Join us to discover the enigmatic atmosphere, learn its importance and function, its characteristics, properties, its composition and layers (structure), welcome to the world of the outer layer of the earth that allows life on our planet.
What is the earth’s atmosphere?
The terrestrial atmosphere is a combination or mixture of gases that are stable around our planet, its importance lies in the fact that it contains the oxygen that helps us breathe, but also allows life in various ways.
Its main gaseous composition is oxygen (20.9%), nitrogen (78.1%) and other gases that surround 0.1% of its volume, including water vapor (H2O), carbon dioxide (CO2), argon, etc.
The atmosphere is very important for life because it protects humans, animals, plants and microorganisms from most of the ultraviolet (UV) radiation that originates from and comes from the sun.
In addition, it allows the planet’s environment to regulate itself at an average temperature of 33°C (59°F), thus avoiding a large temperature difference between day and night.
Its average density is 1,225 km/m3.
The atmosphere is divided into: troposphere, stratosphere, mesosphere, ionosphere and exosphere.
Chemical composition of the atmosphere
| Nitrogen (N2) | 78.1% |
| Oxygen (O2) | 20.9% |
| Argon (Ar) | 0.9% |
| Carbon dioxide (CO2), methane (CH4), rare gases (inert) | 0.1% |
| Water vapor (H2O) | 0.001% |
In the table it can be seen that nitrogen and molecular oxygen are the most abundant gases in the atmosphere, in fact, Nitrogen makes up 78.1% of the total volume, while oxygen represents 20.9% of the total volume of the atmosphere.
Meanwhile, argon, an inert gas, reaches 0.9% of the total volume.
Less than or equal to 0.1% are Carbon Dioxide (CO2), Methane (CH4) and rare or inert gases.
Remember that the increase in the percentage of CO2 is what causes the “Greenhouse Effect” on earth, so care must be taken to keep the carbon dioxide content on the planet stable to prevent global warming from occurring.
What are the layers of the atmosphere?
The atmosphere is divided into 5 layers or main parts, which cover the layers of the solid earth that we list from the lowest layer to the outermost.
- Troposphere (is where we live)
- Stratosphere
- mesosphere
- Ionosphere
- exosphere
The troposphere
The troposphere is the layer closest to the earth’s surface, it is the one that occupies the largest volume of atmosphere (between 75% and 80%) and where clouds are generated and most of the climatic processes that occur in the atmosphere occur. planet.
This layer is considered the most important of the layers of the atmosphere because it is where all living beings interact, where the weather occurs, where the temperature, humidity and gases are adequate to preserve life.
The stratosphere
It is the second layer that makes up the structure of the atmosphere and is above the troposphere and below the mesosphere.
In this layer, ozone is abundant, this important gas because it absorbs a large part of the ultraviolet radiation that comes from the sun, and this causes the temperature in this layer to increase with height, quite the opposite of what happens in the other layers..
The mesosphere
This is the third layer that makes up the structure of the atmosphere, it is above the stratosphere at the stratopause limit and below the thermosphere at the mesopause limit.
The coldest temperatures in Earth’s atmosphere, about −90 °C (−130 °F), lie near the top of this layer.
Thermosphere
This is the fourth layer that makes up the structure of the atmosphere, it is located above the mesosphere at the limit called “mesopause” and below the exosphere at the limit called “thermopause”.
It ranges from about 90 km (56 miles) to between 500 and 1,000 km (311 to 621 miles) above our planet.
Exosphere
The exosphere is the highest region of Earth’s atmosphere (the furthest away), as it gradually fades into outer space. The air in the exosphere is extremely thin, in many ways almost the same as the airless vacuum of outer space..
It is above the thermosphere on the thermopause boundary.
Why are there several layers in the atmosphere?
The different layers of the atmosphere exist because the gas atoms interact differently as we move away from the earth’s surface, that is, these layers are generated by the interaction of the gas atoms with the decrease in pressure, temperature and density as we increase the height.
Atoms and molecules travel quickly within the same layer, but very slowly between layers. The stratification of the atmosphere is the result of temperature variations of the gas molecules with the variation of height mainly.
What is the most important layer of the atmosphere?
In this sense, we could consider that the most important layer of the atmosphere is the troposphere (the layer closest to the earth’s surface), because it is where all living beings live and interact.
In this layer all the climatic events that allow the water cycle are generated, create an adequate environment (temperature and pressure) and where the greatest amount of vital oxygen for life is concentrated.
However, equally nothing could survive without the existence of the stratosphere, it is here where ozone manages to deflect or absorb the greatest amount of ultraviolet radiation that comes from the sun and which is also of vital importance for the survival of living beings and life. generally planet earth.
So it’s up to you
How was Earth’s atmosphere formed?
Origin of the atmosphere (first atmosphere)
Earth’s primordial atmosphere was likely similar to the gas cloud that created the sun and planets, the same one that consisted of hydrogen and helium, along with methane, ammonia, and water. This was a reducing atmosphere and there was no molecular oxygen or other reactive oxides.
Over time, some of this early atmosphere, particularly the lighter gases, degassed and was lost to space.
Evolution of the atmosphere (The second atmosphere)
The “second atmosphere” was very likely already formed on the planet. At this stage there were already many volcanoes, and they were much more abundant than now because the earth’s crust was still forming.
Early in volcanic activity, Earth created major changes with the release of water vapor (H2O), carbon dioxide (CO2), and ammonia (NH3) along with small amounts of SO2, H2S, HCl, N2, NO2, He, Ar and other noble gases. These components produced the second atmosphere.
It is also possible that the impacts of comets and meteorites may have increased the amount of water, at the same time that the water vapor formed clouds and these clouds produced rain.
Over thousands of years, liquid water accumulated as rivers, lakes, and oceans on the Earth’s surface. Bodies of liquid water acted as sinks for carbon dioxide, and chemical and biological processes transformed CO2 gas into carbonate rocks.
Nitrogen and argon accumulated in the atmosphere do not react with water or other atmospheric components.
Therefore, oxygen existed only in trace amounts before life began.
Current atmosphere (third atmosphere)
Living beings created much of the third atmosphere, the one that now exists on Earth, in this step cyanobacteria were responsible for the increase in atmospheric oxygen concentration that began 2.3 billion years ago.
These bacteria, algae, and other plants produce oxygen by photosynthesis, however most of this oxygen is used in respiration (biological oxidation) or atmospheric oxidation of carbon-containing products, about 0.1% of organic matter. it is sequestered in sediment and that amount of oxygen is added to the atmosphere.
Over time, the excess oxygen has accumulated, so that it now makes up almost 20% of the gases near Earth.