A
light pillar is an
atmospheric optical phenomenon in the form of a vertical band of light which appears to extend above and/or below a light source. The effect is created by the
reflection of
light from numerous tiny
ice crystals suspended in the atmosphere or clouds. The light can come from the
Sun (usually when it is near or even below the horizon) in which case the phenomenon is called a
sun pillar or
solar pillar. It can also come from the
Moon or from terrestrial sources such as streetlights.