Whose calculations showed that light from stars can be shifted by gravity?

Albert Einstein’s general theory of relativity predicts that light loses energy when it climbs out of a strong gravitational field, causing a shift toward longer wavelengths. This effect, called gravitational redshift, was first tested on Earth and later measured far more precisely in space and astronomy. Einstein’s prediction is one of the classic tests of general relativity and is important in astrophysics and GPS technology. It also helps scientists probe compact objects like white dwarfs and neutron stars.