Formation of the atmosphere

formation of the primitive atmosphere

The atmosphere is the layer of gas that surrounds a celestial body, such as the Earth, which is attracted by gravity. Protects against solar ultraviolet radiation, controls temperature and prevents the entry of meteorites. If the atmosphere did not have the characteristics it currently has, planet earth could not support life. However, many people wonder what is the atmosphere formation.

For this reason, we are going to dedicate this article to telling you about the formation of the atmosphere, when it was created and how it was formed.

Formation of the atmosphere

formation of the atmosphere

The atmosphere is the gaseous layer that surrounds our planet, and its existence is caused by the gravitational pull of the Earth. It began to form with the origin of the Earth about 4.600 billion years ago. During the first 500 million years, the atmosphere began to evolve; As the interior of our young planet continued to adapt, it became unusually dense with expelled vapors and gases. The gases that compose it can be hydrogen (H2), water vapour, methane (CH4), helium (He) and carbon oxides. That is a primordial atmosphere because a complete atmosphere could not have existed 200 million years ago. Earth was still too hot at the time, which encouraged the release of light gases.

Earth's gravity is slightly lower than it is today, which prevents Earth from retaining molecules in its environment; the magnetosphere still it has not formed and the solar wind blows directly on the surface. All this caused most of the primitive atmosphere to disappear into space.

Our planet, due to its temperature, size and average mass, cannot retain very light gases such as hydrogen and helium, which escape into space and are dragged by the solar wind. Even with Earth's current mass, it is impossible to maintain gases like helium and hydrogen, unlike larger planets like Jupiter and Saturn, which have gas-rich atmospheres. The rocks that formed our planet continually released new gases and water vapor for a considerable period of time until about 4.000 billion years ago, when the atmosphere began to be composed of carbon molecules. carbon dioxide (CO2), carbon monoxide (CO), water (H2O), nitrogen (N2), and hydrogen (H).

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origin of the atmosphere

The presence of these compounds and the drop in Earth's temperature below 100°C led to the development of the hydrosphere that it began to form about 4 billion years ago.

Years of water vapor condensation resulted in the formation of large amounts of water that allowed for the deposition process. The presence of water favors the dissolution of gases such as sulfur dioxide, hydrochloric acid or carbon dioxide, the formation of acids and their reaction with the lithosphere, resulting in a reducing atmosphere. Gases such as methane and ammonia. In the 1950s, American researcher Stanley Miller designed a classic experiment to prove that through the action of some external energy used electrical discharges to obtain a mixture of amino acids in that environment.

In doing so, he intends to recreate the pristine atmospheric conditions that could have produced the origin of life. It is generally accepted that there are three minimum conditions for life as we understand it: a stable atmosphere rich in components such as oxygen and hydrogen, a permanent source of external energy, and liquid water. As we have seen, the conditions of life are almost established. Nevertheless, without free oxygen, life itself may be millions of years away. Rock formations that contain trace amounts of elements such as uranium and iron are evidence of an anaerobic atmosphere. Therefore, these elements are not found in rocks from the middle Precambrian or at least 3 billion years later.

Importance of oxygen

primitive atmosphere

For organisms like us, the most important atmospheric process is the formation of oxygen. Neither direct chemical processes nor geological processes such as volcanic activity produce oxygen. Therefore, it is believed that the formation of the hydrosphere, the stable atmosphere and the energy of the sun are the conditions for the formation of proteins in the ocean and the process of amino acid condensation and synthesis. of nucleic acids carrying the genetic code, in 1.500 million years Later, unicellular anaerobic organisms appear in the ocean. Just a billion years ago, aquatic organisms called cyanobacteria began using the sun's energy to break down molecules.

Water (H2O) and carbon dioxide (CO2) are recombined into organic compounds and free oxygen (O2), that is, when the chemical bond between hydrogen and oxygen is broken, the latter is released into the environment from oxygen. produced by photosynthesis combines with organic carbon to form CO2 molecules. The process of converting solar energy into free oxygen through molecular dissociation is called photosynthesis and occurs only in plants, although it is a giant step towards the Earth's atmosphere we have today. This is a big disaster for anaerobic organisms, because if the oxygen in the atmosphere increases, the CO2 decreases.

Formation of the atmosphere and gases

At that time, some oxygen molecules in the atmosphere absorb energy from ultraviolet rays emitted by the sun and split to form individual oxygen atoms. These atoms combine with the remaining oxygen to form ozone molecules (O3 ), which absorb ultraviolet light from the sun. For 4 billion years, the amount of ozone was not enough to block the entry of ultraviolet light, this would not allow life to exist outside the oceans. About 600 million years ago, due to marine life, the Earth's atmosphere reached ozone levels high enough to absorb harmful ultraviolet light, which led to the emergence of life on the continents. At this point, the oxygen level is about 10% of the current value. That is why, before this, life was limited to the ocean. However, the presence of ozone causes marine organisms to migrate to land.

Continuous interactions with various terrestrial phenomena continued to occur in the atmosphere until it reached a composition that is currently 99 percent hydrogen, oxygen, and argon. Currently, the atmosphere not only functions to protect the various physical phenomena that occur in space, but also acts as an extraordinary regulator of the thermodynamic, chemical and biological processes inherent in evolution and Earth events, without which life would not be as we know it. That constant interplay of ocean temperatures, ozone's protection from the sun's harmful rays, and a relatively calm climate allowed life to continue to evolve.

I hope that with this information you can learn more about the formation of the atmosphere and how it was carried out.


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