Why is the moon actually moving in the earth's atmosphere?

does the atmosphere have boundaries? You can say yes or no.

No, because the density of the atmosphere changes gradually, and the sphere of influence of the atmosphere is very large, so it is difficult for us to draw a clear boundary, saying that the atmosphere disappears after crossing this line.

the density of the earth's atmosphere began to drop obviously about 3 kilometers from the ground, and it was within its sphere of influence until it was 1.6 million kilometers from the ground. So some people say that the moon runs in the earth's atmosphere-because the average distance between the moon and the earth is only about 38 thousand kilometers.

but from another perspective, the atmosphere has boundaries. This boundary is set based on the physical characteristics of the atmosphere and the technical characteristics that the aircraft needs to use. Below this boundary, the aircraft can fly with the help of aerodynamic principles; And above this boundary, the aircraft must use rocket propulsion to move forward.

this border is about 8km to 1km from the ground, and it is called "Kármán line".

"Carmen Line" is named after Theodore von Kármán, the pioneer of aviation industry. Born in Hungary, von Carmen is an engineer and physicist. During World War I, he designed helicopters. After immigrating to the United States in 193, von Carmen became a leading expert in rocket and supersonic flight. In 1944, with the participation of von Carmen, the famous Jet Propulsion Laboratory (JPL) was established.

von Carmen believes that the boundary between the atmosphere and space should be defined by whether the aircraft can only use rocket propulsion technology, and 1 kilometers above sea level is an ideal altitude. But von Carmen did not officially express this view. "Carmen line" is more like a conventional saying.

it was Andrew Gallagher Haley who first discussed the Carmen line. In the 196s, Harry thought that the actual height of the "Carmen Line" should be 84 kilometers above sea level. The atmosphere at this height is regarded as the mesosphere pause in meteorology, which is above the height where the meteor will burn after the meteorite enters the atmosphere.

So below the Carmen Line, it is the home of meteors, and it is the ultimate height that human beings can fly by air lift. Above the "Carmen Line", it is the territory of Aurora, a variety of low-orbit aircraft and the place where the space station is located.

von Carmen thinks that "Carmen line" is the boundary of the atmosphere in the physical sense. But the "Carmen Line" is actually a jurisdictional boundary. Below this height, the sky can belong to different political entities and has the attribute of airspace; And on top of that, it is the universal space possessed by all mankind.