Structure of Earth
In geography and cartography, the hemispheres of Earth refer to any division of the globe into two hemispheres (from Ancient Greek ??????????? hemisphairion, meaning "half of a sphere"). The division of Earth by the Equator and the prime meridianMissing: parts. Mar 18, · Earth Divided into Two Major Systems Some scientists organized of the parts of the Earth can be divided into two main systems. These two systems include all the organic and inorganic matter of the world. Every living and non-living thing on Earth falls under one of these two main spheres which are the Earth’s geosphere and biosphere.
These four subsystems are known as spheres. Three of these spheres are abiotic and one sphere is biotic. Abiotic describes substances that are made from non-living materials.
Biotic relates to living things like bacteria, birds, mammals, insects, and plants. This includes surface water such as rivers, nito, and oceanswater in the ground, ice and snow, and water in the atmosphere in the form of water vapor.
The bottom layer, which is the layer closest to the Divlded, is the most dense of pwrts five layers. This layer is known as the troposphere. In addition, trace gases carbon dioxide, nitrous oxides, methane, and ozone account for another hiw of a percent.
Water vapor, dust particles, pollutants, and pollen also can be found in mixed into the atmosphere at this level. The next layer is the stratosphere. Unlike the troposphere, the stratosphere has no turbulence. Unlike the air in the troposphere, the air in the stratosphere gets warmer higher partz in this layer.
Above the stratosphere is the mesosphere. There are dividfd gases in the mesosphere to create friction which causes the meteors to burn up. We can see those at night as shooting stars. The atmosphere in the thermosphere is very thin. Temperatures can reach up to earthh, Fahrenheit due to high-energy X-rays and UV radiation from the Sun. Many earth orbiting satellites and the International Space Station are found in this layer.
The atmosphere is extremely thin in this layer with gases like hydrogen and helium. Auroras occur in the ionosphere where high-energy particles from the sun interacting with the atoms in this layer. Ia is water found in the air, the soil, in glaciers, the oceans, rivers, lakes, and streams of how to tie a ring sling for baby world.
In liquid form water is found in streams, rivers, lakes, ponds, and oceans along with mist in the air and as dew on the surface of the mmany. The lithosphere contains the elements of the Earth crust and part of the upper mantle. Eatth is the hard and rigid outer layer of the Earth. This part of the Earth includes soil. There is an estimated 20 million to millions different species in the world organized into the phyla that make up the five kingdoms of life forms.
These organisms can be found in almost all parts of the geosphere. There are organisms in the air, soil, and water on Earth. Some scientists organized of the parts of the Earth can be divided into two main systems.
These two systems include all the organic and inorganic matter of the world. This includes the air that we all breath. The lithosphere is the solid part of the Earth such as rocks and mountains. The hydrosphere is the liquid water such as the rivers, lakes, and oceans. The cryosphere is the ddivided water of the earth and is further broken into four types: glaciers, snow cover, floating ice, and permafrost.
Ask how to test for stabilizer in pool Astronomer. Cool Cosmos. Geological Survey Publications Warehouse.
Williams, R. The Earth System. World of Change: Global Biosphere. Images: USGS, public domain. Photo: USGSpublic domain. Public domain.
An aurora borealis over the Pacific Northwest in the United States. Dibided NASApublic domain. An ocean cave on the coast of Capri Island, Italy. Photo: John J. MosessoUSGS. Sandhill cranes flock together on a grassy area in Medaryville, Indiana. Mosesso, How to get water out of your crawl space. The Earth can be divided into two main systems: the geosphere and the biosphere.
Image: James A. Tomberlin, USGSpublic domain. Share Tweet Pin. Explore More Geography Articles.
Earth is the third planet from the Sun and the only astronomical object known to harbor life. About The remaining Much of Earth's polar regions are covered in ice. Earth's outer layer is divided into several rigid tectonic plates that migrate across the surface over many millions of years, while its interior remains active with a solid iron inner core , a liquid outer core that generates Earth's magnetic field , and a convective mantle that drives plate tectonics.
Earth's atmosphere consists mostly of nitrogen and oxygen. More solar energy is received by tropical regions than polar regions, and is redistributed by atmospheric and ocean circulation.
Greenhouse gases also play an important role in regulating the surface temperature. A region's climate is not only determined by latitude, but also by elevation, and by proximity to moderating oceans, among other factors. Severe weather, such as tropical cyclones, thunderstorms, and heat waves, occurs in most areas and has a large impact on life.
