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Studies with high-speed cameras have shown that most lightning
bolts are multiple events, consisting of as many as 42 main
strokes, each of which is preceded by a “leader” stroke. All
strokes follow an initial ionized path, which may be branched, along
with the current flows.
Scientists say that the
average interval between successive lightning strokes is 0.02
seconds and that the average flash lasts for 0.25 seconds. Because
the duration of one powerful stroke is no more than 0.0002 seconds,
the intervals between strokes account for most of the duration of a
lightning flash.
Let’s take a look at different types of lightning. Sheet lightning
is the reflection of an ordinary lightning flash on clouds. Ball
lightning is a rare phenomenon in which the discharge takes the form
of a slowly moving, luminous ball that sometimes explodes and
sometimes simply decays.
A
possible new class of lightning has been discovered. This new class
consists three types of lightning and they are associated with
severe thunderstorms. All three types, referred to as red sprite,
blue jet and Elves, occur far above the cloud layer, jumping from
the top of the clouds into the stratosphere (12.9 to 19.3 kilometers
above the surface of the earth), and are much rarer than normal
lightning.
There are some interesting facts about that seek to dispel some
myths associated with lightning. Firstly, that lightning never
strikes twice in the same place. Photographic evidence shows that
skyscrapers and other tall structures may be struck many times in
the course of a single storm. Secondly, it is said the safest place
to stay in a thunderstorm is under a tall tree. It is considered
totally false. Trees, because of their height, are more susceptible
and are, therefore, actually dangerous during violent electric
storms. The safest places for a person caught outdoors in a
thunderstorm are inside a metal-bodied car or lying flat on the
ground in the open. |
