Why is earth called the blue planet? Why is Earth the only planet where life exists? The answer to these important questions is one Water!
Images of the Earth captured from space, depict a beautiful blue planet, covered in oceans and seas that make up almost ¾ of the surface of the earth. It is the only planet in the solar system where humans can live thanks to the presence of water. No other planet in our solar system has other life forms, oceans, or oxygen to breathe comfortably. Earth is referred to as the blue planet because of the immense water content. 71% of the surface of earth is water.
Earth Is A Water Planet
Though 71% of the earth is covered with water, it is not drinkable, as it is either in a frozen form or is salty. Earth is the only planet orbiting the Sun, that is called a water planet, water is present on it surface in the form of gas, ice and liquid. Fresh water covers rivers and lakes by less than 1%. Thick sheets of ice cover the Polar Regions while glaciers are spread across the high mountains. Half of the surface of the earth is covered by masks of clouds, while volcanic eruptions continuously extract gases and water from the Earth’s interior surface. The presence of so much liquid on the planet makes it quite unique. Due to the presence of so much water, Earth is often referred to as the Blue Planet.
Earth is often referred to as the blue planet, due to the presence of huge water across its surface. Water usually moves rapidly throughout the surface in cycles, which are normally powered by the solar energy. Hydrologic cycle is the process by which water evaporates from the surface of the oceans which is warmed by energy received from the sun. This vapor soon condenses and falls over the oceans in the form of rain. The vapor which does not fall as rains travels a bit forward and falls on the land. It falls over land as rain and again in the cyclic order returns to the ocean through river discharges or ground water discharges.
Ocean water present near the poles cools down and they tend to become denser and denser and start sinking just below the surface. They flow slowly towards the equator and they soon return to the surface to get warmed up and so that the cycle starts again. This subsurface take several years for each cycle and these are an important part of the heating system of our Earth. This is the process by which cool waters return to the tropics, so that they get warmed up again and return in the form of surface currents and flow back to the polar oceans. The presence of water makes Earth unique and habitable and this is why, Earth is often called the blue planet.