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.
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.
Planet Earth makes two main movements: rotation on its own axis and translation around the Sun.
The Earth’s atmosphere is made up mostly of nitrogen and oxygen. Other gases, such as argon, carbon dioxide, neon, helium, methane, and water vapor, are present in much smaller quantities. The atmosphere also has an average temperature of 14.7 °C.
The interior of the Earth is divided into different layers. The most superficial is the bark. Below it, there are the upper mantle or asthenosphere and the lower mantle. In the depths, the outer core and the inner core are found.
The name Land comes from ancient Roman mythology: Terraincarnation of a primal goddess who was associated with femininity, fertility and the origin of most things. It is also associated with motherhood in various cultures, as in the case of Pachamama for 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 orbital 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 harbors life.
Location and dimensions of the Earth
The Earth is 150 million kilometers from the Sun. In 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
The Earth has two main movements:
- Rotation. The Earth rotates on its own axis, in a west-east direction, and takes 24 hours to complete one rotation. 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 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:
- Troposphere. It is the layer that is in contact with the Earth’s surface and in which climatic and meteorological processes are generated. It is mainly composed of nitrogen, oxygen and water vapor.
- Stratosphere. It is where the ozone layer is located, which acts as a filter for ultraviolet rays that come from the Sun.
- Mesosphere. It 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.
- Exosphere. It is the transition zone between the Earth’s atmosphere and outer space. Several artificial satellites usually orbit in the exosphere, providing information for telecommunications, climate predictions and the Earth’s surface.
Layers of the Earth
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 made up of different geological layers:
- Crust. 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 mantle. It extends from 660 kilometers to 2,890 kilometers deep. It is mainly made up of solid rocks.
- Outer core. It is a layer of liquid matter that surrounds the inner core. It extends from 2,890 to 5,150 kilometers deep.
- Inner core. It is mainly composed 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 planet. It ranges 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.
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.
Earth’s hydrosphere
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 constitute 97% of the total hydrosphere on Earth. For their part, surface waters such as rivers, lakes and lagoons and groundwater present 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 approximately 4.5 billion years ago, from debris generated by a collision between the early Earth and a Mars-sized object known as Theia.
The Moon’s gravitational influence 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 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 oxygen. Earth’s atmosphere contains oxygen in sufficient quantities to support 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.
References
- Gullo, J., Nardulli, JP, Echeverría, MJ, Capuz, SM, Lazzaro, Y. (2020). The hominization process. In Social Sciences. Societies and environments of the world. From the first societies to the end of the Middle Ages (pp. 139-152). AZ. http://az.com.ar/
- NASA Science. (2021). Everything on Earth. https://spaceplace.nasa.gov/
- Nuñez, S. (2020). Elements and factors of climate. EcologyGreen. https://www.ecologiaverde.com/
- Tarbuck, E. and Lutgens, F. (2005). Earth Sciences. An introduction to physical geology. Pearson Education.
