Thermosphere

Temperature

The thermosphere is characterized by extremely high temperatures, which can range from about 500°C (932°F) to over 2,000°C (3,632°F), and even reach up to 4,500 degrees Fahrenheit in some instances[1][5][8][11][15][16]. These high temperatures are a result of the thermosphere absorbing X-rays and extreme ultraviolet radiation from the Sun[16]. Despite these high temperatures, the thermosphere would feel cold to a human because the air is so thin that there are not enough gas molecules to transfer the heat[5][14][15].

Composition

The composition of the thermosphere is primarily nitrogen (N2) and oxygen (O2), similar to the lower and middle atmosphere. However, in the upper thermosphere, atomic oxygen (O) becomes more prevalent[2][6][9]. The density of the gas in the thermosphere is extremely low, with the mass of the thermosphere and above being only 0.002% of the total mass of the atmosphere[15].

Importance

The thermosphere plays a crucial role in protecting life on Earth by absorbing some of the Sun's most harmful radiation, including X-rays and ultraviolet rays[3][12]. It is also home to the ionosphere, which is important for radio communication as it allows shortwave radio waves to bounce off and travel long distances[16]. Additionally, the thermosphere is where the International Space Station orbits and where many satellites are located[5][12].

Characteristics

The thermosphere lies between the exosphere and the mesosphere and is about 319 miles (513 kilometers) thick[5]. It is part of the ionosphere, where photoionization and photodissociation of molecules create ions[8]. The thermosphere experiences significant expansion and contraction in response to the Sun's heat, which can affect satellite orbits due to drag[12]. Auroras also occur in this layer[12]. Despite the high temperatures, the thermosphere has a very low density, and sound waves cannot travel through it[15]. The thermosphere's temperature and density are highly dependent on solar activity[8][10].

Citations:

[1] https://scied.ucar.edu/learning-zone/atmosphere/thermosphere

[2] https://www.sciencedirect.com/topics/earth-and-planetary-sciences/thermosphere

[3] https://homework.study.com/explanation/what-is-the-importance-of-the-thermosphere.html

[4] https://www.noaa.gov/jetstream/atmosphere/layers-of-atmosphere

[5] https://spaceplace.nasa.gov/thermosphere/en/

[6] https://link.springer.com/chapter/10.1007/978-3-540-46315-3_9

[7] https://homework.study.com/explanation/what-does-the-thermosphere-do.html

[8] https://en.wikipedia.org/wiki/Thermosphere

[9] https://cpaess.ucar.edu/sites/default/files/heliophysics/resources/presentations/2021-HelioSS-Zou-Ionosphere-Basics-Dynamics.pdf

[10] https://progearthplanetsci.springeropen.com/articles/10.1186/s40645-021-00433-8

[11] https://study.com/learn/lesson/thermosphere-overview-facts-composition.html

[12] https://www.online-sciences.com/earth-and-motion/the-characteristics-and-the-importance-of-the-thermosphere-layer/

[13] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/thermosphere

[14] http://www.ecoca.ro/meteo/tutorial/atmosphere/older/Thermosphere.html

[15] https://earthhow.com/thermosphere/

[16] https://simple.wikipedia.org/wiki/Thermosphere