In this vast universe the existence of Earth is like a minute dot in expanse of stars, galaxies and void space that constitutes it.
Earth or the “blue planet” as it is also referred to, is the third closest to the Sun after Mercury and Venus. It is the densest of all planets and fifth biggest in size in our solar system. Earth is the only planet which sustains life and this unique capability is due to the presence of water bodies.
Research and universe science has dated the formation to earth to nearly 4.5 billion years back. Scientists are of the view that earth was a hot ball of fluid matter and gases revolving around the sun. This heat was gradually radiated into the space and as a result the outer crust of it cooled and solidified. It is believed that it took another1 billion years for life to appear on the surface of planet earth. During this period earth’s biosphere caused significant changes in the atmospheric conditions, allowing organisms and other physical conditions to evolve. Ozone layer was also formed and this enabled harmful rays of the sun from permeating into earth‘s atmosphere.
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Earth’s magnetic field also assisted in formation of ocean bodies which could flow freely on earth‘s surface. All these physical characteristics of earth and its orbit of rotation and revolution allowed life to persist. Predictions suggest that Earth can continue to support life for another 500 million to 2.3 billion years.
Earth has a mild climate and water is present in all three forms namely: solid, liquid, gas. The shape of earth which appears like a flat structure is almost spherical. In fact, it is flat at the poles and has a little bulge at the equator. The time taken by earth to complete one revolution around the sun is 365 days which forms a year.
Rotation of earth around its own axis is the phenomenon that is responsible for the formation of day and night. Earth completes 1 rotation in 24 hrs which make up a day. Earth has one moon or natural satellite which revolves around it with a diameter of 7921 miles or 12,756 kilometers.
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The Earth has four layers: Crust, Mantle, Outer Core and Inner Core. The Crust or the Lithosphere is the outermost layer which was formed from the solidification process during the formation of earth .Slowly, it got covered with soil. Sand is made up of clay, humus, sand etc.
Crust varies in depth from one place to another; average depth being close to 50 km. Soil is the loose material that supports vegetation. Below the innermost layer is the magma which is constantly spinning inside the earth. Volcanic eruptions result in places where the magma stops revolving and excess of pressure inside erupts out. The magma goes up and comes out as hot lava, stones and ashes. Any displacement of layers within the crust causes destructive phenomenon like earthquakes and land slides.
Various types of Soils like Alluvial Soils, Red Soils, Laterite Soils, Black Soils are present in the different parts of earth.
Earth’s surface can be divided into 5 spheres:
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1. Lithosphere:
Lithosphere or Earth’s Crust comprises of solid rocks and soil. It is relatively thin and forms various kinds of soil.
2. Hydrosphere:
All water bodies like oceans, rivers, seas, ponds, ice-sheets etc. and even water in the atmosphere makes up the hydrosphere.
3. Atmosphere:
This is the layer of air that envelopes the earth.
4. Biosphere:
The existence of life forms is supported in this portion of the earth.
5. Magnetosphere:
This is the space around the earth where the magnetic field of the earth acts.
Planet Earth with a radius of 6400 km may seem like a tiny speck in this vast outstretched universe but it stands unique among other planets as it has the atmosphere, abundant water and surface temperature to support life. Evidences prove that actions of water and air have resulted in erosion of the earth’s suit but is less significant compared to the meteoritic depressions on other planets.
Earth is a home to millions of species including human beings. Earth is a storehouse of minerals, ores, natural elements and its crust can grow plants, shrubs, trees and vegetables which are essential to the survival of human population. Human population that inhabits this planet has expanded and occupied almost every part of this planet where life is supported.
Antarctica is one planet which is covered with ice throughout the year and hence survival conditions like temperature, plants and vegetation cannot exist. Still many animals like polar bears, penguins, kiwis are adapted to this kind of climate and live there.