A light pillar, sometimes known as a ‘crystal beam’, is an atmospheric phenomenon in which a column of light appears to extend vertically above or below a light source. The effect is created by the reflection of light from ice crystals suspended in the atmosphere. The light can come from any source, including the moon, street lamps, buildings, fires, or the Sun (in which case they are called ‘sun pillars’ or ‘solar pillars’).
A Middleground 