Basic objective of this lecture is to present on Atmosphere: Surrounding Air of the Earth. Earth’s atmosphere can be divided into five main layers. Excluding the exosphere, Earth has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere. This is the layer that is closest to the surface of the earth. It’s elevation ranges from 0 to 10 km. This layer sits on top of the troposphere. It’s elevation ranges from 10 km to around 25 km. This layer contains the ozone layer, which protects us from harmful sunlight.