Have you ever wondered what an atmosphere is? Why is it important? What are the features of the atmosphere? If these questions have tormented your mind for long, the answers are all here in this article on Earth’s atmosphere facts. In this write-up, we are going to learn about the Earth’s atmosphere in details. We will learn about its layers, its chemical makeup, its physical properties and more. Are you ready?
Earth’s Atmosphere Facts: 1-4 | What is the Atmosphere?
1. The atmosphere is a series of layers of gases that surround a celestial object. A body can have an atmosphere if there is gravity and if the temperature is low.
2. The atmosphere of stars is called stellar atmosphere. It is present above the photosphere (the shell of the star which radiates light).
3. Stars which have low temperature may have an atmosphere with compound molecules.
4. The composition of the atmosphere of each celestial body differs. The atmosphere gradually changes as the climate and weather changes.
Earth’s Atmosphere Facts: 5-18 | Composition of the Atmosphere
Earth’s Atmosphere Facts: Primary Gases in the Atmosphere
6. The amount of water vapor (H2O) present in the Earth ’s atmosphere varies with the location. In cold regions, the water vapor is around 10 ppm (parts per million) by volume whereas, in hot, and humid areas, the amount may go up to 5% of the atmosphere.
Earth’s Atmosphere Facts: Secondary Gases in the Atmosphere & Greenhouse Effect
7. The other gases in the atmosphere are generally termed as trace gases as they are present in trace amounts in the Earth’s atmosphere. They are also known as secondary gases.
9. Greenhouse gases are the gases which trap the Sun’s heat and helps in keeping the Earth warm. This is the greenhouse effect.
10. Contrary to popular belief, the greenhouse effect is necessary for the survival of life.
11. However, if the percentage of these gases in the atmosphere is increased, it leads to something called enhanced greenhouse effect or the anthropogenic greenhouse effect.
12. The enhanced greenhouse effect is warming the Earth more than needed, and the world is experiencing global warming and climate change.
13. The percentage of gases present in the Earth’s atmosphere is given below:
|Name of the gas in the atmosphere||Percentage||Contribution to the greenhouse effect|
|Carbon Dioxide (CO2)||0.03%||9% to 26%|
|Methane (CH4)||0.000179%||4% to 9%|
|Water Vapor (H2O)||0.001% to 5%||36% to 70%|
|Ozone (O3)||0.00006%||3% to 7%|
14. Ozone forms a layer in the Stratosphere layer. It absorbs UV (Ultraviolet) rays that the Sun emits, and thus, very important.
15. If there were no ozone, life wouldn’t have existed on the Earth.
16. Water vapor is the source of all types of precipitation. Its proportion decreases as we move up from lower latitudes to higher latitudes. It also decreases with increasing altitude or height.
17. Dust particles are also present in the Earth’s atmosphere in minute amounts. Sand, oceanic salt, ash, pollen, and smoke constitute the dust particles.
18. These particles help in condensing the water vapor, in turn helping the formation of clouds.
Earth’s Atmosphere Facts: 19-55 | Layers of the Atmosphere
Now that we know the composition of the Earth’s atmosphere, it is time to learn about the various layers of the atmosphere of our planet.
19. Did you know that the atmosphere extends up about 1600 kilometers? However, 97% of the mass of the atmosphere is present in the first 30 kilometers.
20. There are five layers of the atmosphere. The division is based upon the difference of temperature and density.
21. The five layers of the atmosphere are – Troposphere, Stratosphere, Mesosphere, Ionosphere, and Exosphere.
Earth’s Atmosphere Facts: Troposphere Facts – the First Layer of the Atmosphere
22. The Troposphere is the lowest layer. It extends up to 18 kilometers near the equator and 8 kilometers near the poles. The average height is about 12 kilometers.
23. The reason for the higher altitude near the equator is the presence of the hot convection currents which push the gases upwards.
24. The temperature and density the Troposphere decrease as we move upwards, which means the lowest layers of Troposphere is the warmest and densest.
25. There is a decrease in temperature by 1 degree Celsius for every 165 meters in height. This decrease is called the normal lapse rate.
26. The Troposphere comprises 80% of the atmosphere of the Earth. 50% of the Earth’s atmospheric mass is present in the first 5.6 kilometers of the altitude of the Troposphere.
27. Most of the water vapor is present in this layer which is why almost all the phenomena related to weather takes place in the
28. The air doesn’t remain static in this layer. Hence this layer is called Troposphere (tropo in Greek means ‘turn’) or changing sphere.
29. The transition zone between the Troposphere and Stratosphere is called Tropopause.
30. Tropopause contains the characteristics of both Troposphere and Stratosphere. The temperature drops to minus 80 degrees Celsius at Tropopause.
Earth’s Atmosphere Facts: Stratosphere – the Second Layer of the Atmosphere
31. The layer above Troposphere is Stratosphere. It extends up to 50 kilometers from the Earth’s surface. Its average height is 40 kilometers.
