Skip to main content

Atmosphere: Meaning, Definition and Characteristics

Image
By

Introduction

Of all the planets known so far, our Earth is the only planet where life is possible and this is because life-sustaining water and oxygen exist here. air which is a mixture of many gases; has surrounded the earth from all sides. This circle of air is called the atmosphere. Atmosphere is an integral part of our earth which is attached to it due to the gravity of the earth.

It is very important in blocking harmful ultraviolet rays and maintaining a temperature conducive to life. Apart from gases, water vapor and dust particles are also found in the atmosphere. Weather events are possible only because of the atmosphere. Let us now know about the meaning and definition, characteristics and composition of the atmosphere.


Meaning of Atmosphere:

Atmosphere is a thin layer of colourless, odourless, tasteless gases and dust particles and water vapour, which surrounds the earth and which forms a protective boundary between the space and the biosphere. Scientists have not been able to estimate the height of the atmosphere accurately till date.

Some scientists believe its upper limit to be 480 km, some 1000 km and some 30000 km. It remains with the Earth due to its gravity and it revolves around the Sun along with the Earth's rotation.

Definitions of Atmosphere:

According to Monkhouse, “The atmosphere is a thin layer of gas held together by the earth by gravity.”

According to Critchfield, “Atmosphere is such a deep cover of gases and suspended solid and liquid particles that it completely surrounds the earth.”

According to Finch and Trivartha, “A cover of gases is wrapped around the earth as an integral part of the earth, which is called the atmosphere.

Characteristics or features of the atmosphere:

  1. The air of the atmosphere is a colourless, odorless and tasteless substance. Along with this it is also dynamic. We feel wind only when horizontal flow is generated in it.
  2. Although air is not as dense as water, yet it has its own weight which exerts pressure on the surface, which is called air pressure. This air pressure above sea level is 1034 grams per square centimeter.
  3. The density of air decreases with increase in height from the ground. The air near the ground becomes heavy and becomes lighter as it goes upwards. This happens because of the gravity of the earth. Due to gravity, heavy substances or gases get collected near the surface and lighter gases remain above.
  4. About half of the total weight of the atmosphere is found up to a height of 5.5 km and 99% of it is found up to a height of 30 km.
  5. Due to the atmosphere, the meteor bodies coming from space towards the earth are destroyed before reaching the ground.
  6. The atmosphere also controls the surface temperature. Due to the atmosphere, the surface temperature does not become very high during the day and very low during the night.
  7. Earth's atmosphere itself is the originator of various types of weather events, such as: - formation of clouds, movement of wind, storm etc.

If there was no atmosphere, life would not have been visible on this planet like the Moon.

Comments

Post a Comment

Popular posts from this blog

The Geology and Formation of the Shiwalik Range: A Result of Tectonic Processes in the Himalayas.

By
The Shiwalik Range , also known as the Shivalik Hills or the Outer Himalayas , is a mountain range in northern India and southern Nepal. It is the southernmost and outermost range of the Himalayas. The formation of the Shiwalik Range is closely linked to the geological processes that shaped the Himalayan Mountain system. The Himalayas, including the Shiwalik Range, have been formed through the collision of the Indian and Eurasian tectonic plates over millions of years. Around 50 million years ago, the Indian plate, which was originally located south of the equator, began moving northward towards the Eurasian plate. As the Indian plate approached the Eurasian plate, it started to subduct beneath it. Subduction is the process where one tectonic plate sinks beneath another due to the difference in density. The subduction of the Indian plate led to the upliftment of the overlying sedimentary and crustal rocks, creating the Himalayas. The Shiwalik Range specifically formed during the ...
Post a Comment
Read more

Why is Earth called a Dynamic Planet

By
Earth is often referred to as a "dynamic planet" because it is constantly undergoing various dynamic processes and changes. These processes occur on different spatial and temporal scales, and they shape the planet's surface, atmosphere, and even its interior. Here are some reasons why Earth is called a dynamic planet: 01. Plate Tectonics : Earth's lithosphere, the rigid outer layer composed of tectonic plates, is in constant motion. This movement, known as plate tectonics, leads to the creation of mountains, the opening and closing of ocean basins, and the formation of earthquakes and volcanoes. It is a dynamic process that continuously reshapes the Earth's surface. 02. Earthquakes and Volcanoes : Earth is seismically active, with earthquakes occurring regularly around the world. These seismic activities are a result of the movement and interaction of tectonic plates. Volcanoes are also a consequence of plate tectonics, where molten rock (magma) rises to the surf...
Post a Comment
Read more

Heat Budget of Earth

By
Earth and its atmosphere are continuously receiving solar energy. Most of the solar energy reaches the surface of the earth in the form of short waves . Earth absorbs it and converts it into heat. Due to its special temperature, the earth sends the heat absorbed by terrestrial radiation back to the space through long waves . Earth absorbs black body that means each and everybody whereas atmosphere is very selective, and it absorbs 85% of long waves and it is transparent for short waves, that transparency is known as atmospheric window . In this way the earth does not store solar energy but sends the same amount of energy back to the space through terrestrial radiation. This exchange of energy is made possible by highly complex processes of radiation. This is the reason why the annual average temperature of the earth's surface remains constant. There is no significant change in it. Let the temperature received at the upper surface of the atmosphere be 100 units . Out of this, only ...
Post a Comment
Read more