I’ve always been fascinated by thunderstorms. Can someone explain why we see lightning before we hear thunder, and what exactly causes both of these phenomena?
In: Physics
Lightning is an electrical current. The turbulent atmosphere creates areas of opposite charge. Eventually, these charges become so large that they overcome the resistance between them and equalize by conducting a current. This is lightning. We’re talking something like several billion volts (your wall outlet is 120 or 240 volts) and millions of amps (your wall outlet is maybe 15-30 amps). It’s a vast amount of energy, and lightning is exceptionally hot. Perhaps ten times hotter than the photosphere of the Sun.
Thunder is what happens when the lightning superheats the air it’s passing through, creating a shockwave that manifests as sound. It’s so hot that the air expands extremely rapidly. You hear thunder after seeing lightning because light travels at the speed of light, sound travels at the speed of sound, which is much slower. They happen at the same time, but take different amounts of time to reach you.
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