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Thermosphere Definition

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Thermosphere meaning is quite simple. The thermosphere is one of the layers of the earth's atmosphere that extends in an outward direction. It lies in between the mesosphere and exosphere layers of the atmosphere, the thermosphere layer is above the mesosphere and below the exosphere layer and it covers a major part of the Ionosphere, which is a part of the earth's atmosphere.

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About Thermosphere Layer in Detail

The altitude of the thermosphere layer begins from about 80kms above sea level and extends up to 700kms to space. The altitude makes the thermosphere enter the space and it’s a part of space too. In this layer the ultraviolet radiation causes photoionization of molecules, that is, ions are created in this layer of the atmosphere by the interaction of a photon with an atom or molecule. The thermosphere contributes majorly to the ionosphere of the earth's atmosphere, that is why photoionization or dissociation takes place in the thermosphere, as it lies in the ionosphere region.

Thermosphere and its Temperature

Here you will get to know about the thermosphere temperature range. The temperature of the upper thermosphere layer ranges from 500-degree Celsius to 2000-degree Celsius. It can even range higher than 2000- degree Celsius. Another fact of the temperature in the thermosphere layer is it can get 200 degrees Celsius higher in the daytime than at night. And it can get 500-degrees hotter than usual when the sun is very active. Thermosphere is the name derived from the language Greek, it means Heat. The temperature is always high in this layer of the temperature and the name is apt for the layer.

Air Present in the Thermosphere

The thermosphere is composed of air. The major components are atomic oxygen, atomic helium and atomic nitrogen. Here due to turbulence in the atmosphere, the different types of gas molecules are mixed together thoroughly. 

In the thermosphere, there is an infrequent collision of gas particles that leads to the separation of gases according to the chemical elements the gas contains. 

Much More Information About the Thermosphere

In this layer of atmosphere, the particles are electrically charged because of the radiation. It enables radio waves to be refracted and it can receive beyond the horizon. Much of X-ray and UV radiation from the sun is largely absorbed by the thermosphere when the sun is much active. When it absorbs this radiation the thermosphere expands due to heat and puffs up.

As the thermosphere is below the exosphere layer of the earth’s atmosphere, the exosphere begins at 600km from above sea level and extends into space. There is a Karman line that defines the boundary between the earth’s atmosphere and outer space, according to that thermosphere is a part of outer space. Because the exosphere begins in outer space that is from 600km above sea level, the thermosphere layer is extended to 700 km above sea levels, hence that makes the thermosphere a part of outer space.

As we know oceans have tides and waves, similarly, the earth's atmosphere including the thermosphere has tides and waves, which helps to move the energy along. This results in the production of electrical currents In some parts of the thermosphere.

The atmospheric pressure on the thermosphere is around the 0.0005 kPapressure level, there is a very minimal activity of air pressure at the top of the thermosphere.

Thermosphere and the Other Atmospheric Layers

Let’s understand the thermosphere atmosphere. The thermosphere is the fourth atmospheric layer which is above the mesosphere and below the exosphere. The thermosphere layer begins in the mesosphere region and ends in the exosphere region. But the atmospheric components don’t mix with the other. The transitional space between the mesosphere and thermosphere Is called mesopause. And between the thermosphere and exosphere, it's called thermopause. There is another important fact here, that is the Ionosphere, parts of the thermosphere, mesosphere, and exosphere is included in the ionosphere. There is an interdependence of thermosphere and ionosphere here, as the thermosphere is very hot, it ionizes the atoms in its layer, and produces an electric current.

The thermosphere layer is a thicker layer than other layers of the atmosphere, but not as thick as the exosphere. The thermosphere is home to the International Space Station as it orbits Earth, this is also where you'll find low Earth orbit satellites.

FAQ (Frequently Asked Questions)

1. What are the Three Facts of the Thermosphere?

Answer: The facts about the thermosphere are as follows:

  • The main components of thermospheric air is atomic helium, atomic nitrogen and atomic oxygen.

  • The thermosphere absorbs a lot of radiation from the sun, like UV radiation and X-ray.

  • When the thermosphere gets heated up in the daytime, it's more likely to increase in temperature by about 200 degrees celsius than usual and it expands when overheated and increases the size of the earth’s atmosphere.

2. Why is it Hot in the Thermosphere?

Answer: The name thermosphere itself suggests that this layer of atmosphere is hot, that’s why they’ve named this particular layer as Thermosphere. The layer absorbs UV radiation and X-ray to its fullest, which increases the temperature rapidly. The high-energy radiation from the sun is absorbed by the atoms of nitrogen and oxygen. The radiation is converted to heat, energy, and temperature. The temperature can range more than 2000-degrees celsius. Hence, these are the reasons for the thermosphere to be so hot.

3. Is the Thermosphere Helping the Environment on Earth? If Yes, Explain.

Answer: Yes, the Thermosphere is helping the environment on earth. It's keeping humans, animals, and plants away from the harmful rays of the sun. The sun emits a lot of harmful radiation like ultraviolet radiation and X-ray. The thermosphere layer being the protector it absorbs all the radiation into it, and that in turn increases the temperature on its layer. Hence it acts as a bodyguard and blocks the rays away.