Our atmosphere has different layers and every layer possess different characteristic features. Mesosphere layer is the third layer of the earth's atmosphere. Apart from this, there are four more layers. Closest to the earth is the troposphere then above it is stratosphere, then comes the mesosphere.
On top of mesosphere there are two more layers namely thermosphere and the last one which is the top most layer is the exosphere. Lower part of thermosphere, mesosphere and stratosphere, together referred to as 'middle atmosphere'.
What is Mesosphere?
'Mesosphere' word is derived from the Greek word mesos which means middle and sphaira means ball. It is the third layer of the earth's atmosphere. It is found in between two layers stratosphere from the bottom and thermosphere from the top. Mesopause separates the mesosphere from thermosphere.
Mesosphere is about 30 to 50 miles i.e., 50 to 85 kilometers above the earth's surface. If we talk about information, there is very less information available about mesosphere because of its height. It is located below the minimum height of an orbital spacecraft and above the maximum height of an aircraft or a weather balloon.
Because of this reason, it becomes very difficult to get more information about it. To get details about mesosphere, scientists send small sound rockets which though bring information, are unable to stay there for a long time and hence the mystery of mesosphere is still unsolved.
Characteristics of mesosphere are not totally known. Apart from the few mesosphere facts there is still lot to explore. The information gathered by the sound rockets and by the efforts of the scientists are as follows:
Mesosphere holds the lowest temperature in the earth's atmosphere. Temperature falls down as we go up in the layer and reaches to -100º C or -148º F at the mesopause. This is because mesosphere layer does not have the capacity to absorb the sunlight hence the temperature falls drastically. Mesosphere temperature varies according to the latitude and season. Temperature above this layer becomes non-uniform but does not decrease below the mesosphere temperature.
In the mesosphere layer, concentration of air is very thin which results in low atmospheric pressure. Even the concentration of oxygen in the thermosphere layer is higher than mesosphere.
According to the information available, this layer consists of N2, O2, CO2, O3, Ar, O, etc. Metal ions are also found in this layer. There are many other minor constituents of ions which are still not known.
Formation of Noctilucent Clouds
Although there is no formation of clouds in the lower layer of stratosphere there is sometimes formation of strange clouds in mesosphere. As mesosphere is cold enough to freeze the water vapors, these vapors are converted into ice clouds. When the sunlight struck these clouds at the time of sunset they glow. They look like electrical discharges known as 'sprites' or 'ELVES' and are formed at a great height. According to some scientists, because of the increasing earth's temperature or we can say global warming, there is an increase in the intensity of these clouds or their glow.
Approximately 40 tons of meteorites fall on earth everyday. Most of these meteorites that enter the earth atmosphere either vaporize or melt down due to the friction with the molecules present in the mesosphere layer. Due to this melting down of the meteors this layer has a high concentration of various metals like iron. As the meteors fall at a very high speed, they transfer their energy to the atoms with which they colloid. This transfer of energy is seen as a glow and is usually mistaken as a falling star or shooting star.
Mesosphere layer of the earth's atmosphere needs an equipment that can stay there for a longer period and can provide authentic information. This may come up with some more interesting facts and can help in the further research.