What is Elmo’s fire?

It is a weather phenomenon that takes place during an electrical storm. A bluish glow appears on high, grounded and projecting metal objects such as airplane wings, church steeples and ship masts.

In olden times, sailors on the high seas observed that the fiery glow that seemed to engulf the masts did not harm their ships. Instead, it disappeared after a few seconds as the electric charge dissipated. Soon the storm would die out and the turbulent waters would become calm again. Superstitions sailors ascribed the mysterious glow to St Erasmus, also known as St. Elmo, the patron saint of sailors. They believed the light to be a protective sign of St. Elmo, hence it came to be called St. Elmo’s fire.

The luminous light is plasma created by a corona discharge. It occurs when there is high voltage in the air between the clouds and the electrically charged ground. It takes about 30,000 volts per centimetre of space to start a St. Elmo’s fire. The high voltage ionizes the nitrogen and oxygen in the atmosphere, producing blue or violet coloured light.

St. Elmo’s fire is a persistent blue glow that occasionally appears near pointy objects during storms. The name is something of a misnomer, as the electric phenomenon has more in common with lightning or the northern light than it does with flame.

Fortunately for hikers and sailors, St. Elmo’s fire doesn’t burn or present any immediate danger beyond the potentially stormy weather itself.

 

Picture Credit : Google