Hi Tom,
My wife and I are having a disagreement as to what comes first: thunder or lightning.
There is a lot riding on your answer.
-Bill & Maureen Lahtinen, Elk Grove Village, Ill.
Dear Bill and Maureen,
Lightning always occurs first -- always -- because lightning causes thunder. The
electric spark that constitutes a lightning bolt heats the air through which it passes to
at least 50,000 degrees in thousandths of a second. Explosive expansion of the air
immediately occurs, followed by cooling and sudden contraction. These events trigger
waves in the air which we interpret as thunder. The initial thunder that you hear comes
from the point on the lightning channel closest to you; the last sound comes from the
most distant point.
It will be difficult, probably impossible, to pair each lightning discharge with the
thunder that it produces when an active thunderstorm is generating very frequent
lightning strokes.