32. The temperature in the first 20 kilometers remains almost the same. For the next 20 kilometers, the temperature increases as we move upwards.
33. The reason for the increase in the temperature is the presence of the ozone layer in the Stratosphere.
34. As there are almost zero weather phenomena and almost no clouds, this layer is perfect for aviation.
35. The pressure near the Stratopause (transition zone between Stratosphere and Mesosphere) is merely 1/1000th pressure of the pressure present near the sea level.
36. The temperature at stratopause is nearly 0 degree Celsius.
Earth’s Atmosphere Facts: Mesosphere Facts – the Third Layer of the Atmosphere
37. The Mesosphere is the next layer of the Earth’s atmosphere. It spreads up to 80 kilometers from the surface of the Earth. It has a height of 30 kilometers.
38. Temperature decreases with increasing altitude. The temperature at Mesopause (transition zone between Mesosphere and Ionosphere) is near minus 85 degrees Celsius. This part is the coldest place on the Earth (considering not just the Earth but also its atmosphere).
39. The air below the Mesopause is pretty cold and whatever little water vapor is present, condenses to form noctilucent or night-shining clouds (cloud-like phenomena which occur in upper layers of the Earth’s atmosphere).
40. These clouds are the highest clouds in the Earth’s atmosphere. They can be seen only during dusk or dawn.
41. This is the layer where the meteors burn up completely. Rockets and rocket-powered aircraft can access this layer.
Earth’s Atmosphere Facts: Thermosphere Facts – the Fourth Layer of the Atmosphere
42. The Thermosphere is the fourth layer of the atmosphere. It is present above the Mesosphere and below the Exosphere.
43. It starts a height from 80 kilometers above Earth’s surface. It has an extent of about 420 to 880 kilometers.
44. The temperature increases as the height increases in this layer. The temperature can increase up to nearly 1500 degrees Celsius.
45. However, a human cannot feel the difference because the individual molecules may have a high proportion of energy but still the density is low to conduct enough energy from or to the skin.
46. No clouds or water vapor is present in the Thermosphere. Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights)- both termed as polar lights – are seen in this layer of this atmosphere occasionally.
47. The ISS or the International Space Station that revolves around the Earth is present in this layer. It orbits the Earth at a height of 350 kilometers to 420 kilometers.
49. Because of the changes in the solar activity, the height of the Thermopause (the transition zone between Thermosphere and Exosphere) varies.
50. Thermosphere’s lowest part (from 80 to 550 kilometers) is known as Ionosphere.
51. Electrically charged ions flow in this layer and hence the name Ionosphere. Radio broadcasting is possible because the radio waves are reflected back to the Earth from the Ionosphere.
Earth’s Atmosphere Facts: Exosphere Facts – the Fifth Layer of the Atmosphere
52. The last or the top layer of the atmosphere is the Exosphere. It starts from Exobase or Thermopause (at a height of 700 kilometers from the sea level).
53. It extends up to 10,000 kilometers and eventually mixes with solar wind (stream of charged particles emitted by the upper layers of the atmosphere by the Sun).
54. Gases like Oxygen, Nitrogen, Carbon Dioxide etc. are present at the exobase whereas Hydrogen, Helium etc. are present at the top of the exosphere.
55. The molecules or atoms of these gases are so far from each other that they can easily travel without any collision, and therefore the gases escape into space. The lack of gravitational pull makes the air density very less in this layer.
56. The exosphere is so far away that meteorological phenomena may not be possible. However, the part of exosphere which is close to thermosphere may also experience Aurora Borealis and Aurora Australis.
Quick Review of the Layers of Earth’s Atmosphere:
|Layer of atmosphere||Temperature||Height|
|Troposphere||Decreases as height increases||0 to 12 kilometers|
|Stratosphere||Increases as height increases||12 to 50 kilometers|
|Mesosphere||Decreases as height increases||50 to 80 kilometers|
|Thermosphere||Increases as height increases||80 to 700 kilometers|
|Exosphere||Remains constant||700 to 10,000 kilometers|
Earth’s Atmosphere Facts: 56-61 | Other Layers of Earth’s Atmosphere
Basing on other physical properties, the atmosphere of Earth can be divided into few other layers which are briefly described below.
56. The planetary boundary layer is a part of the first layer of the atmosphere – the Troposphere. The height of the planetary boundary layer ranges from 100 meters (clear night) to 3,000 meters in the daytime in the dry region.
57. The ozone layer is the layer where ozone gas concentration is the highest. It is present at a height of 15 to 35 kilometers, but the thickness differs with seasons and geographic locations. Stratosphere has 90% of the ozone present in the atmosphere.
