The solar system comprises of the sun, nine significant planets, other unknown planets and other forms of planetary bodies like the satellites, ice material, rock materials etc. the primary concern for this article is to examine the earth as a planet, what gives it unique ability to sustain life because it is generally known that earth is the only planet that got life in it, though a whole lot of research is carried out to find an alternative life-supporting planet none is still close to Earth in terms of life support.
Earth is the third planet closest to the sun with a distance of about 149 million kilometres. With that much distance sun still has a powerful effect on some portion of the earth surface like the equator which represents the centre of the earth. The earth is the fifth most massive planet in the solar system with a diameter of 12,762 kilometres. Earth is more prominent than mercury, Venus, Mars and Pluto.
There are unique features that enable earth supports life these features include:
- Presence of the hydrosphere
- Presence of the atmosphere
- The existence of plate tectonics
PRESENCE OF THE HYDROSPHERE
The hydrosphere is the liquid portion of the earth surface, it includes water on the earth surface example the ocean which accounts for 97% of water in the hydrosphere, Lakes, Streams Rivers and water got from the earth crust the hydrosphere also extends to water in the atmosphere which are in the form of rain, frost, ice and snow.
70% of the earth surface is made up of water (hydrosphere) this amount is just right to sustain life and remain a in liquid form unlike other planets where the water either fries up due to high surface temperature, for example, water in mercury or Venus while for planet farther away from the sun the water freezes as in the case of Neptune.
As the old saying goes water is life without it; indeed there won’t be any form of life on the planet.
PRESENCE OF TECTONICS PLATES
Earth is the only planet in the Solar System with plate tectonics. Basically, the outer crust of the Earth is broken up into smaller regions called the tectonic plates which float on top of the magma interior of the Earth and can move against one another. Plate tectonics and water are inextricably linked.
Not only do plate tectonics enable liquid water to exist by way of regulating the temperature, but many scientists have argued water allows plate tectonics to happen. Water is what lubricates plate tectonics, which is what leads to the extreme difference between continents and seafloors, a significant amount of earthquakes and volcanoes, fresh mountain-building these activities are essential for carbon cycle this cycle is carried out in long periods of time, all carbons released from operations on the earth surface are carried back into the interior of the Earth and recycled. This pulls carbon out of the atmosphere, which makes sure we don’t suffer any form of the greenhouse effect. Without the action of plate tectonics, there would be no way to recycle this carbon, and the Earth would have become overheated, making the surface inhabitable by living things.
PRESENCE OF THE ATMOSPHERE
The atmosphere is a gaseous sphere, it is the layer of gasses which surrounds the earth it kind of envelope the planet with gases like Nitrogen, Oxygen, and Carbon dioxide also on the rare gases like argon, and these gases have their different uses on the earth. Oxygen and Carbon dioxide are needed for respiration, Nitrogen for plant growth, rare gases for some reactions required for the planet and other uses too.
The atmosphere blocks out harmful rays from the sun. Ozone layer which lies in the stratosphere 11-50 kilometres from the Earth’s surface, blocks out many dangerous forms of radiation. Without the ozone layer, ultraviolet rays would destroy most life on Earth. Gases in the atmosphere also hold in heat, this heat helps to maintain the temperature of the earth and ensuring that water on earth surface doesn’t freeze up.
Water on the planet is also located in the atmosphere. The water is released into the atmosphere through evaporation (respiration in animals, transpiration in plants) in the form of water vapour which rises to the atmosphere and forms clouds through a process called condensation. This process is necessary for replenishing water to the earth surface in the form of rain, ice and snow this process is called the hydrological cycle.
Other reasons for these uniqueness includes the size of earth compared to other planets as Jupiter helps to cover earth from planetary dust which is in the form of giant size rock materials that can collide with earth and cause unbalanced of the planet and also presence of moon helps to stabilize earth rotation on its axis which is slowly done and living things on the planet don’t even feel it.