Why does a cloud-like smoke form around the aircraft when it breaks the sound barrier?

Because when the speed of an object is close to the speed of sound, the surrounding air is superimposed by sound waves and becomes very high-pressure. Therefore, once the object crosses the sound barrier, the surrounding pressure will drop sharply. In relatively humid weather, sometimes the instantaneous low temperature caused by the sudden drop in pressure may bring the temperature below its dew point, causing water vapor to condense into tiny water droplets, which looks like a cloud to the naked eye. . However, since this low-pressure zone will return to normal pressure as the distance between the air and the fuselage increases, the overall shape looks like a cone-shaped cloud with the object as the central axis and evenly spreading around. Some people call it a sound barrier cloud or a sonic boom cloud, because the sonic boom shock wave generated when the sound barrier is broken causes the atmospheric pressure near the body to increase suddenly, causing the water vapor in the air to atomize. The length of time a sonic boom cloud lasts and whether it occurs is closely related to the air humidity. Similar phenomena can be seen in the shock waves produced when powerful bombs explode. Normal air shock waves should be colorless and transparent, but from the bomb explosion video captured by a high-speed camera, you can clearly see a milky white shock wave spreading. The color of the shock wave here is also caused by the atomization of water vapor in the air caused by high pressure. This is because when the speed of the object is close to the speed of sound, the surrounding air is superimposed by the sound waves and presents a very high pressure state. Therefore, once the object passes through the sound barrier, , the surrounding pressure will drop sharply. In humid weather, sometimes the instantaneous low temperature caused by the sudden drop in pressure may make the temperature lower than its dew point temperature, causing water vapor to condense into tiny water droplets, which looks like a cloud to the naked eye. However, since this low-pressure zone will return to normal pressure as the distance between the air and the fuselage increases, the overall shape looks like a cone-shaped cloud with the object as the central axis and evenly spreading around.