system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do things that go above the speed of sound make a huge boom?
gpt
This sound is the sonic boom. It is the sound of the air crashing.

When the thing moving fast moves so fast the air can't keep up. It leaves a "hole" in the air where it was before. The sound is the air slapping back together, filling the hole.

It's like if you throw a big rock into the water, the splash of water will slap back against itself, making the splash noise.