Gravitational redshift is a phenomenon predicted by Einstein's theory of general relativity, which describes how light is affected by the presence of a gravitational field. It refers to the shift of light (or other electromagnetic radiation) to longer wavelengths as it escapes from a massive object, such as a star or a black hole. Here's how it works: when light is emitted from the surface of a massive body, it climbs out of the gravitational well created by that mass.
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