27 Interesting Facts About Earth’s Atmosphere

The shiny blue marble (Earth) has fascinated us since we have first begun to walk across its surface. To date, it remains the only planet we know of where life exists. Over the past few centuries, we have learned a lot about Earth, but how much does an average person really know about our planet?

How much do you really know about the atmosphere surrounding you? You probably have tons of facts rattling around your brain. Check out what we have collected – The 27 interesting facts about Earth’s atmosphere that you may or may not know.

1. Mixture

The Earth’s Atmosphere is 480 km thick, and it is made of a mix of about 16 gases: 

  • Nitrogen (78.08%)
  • Oxygen (20.94%)
  • Argon (0.934%)
  • Carbon dioxide (0.035%)
  • Neon (0.0018%)
  • Helium (0.00052%)
  • Methane (0.00017%)
  • Krypton (0.000114%)
  • Hydrogen (0.000053%)
  • Nitrous oxide (0.000031%)
  • Xenon (0.0000087%)

Other gases are Carbon monoxide, Sulfur dioxide, Nitrogen dioxide and Ammonia, which occupy 0.00003% of Earth’s atmosphere.

2. The Five Layers

The atmosphere is divided into 5 layers:

  1. Troposphere is the layer closest to the Earth’s surface. It is 7 to 20 km thick and contain’s half of the Earth’s atmosphere.
  2. Stratosphere starts above the troposphere and ends about 50 km above ground. Planes fly in this layer to avoid turbulence and cover more distance using less fuel. 
  3. Mesosphere starts at 50 km and extends to 85 km high. It is the coolest part of atmosphere with temperature averaging minus 90 degree Celsius.
  4. Thermosphere extends from 90 km to between 500 and 1000 km. Temperature can get up to 1500 degree Celsius. This is where space shuttle flew.
  5. Exosphere is the highest layer, and widely contains particles of hydrogen and helium.

3. High Altitude, Thin Atmosphere

As the altitude increases, the atmosphere becomes thinner and thinner. The air pressure in the Exosphere (highest layer) is extremely low due to its high altitude and the distance between the molecules it has.

4. Karman Line

According to the Federation Aeronautique Internationale, an altitude of 100 km above the Earth’s sea level represents the boundary between atmosphere and outer space. This border is called Karman line.

5. Troposphere is Denser

The lowest part of the troposphere is the warmest section of the layer, and it is denser than all its overlaying layers because a larger atmospheric weight sits on top of the troposphere and causes it to be severely compressed.

6. Earth’s Temperature is Rising

Image credit: emaze

The global climate has warmed and cooled throughout history. At present, we are seeing unusual rapid warming. This is due to greenhouse gases that are increasing because of human activities, and they are trapping heat in the atmosphere.

7. Ozone Layer

Image credit: wikimedia

One of the most essential things in the atmosphere is the Ozone layer. It is 19-32 km above the Earth’s surface. It’s a pungent smelling blue gas that absorbs most of the sun’s ultraviolet radiation.

In 1985, a hole in the ozone layer was discovered above the Antarctic. The situation has improved following the ban of Chlorofluorocarbon.

8. Chlorine Affects Ozone

A single atom of chlorine can destroy more than hundred thousand ozone molecules. This deterioration lets a huge amount of ultraviolet B rays to reach Earth that can cause skin cancer and cataracts in humans, and harm animals as well.

9. The Northern Light

Image source: Nasa 

Aurora(s) (also called polar light) is seen in the high latitude regions. They are shimmering curtains of light seen at night. They are formed due to charged particles from the Sun striking the upper atmosphere above the poles.

10. Why Earth Appears Blue?

Image source: Nasa

Sunlight is scattered in every direction by all the gases present in the Earth’s atmosphere. Since the blue light has short wavelengths, it’s scattered more than other colors. This gives Earth a blue halo when seen from space onboard ISS at height of 402 to 424 km.

11. Temperatures at Each Layer

Image source: britannica.com

The temperature at different layers of the Earth’s atmosphere depends on humidity, solar radiation, and altitude. The coldest temperatures can be found near the mesopause (85 km – 100 km above Earth’s surface). While warmest temperatures lie in the thermosphere that receives strong ionizing radiation.  

12. Meteors Burn up in Atmosphere

Meteors burn up in Earth’s coldest atmosphere – mesosphere layer. As meteor starts entering this layer, it quickly bumps into particles of the mesosphere and scrapes against them. And since the meteor’s speed is very high, it quickly generates a large amount of heat (due to high friction between mesosphere’s particles and meteor). It begins to glow and rocks start to fly off.

13. Acidic Rain

Image credit: buzzle

Acid rains are formed by a chemical reaction that begins when sulfur dioxide and nitrogen oxides combine in the atmosphere with water vapors. This results in acidic rain capable of destroying animals and plants, and whole forests. In fact, it can kill organisms living in oceans. 

