Alpenglow

Alpenglow is a horizontal reddish glow that appears near the horizon opposite the Sun once the solar disk itself has dropped below it, in the strict sense of the term only after sunset or before sunrise, distinct from ordinary direct sunset or sunrise light on mountains or clouds, with which it is often confused. It is caused by indirect sunlight that is reflected or diffracted by airborne precipitation, ice crystals, or other particulates in the lower atmosphere, rather than by light reaching the observer directly from the Sun. A related effect occurs on the opposite side of the sky, where aerosols can be lit by the same scattered reddish light above the edge of the shadow of the Earth itself, producing the pinkish Belt of Venus.