Figure 12-35Trapping of Light by a Black Hole (a) The paths and colors of light rays departing from a main-sequence, giant, or supergiant star are affected very little by the star’s gravitational force. (b) Light leaving the vicinity of a white dwarf curves and redshifts more, whereas (c) near a neutron star, some of the photons actually return to the star’s surface. (d) Inside a black hole, all light remains trapped. Most photons curve back in, except those that fly straight upward, which become infinitely redshifted, thereby disappearing.