Thermosphere
Emily M.
The thermosphere is above the mesosphere, at
the height of 80 km. The air in the thermosphere is very thin. The word thermosphere means "heat
sphere" or "warm layer." The temperature is very high in
this layer and may reach 2000° or more. To give you an idea of how hot
2000° the bottom of a furnace used for steel reaches 1900°. At this
temperature, steel is a liquid! The oxygen and nitrogen in the
thermosphere absorb ultraviolet radiation from space and make it into to
heat.
The temperature is not measured with a thermometer in the thermosphere, but with special instruments. If the temperature were measured with a thermometer, it would go far below 0°! The faster the particles move, the hotter the temperature.
The lower part of the thermosphere is called the ionosphere. The ionosphere is from 80 kilometers to 550 kilometers. The size varies with the amount of ultraviolet and X-ray radiation, two types of invisible energy given off by the sun. Nitrogen oxides, oxygen, and other gas particles absorb ultraviolet radiation and X-ray given off by the sun.
There are also electrically charged particles called ions in the ionosphere. They are important to the radio systems. AM radio waves bounce off the ions and backed to the Earth's surface. Sometimes sun flares cause number of ions to increase. This can effect with the transmission of some radio waves.
