A single bolt of lightning is hotter than the surface of the sun.

The channel of air a lightning bolt tears through can briefly reach temperatures around 30,000 kelvin — roughly five times hotter than the Sun’s surface, which sits at about 5,800 kelvin. That heat lasts only a few dozen microseconds, but it’s enough to instantly ionize and vaporize the air along the strike’s path.

That explosive heating is what produces thunder. The superheated air expands faster than the speed of sound, generating a shockwave that rolls outward from the strike and reaches our ears as a rumbling boom, with the delay between the flash and the sound telling you roughly how far away the strike occurred.