What is Earth


           What is Earth

In this article, we will learn what is Earth. We will see how our Earth is different from other planets. 

There are 8 planets in our solar system and each planet is different from the other. Our Earth is the only planet of the solar system in which life exists. We will learn all the interesting facts about Earth.

Our Earth is different from other planets in -  Shape, Diameter, Radius, Density, Volume, Mass, Temperature. 

We will try to get complete information about the Earth through this article.

So let’s start our topic: What is Earth?

Our Earth is one of the 8 planets of the solar system. Due to the excess of water, the Earth appears blue from space, So it is called a ‘Blue Planet’. 71% of Earth’s surface is covered by water and 29% is covered by land. The land area of the Earth is called the Lithosphere. And the water area of the Earth is called Hydrosphere.

The lithosphere is divided into 7 continents. These are Asia, Europe, Africa, North America, South America, Australia, and Antarctica.

The Hydrosphere is divided into 5 Ocean: Pacific Ocean, Indian Ocean, Atlantic Ocean, Arctic Ocean, Southern Ocean.

There is an excess of nitrogen and oxygen in the Earth's atmosphere. The atmosphere of the Earth is composed of 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases.

Earth is a planet on which water is found in all three states: Solid, Liquid, and Gas.

Earth is the third planet in the solar system in order of distance from the Sun. 

Earth is the fifth largest planet in the Solar System in size.

According to radiometric dating estimation, the age of Earth is estimated at 4.5 billion years.

Let’s know some interesting facts about the Earth.

Shape of Earth

Whenever we think about the Earth, the first question which comes to our mind is, what is the shape of the earth? For many years, humans kept thinking of the Earth as flat because if we stand on the Earth and see it from all around, then we will see it flat. 

Many astronomers later discovered that the shape of the Earth is round.

We cannot tell by standing on the Earth that the Earth is round because the size of the Earth is much larger than the human and due to this we do not feel that it is round and we see it flat.

But now man has gone into space, so the real shape of the Earth has been found out. The Earth is neither flat nor completely round, the actual shape of the Earth is elliptical/spherical. The shape of the Earth is called GEOID.

In the below image you can see the shape of Earth.

The Diameter of the Earth

The reason for the Earth being spherical is that the equatorial diameter of the Earth is 42 km more than the polar diameter of the Earth. The equatorial diameter of Earth is 12756 km (7926 miles) and the polar diameter of Earth is 12714 km (7899.86 miles). The mean diameter of the Earth is about 12742 km.

                                                                           diameter of Earth

The radius of the Earth

The distance from the center of the Earth to the surface of the Earth is called the radius of the Earth. The equatorial radius of the Earth is 6378 km (3,963 miles), but the polar radius of the Earth is 6357 km (3,950 miles). It means that the equatorial radius of theEarth is 21 km more than the polar radius of the Earth. 

The mean radius of the Earth is about 6,371 km (3,959 miles). 

                                                                                radius of Earth

Circumference of the Earth

The distance around the Earth is called the circumference of the Earth. The Equatorial circumference of the Earth is about 40,075.017 km (24,901.461 miles) and the Polar circumference of the Earth is about 40,007.863 km (24,859.734 miles).

Temperature of Earth

The average temperature of the Earth's surface is about 15 °C and the temperature of the center of the Earth (Core) is about 6000°C.

Earth's temperature is constantly increasing due to the effect of greenhouse gases.

Know about the temperature of the different layers of the Earth.

Distance of Earth from Sun

The Earth is about 150 million km (93 million miles) far from the Sun. The distance between Sun and Earth is called the Astronomical unit.

The Earth is closest to the Sun on 3 January. At that time, it is at a distance of 147.1 million km (91.4 million miles) from the Sun. It is called Perihelion.

And the Earth is farthest from the Sun on 4 July. At that time, it is at a distance of 152.1 million km (94.5 million miles) from the Sun. It is called Aphelion.

The line joining Perihelion and Aphelion passes through the center of the Sun. This is called the Apside line.

The light of the sun takes approximately 8 minutes 20 seconds (500 seconds) to reach the Earth.

                                                           Perihelion and Aphelion

The surface area of the Earth

The surface area of the Earth is approximately 510 million km^2 (197 million sq miles). 361.13 million km^2 (139.43 million sq miles) (70.8%) of the surface area is covered by water and the remaining 148.94 million km^2 (57.51 million sq miles) (29.2%) of the surface area is covered by the land.

About 97.5% of water is saline, the remaining 2.5% is freshwater, mostly freshwater, about 68.7%, present in the form of ice mountains and glaciers.

Mass of Earth

The currently estimated mass of Earth is 5.97237×10^24 kg

Volume of Earth

The volume of Earth is 1.083 x1012  km^3.

Escape Velocity of Earth

The escape velocity of Earth is 11.186 km/s. 

If an object is thrown at such a speed that it goes out of the Earth's gravitational field and does not come back. So the minimum velocity that an object needs to cross the Earth's gravitational field is called the escape velocity.

The density of the Earth

The density of Earth is 5.514 g/cm^3.

Rotation and Revolution of Earth

There are two types of motion of the Earth: Rotation and Revolution.

Rotation of Earth: When the Earth moves around its axis, it is called the Rotation of the Earth.

Earth rotates from west to east on its axis, which is called the daily movement of the Earth. The earth rotates on its axis in 23 hours 56 in 4.09 seconds.

It is tilted vertically 23.5 degrees on its axis.  Due to the rotational motion of the Earth, there are days and nights. The rotation of Earth is also called the daily motion of Earth.

Rotation speed of Earth: The rotation speed of Earth is about 1600 km/h (1000miles/h).

Revolution of Earth: When the Earth revolves around the Sun, it is called the Revolution of the Earth. The Earth revolves around the Sun on an elliptical path (Geoid), which is called Earth orbit.

The Earth completes a revolution around the Sun in 365 days 6 hours 48 minutes and 45.51 seconds. The seasons change because of the annual motion of the Earth.

Revolution speed of Earth:  The Revolution speed of Earth is about 29.78 km/s or 107,208 km/h ( 66,616 miles/h).

                                               Rotation and Revolution of Earth

Natural Satellite of Earth

Moon is the only natural satellite of the Earth. It is the fifth, largest natural satellite of the solar system. It is estimated that the Moon formed about 4.51 billion years ago.

The distance of the Moon from the Earth is about 384,400 km (238,900 miles).

The Moon takes 27.3 days to revolve around the Earth, while it also rotates around its axis in  27.3 days. So it is the reason that only 59% of the Moon’s surface is visible from the Earth.

Moon is the second-highest density satellite in the solar system after Jupiter's satellite.

Mean Diameter : 3,475 km

Radius: 1,737 km

Equatorial radius: 1738.1 km

Polar radius: 1736.0 km

Distance from Earth : 384,400 km

Gravitational force : 1.62 m/s²

Surface area: 3.793×107 km²

Volume: 2.1958×1010 km^3

Mass: 7.342×1022 kg

Density: 3.344 gm/cm^3

Escape velocity: 2.38 km/s

What is Earth made of?

The Earth is made of three different layers: Crust, mantle, and Core

The crust is the uppermost layer of the Earth. There are two types of Crust layers: Continental Crust and Oceanic Crust.

The mantle is the middle layer of the Earth. It is divided into two parts: Upper Mantle and Lower Mantle.

The core is the center layer of the Earth. It is also divided into two parts: Outer Core and Inner Core.

Read about the Layers of the Earth in detail.