A light pillar is an atmospheric optical phenomenon in which a vertical beam of light appears to extend above and/or below a light source.

The effect is created by the reflection of light from tiny ice crystals that are suspended in the atmosphere or that comprise high-altitude clouds (e.g. cirrostratus or cirrus clouds).

If the light comes from the Sun (usually when it is near or even below the horizon), the phenomenon is called a sun pillar or solar pillar.

Light pillars can also be caused by the Moon or terrestrial sources, such as streetlights.

https://en.wikipedia.org/wiki/Light_pillar

Reposted from manxx via greenka2000