Earth

The Earth is an incredibly diverse and beautiful planet, the only one known to be capable of sustaining life. It's the third planet from the Sun, orbiting at a distance of 93 million miles (150 million km). It's just slightly larger than nearby Venus and is the fifth largest in the solar system. Its atmosphere is 78% nitrogen, 21% oxygen and 1% other ingredients, making it the perfect balance of gases to breathe and live on.

The surface of the earth is made up of land and water. Land covers about 29 per cent and water covers about 71 per cent of the earth's surface. The large landmasses are called continents, while the large water bodies are called oceans.

There are seven continents on Earth: Asia, Europe, North America, South America, Africa, Oceania. There are four oceans on Earth: the Atlantic, Pacific, Indian, and Arctic. However, most countries now recognize the Southern (Antarctic) as the fifth ocean. There are 195 countries in the world today.

Earth has lush forests and rolling hills, mountain ranges and vast deserts. It is also home to a wide variety of animal and plant life, making it the better place for humans and other forms of life to exist. It's also the only planet that is known to have liquid water on its surface, making it a unique haven compared to other planets in our solar system.

The structure of the Earth can be divided into several layers based on their composition, physical properties and location.

Inside Earth

Earth's interior consists of four distinct layers: the inner core, outer core, mantle, and crust. The crust and the uppermost part of the mantle are joined to form a rigid structure called the lithosphere, which is divided into sections called tectonic plates. These move very slowly over time, changing the shapes of continents and oceans.

The structure of the Earth can be divided into several layers based on their composition, physical properties and location. Starting from the centre and moving outward, the layers are as follows:

Inner Core: The innermost layer of the Earth is the inner core, which is primarily composed of solid iron and nickel. It has an extremely high temperature and pressure due to the immense weight of the overlying layers.

Outer Core: Surrounding the inner core is the outer core, which is a layer of liquid iron and nickel. It is also very hot and under high pressure. The movement of this molten material generates the Earth's magnetic field through a process called convection.

Mantle: The mantle is the thickest layer of the Earth, located above the outer core. It is composed of solid rock, but it can flow like a thick, viscous fluid over long periods of time under high pressure and temperature.

Crust: The crust is the Earth's outermost layer, forming the Earth's solid surface. The crust primarily comprises lighter materials such as oxygen, silicon, aluminium and magnesium, along with other elements.

Atmosphere

The atmosphere is a gaseous envelope that surrounds the Earth. It is divided into several layers based on temperature changes with increasing altitude. Earth's atmosphere is a mixture of gases that are held in place by gravity. It has no clear upper edge and fades gradually into space.

Beyond the solid layers of the Earth, there are also the following atmospheric layers:

Exosphere: The exosphere is the outermost layer of the Earth's atmosphere. It extends from the top of the thermosphere to the edge of space. This layer contains very thin amounts of gases, primarily hydrogen and helium, and it gradually merges with the vacuum of space.

Thermosphere: The thermosphere is the layer above the mesosphere and below the exosphere. It is characterized by high temperatures caused by the absorption of high-energy solar radiation. The thermosphere is also where the auroras occur.

Mesosphere: The mesosphere is the layer above the stratosphere and below the thermosphere. It is characterized by a decrease in temperature with increasing altitude and is where meteors burn up upon entering the Earth's atmosphere.

Stratosphere: The stratosphere is the layer above the troposphere and below the mesosphere. It contains the ozone layer, which absorbs much of the Sun's harmful ultraviolet (UV) radiation. The stratosphere's temperature increases with altitude.

Troposphere: The troposphere is the lowest layer of the Earth's atmosphere. It is where weather phenomena occur and is characterized by a decrease in temperature with increasing altitude.

These layers collectively form the structure of the Earth, from its solid interior to its gaseous outer envelope.