58. The ionosphere is a region which gets ionized by the solar radiation. During daytime, the extent of ionosphere includes mesosphere, thermosphere and a part of exosphere. At night time, ionosphere includes only exosphere and thermosphere. This is the layer of the atmosphere which is responsible for the auroras.
59. Ionosphere forms the inner margin of the magnetosphere (the region surrounding the celestial object where the charged ions or particles get affected by the magnetic field of the celestial object).
60. Then there is something called Homosphere and Heterosphere. Homosphere is characterized by the homogenous mixing of the atmospheric gases. Troposphere, Stratosphere, mesosphere and lowest part of the thermosphere make up the Homosphere. Homosphere extends to a height of 100 kilometers (known as Karman line) from the surface of the Earth.
61. In Heterosphere, the chemical composition of the atmosphere changes with the altitude. The lower part of Heterosphere consists of Oxygen, Nitrogen etc. and the upper parts of Heterosphere contains mostly Hydrogen.
Earth’s Atmosphere Facts: 62-70 | Evolutionary History of Earth’s Atmosphere
62. The atmosphere when Earth was formed was way different from what we experience today.
63. The atmosphere when Earth was formed was dominated by gases like Hydrogen, Water Vapor, Ammonia (NH4), and Methane.
65. The net result of these two phenomena was an atmosphere dominated by Nitrogen, Carbon Dioxide, and Noble Gases.
66. This atmosphere dominated by Nitrogen was stable and supported life (around 3.4 billion years ago).
67. This atmosphere was called reducing atmosphere because there was no Oxygen present in it.
68. Oxygen which was produced due to photosynthesis was used up by reducing materials like Iron, etc.
69. Around 280 million years ago, the atmosphere was more or less as today’s atmosphere. The percentage of Oxygen was 30% as against 21% of present times.
Earth’s Atmosphere Facts: 71-75 | Physical Properties of Earth’s Atmosphere
71. The pressure of the atmosphere is 101325 pascals or 760 mmHg. The pressure is not uniform.
72. As mentioned earlier 50% of the atmospheric pressure is present in the first 5 to 6 kilometers of height. 99.99% of the pressure is seen in the first 100 kilometers. Anyone crossing this range is termed as an astronaut.
73. The speed of the sound varies with the temperature of the layer of the atmosphere. Sound’s speed doesn’t get affected by the atmosphere’s density or atmospheric pressure.
74. The density of the air at the sea level is around 1.2 kg/m3. The density of the atmosphere decreases with the increase in the height or altitude.
75. The mass of the atmosphere is about 1/1,200,000 the mass of our Earth which is equal to 5 quadrillion tons.
Earth’s Atmosphere Facts: 76-93 | General and Fun Facts About the Atmosphere
76. Oxygen is extremely vital for living organisms now, but did you know that Oxygen was the reason for the first extinction on Earth? Oxygen was not produced in surplus before 2.4 billion years ago.
77. At that time, the living organisms were anaerobic (meaning they did not require Oxygen to survive). Excess of Oxygen was toxic to them. When Oxygen was produced more, it cleanly wiped out those anaerobic organisms.
78. Earth experienced much worse global warming in the Cambrian period. The emissions of Carbon Dioxide were 11 times higher than the present times’ emissions. Quaternary ice age eventually cooled down the Earth.
79. The color of the sky is actually violet. But why do we see it blue? We see blue because of a phenomenon called the Rayleigh Scattering (coined after the scientist who first described it).
80. As you might know, that light when scattered produces seven colors (VIBGYOR – Violet, Indigo, Blue, Green, Yellow, Orange, and Red).
81. Each color has a particular wavelength. Colors like blue, violet etc. have a shorter wavelength than colors like orange or red.
82. The colors with short wavelength are scattered more in the atmosphere and hence we can see those colors more.
83. But here is the catch. When we compare the wavelengths of blue and violet, violet has a small wavelength.
84. Then why don’t we see the sky as purple? It is because the human eye is more sensitive to the color blue.
86. It happens because the pressure and the boiling point drop drastically and hence this height is called the Armstrong-Limit. Therefore, it is necessary to be in a pressurized suit if you ever want to get to that height.
88. Did you ever wonder why some white streaks are seen after some planes move through? It is because the engine releases hot, humid water vapor which meets with cold air in the outside.
89. The water vapor freezes and is visible. This is the same phenomenon used when you exhale the air through your mouth in cold weather.
90. These white streaks (technically known as the condensation trails or contrails) can indicate the weather. If the streaks are faint, the humidity is less and the day is going to be Sunny but if the contrails are thicker than you may expect some showers.
91. Did you know that ozone is formed when Oxygen atoms are stirred together by the UV light? It is the same UV light that the ozone prevents from entering the Earth.
92. Acid rains are formed when Sulfur Dioxide or Nitrogen Oxide react with Water Vapor to form Sulfuric Acid or Nitric Acid respectively. Acid rain can destroy anything – living and non-living alike.