Re: What is St Elmo's Fire.?

Area: Physics
Posted By: David Winsemius, M.D., BA (physics), MPH
Date: Fri Aug 15 17:25:08 1997
Area of science: Physics
ID: 870544839.Ph

Message:

During thunderstorms large electric fields build up between clouds and the earth. These electric fields are most intense at the tops of pointed objects. The fields may be so strong that they excite (or ionize) the air molecules. When excited molecules release their energy, it may be in the form of visible light. So the air near tops of buildings or the tops of boat masts start to glow. This phenomenon was given the name St. Elmo's fire by sailors, who incorrectly believed that the Saint was protecting them from lightning strikes. In point of fact the appearance of St. Elmo's fire may well be a prelude to a strike.

I tried to find a picture of St. Elmo's fire on the Web, but after several days of trying have given up. You may want to examine these other links that deal with other related phenomena, but as always don't believe everything you read:

In addition to the dangerous electric fields that develop during electrical storms, there is also a normal electric field in the atmosphere that is typically about 100 volts per meter. No useful energy can be extracted from this field, but that didn't stop writer Ayn Rand from incorporating a science fiction premise in "Atlas Shrugged" that its hero had been able to create such a device.

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