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Name: Michael C.
Status: other
Age: 40s
Location: N/A
Country: N/A
Date: 5/10/2004


Question:
I know your web page states the speed of lightning is about 186,000 miles per sec, however there are other web sites that claim half the speed of light and even one third the speed of light. I work at a news station and a debate goes on here over the speed of lightning. Any light you may shed on this would be most appreciated.


Replies:
I believe that the response of 186,000 miles/sec is a misunderstanding, and refers to the "speed of light" which is very different than what I think you are asking about. I assume that you mean what is the speed of a lightning discharge from cloud-to-ground, ground-to-cloud, or cloud-to-cloud. That is a much more complicated question to answer because it depends upon the path and speed that the atmospheric plasma advances and that depends upon many factors. The web site:

http://wsx.lanl.gov/Publications/lightning_bolt.html

gives a rather in-depth analysis of the question.

Vince Calder


Michael,

Actually, someone asked this question of our web site a while ago and the answer is posted.

However, the speed is normally no more than half the speed of light, usually substantially less.

The process that creates a lightning stroke is not light transfer, but is the transfer of electrical energy (charge) through the air. Much like an electrical cable, the air, even though it is ionized, has some resistance to charge transfer. The speed of the stroke is impeded by having to transfer the energy from molecule to molecule along the way, in the process literally exploding the molecules into atoms.

David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory


Michael C., Per the MEDICAL MYSTERIES LIGHTNING STRIKES video put out by the Discovery Channel (2000 Publication), it states that lightning travels at a rate of 60,000 miles a second. I hope that this helps. Sincerely,

Bob Trach


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