We explain what planet Earth is, its location in the solar system and its dimensions. Also, what are its characteristics, its climate and its composition.
Earth is the only known planet capable of supporting life.
What is planet Earth?
The Earth is a planet in the solar system, the third furthest from the planet. Sun and the fifth largest. It formed approximately 4.6 billion years ago, along with the solar system. It is the only planet where the existence of life has been confirmed to this day.
The planet Earth performs two main movements: the rotation on its own axis and the translation Around the sun.
The Earth’s atmosphere is composed mainly of nitrogen and oxygen. Other gases, such as argon, carbon dioxide, neon, helium, methane and water vapour, are present in much smaller quantities. The atmosphere also has an average temperature of 14.7 °C.
The Earth’s interior is divided into different layers. The most superficial is the crust. Below it are the upper mantle or asthenosphere and the lower mantle. In the depths are the outer core and the inner core.
Name Land comes from ancient Roman mythology: Earthincarnation of a primordial goddess who was associated with femininity, fertility and the origin of most things. She is also associated with motherhood in various cultures, as in the case of Pachamama in the Inca worldview.
Earth Features
The main characteristics of the Earth are:
- It was formed 4.6 billion years ago.
- It has a diameter of 12,742 kilometers.
- It is located 150 million kilometers from the Sun.
- Its rotation time on its axis is 24 hours.
- Its translation time around the Sun is 365 days and 6 hours.
- The average temperature of its atmosphere is 14.7 °C.
- It is the only planet that has liquid water on its surface.
- It is the only planet that hosts life.
Location and dimensions of the Earth
The Earth has a diameter of 12,742 kilometers.
The Earth is 150 million kilometers from the SunIn the solar system, it is located between the planets Venus and Mars.
It has an average diameter of 12,742 kilometers and a maximum equatorial circumference of 40,075 kilometers.. Its structure is characterized by having various layers, which include the crust, the upper mantle, the lower mantle, the outer core and the inner core.
The Earth has its axis of rotation tilted at 23.5 degrees. This inclination determines the changes of season and the different climates throughout the year, since it causes a variation in the distribution of solar radiation on the Earth’s surface.
Origin and formation of the Earth
Planet Earth formed 4.6 billion years ago when a vast cloud of gas and dust, known as the solar nebula, rapidly contracted.. This phenomenon led to the formation of a protosolar disk, the rotation of which became increasingly rapid. Within this disk, matter began to group together into small solid particles called planetesimals. These bodies collided and merged over millions of years. In this way, the Earth became bigger and bigger.
In addition, the heat generated by the collision of impacting and disintegrating bodies contributed to the warming of the planet. This extreme heat led to differentiation of the Earth’s layers, where denser materials sank toward the core and less dense materials cooled and formed the crust.
Over time, the Earth cooled and solidified until it reached the composition we know today. This process, known as planetary accretion, laid the foundations for the subsequent development of life and the geological evolution of the planet.
Earth Movements
It takes the Earth 24 hours to complete one rotation on its axis.
The Earth has two main movements:
- RotationThe Earth rotates on its own axis, in a west-east direction, and takes 24 hours to complete one revolution. This movement gives rise to day and night.
- Translation. The Earth revolves around the Sun through an orbit. One orbital revolution is completed every 365 days and 6 hours. The 6 hours are accumulated and, after four years, one more day is added to the calendar (leap years). This movement gives rise to the different seasons of the year.
Earth’s atmosphere
The atmosphere is composed mainly of nitrogen and oxygen.
The atmosphere is the gaseous layer that surrounds the Earth.. It is mainly composed of nitrogen (about 78%) and oxygen (about 21%), along with other gases in smaller proportions. This mixture of gases is retained by Earth’s gravity.
The layers of the Earth’s atmosphere, from lowest to highest altitude, are:
- TroposphereIt is the layer that is in contact with the Earth’s surface and in which climatic and meteorological processes are generated. It is composed mainly of nitrogen, oxygen and water vapor.
