Sonic boom Sonic boom A sonic boom is the sound associated with the shock waves created whenever an object travelling through the air travels faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding similar to an explosion or a thunderclap to the human ear. The crack of a supersonic bullet passing overhead or the crack of a bullwhip are examples of a sonic boom in miniature. Sonic booms due to large supersonic aircraft can be particularly loud and startling, tend to awaken people, and may cause minor damage to some structures. They led to prohibition of
Sound speed gradient creates a negative sound speed gradient. The sound wave front travels faster near the ground, so the sound is refracted upward, away from listeners on the ground, creating an acoustic shadow at some distance from the source. The opposite effect happens when the ground is covered with snow, or in the morning over water, when the sound speed gradient is positive. In this case, sound waves can be refracted from the upper levels down to the surface. In underwater acoustics, speed of sound depends on pressure (hence depth), temperature, and salinity of seawater, thus leading to vertical speed gradients similar