Why is there air on Earth and how is it formed?

Air is formed by a mixture of many gases.

Air is formed by the mixture of hundreds of millions of notes.

The presence of air on the earth is determined by the size of the earth's gravitational orange. The reason for the formation of air composition is first of all the activities in the earth's interior, which produce water vapor, ammonia, carbon dioxide, etc. Then, the primordial organisms are produced, making the air composition gradual.

In particular, after the appearance of green plants, the current air composition was gradually formed.

Supplement: The Earth's atmosphere is composed of 77 percent nitrogen, 21 percent oxygen, trace amounts of argon, carbon dioxide, and water. When the Earth was first formed, there may have been a large amount of carbon dioxide in the atmosphere, most of which was combined into carbonate rocks, and a small part was dissolved into the ocean or consumed by living plants.

Plate tectonics and biological activities now sustain the constant flow of carbon dioxide from the atmosphere to other places and back again. The small amount of carbon dioxide that is stably present in the large circle is judged by the greenhouse effect.

1. The temperature of the universe is very high, with the expansion of the universe, some gases with low boiling points will slowly become droplets and fall, and when the temperature of the sunshine rises, it will become gas, and so on, so that it rises and falls repeatedly around the planet, forming the air that is as if there is nothing, when it expands to a certain extent, coupled with the temperature interference of the gas and the absorption of radiation, the temperature of the planet becomes higher and more stable, plus the gravitational pull of the earth, Thus the air (except water vapor) that has always existed as a gas is formed. This applies to every planet, including Earth.

2. Air refers to the mixture of gases in the earth's atmosphere. It is mainly composed of 78% nitrogen, 21% oxygen, and 1% noble gases and impurities. The composition of air is not fixed, and as the altitude changes, the air pressure changes, and the proportion of air composition also changes.

But for a long time, it was believed that air was a single substance, until later the French scientist Lavoisier first came to the conclusion that air is composed of oxygen and nitrogen through experiments. At the end of the 19th century, scientists discovered through a large number of experiments that there are rare gases such as helium, argon, xenon, and neon in the air.

I think that the air on the earth should be attacked because of the lack of ridges to cover the universe**, the temperature of the universe is very high, and then some gases slowly turn into liquid, and after falling down, due to the exposure of the sun, then the earth will evaporate these hot liquids in Volzhou, and it will become the current air.

It is formed according to the development of various organisms on the earth, and the air on the earth is closely related to many things, and many things are inseparable from the air.

1. About 5 billion years ago, the atmosphere mysteriously "came out of the void" with the birth of the earth. That is, when the nebula began to condense, the earth was already surrounded by a large amount of gas. The main components of the primordial atmosphere were hydrogen and helium.

After the formation of the earth, the decay of radioactive materials in the earth's interior causes the conversion of energy. This conversion had an effect on both the maintenance and the extinction of the Earth's atmosphere, and the strong effect of the solar wind and the low gravitational pull of the Earth when it was first formed caused the primitive atmosphere to disappear very quickly.

2. After the formation of the earth, due to the drop in temperature, the condensation of the earth's surface occurs, and the high temperature inside the earth promotes the frequent activity of volcanoes, and the volatile gases formed by volcanic eruptions gradually replace the original atmosphere and become the secondary atmosphere. The main components of the secondary atmosphere are carbon dioxide, methane, nitrogen, hydrogen sulfide and ammonia, which are some gases with heavy molecular weights. These gases and the solid matter of the earth are attracted to each other and depend on each other.

The gas was not abandoned by the great centrifugal force of the Earth, and became the second life of the atmosphere.

Air was formed by a complex series of changes in the primordial atmosphere.

The formation of the primordial atmosphere is closely related to the formation of galaxies. There are complex nuclear reactions inside the star, and in the process of hydrogen consumption, the abundance of heavier elements gradually increases, and some more important elements are formed, and the results of spectroscopic analysis show that the abundance of atoms decreases with the increase of atomic number.

The Earth's secondary atmosphere is formed by the process of exhausting (a phenomenon called "exhaust" in which gases that were accreted and confined to the Earth's interior at the time of the Earth's formation and are discharged from the surface through orogeny and volcanic activity) throughout the world at the beginning of the Earth's formation.

When the secondary atmosphere is formed, a large amount of water vapor is discharged into the atmosphere, when the surface temperature is high, the development of atmospheric instability and convection is very strong, and the strong convection causes the water vapor to rise and condense, and the wind and rain and lightning are frequent, and rivers, lakes and seas and other water bodies appear on the surface. This has a lot of significance for the emergence of life and the formation of the current atmosphere.

Formed by changes in the original atmosphere. The earth began as a loose mass of matter, without a crust. At that time, there was not only some air on the surface of the earth, but also air inside the earth, but those were primordial air, hundreds of millions of years passed, the earth slowly cooled down, the surface condensed the crust, volcanoes began to erupt, the various gases stored in the earth's crust were ejected out, these gases were absorbed by the earth's gravity, and rolled up on the outside of the earth to form an atmosphere.

Air refers to the mixture of gases in the earth's atmosphere, so air belongs to the mixture, which is mainly composed of nitrogen, oxygen, noble gases (helium, neon, argon, krypton, xenon, radon), carbon dioxide and other substances (such as water vapor, impurities, etc.). Among them, the volume fraction of nitrogen is about 78%, the volume fraction of oxygen is about 21%, the volume fraction of rare gases (helium, neon, argon, krypton, xenon, radon) is about, the volume fraction of carbon dioxide is about the latest annual data), and the volume fraction of other substances (such as water vapor, impurities, etc.) is about.

Due to the strong attraction of the earth, 80% of the air is concentrated in an average of 15 kilometers above the ground. This layer of air has a great impact on human life and production activities. What people often refer to as air pollution refers to air pollution in this range.