Four Spheres of Earth

Our planet Earth is a very complex place. Although it looks like one large structure, it is in fact made up of several unique properties, characteristics, and compositions. They all affect the processes of the earth differently.

All the elements and properties in the earth’s system are divided into four major subsystems. The scientific term for these subsystems is biophysical elements. There are four spheres of earth including hydrosphere, biosphere, lithosphere and atmosphere.


  • 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 non-salty. 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.
  • 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 10 feet into the ground or approximately 600 feet above it. There are different ecological communities divided in six main biomes which are desert, aquatic, forest, grassland, tundra and chaparral. It is the biggest one of all four spheres of earth.
  • Lithosphere: – The lithosphere can be defined as the outer boundary layer of solid earth and discontinuity within the mantle. It is a crustal 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 range from roughly 40 kilometer to 280 kilometer.
  • Atmosphere: – The atmosphere is a complex fluid system of gases and suspended particles. This fluid system forms a gaseous envelope around the earth with no defined boundaries. The total volume of atmosphere is made up of gases like nitrogen, argon, oxygen, carbon dioxide and water vapour etc.