What makes Earth suitable for life?
When we heard the term Earth, the first things came up in our mind that a terrestrial planet where all forms of life: from basic living micro-organisms to highly sophisticated and intelligent human beings exists. In this write-up, we discussed the factors that are responsible for the existing life on the Earth. There are many factors which make Earth suitable for life are discussed below:
Distance of the Earth from the Sun
The Earth and the Sun are equally important because without the Sun's heat and light, the Earth would be a lifeless ball of ice-coated rocks. It regulates the temperature of water bodies, weather patterns and provides energy to the growth of plants. The distance of the Earth from the Sun makes it a perfect reason for the life because it receives the perfect amount of heat and light to allow life to be created and to support it.
Importance of light on the Earth
Earth is the only planet that uses the Sun’s light as useful as a source of energy. That energy is used to convert elements, by living things, into a useable form. A plant uses the energy provided by the sun to drive photosynthesis and provide food to grow. As a by-product, oxygen is released which we then use as an energy source of our own.
Importance of Earth’s Atmosphere
It is the layers of gases surrounding the earth that consists of exosphere, thermosphere, mesosphere, stratosphere and troposphere. The air content and favourable atmospheric pressure also supported life of most creatures. The air content of carbon dioxide on the Earth is less than that of planets like Venus and Mars. Hence, the less air content of carbon dioxide helps to moderate the Earth's temperature and is absorbed by plants during photosynthesis to produce oxygen.
Importance of Ozone Layer
It is the Ozone layer that is a part of Earth's atmosphere situated in an area known as the stratosphere, which makes protecting life on Earth from its potentially harmful effects of shorter wavelength and highly hazardous ultraviolet radiation (UVR) from the sun.
As we know that the Sun is the primary source of energy to the Earth, but the only planet that optimises the amount of heat and light which is necessary for the life process. The Sun emits enormous heat and light that also consists of ultraviolet radiation, or UV rays which we can't see or feel. Only about 1% of the ultraviolet radiation that the Sun sends to Earth actually reaches the surface. Small amounts of exposure to UV rays are beneficial.They cause the body to produce Vitamin D, which has several health benefits. But you know what, if get more that amount of what we getting will not give more Vitamin D but causes serious issues on our skin and health.
Favourable Climatic Condition
The Earth has a suitable climate for the existence of all forms of life because of moderate amount of carbon dioxide, which is the driving factor for the survival of life forms. The temperature of planet Mercury ranges from 200°c below freezing to 375°c above. At 375°c, the water would only exist as a gas, and the planet would be completely dry. Venus has a surface temperature of 480°c, which would be much too hot for anybody to live in. Mars, although it can reach 25°c, is usually freezing and can be as cold as -140°c, a temperature which would freeze blood and water. Other planets are colder still.
Water is very important for life because it contains the oxygen needed for life and allows life-providing molecules to move around easily. It continually changes its form through the water cycle. The process by which water continually changes its form and circulates between oceans, atmosphere and land is known as the water cycle.
The major sources of fresh water are the rivers, ponds, springs and glaciers. The ocean bodies and the seas contain salty water. The water of the oceans is salt or saline as it contains a large amount of dissolved salts. Most of the salt is sodium chloride or the common table salt that we eat. The earth is covered by three-fourth of the water. 97.3% water is saline or salty in oceans and seas, 3% is fresh water that consists ice-cap, ground water, fresh water lakes, inland and salt lakes.
Force of attraction (Earth's gravitational pull)
Think for a second why water flows from up to downwards- why don’t float in the air; what hold our atmosphere; why we walk on the surface not floating in the air. The Sun's gravitational pull keeps our planet orbiting the Sun and the Earth firmly hold everything from topography to all forms of life through its gravitational pull. The force of gravity doesn’t just keep us anchored to the ground, but also affects our biological system.
Hence, we can say, Earth is the only planet which hosts liquid water on its surface, allowing for a direct transfer of energy from the sun in order for photosynthetic life forms to evolve. It has unique surface which neither too hot nor too cold for the occurrence of complex biochemical process.