Earth

EARTH

•           Earth is different from all other planets in the solar system.

•           Earth is the only planet on which water can exist in liquid form.

•           Water is essential for life.

•           The Earth's vast oceans keep temperature stable which is important for life on our planet.

•           Water is also responsible for most of the erosion and weathering of the Earth's continents, a process unique in our solar system.

•           The Earth's atmosphere constitutes 78% nitrogen, 21% oxygen, with traces of other gases like argon, carbon dioxide and water.

•           The carbon dioxide in the Earth's atmosphere is very important.

•           Carbon dioxide helps to maintain the Earth's temperature.

•           There is a blanket of air around the Earth, called the atmosphere, which protects it from the harmful ultraviolet rays of the sun.

•           The Earth is like a big ball covered by water and rocks.

•           The surface of the Earth has various features such as oceans, rivers, mountains, and valleys.

Structure of Our Earth:

Internal Structure of the Earth:

•           According to the scientists, the Earth is not a uniform solid sphere.

•           It consists of different layers.

•           These layers are called the crust, mantle, and core.

•           The core is further divided into the outer and the inner core.

Figure 2: Distinct layers of the internal structure of the Earth

The Earth’s Crust:

•           The first layer consists of about 10 miles of rock and loose materials.

•           What we see as soil and mountains is the only surface of the Earth; which is also called as the crust.

Figure 3: The Earth’s crust

•           The crust ranges from 5 to 70 km in depth.

•           It is made up of rocks.

The Earth’s Mantle:

•           Travelling beyond the Earth’s crust; the Earth’s mantle can be seen.

•           The mantle extends to a depth of approximately 1800 miles and is made up of a thick solid rocky substance.

Figure 4: The Earth’s mantle

•           It is about 2900 km thick.

•           It is largely composed of substances rich in iron and magnesium.

The Earth’s Core:

•           There are two cores of Earth:

The Earth’s Outer Core:

•           Travelling still deeper within the Earth; the outer core extends to a depth of around 3000 miles beneath the surface.

•           The outer core is made up of superheated lava.

Figure 5: The Earth’s Outer Core

•           The outer core is about 2300 km thick.

•           It contains iron and nickel in molten state.

The Earth’s Inner Core:

•           The inner core extends upto 900 miles inward towards the centre of the Earth.

•           The inner core is a solid ball mostly made up of iron.

Figure 6: The Earth’s Inner Core

•             It is 1200 km thick.