14. Ionospheric Layer

Image source: astrosurf

The ionosphere is a region of upper atmosphere from 60 km to 1000 km altitude, which covers thermosphere, and parts of the mesosphere and exosphere. It is charged by radiation coming from the Sun. Ionosphere plays a crucial role in radio signal propagation around the Earth.
Geomagnetic solar storms caused by solar winds and solar flares can disrupt activity in the ionosphere, which can cause difficulty with radio signal transmission and global positioning system signals.

15. Earth’s Magnetosphere is Strongest

Image source: Nasa

Earth’s magnetic field reaches 58,000 km into space and this region is called Magnetosphere. It prevents most of the particles from the Sun, carried in solar wind, from hitting the Earth. The Sun and other planets have magnetospheres but the Earth has the strongest one of all. Also, Earth’s south and magnetic poles reverse at irregular intervals of hundreds of thousands of years.

16. Nature of Exosphere

The particles present in the exosphere doesn’t actually behave like gases. This is due to the fact that particles are so far apart to each other that they can move thousands of kilometers without colliding. The free-moving particles continuously escape into space, following ballistic trajectories.

17. Contrails

Image source: wikimedia

You may have seen jets leaving white, condensation trails. They are usually formed when the cold atmospheric air mixes with the hot, humid exhaust. Within fractions of a second, the vapor coming out of exhaust freezes and becomes visible. This is very much similar to your warm breath in cold weather. 

These contrails become thin at high altitudes and low humidity. The more humid the atmosphere, the thicker the contrails.

18. Contaminated Air

Approx. 20 percent of the world’s population breathes severely contaminated air, especially with sulfur dioxide and carbon monoxide resulting from industrial operations. This raises the number of respiratory problems, especially amongst elders and children. 13 percent of British children suffer from asthma caused by air contamination.

19. Total Amount of Water in the Atmosphere

Our atmosphere carries nearly 37.5 million billion gallons of water at any specific moment. All this water — present in the form of vapor (invisible to the naked eye) — is enough to cover the whole surface of the Earth with 2.5 cm of rain. 

Every year, this enormous amount of water is recycled 40 times. If you do the math, each water vapor molecule spends only 9 days in the atmosphere.

20. Energy Required to Evaporate Water

It takes approximately 600 calories of energy to evaporate one gram of water. And when nature converts this water into liquid, the same energy is released into the atmosphere.

21. Trade Winds

Image credit: wikimedia

The trade winds blow in the warmest parts of the Earth, between 23.5°S and 23.5°N. This is the reason most thunderstorms and monsoons originate in these volatile regions. The weaker the trade winds become, the more rainfall can be expected in the neighbor landmasses.

22. Earth’s Atmosphere is Leaking

Image source: dailygalaxy

Earth is losing its atmosphere continuously – Every day, approx. 90 tonnes of material escapes from the upper atmosphere and streams out into space. However, 90 tonnes per day amounts to a tiny leak. Earth’s atmosphere weighs 5 quadrillion tonnes, so we are in no danger of running out of atmosphere any time soon.

23. Why Sunset Appears Red?

At sunset, most of the light rays are reflected and scattered in the atmosphere and the Sun appears dimmer. The color of the Sun itself appears to alter, first to orange and then to red. This happens because shorter wavelengths (green and blue) scatter more, leaving only the longer wavelengths (red and orange) to be seen. That’s why sunset appears red.

Read: 13 Very Interesting Questions with their Answers | Explained

24. Alive Microbes

paper published in the journal Proceedings of the National Academy of Sciences shows that there are many different types of microorganisms present in the atmosphere 8 to 15 km above the Earth’s surface. Many of the microbes discovered high in the sky are similar to those in the oceans and freshwater environments. About 25 percent of the microbes were similar to those found in feces.

25. Heat from Lightning

A single stroke of a lightning bolt can heat the surrounding air to 27,000 degree Celsius. Since the lightning travels at extremely fast speed (299,792,458 m/s), the heated air has no time to expand. This rapid heating causes an explosive expansion of the nearby air, which forms a shock wave of compressed particles in all directions. Similar to an explosion, the rapid expanding waves produce a very loud, booming burst of sound.

Read: All Interesting Facts About The Earth’s Moon

26. Refractive Index of Air

The refractive index of air is slightly greater than 1. Variations in the refractive index can lead to the blending of light rays over long optical paths. The refractive index of air depends on temperature. Refraction effects rise with the increase in a temperature gradient. Mirage is a perfect example.

27. Breaking Sound Barrier

Image: Brian Nevins/Red Bull Content Pool

Read: 28 Gripping Facts About Gravity

In 2012, Austrian skydiver Felix Baumgartner jumped from a helium balloon at 37 km altitude (upper stratosphere). He initially free-fell in the low-pressure atmospheric level at a rate faster than the speed of sound, reaching a top speed of 1,358 km per hour. Doing so, he became the first human to break the sound barrier without vehicular assistance. As he fell, the air thickened, helping to slow him down.

Written by
Varun Kumar

Varun Kumar is a professional science and technology journalist and a big fan of AI, machines, and space exploration. He received a Master's degree in computer science from Indraprastha University. To find out about his latest projects, feel free to directly email him at [email protected] 

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