Planet Earth

Planet Earth or the globe is one of the planets of the solar system, and the largest of the four rocky planets: Mercury, Venus, Mars, and Earth, and the densest in terms of density, and the third planet farthest from the sun, about 150 km away from it, and it is the only planet in which humans live because of Its internal structure is metallic and rocky. Planet Earth has formed about 4.5 billion years ago and has one moon, and water covers approximately 70% of its surface, and planet Earth is the only planet covered by water in its liquid form. 50 to -87 degrees Celsius.

Earth's composition

From the outside, the planet is divided chemically into a hard crust known as silicon, a very sticky crust known as the Earth's mantle, and a solid inner core, and the outer layer is weak and has a magnetic field and consists of an inner core.

• 34.6% iron.
•  29.5% of the oxygen.
•  15.2% silicon.
•  12.7% of magnesium.
• 2.4% nickel.
•  1.9% sulfur.
•  0.05% titanium.

 Dimensions of planet earth

The size of the planet is estimated at one million km³, its average density is estimated at 5.52 g/cm³, and its mass is estimated at six thousand million million million tons.

 Earth's structure

• The crust: It is the outer surface of the planet and is about 48 km thick, and the bottom of the seas and oceans, and its thickness is between 50-80 km, and its temperature is approximately 2000 degrees Celsius. Casing: consists of a very thick layer of molten iron; Because the temperature of the core reaches 6000 degrees.
• The inner core.
• Outer nucleus.

Earth's motion

• The movement of the planet around itself: the planet rotates around itself from west to east daily during twenty-four hours, and this movement results in the occurrence of night and day, and the deviation of moving objects on the surface of the earth; Ex: wind and water currents.
•  Movement of the Earth around the Sun: The Earth revolves around the Sun counterclockwise for 365 and a quarter days, and this movement results in the occurrence of the four seasons.

Geography of planet earth

• Planet Earth contains seven large landmasses, known as continents: Asia, Europe, Africa, South America, North America, Antarctica, and Oceania.
• Planet Earth contains five major bodies of water known as oceans: the Indian Ocean, the Pacific Ocean, the Atlantic Ocean, the Arctic Ocean, and the Southern Ocean.
• The planet Earth has the highest point above sea level known as Mount Everest and the lowest point known as the Mariana Trench.

Planet Earth

Planet Earth is the only planet among the solar system planets known to have life on it. It is ranked third in the solar system and is 150 million km from the sun. The planet needs 365.25 days to revolve around the sun because it travels in space at a speed of 108 thousand km/hour. [1] It should be noted that its diameter is 12,756 km, while it consists of iron and nickel, so it is a large magnetic field, surrounding the planet Earth with an atmosphere that protects it from harmful radiation from the sun and meteors, and this atmosphere consists mostly of nitrogen gases by 78% and oxygen by 21%.

Formation of planet earth

There are several hypotheses explaining how the planet was formed, but the most accepted among scientists is the theory that claims that the solar system was a huge cloud of dust and gases known as the solar nebula, with the passage of time gravity arose in the center of the cloud that led to the collapse of matter on itself, then began By rotating and forming the solar system, its center is the sun.

 With the rising of the sun, the remaining materials gathered with their collision and bonded together, the denser material agglomerated and sank in the center to form the rocky core of the Earth, while the lighter material formed the Earth's crust, and scientists assume that the Earth's magnetic field was formed at this time.

 life on planet earth

What distinguishes the planet Earth is its suitability for life, as it is the only inhabited planet according to human discovery, and it is the planet that contains the human race and all that we know of plants and animals and is characterized by a moderate and acceptable climate for the continuation of life, and it is one of the few planets that contain water.

 As scientists increasingly discovered the beginning of life on Earth, it became clear to them that life appeared earlier than they previously knew, as it was known that it appeared 3.8 billion years ago, but with recent discoveries made by the University of California, it was found that life existed on Earth 4.1 billion years ago.

 Earth's planet

 The Earth’s surface consists of several inner layers and an outer layer. The core is the inner layer located in the center of the earth and is composed mainly of iron and nickel. It should be noted that the core is divided into two layers: the inner core and the outer core. The outer core is followed by the mantle layer, which is A sticky layer of molten rock with a thickness of about 2,896.81 km, followed by the Earth's outer layer called the crust, which includes two types: an oceanic crust that forms the seafloor with a thickness of about 5 km, and a continental crust located under the land, about 30 km thick.

 Gravity

Planet Earth is characterized by containing the Earth's gravity suitable for human life, and gravity has occupied many philosophers and scientists for centuries, including Galileo Galilei, who is one of the first scientists to research the way things move, and the situation continued as it is, until Isaac Newton reached He led to the discovery of the mechanism of action of gravity, as well as the laws explaining it in 1687 AD.

Earth's outer surface

The surface of the planet Earth is considered to be very diverse between mountains, rivers, oceans, continents, plants, and other great diversity in each region. Planet Earth is the only known planet that has both land and water on its surface; Where the proportion of water on it is 71%, and land makes up 29%. The pieces of land on the planet are called continents, while the waters are called oceans.

 Asia is the largest continent with 30% of the Earth's land area, followed by Africa, which occupies 23% of the total land area. As for the oceans, which are the largest bodies on the Earth's surface, 97% of the water on the Earth's surface is collected, and these oceans are separated by the continents between them.

 There are 5 oceans on Earth, which are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Arctic Ocean, and the Southern Ocean. The Pacific Ocean is the largest ocean in area, and it is also larger than the area of ​​all the continents in common, and there is more than half of the water on the planet, and it is located between the continents of America, Asia, and Australia. As for the other small bodies of water, they are called seas, lakes, and gulfs.

Earth's Atmosphere 

The atmosphere consists of 5 layers that differ in characteristics and temperature, namely:

Troposphere

Stratosphere

• Tropopause: forms the lower part of the stratosphere and extends to a height of 50 km, contains the highest concentration of ozone gas (a molecule consisting of 3 atoms of oxygen O3), the temperature in the stratosphere increases with altitude because ozone gas absorbs part of the solar radiation to protect Life on the planet from harmful ultraviolet rays, which increases the temperature of this layer with increasing altitude.
•  Stratopause: It forms the upper part of the stratosphere.

Mesosphere

It is the third layer located above the stratosphere, extending to an altitude of 85 km, in which the temperature decreases with altitude, as the coldest temperature in the atmosphere is recorded in the upper part of the mesosphere known as the Mesopause, which is about -90°. Meteorites burn in this layer as they pass through the atmosphere before reaching the Earth's surface.

Thermosphere

 It is the fourth layer located above the mesosphere, and extends to an altitude of 600 km, in which the temperature rises sharply with altitude, reaching 2000 ° due to solar radiation.

Exosphere

 It is the last layer in the atmosphere opposite outer space, in which the force of Earth's gravitational force is so small that the gas molecules of the exosphere escape into space.