Modern jet fighters are loud enough – especially when they put their afterburners on – but have you ever been startled by the thunderous boom of a plane breaking the sound barrier? This is the noisy result of some super-speed physics that engineers are now looking to quieten down.
In flight, an aircraft disrupts the air around it, creating sound waves that push ahead of the vehicle. These pressure waves travel at around 767 miles per hour – the speed of sound – and, as a result, are evenly spaced as they move away from the aircraft. Because most aircraft are subsonic, the aircraft doesn’t
catch up to the sound waves as it flies. Supersonic aircraft, however, cause much more disruption. These jets travel faster than the speed of sound. As they approach the pressure waves ahead of them, the sound waves begin piling up, forming shock waves. When these combine, a thunderous roar called a sonic boom is released across the sky.