WHAT ARE THE NATURAL COMPONENTS OF THE EARTH? - ENVIRONMENT - 2024

The natural components of the Earth are those elements that are present in the environment and whose formation does not depend on the intervention of human beings.

These elements are contemplated in the three main systems that make up the Earth, the atmosphere, which is its gaseous envelope, the hydrosphere, the surface coating of water and the lithosphere, which is the solid earth.

Of all the planets in the solar system, Earth stands out for the presence of water. When viewed from space, the first notable feature of the planet is its blue color.

This color comes from the oceans that cover more than 70% of its surface. No other planet in the solar system has water on the surface.

The next feature that stands out is the scattered clouds moving around. These clouds indicate that the Earth is surrounded by an atmosphere that contains gases and water vapor. Beneath the clouds the land surface is also interesting because it shows signs of geological processes that form mountains.

Due to the force of gravity, the heaviest components, such as solids and liquids, are arranged in the center of the Earth, while the outermost layer is made up of light gases.

The natural composition of the Earth is presented below, evaluating the elements present in solid, liquid and gaseous states in each of the systems.

Natural components of planet Earth

- The atmosphere

It is a relatively thin gaseous envelope, composed mainly of nitrogen (N2) and oxygen (O2), with small amounts of other gases, such as water vapor (H2O) and carbon dioxide (CO2). Within the atmosphere are clouds of liquid water and ice crystals.

Although the atmosphere extends upwards for several hundred kilometers, its density progressively decreases with increasing altitude.

Almost 99% of the atmosphere is located about 30 km (about 19 miles) from the Earth's surface (see Figure 1). In fact, if the Earth were reduced to the size of a large beach ball, its habitable environment would be thinner than a piece of paper.

Figure 1. Earth's atmosphere seen from space. The atmosphere is the thin bluish-white region along the Earth.

The thin blanket of air constantly protects the surface and its inhabitants from the sun's dangerous ultraviolet radiation, as well as material from interplanetary space.

There is no defined upper limit for the atmosphere, rather, it becomes thinner and thinner and eventually merges with empty space, which surrounds all planets.

Table 1 shows the different gases present in a volume of air near the Earth's surface. Note that molecular nitrogen (N2) occupies about 78% and molecular oxygen (02) about 21% of the total volume of dry air.

Table 1. Composition of the atmosphere near the earth's surface. (*) For CO2, 405 parts per million means that out of every million air molecules, 405 are CO2 molecules. (**) The values ​​of stratospheric altitudes between 11 km and 50 km are 5 and 12 ppm.

If all other gases are removed, these percentages of nitrogen and oxygen remain fairly constant up to an elevation of about 80 km (or 50 miles).

- The hydrosphere

It is the combination of all free water on Earth that is not confined chemically and / or physically within the minerals of the earth's crust.

The hydrosphere occupies most of the Earth's surface, that is, more than 75% of the total area of ​​the planet. The volume of the hydrosphere is 1.4 trillion cubic kilometers.

Oceans and seas

Oceans and seas make up most of the hydrosphere. They contain 1.37 x 109 cubic kilometers of water or about 94% of the total volume of the hydrosphere.

The storage of heat in the oceans and seas is large and controls the energy regime on the Earth's surface, producing the conditions necessary for life.

Underground water

Groundwater is the second largest component of the hydrosphere, its volume is approximately 0.6 x 109 cubic kilometers, or 4% of the total mass of the hydrosphere.

The zone of intensive water exchange extends to a depth of 0.3 to 0.5 km, where groundwater is present as moisture in the soil and subsoil.

The slower water exchange zone extends more than 1.5 to 2 km from where the exchange between surface and groundwater is difficult.

Snow and ice

The accumulation of snow and ice follows groundwater in volume. Most of the ice is found in glaciers and is approximately 2.4 x 107 cubic kilometers, of which more than 90% is concentrated in Antarctic glaciers.

Minor components

The portions of the other components of the hydrosphere, in addition to the three above, are small and can be considered as "minor components."

These components include water in rivers, lakes and swamps, soil moisture, and water vapor in the atmosphere.

River water is the most important for human life because it provides most of the fresh water necessary for survival. The waters of the hydrosphere are interrelated not only by their origin, but by the water cycle.

In this process all the parts of the hydrosphere are united by the main dynamic forces that cause movement, that is, the gravitational force and solar energy.

Table 2. Volume of water in the components of the hydrosphere. * Includes around 5,000 km3 of water in the reservoirs.

- The lithosphere

It is the solid and rigid outer layer of our planet. It includes the crust, the mantle and the nucleus (exterior and interior).

Cortex

It is the thinnest exterior of the Earth where we live. The crust varies from about 5km thick (at the bottom of the ocean) to about 70km thick (continental crust). The continental crust is made up of rocks consisting mainly of silica and an alumina called "sial."

Mantle

It is much thicker than the crust at almost 3,000km deep. It is made up of slightly different silicate rocks made up of magnesium and iron.

External nucleus

It is made of iron and nickel and is very hot (4,400 to approximately 5,000 ° C). It is so hot that the iron and nickel metals are liquid.

The outer core is very important, as it creates a magnetic field that creates a protective barrier around the Earth that protects us from the damaging solar wind.

Inner core

It is composed of iron and nickel, just like the outer core, yet it is so deep within the Earth that it is under immense pressure.

It is the hottest part of the Earth, with a temperature above 5,000 ° C, it is almost as hot as the surface of the sun.

Figure 2: structure of the lithosphere.

The lithosphere contains rocks, minerals, and soils. It is made up of more than 100 chemical elements, but most of them are poorly understood.

Eight elements constitute approximately 99% of the total volume of the lithosphere: oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K) and magnesium (Mg).

Table 3. Composition of the earth's crust.

In the earth's crust, these elements generally form solid crystalline compounds of defined composition known as minerals.

Chemically, minerals can be sulfides, oxides and hydroxides, halides, carbonates, nitrates, borates, sulfates, phosphates, and silicates.

Most rock-forming minerals are aluminosilicates of calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K). Rocks can be igneous, sedimentary, and metamorphic.

Igneous rocks are formed by solidification of magma or lava, sedimentary rocks are formed by lithification of sediments or by consolidation of plant and animal remains, and metamorphic rocks are formed from pre-existing rocks by changes in temperature and pressure in the solid state.

By the action of natural forces on geological time, rocks and minerals disintegrate and decompose into new minerals and new compounds such as salts, acids, bases and soluble substances. These processes are collectively known as weathering.

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