system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 What is rolling thunder?

As I understand thunder is the sound of the air collapsing as lightning creates the vacuum. But what is rolling thunder, that deep long continuous thunder that happens when you might not see lightning?
gpt
Lightning creates thunder by super heating the air it passes through, which expands rapidly. If you're close to it, it's one sharp CRACK.

When it's further away, though, it usually can't travel directly to you. It bounces off surfaces, echos, and comes to you through multiple routes. That spreads the sound out, so you are hearing the one crack many times.

The same thing happens with a gunshot. Nearby its louder but also more distinct. Further away quieter and more rumbly and spread out.