“The Physics Behind Sonic Booms: Speed and Shock Waves”
Sonic booms, the thunderous and audible shock waves produced when an object exceeds the speed of sound, are a fascinating acoustic phenomenon. According to the United States Department of Defense, the speed of sound is approximately 750 miles per hour (1,207 kilometers per hour) at sea level, a threshold that when surpassed generates shock waves that propagate in multiple directions.
When an object, such as an airplane, accelerates and surpasses the speed of sound, it compresses the forward air creating a pressure wave that expands in the shape of a cone, known as a Mach cone. This sudden change in pressure in the surrounding air results in the characteristic sonic “boom,” which can vary in intensity based on factors such as altitude, aircraft shape, and atmospheric conditions.
The perception of sonic booms can vary, sometimes resulting in a double “boom” effect. Longer aircraft can produce booms from both the leading and trailing edges, making them easily noticeable. High-performance military jet aircraft, like the Lockheed Martin SR-71 Blackbird and the F-35 Lightning II, commonly conduct supersonic maneuvers, creating loud reverberations as they break the sound barrier.
Practical consequences of sonic booms include restrictions on supersonic flights over populated areas due to the disruptive nature of the shock waves. At low altitudes, the intensity of the shock waves can cause property damage, such as breaking glass. While supersonic aviation, exemplified by the Concorde’s transatlantic flights at speeds exceeding Mach 2, marked a milestone in air travel, concerns about the environmental and acoustic impact have limited the adoption of such operations in commercial aviation.
In addition to the sonic boom, the Mach cone serves as another visually striking phenomenon associated with supersonic aviation. Observable from the ground as the aircraft passes through it, the shock wave cone offers a spectacle worth witnessing, though it also signifies the disruptive sonic disturbance caused by exceeding the speed of sound.