Know Your Home: The Earth

Know Your Home: The Earth

(By Suhana Ahmed ) 

   

Image By:- Darshika Singh

What is a Planet?

A planet is a celestial body that is in orbit, revolving around the Sun. It has sufficient mass for the self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium shape. It also has cleared itself of the neighbourhood around its own orbit. 

Solar System 

Google defines the solar system as the collection of eight planets and their moons in orbit around the sun, together with smaller bodies in the form of asteroids, meteoroids, and comets.

The planets of the Solar System can be divided into categories based on their composition which also depends upon their distance from the sun

Terrestrial Planets include Mercury, Venus, Mars and Earth 

Gas giants include Jupiter and Saturn 

Ice giants include Uranus and Neptune

 

Our Home: Earth

Earth, our home, is the 5th largest planet in the solar system and the third nearest planet to the sun. It is the only planet known to have an atmosphere containing free oxygen, oceans of water on its surface and, of course, life.

Earth’s Orbit

It orbits the sun, on an imaginary line called an axis that runs from the North Pole to the South Pole. 

It takes 23.934 hours to complete a rotation on its axis and 365.26 days to complete an orbit around the sun.

Earth's orbit is not a perfect circle, but rather an oval-shaped ellipse

Internal Structure 

• The Core:

The inner core of the earth is solid and is composed of minerals like iron and nickel. It is approximately 1,221 km thick and has a density of 12.8g/cm3 at the top of the section and 13.1g/cm3 at its deepest point.

The outer core is composed of components such as  liquid iron and nickel. It is approximately 2,259 km thick. It has a density of 9.9g/cm3 at the top and 12.2g/cm3 at the bottom where it changes into the inner core.

• The Mantle :

The mantle is the thickest layer, being approximately 2,800 kilometer thick. It lies between the core and the crust. It is a solid layer but acts like a viscous liquid due to the temperatures being close to the melting point of key minerals in this layer.

All of this mantle rock is composed of a variety of oxides. Their atomic elements include oxygen, silicon and magnesium.

• The Crust :

This is the thinnest layer and forms the outer shell on which life exists. It varies in thickness from just 1 kilometer in some places to more than 80 kilometres in others.

Earth’s Atmosphere 

Earth is composed of  roughly 78% of  nitrogen and 21% of oxygen, with trace amounts of components such as water, argon, carbon dioxide and other gases. Nowhere else in the solar system is there an atmosphere loaded with free oxygen, which is vital to one of the other unique features of Earth: life, at least not as of known to the date.

Earth’s Natural Satellite

Earth's natural satellite, or as called, the moon is 2,159 miles (3,474 km) wide, which is about one-fourth the size of Earth's diameter. Our planet has one natural satellite, while Mercury and Venus have none and the rest of  planets in our solar system have two or more.

Chemical Composition of Earth

Oxygen is the most abundant element in rocks in Earth's crust, composing roughly 47% of the weight of all rocks. The second most abundant element is silicon at 27% , followed by aluminum at 8% ; iron at 5% ; calcium at 4% ; and sodium, potassium and magnesium at about 2% each.These are some of the major components comprising the earth.

Earth's core consists mostly of iron and nickel and potentially smaller amounts of lighter elements, such as sulfur and oxygen. The mantle is made of iron and magnesium-rich silicate rocks.

The Big Bang Theory

The Big Bang theory is basically a cosmological model of the universe since the beginning and throughout its evolution. Science claims that the earth is formed as a result of the big bang.

When the earth was a newborn, it was said to have a vigorously high temperature and a very high density, and the basic components supporting life were not in existence. It took a long time for the earth to cool down and the components such as oxygen, water and other necessary materials to form.

The hollows were filled with water, forming water bodies and the rest of the area remained the land. The first form of life was single celled, autotrophic and aquatic. The process went on and multicellular organisms started to evolve, which later on turned into amphibians (the organisms which can live both on land and water) and then slowly terrestrial and aerial organisms were born. The evolution continued and heterotrophic and parasitic organisms were evolved too.

As the time went on, the formation of the land changed. The biodiversity, the climatic conditions, the soil states changed and complex organisms were started to create. Every organism began with the simplest form millions of years ago and today has turned into what we can see.

This earth is our home and we need to protect it. The earth has come a long way and there is a lot to learn. This place has been a home for billions of years and it is only our responsibility to prevent any harm reaching it.

Disclaimer:-

The opinions expressed in this article are the personal opinions of the author. The facts and opinions appearing in the article do not reflect the views of Light de Literacy and LDL does not assume any responsibility or liability for the same.