Earth Meaning – Definition & Synonyms
The term earth, originating from the Latin terra, has several uses and meanings. It can refer to the crumbly material that makes up the natural soil, the land dedicated to cultivation, or the floor/soil. Land is also used as a synonym for nation, country, region, or territory: “Nadal consecrated himself to his land, ” “The men of this land are quiet and solitary. ”
Table Of Content
1. Planet Earth
2. Internal structure models
3. Documentary “Earth”
4. The geological units
Planet Earth
When written with a capital letter, the notion of Earth allows us to name the planet we inhabit. It is the only planet on which, so far, the existence of life has been proven.
The Earth is located 150 million kilometers from the Sun and is the fifth largest planet in the Solar System. It was formed about 4.57 billion years ago and has the only natural satellite: the Moon.
Internal structure models
With a geoid shape (flattened sphere at the poles), the Earth has a diameter of 12,700 kilometers and 71% of its surface is covered with water. Specialists have designed two models to refer to the internal structure of the planet: the geostatic model and the geodynamic model.
The geostatic model establishes three layers: the crust (the most superficial layer, composed of the granite of the continents and the basalt of the ocean basins), the mantle (the intermediate layer, which reaches a depth of 2,900 kilometers) and the core. (the deepest layer, with a thickness of 3,475 kilometers).
The geodynamic model, on the other hand, mentions the lithosphere (the most superficial part), the asthenosphere (which behaves fluidly), the mesosphere (also known as the lower mantle), the D layer (a transition zone) and the endosphere (which corresponds to the core of the geostatic model).
Documentary «Earth»
There is a film documentary called “Earth” and it is an exquisite material in which a series of theories come together that allow us to know the actions that human beings have carried out on the planet and the consequences that they have had on the planet. The ecology. The material was collected over five years and allows us to see the devastation process of the same place over the course of a year; being able to visualize the geographical and climatic changes of more than 200 places throughout the Earth.
It is a work that has been produced by the BBC Natural History Unit, it has been filmed absolutely in high definition (HD) and belongs to the television series titled “Planet Earth”, broadcast on the small screen in 2006.
In this work the fundamental protagonists are polar bears, African elephants and humpback whales, species that are in danger of extinction and that must face each cycle the absence of water, ice or food, increasing each year the risks to lose their lives, and become completely extinct.
The geological units
To understand the history of the Earth, the various cycles of life have been divided into geological units. They are classified into larger units: composed of eons, which in turn are divided into eras and these into periods. Periods are made up of times and ages. Currently, we live in the Phanerozoic eon, in the Cenozoic era, in the Quaternary period, and in the era called Holocene.
The data that scientists analyze to determine and temporally divide the various stages are:
* Extinctions and changes or changes in fauna and flora (disappearance of species or transfer of a group that was settled in one place to another where its chances of survival are greater);
* Large tectonic episodes (movements in some terrestrial layer that modify the surface and therefore the survival of the flora and fauna that reside there);
* Profound changes in the climate (modification of the climate that causes the extinction or migration of species towards more favorable spaces, therefore flora and fauna are also modified);
* Significant changes in sea level (due to melting ice or other variations in the composition of the earth, sea level may increase or decrease, shortening space for the beings that inhabit the area).