The specific explanation is copied from Baidu Encyclopedia (nonsense, I'm not from the physics department. How can I understand these terms-): When an object approaches the speed of sound, there will be strong resistance, which will cause the object to oscillate strongly and the speed will be attenuated. This phenomenon is often called sound barrier. When breaking through the sound barrier, because the compression of air by the object itself cannot spread quickly, it gradually accumulates on the windward side of the object, and finally forms a shock wave surface, on which the sound energy is highly concentrated. When these energies reach people's ears, people will feel a short and extremely strong explosion, which is called sonic boom.