The Spheres of the Earth
Our planet Earth is a very complex place. It is made up of several compositions. They all affect the processes of the earth differently.
All the elements in the earth’s system are divided into four major subsystems. There are four spheres of earth including hydrosphere, biosphere, geosphere and atmosphere.
THE GEOSPHERE (or LITHOSPHERE)
The lithosphere is konwn as the solid earth. It is a system composed of various layers which are core, mantle and outer crust. It is also known as geosphere. The actual thickness of this sphere varies considerably and can reach from 40 kilometer to 280 kilometer.
THE ATMOSPHERE
The atmosphere is a system of gases and suspended particles. This system forms a gaseous envelope around the earth with no defined boundaries (frontiers). The total volume of atmosphere is made up of gases like nitrogen, argon, oxygen, carbon dioxide and water vapour etc.
THE BIOSPHERE
The biosphere of earth includes all living things on planet Earth like animals, plants and microorganisms. Most of this life exists no deeper than about 3 meters into the ground or approximately 180 meters above it. There are six main biomes which are desert, aquatic, forest, grassland, tundra and chaparral. It is the biggest one of all four spheres of earth.
THE HYDROSPHERE
The hydrosphere contains all the solid, liquid and gaseous water of the planet. Approximately 97% of the earth’s water is salty and only a small portion (about 3%) is fresh water. The saltwater gets collected along the earth’s surface in deep valleys. This sphere ranges from 10 to 20 kilometers in thickness. It stretches all the way from the earth’s surface down numerous miles into the lithosphere and high above the crust into the atmosphere.
