The conventional Doppler shift and the equivalence principle imply a gravitational redshift for a photon. See page 102: https://preposterousuniverse.com/wp-con

The conventional Doppler shift and the equivalence principle imply a gravitational redshift for a photon. See page 102: https://preposterousuniverse.com/wp-content/uploads/grnotes-four.pdf https://preposterousuniverse.com/wp-content/uploads/grnotes-...