Held by the Earth’s gravitational pull, the atmosphere is a layer of multiple gases that envelops the Earth. Like land and water, the atmosphere is also an important and essential part of the Earth. It is not as dense as land or water, but it is mobile and exerts pressure. It acts as an invisible shield to block the blasts of heat and radiation emanating from the Sun. It warms the planet by day and cools it at night. The blanket of gases of the atmosphere contains the air, one of the most essential factors for life.
Earth is the only planet in the solar system which is equipped with an atmosphere that can sustain life. Held by the gravitational pull, it is densest near the surface of the Earth and decreases rapidly upward. It is composed of various gases, the ratio of which varies somewhat with height. The bulk of the atmosphere (about 78%) is made up of Nitrogen, which dilutes the Oxygen, slows down the process of oxidation and prevents rapid burning at the Earth’s surface.
It is very much required for the growth of plant life. About 21% of the atmosphere consists of Oxygen, which is necessary for breathing and burning. There is also a small amount of Carbon dioxide in the atmosphere, which plants use to release Oxygen by photosynthesis. This gas acts as a blanket and prevents the escape of heat into the outer space. Apart from that, the atmosphere also contains traces of Argon, Ammonia, Neon, Helium, water vapor and dust particles.
Layers of Atmosphere
The atmosphere of Earth consists of a series of layer. Starting upward from the surface, these layers are called the Troposphere, Stratosphere, Mesosphere, Thermosphere and Exosphere. Gradually and steadily, the Exosphere fades away into the vast interplanetary realm.