What is the distance between heaven and earth?

If only the atmosphere is considered as the standard, the distance between heaven and earth is about 30 kilometers. About 30 kilometers away, it has gone beyond the outermost layer of the atmosphere and entered the vast universe.

Under the action of the earth's gravity, a large number of gases gather around the earth, forming thousands of kilometers of atmosphere. The gas density becomes thinner and thinner with the increase of height from the ground. Sounding rockets still found a thin atmosphere at an altitude of 3000 kilometers. Some people think that the upper boundary of the atmosphere may extend to about 6400 kilometers above the ground. According to scientists' estimation, the atmospheric quality is about 60 trillion tons, accounting for almost one millionth of the total mass of the earth, including: nitrogen 78%, oxygen 2 1%, argon 0.93%, carbon dioxide 0.03%, neon 0.00 18%, in addition to water vapor and dust.

According to the different characteristics of each layer of atmosphere (such as temperature, composition and ionization degree, etc. ), divided into troposphere, stratosphere, mesosphere, thermosphere (ionosphere) and outer atmosphere from the ground.

A layer of atmosphere close to the earth's surface, the movement of air is a convective movement dominated by updraft and downdraft, which is called "troposphere". Its thickness varies, 8km above the earth's poles and 17km above the equator, making it the densest layer in the atmosphere. Almost all the water vapor in the atmosphere is concentrated here, which is a "big stage" to show the changes: wind, rain, snowfall and other weather phenomena all occur in the troposphere.

Above the troposphere, up to the layer 50 kilometers above sea level, the airflow is mainly horizontal, and the convection phenomenon is weakened. This kind of atmosphere is called stratosphere, also known as stratosphere. There is basically no moisture here, it is clear and cloudless, and the weather has not changed much, which is suitable for aircraft navigation. At an altitude of 20 ~ 30 kilometers, oxygen molecules form the ozone layer under the action of ultraviolet rays, which acts as a barrier to protect life on earth from the attack of high-energy particles from the sun.

Above the stratosphere, 85 kilometers away from the earth's surface, it is called the "middle layer" and also called the "escape layer". Above the mesosphere, 500 kilometers away from the earth's surface, it is called the "thermosphere". In these two floors, there are often many interesting astronomical phenomena, such as aurora and meteors. Humans also use the thermosphere to realize short-wave radio communication, so that people far away from the ocean can communicate with each other. Because the atmosphere in the thermosphere is heated by solar radiation, a large number of gas molecules or atoms are ionized, and there is little chance of recombination, forming an ionosphere, which can conduct electricity and reflect short-wave radio.

Above the top of the thermosphere is the outer atmosphere, which extends from the earth's surface to 1000 km. The temperature here is very high, reaching several thousand degrees; The atmosphere is extremely thin, and the density is one billionth of the sea level.