A light pillar or ice 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).[1] 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 and erupting volcanoes.[2]
- ^ "Colonne lumineuse". World Meteorological Organization. Archived from the original on 23 September 2016.
- ^ "Light Pillar over Volcanic Etna". apod.nasa.gov. NASA. 15 November 2021. Retrieved 2 June 2024.