Search results
Results from the WOW.Com Content Network
Gravitational redshift can be interpreted as a consequence of the equivalence principle (that gravitational effects are locally equivalent to inertial effects and the redshift is caused by the Doppler effect) [5] or as a consequence of the mass–energy equivalence and conservation of energy ('falling' photons gain energy), [6] [7] though there ...
The gravitational redshift of a light wave as it moves upwards against a gravitational field (caused by the yellow star below). Einstein predicted the gravitational redshift of light from the equivalence principle in 1907, and it was predicted that this effect might be measured in the spectral lines of a white dwarf star , which has a very high ...
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.
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 measurements provide a direct measure of LPI. Of the three hypotheses underlying the equivalence principle, LPI has been by far the least accurately determined. There has been considerable incentive, therefore, to improve on gravitational redshift measurements both in the laboratory and using astronomical observations. [ 11 ]
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]
The integrated Sachs–Wolfe (ISW) effect is also caused by gravitational redshift, but it occurs between the surface of last scattering and the Earth, so it is not part of the primordial CMB. It occurs when the Universe is dominated in its energy density by something other than matter.
The gravitational redshift of a light wave as it moves upwards against a gravitational field (caused by the yellow star below) The first new effect is the gravitational frequency shift of light. Consider two observers aboard an accelerating rocket-ship.