What is atmosphere?? How many layers are of atmosphere???
Answers
Answer:
An atmosphere is a layer of gas or layers of gases that envelope a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low.The atmosphere is comprised of layers based on temperature. These layers are the troposphere, stratosphere, mesosphere, thermosphere and exosphere
Answer:
Atmosphere is a thin blanket of air which covers our planet earth.
Explanation:
Layers of atmosphere::
a). Troposphere ::
The troposphere is the lowest layer in the atmosphere. It extends upward to about 10kms above sea level starting from ground level. The lowest part of the troposphere is called the boundary layer and the topmost layer is called the tropopause. The troposphere contains 75% of all air in the atmosphere. Most clouds appear in this layer because 99% of the water vapour in the atmosphere is found here. Temperature and air pressure drop as you go higher in the troposphere. When a parcel of air moves upwards it expands. When air expands it cools. Due to this reason, the base of the troposphere is warmer than its base because the air in the surface of the Earth absorbs the sun’s energy, gets heated up and moves upward as a result of which it cools down.
b). Stratosphere::
Above the troposphere lies the stratosphere which extends from the top of the troposphere to about 50 km (31 miles) above the ground. The ozone layer lies within the stratosphere. Ozone molecules in this layer absorb high-energy ultraviolet (UV) light from the Sun and convert it into heat. Because of this, unlike the troposphere, the stratosphere gets warmer the higher you go!
c). Mesosphere ::
Above the stratosphere is the mesosphere and it extends to a height of about 85 km (53 miles) from the ground. Here, the temperature grows colder as you rise up through the mesosphere. The coldest parts of our atmosphere are located in this layer and can reach –90°C.
d). Ionosphere::
The ionosphere isn’t a distinct layer unlike other layers in the atmosphere. The ionosphere is a series of regions in parts of the mesosphere and thermosphere where high-energy radiation from the Sun has knocked electrons loose from their parent atoms and molecules
e). Thermosphere::
Thermosphere lies above the mesosphere and this is a region where the temperature increases as you go higher up. The temperature increase is caused due to the absorption of energetic ultraviolet and X-Ray radiation from the sun. However, the air in this layer is so thin that it would feel freezing cold to us! Satellites orbit Earth within the thermosphere. Temperatures in the upper thermosphere can range from about 500° C to 2,000° C or higher. The aurora, the Northern Lights and Southern Lights, occur in the thermosphere.
f). Exosphere::
Exosphere is the final frontier of the Earth’s gaseous envelope. The air in the exosphere is constantly but gradually leaking out of the Earth’s atmosphere into outer space. There is no clear cut upper boundary where the exosphere finally fades away into space.
g). Magnetosphere::
It is the last or most extreme layer of atmosphere where temperature doesn't increases nor decreases.
Region Altitude Range (km) Temperature Range(0oC)
Troposphere 0-11 15 to -56 Weather occurs here
Stratosphere 11-50 -56 to -2 The ozone layer is present here
Mesosphere 50-85 -2 to -92 Meteors burn in this layer
Thermosphere 85-800 -92 to 1200 Aurora’s occur here