Wonderful pictures from airplanes, which breaks the sound barrier, although there were many articles about the denial of sound barriers. For Shipka smart Effect of Prandtl - Gloerta - phenomenon is the appearance of clouds behind an object flying at transonic speeds in conditions of high humidity. Most often seen in airplanes. At very high humidity, this effect also occurs when flying at lower speeds. The reason for its occurrence is that flying the plane at high speed creates a region of high air pressure in front of him and behind the low pressure area. After the flyby plane area of low pressure begins to fill the surrounding air. By virtue of the rather high inertia of the air mass at first the whole area is filled with low pressure air from the surrounding areas adjacent to areas of low pressure. This process is a locally adiabatic process where the volume occupied by the air increases and the temperature drops. If the humidity is high enough, the temperature can drop to a value that is lower than the dew point. Then, the air contained in the water vapor condenses to form tiny droplets that form a small cloud.