Environmental Chemistry

Thermosphere – Characteristics and Temperature

While looking up at the sky you probably see a soft blue, maybe with some clouds. Sometimes it might be grey or rainy as shown here. But what is above this blue and cloud cover? Beyond the clouds, there are additional layers of the atmosphere. In this topic, we are going to cover the thermosphere, which is the layer of the atmosphere right before we get to outer space. This thermosphere greatly helps in protecting the Earth and making complete exploration of the space and making space communication possible.


Layers of the Atmosphere

First, we need to understand the other layers of the atmosphere starting from the Earth’s surface. Above this surface to about 7 miles above there is the troposphere. Next to it there is the stratosphere, where airplanes fly. This layer extends from 7 miles to 20 miles above the surface.

After the stratosphere there is the mesosphere, extending upwards till 50 miles above the surface. After the mesosphere, the thermosphere exists which extends from about 50 miles to about 600 miles above our planet. Beyond this, there is an exosphere, which turns into outer space at the edge.


It is the layer that is located between the mesosphere and the exosphere. It has an extension that begins between 80 and 120 kilometers from the Earth. In this layer, the ultraviolet radiation, and especially the gamma rays and X rays originated by the Sun.

There is constantly ionization of sodium atoms and various types of molecules going on. This process of ionization makes the gases due to which temperature of thermosphere raises by several hundred degrees.

In this atmospheric layer, we can observe space shuttles. The air particles inside this layer are very separate. This layer has this name only due to the high temperatures caused by already ionized gases.

Characteristics of Thermosphere

  1. In this layer occurs molecules ionization due to ultraviolet radiation, gamma rays and X rays of the Sun.
  2. In this layer, the meteorites disintegrate as soon as they touch the air.
  3. At the poles of the Earth particles which are carried by the solar wind are trapped in the Earth’s magnetic field giving rise to the aurora borealis.
  4. It is located above the mesosphere and is the fourth layer of the earth.
  5. Its temperature changes with solar activity.
  6. In its interior sublayer i.e. ionosphere the radio waves are reflected.
  7. The boundary between the thermosphere and the exosphere is called Thermopause.
  8. It is estimated that almost 99.99% of the earth’s atmosphere is below the thermosphere, despite its size. This is because the air is so thin.
  9. Since outer space is believed to begin at 62 miles above the earth’s surface, so the thermosphere could be considered part of space.
  10. The charged particles in the area of the thermosphere, long-distance communication via radio are possible.
  11. When large magnetosphere storms occur in the thermosphere layer, thermospheric storms are produced.

Temperature of Thermosphere

Although it is known that temperatures in the thermosphere can reach 2000 degrees Celsius or even more. But actually reading this temperature is very difficult for scientists, because air is so thin.

The word ‘thermosphere’ is derived from the Greek word ‘thermo’ meaning of which is heat. The temperature in the thermosphere increases considerably as it rises in distance and does so very quickly.

At the top, the temperature does not change much. This temperature is oscillating depending on the day or night.

Much solar activity temperature in the thermosphere is largely influenced by much solar activity. The time of day also affects the temperature, as higher temperatures in the day than at night.

Thus the way we can say that the thermosphere has a warmer temperature when the sun is very active. This phase is solar maximum and it is less hot during the phase solar minimum.

Questions on Thermosphere 

Q: What are auroras?

Ans: During certain times of the year toward the Northern and Southern poles, the Earth’s atmosphere puts on a very amazing light show! The sky fills with patches of dazzling colors like ribbons of light. These light shows are auroras.

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