Earth, the planet we live on is an ellipsoid with a circumference of about 40,000 km. Surrounding it, is a layer of gases that forms what we call the atmosphere. The atmosphere is vital for life on earth, as it contains the oxygen we need to live. It also protect us from harmful ultraviolet solar radiation.

Earth's atmosphere is built up of 78.8% Nitrogen and 20.95% Oxygen. Along with a small amount of other gases including 0.95% Argon, 0.000009% Xenon, 0.0018% Neon, 0.00005% Hydrogen, 0.0005% Helium, 0.0001% Krypton and Carbon Dioxide 0.038%. All these gases combined makes up the total composition of earth's atmosphere.

The Five Layers of Earth's Atmosphere

According to atmospheric science the atmosphere is built up of five main layers. These layers starts close to Earth's body and reaches all the way up to 10,000km or 6,200 miles above sea level.

1. Troposphere (6-20km above sea level)

The Troposphere, the lowest layer of earth's atmosphere which ranges from 6-20km above sea level. In total, it contains 75% of the total mass of the planetary atmosphere. The Troposphere contains the air we breathe and the clouds in the sky that is vital for our ecosystem. In the North and South Pole the troposhpere is the thinest, and the air is densest in this lowest layer of the troposphere.

2. Stratosphere (20-50km above sea level)

The Stratosphere is the second layer of the atmosphere of the Earth. This layer is located between the Troposphere and the Mesosphere and ranges from 20-50km above sea level. In the Stratosphere we find Earth's important ozone layer, which helps protect us from ultraviolet radiation (UV) comming from the sun.

3. Mesosphere (50-85km above sea level)

The Mesosphere is the third layer of Earth's atmosphere. It's situated above the Stratosphere and below the Thermosphere. In the Mesosphere, the temperature decreases drastically as the altitude increases. At the outer most layer of the Mesosphere the temperature can reach -90Β° C (-130Β° F) which makes it inhospitable to life as we know it.

4. Thermosphere (85-690km above sea level)

The Thermosphere is the fourth layer of the atmosphere of the Earth. It is located between the Mesosphere and the Exosphere 85-690km or 311-621 miles above Earth's sea level. One part of the Thermosphere is called the Ionosphere, which is where particles can become ionized causing the Aurora Borealis (Northern Lights) phenomenon A breathtaking phenomenon that produces green-shaded dancing waves of light that have captivated people in the northen hemisphere for millennia.

5. Exosphere (690-10,000km above sea level)

The outer most layer of the Atmosphere is called the Exosphere which ranges from 690-10,000km or 428-6,200 miles above sea level. The very word "Exo" actually means "outside", "outer", or "external", hence the name Exosphere. It's a thin, atmosphere-like volume surrounding the very outer parts of Earth's Atmosphere where molecules are gravitationally bound to its body, but where the density is so low that the molecules are more or less collisionless.

Atmospheric Pressure

Accoding to atmospheric science the atmospheric pressure is caused by the gravitational attraction of the planet on the atmospheric gases above the surface and is a function of the mass of the planet, the radius of the surface, and the amount and composition of the gases and their vertical distribution in the atmosphere. It is modified by the planetary rotation and local effects such as wind velocity, density variations due to temperature and variations in composition.

Gases That Make Up the Atmosphere

Carbon Dioxide (CO2) in the Atmosphere

Currently, carbon dioxide has a concentration around 400 parts per million in the atmosphere. It's the fourth most common component in the atmosphere and makes up 0.038% of it. Since the start of the industrial age, the levels have risen from 270 PPM to today's current value. Atmospheric carbon dioxide has been measured between 1980-2024 by laboratories around the world.

Methane (CH4) in the Atmosphere

Atmospheric methane has been messured by NOAA since the start of 1983 to this day. The current concentration of methan in the atmosphere is around 1900 parts per billion. Methane is a strong greenhouse gas with a global warming potential 84 times greater than CO2.

Nitrous Oxide (N2O) in the Atmosphere

Nitrous oxide is naturally present in earth's atmosphere. It is part of the nitrogen cycle and has a variety of natural sources such as soils under natural vegetation, tundra and the oceans. Nitrous oxide molecules stay in the atmosphere on average for 114 years before being absorbed by certain types of bacteria or destroyed by ultraviolet radiation or chemical reactions. Nitrous Oxide (N2O) contents in earth atmosphere has been messured by NOAA from 2001 to 2024

Sulfur Hexafloride (SF6) in the Atmosphere

SF6 or Sulfur Hexafloride is a very stable chemical with an atmospheric lifetime of 3,200 years. When Sulfur Hexafloride is emitted, it accumulates in the atmosphere and stayes there without being degraded for many centuries. Atmospheric Sulfur Hexafluoride (SF6) has been continously studied and recorded since 1997 to 2024.

Atmospheric Escape

CO2 in the Atmosphere

Air and Atmosphere