- Stratosphere. It is where the ozone layer is located, which acts as a filter for ultraviolet rays coming from the Sun.
- MesosphereIt is the layer that protects the planet from the impact of meteorites and asteroids, since it is where they disintegrate when they enter from space.
- Thermosphere or ionosphere. It is the layer of the atmosphere that favors the transmission of radio waves.
- ExosphereIt is the transition zone between the Earth’s atmosphere and outer space. Several artificial satellites often orbit in the exosphere, providing information for telecommunications, weather forecasting and information about the Earth’s surface.
Layers of the Earth
The Earth’s core is 3,500 kilometers thick in total.
The Earth belongs to the terrestrial planetsthat is, it is a rocky body, and not gaseous like other planets in the solar system. Its interior is composed of different geological layers:
- Cortex. It is a rock layer that extends up to 100 kilometers deep. It is the coldest and most rigid layer of all.
- Asthenosphere. It is the layer of magma on which the lithosphere floats. It extends from 100 to 660 kilometers deep.
- Lower mantleIt extends from 660 kilometers to 2,890 kilometers deep. It is composed mainly of solid rocks.
- External nucleusIt is a layer of liquid matter that surrounds the inner core. It extends from 2,890 to 5,150 kilometers deep.
- inner coreIt is composed mainly of iron, nickel and low percentages of sulfur and oxygen. It extends from 5,150 to 6,371 kilometers deep.
Earth’s biosphere
The biosphere is the total set of organic life on the planetIt covers everything from the atmosphere to the oceans and the Earth’s crust. It includes the part of the Earth where organisms can live, whether it is the surface, soil, water or air.
The Earth’s biosphere is the only known place in the universe where life exists. In it, living beings interact with each other and with their environment, and form complex ecological networks and cycles fundamental for the development of life.
The Earth’s hydrosphere
Earth is the only known planet on which water exists in liquid form.
A fundamental difference between Earth and other planets in the solar system is its abundant presence of water.. The Earth’s hydrosphere comprises all of the bodies of water on the planet: oceans, seas, rivers, lakes, glaciers and groundwater. Approximately 71% of the Earth’s surface is covered by water.
The oceans are the main bodies of water on the planet and make up 97% of the Earth’s total hydrosphere. Surface waters such as rivers, lakes and lagoons and groundwater in aquifers are also part of the hydrosphere and contribute to the supply and distribution of water in various regions of the planet.
Earth’s natural satellite: the Moon
The Moon is the only natural satellite of the Earth and the fifth largest in the solar system. Its diameter is 3,474 kilometers, which represents about a quarter of the diameter of the Earth.
The Moon formed about 4.5 billion years ago from the debris left over from a collision between the early Earth and a Mars-sized object known as Theia.
The gravitational influence of the Moon has effects on the Earth. The most important is the generation of tides, which produce the periodic rise and fall of sea level.
Human population
The Earth is home to a population of more than 8 billion people.
The appearance of human life on Earth is due to a combination of factors and conditions that have allowed the development and evolution of complex life forms on the planet. Some of the most important are:
- The presence of liquid water. Earth is the only known planet that has liquid water on its surface. Water is fundamental to life as we know it and is essential for the subsistence of human beings.
- An atmosphere with oxygenThe Earth’s atmosphere contains oxygen in sufficient quantities to sustain aerobic respiration, a vital process for complex organisms such as humans.
- Biological diversity. The Earth is home to a great diversity of life forms, from microorganisms to complex plants and animals. This biological diversity has provided the means of subsistence necessary for the development of human beings.
- A relatively stable climate. Although the Earth’s climate has experienced variations, it has maintained relatively stable conditions for as long as humans have existed. This allowed the evolution and adaptation of human societies throughout history.
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References
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- NASA Science. (2021). Everything on Earth. https://spaceplace.nasa.gov/
- Nuñez, S. (2020). Climate elements and factors. GreenEcology. https://www.ecologiaverde.com/
- Tarbuck, E. and Lutgens, F. (2005). Earth sciences. An Introduction to Physical Geology. Pearson Education.