Why lightning occurs in an instant, but the resulting thunder rolls and rolls and lasts a while

Question

So yesterday we had some thunderstorms where is wasn’t raining yet, but I could see and hear the lighting & thunder. I layed down on our lanai just to enjoy the show. Enjoying counting the seconds between lighting flash and the thunder to determine distance. And I saw this one bolt of of lightning, really bright. Starting counting seconds, only got to 5, before the thunder exploded. So about a mile away. But after the initial bang, the thunder continued booming a rolling across the sky, it must have lasted 10 seconds. Seems like it should should just boom once.

In: Planetary Science

Answer 1

Sound is a wave. Waves bounce off of things. In sound’s case, it will bounce off of pretty much anything solid. Trees, grass, buildings, rocks. you name it.

One loud bang will create billions of tiny reflections that add together to produce a rumble.

Answer 2

Lightning and thunder are two parts of the same phenomenon – when electricity connects ground to sky. While they are both caused by the same thing, they don’t travel to you in the same way.

Lightning is light. It goes from the bolt to your eyes in a fraction of a fraction of a second.

Thunder is not light; it’s sound. It both travels slower and is less absorbed by the things it runs into. When thunder seems to last much longer, that’s because you initially here the rapport from the actual bolt, and then you hear all the echoes of that same sound from the sound waves that didn’t travel directly to you and instead bounced off of one or more other things along the way. Since there’s a LOT of stuff around to echo off of, and sound is kind of slow to reach you at the distances you are likely hearing thunder from, it stretches out the sound.

Lightning has these same “echoes” but light doesn’t reflect off most things nearly as much as sound, and even if it did (like if you had a mirror positioned correctly to reflect the bolt to you), it is so incredibly fast that at normal lightning viewing distances the detours it takes do not noticeably increase the amount of time it takes to make it to you.