Definition
The loud, sharp sound heard on the ground when an aircraft flying at or above the speed of sound passes overhead. It is produced by the shock waves that form when the aircraft compresses the air faster than the air can move out of the way.
Plain English
The bang heard on the ground when a plane flies past faster than sound can travel. The plane builds up pressure waves in the air, and when those waves reach a person on the ground, they hear a sudden loud boom.
Context Anchor
Seen in high-speed flight, aircraft noise discussions, and rules about operating near or above the speed of sound.
Derivation
From sonic, meaning relating to sound, from the Latin sonus (sound), plus boom, an English word imitating a loud, deep noise. Together it literally means a sound-related boom -- a noise caused by something moving at the speed of sound.
Why Pilots Care
Supersonic flight over land is restricted in most countries because the boom disturbs people and can cause property damage complaints.
Analogy
A fast boat leaves a moving wave behind it on the water. An aircraft flying faster than sound creates a moving pressure wave in the air, and the boom is heard when that wave reaches you.
Grounding Statement
Imagine a boat moving across calm water. Below its top speed, ripples spread out ahead of it. Once it moves faster than the ripples can travel, the water piles up into a sharp wake. A sonic boom is the air doing the same thing -- piling up into a pressure wave that hits the ground as a loud bang.
Intuition Check
A sonic boom is not an onboard explosion. It is the sound of a pressure wave from an object moving faster than sound.
Example Sentence 1
Residents near the test range reported a sonic boom shortly after the fighter accelerated past the speed of sound.
Example Sentence 2
Controllers vectored the fighter offshore so its sonic boom would not reach the city.