Inside our Earth

Inside our Earth

Our home planet Earth is the fifth-largest planet in the solar system and the third planet from the Sun. It is the only planet in the universe confirmed to harbour life. About 71% of Earth’s surface is covered with water, and the remaining 30% is the solid crust, consisting of islands and continents. Earth is larger than the other three rocky planets-Mercury, Venus and Mars, but smaller than the gas planets-Jupiter, Uranus, Neptune and Saturn. The diameter of Earth is roughly around 8,000 miles (13,000 kilometres). And the true shape of Earth is “oblate spheroid”. It takes our home planet Earth 23.934 hours to complete a rotation around its imaginary line called an axis and 365.26 days to complete an orbit around the Sun.

Interior of the Earth

The interior of the Earth is divided into three main layers-Crust, Mantle, and Core.

Crust

• The most significant region of the interior of the Earth and the outermost layer of the Earth’s surface
• It floats on top of the soft plastic-like mantle below
• Earth’s crust is made of solid rocks, oxygen and minerals like Silica and Alumina
• It is the surface of the planet on which we live
• It provides the environment, natural resources, and geological hazards that affect humanity
• There are three crustal divisions- continental, oceanic, and transitional- of which continental and oceanic crust dominate
• Continental crust comprises 77% of the crust by volume and just 40% by area and ranges from 30 to 45 km thick. Oceanic crust comprises 17% of the crust volume and 54% by area and ranges from 5 to 10 km. Transitional crust are Islands, continental margins and island arcs that comprises 15 to 30 km thickness

Mantle

• It is predominantly a solid layer that lies beneath the crust
• Even though the mantle is mostly solid, it behaves like a viscous liquid as the temperatures are close to the melting point in this layer
• Mantle is about 1802 miles (2900 kilometres) thick and comprises up to 84% of Earth by volume
• It is composed primarily of oxygen (44.8%), magnesium (22.8%), and silicon (21.5%), which are further bound together in the form of silicate rocky material
• Olivine, garnet, pyroxenes, and spinel are some rocks that you might find inside the mantle
• It is divided into three sections: the upper mantle, the transition zone, and the lower mantle

Core

• It is the innermost layer and the hottest part of our planet Earth
• It lies beneath the brittle crust and the mostly-solid mantle
• It is about 1802 miles (2900 kilometres) below Earth’s surface, and has a radius of around 2165 miles (3485 kilometres)
• The core is entirely made of metal- specifically, iron and nickel, unlike the mineral-rich crust and mantle
• The shorthand for the core’s iron-nickel alloys is NiFe
• Sulphur is another important key element. About 90% of the sulphur on Earth is found in the core of Earth

Rocks and Minerals

Rocks and minerals play an important and valuable role on Earth. They are the building blocks of our planet Earth. Rocks on the earth are composed of nearly hundreds of minerals yet only 20 to 30 minerals are found common in the majority of rocks. Minerals are made up of combinations of about a hundred different elements, but only 8 elements form over 98% of the crust.

Rocks are classified into three types:

• Igneous or Magmatic rocks: These types of rocks are formed when the magma (molten rock) cools and solidifies. They generally have many compositions and can also look different, depending on their cooling conditions. Extrusive and intrusive are two main types of igneous rocks. Extrusive igneous rocks are formed from the lava on the surface of the earth. On the other hand, intrusive igneous rocks are formed from magma that cools and crystallizes within the Earth’s crust
• Metamorphic rocks: These types of rocks are formed when the pre-existing rock is heated, pressured, chemically processed due to the intrusion of hot magma from the Earth’s interior. During this stage, rock usually remains in the solid form, but gradually recrystallizes into a coarse texture or mineral composition. Marble, slate, quartzite, and gneiss are some examples of metamorphic rocks
• Sedimentary rocks: These rocks are formed from the deposits of organic particles and minerals that accumulate on or near the Earth’s surface, in contrast to igneous and metamorphic rocks. They have distinctive layering and bedding. There are four main types of sedimentary rocks-Clastic, Chemical, Biochemical and Organic

Rock cycle

The rock cycle is a concept used to explain the transition of the three main types of rocks in Earth’s crust- Igneous, metamorphic and sedimentary. The concept of the rock cycle was first developed by James Hutton, often known as the “Father of Geology”. It is driven by Earth’s internal heat engine, which keeps the mantle moving and leads to slow but significant changes within the Earth’s crust, and the hydrological cycle, which is the movement of ice, water and air on the Earth’s surface. The transformation processes in the rock cycle take over millions of years. The key processes that transform one rock type into another are erosion and sedimentation, crystallization, and metamorphism.

Conclusion

Earth is the only planet where life is possible. It is a dynamic planet and its interior and exterior goes through constant changes. Earth is composed of three layers : The crust, The Mantle and The Core. The crust is the topmost layer over the Earth’s surface and is around 35 km on the mainland masses and just 5 km on the sea depths and majorly consists of silica and Alumina. The Mantle  stretches out up to a  profundity of 2900 km underneath the outside. The core is the deepest layer with a span of around  3500 km and comprises Nickel and Iron. Earth’s focal centre has exceptionally high temperature and tension. Any average mass of mineral matter that creates the earth’s covering is known as a stone. Rocks can be of various shading, size and surface. The three main types of rocks are: Igneous rocks, sedimentary rock and metamorphic rock. These rocks continuously change their form and go through a cycle known as the Rock cycle.