There are four semi-horizontal layers of “spheres” that are identified by their vertical temperature distribution in the Earth’s atmosphere. These four layers are called the troposphere, the stratosphere, the mesosphere, also called the “mantle” and the thermosphere. Between these layers are spaces called “pauses”; no temperature change happens when the altitude changes. Each of these pauses has a specific name. The tropopause occurs between the troposphere and the stratosphere. The stratopause is found between the mesosphere and the thermosphere. Together, the stratosphere and the mesosphere are called the middle atmosphere. This region overlaps with the ionosphere. The ionosphere is define on the electric charges of the particles found within it.
“Meso” means middle in Greek. The mesosphere, then, means the middle of the sphere. The mesosphere is the third layer of the Earth’s atmosphere. It is found between the stratosphere and the thermosphere and is located about 35 miles (55 kilometers) to around 54 miles (85 kilometers) from the surface of the Earth. The mesosphere’s temperatures are dependent on where you are measuring. At its lowest level, it is the warmest, about 23°F (°C); at its highest, 12°F (0°C). However, depending on the season and latitude, the uppermost portion can drop to 20°F (40°C).
Mesospheric temperatures are lower than temperatures in the troposphere or stratosphere. It is so cold that even Antarctica’s coldest temperature are higher; it is so cold that water vapor becomes ice clouds, sometimes visible after sunset.
The air in the mesosphere is very thin and the atmospheric pressure is low; there is a much lower concentration of oxygen in the mesosphere than the troposphere; there are only insignificant amounts of ozone and water vapor. The mesosphere is where many meteors burn up as they enter the Earth’s atmosphere and collide with other gas particles within it.
Source: World of Earth Science, ©2003 Gale Cengage. All Rights Reserved
The term mesosphere has two meanings; one refers to a layer of the atmosphere and another to a region in the Earth's crust.
The term mesosphere referring to the region between the asthenosphere and the outer core is also known as mantle. The upper edge of the mantle is at a depth of 660 km and the lower edge is at approximately 2700 kilometers below the surface of the Earth.
The mesospheric region is a part of the outer Earth. This has been divided into three regions, the lithosphere and crust, the athenospere and the mesosphere. Under the surface of the Earth the pressures and temperatures are very high and both increase as we descend lower.