Understanding Thunder: The Sound of Lightning

Thunder is the booming sound wave resulting from the rapid expansion of air surrounding a lightning bolt. This expansion is due to intense heating from the lightning, which can reach temperatures of approximately 30,000 Kelvin.

Lightning's temperature outshines the sun's surface, which is around 6,000 Kelvin. The air heated by lightning expands supersonically into a shock wave, similar to a sonic boom, creating the rumbling sound of thunder we hear.

Light travels faster than sound. Thus, we see lightning almost instantly, but sound waves take longer to reach us. Counting seconds from flash to bang and dividing by five estimates the distance in miles.

Thunder can sound like a sharp crack or a low rumble. This is because short, smooth lightning channels create high-frequency sounds, while long, jagged channels result in lower rumbles as sound waves reflect off the environment.

The energy required to generate thunder comes from the atmospheric charge separation within a storm cloud. This build-up and discharge of electrical energy are necessary for lightning and the resultant thunder.

Thunder not only signals a storm's proximity but also plays a role in nitrogen fixation. The high temperatures and pressures created by lightning help to break down nitrogen molecules, allowing them to combine with oxygen.

Thunder produces infrasound, frequencies below human hearing. These sound waves can travel thousands of kilometers and are used to detect distant storms, volcanic eruptions, and even nuclear tests by infrasound monitoring systems.