hole with a quasispherical event horizon.The Kerr metric is an exact solution of the Einstein field equations of general relativity; these equations are highly non-linear, which makes exact solutions very difficult to find.
According to general relativity, in its weak-field and low-velocity linearized approximation, a slowly spinning body induces an additional component of the gravitational field that acts on a freely-falling test particle with a non-central, gravitomagnetic Lorentz-like force.