Earth's gravity interacts with other objects in space, especially the Moon , which is Earth's only natural satellite. Earth orbits around the Sun in about Earth's axis of rotation is tilted with respect to its orbital plane, producing seasons on Earth.
The gravitational interaction between Earth and the Moon causes tides, stabilizes Earth's orientation on its axis, and gradually slows its rotation.
Earth is the densest planet in the Solar System and the largest and most massive of the four rocky planets. According to radiometric dating estimation and other evidence, Earth formed over 4. Within the first billion years of Earth's history , life appeared in the oceans and began to affect Earth's atmosphere and surface, leading to the proliferation of anaerobic and, later , aerobic organisms. Some geological evidence indicates that life may have arisen as early as 4. Since then, the combination of Earth's distance from the Sun, physical properties and geological history have allowed life to evolve and thrive.
In the history of life on Earth , biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinctions. Almost 8 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans increasingly impact Earth's surface, hydrology, atmospheric processes and other life. Historically, earth has been written in lowercase. From early Middle English , its definite sense as "the globe" was expressed as the earth.
By Early Modern English , many nouns were capitalized, and the earth was also written the Earth , particularly when referenced along with other heavenly bodies. More recently, the name is sometimes simply given as Earth , by analogy with the names of the other planets , though earth and forms with the remain common.
Another convention capitalizes "Earth" when appearing as a name for example, "Earth's atmosphere" but writes it in lowercase when preceded by the for example, "the atmosphere of the earth". It almost always appears in lowercase in colloquial expressions such as "what on earth are you doing?
There are a number of adjectives for the planet Earth. From Earth itself comes earthly. The oldest material found in the Solar System is dated to 4. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into a circumstellar disk , and then the planets grow out of that disk with the Sun.
A nebula contains gas, ice grains, and dust including primordial nuclides. According to nebular theory , planetesimals formed by accretion , with the primordial Earth being estimated as likely taking anywhere from 70 to million years to form.
Estimates of the age of the Moon range from 4. Earth's atmosphere and oceans were formed by volcanic activity and outgassing. As the molten outer layer of Earth cooled it formed the first solid crust , which is thought to have been mafic in composition. The first continental crust , which was more felsic in composition, formed by the partial melting of this mafic crust.
The presence of grains of the mineral zircon of Hadean age in Eoarchean sedimentary rocks suggests that at least some felsic crust existed as early as 4. The two models and the data that support them can be reconciled by large-scale recycling of the continental crust , particularly during the early stages of Earth's history. New continental crust forms as a result of plate tectonics , a process ultimately driven by the continuous loss of heat from Earth's interior.
Over the period of hundreds of millions of years, tectonic forces have caused areas of continental crust to group together to form supercontinents that have subsequently broken apart. At approximately Ma , one of the earliest known supercontinents, Rodinia , began to break apart. The continents later recombined to form Pannotia at — Ma , then finally Pangaea , which also began to break apart at Ma.
The most recent pattern of ice ages began about 40 Ma ,  and then intensified during the Pleistocene about 3 Ma. Chemical reactions led to the first self-replicating molecules about four billion years ago.
A half billion years later, the last common ancestor of all current life arose. The resultant molecular oxygen O 2 accumulated in the atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer O 3 in the upper atmosphere. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized Earth's surface. During the Neoproterozoic , to Ma , much of Earth might have been covered in ice. This hypothesis has been termed " Snowball Earth ", and it is of particular interest because it preceded the Cambrian explosion , when multicellular life forms significantly increased in complexity.
Mammalian life has diversified over the past 66 Mys , and several million years ago an African ape gained the ability to stand upright. The development of agriculture , and then civilization , led to humans having an influence on Earth and the nature and quantity of other life forms that continues to this day. Because carbon dioxide CO 2 has a long lifespan in the atmosphere, moderate human CO 2 emissions may postpone the next glacial inception by , years.
Over the next 1. The Sun will evolve to become a red giant in about 5 billion years. Models predict that the Sun will expand to roughly 1 AU million km; 93 million mi , about times its present radius.
The shape of Earth is nearly spherical. There is a small flattening at the poles and bulging around the equator due to Earth's rotation. The point on the surface farthest from Earth's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador 6, Local topography deviates from this idealized spheroid, although on a global scale these deviations are small compared to Earth's radius: the maximum deviation of only 0.
More precisely, the geoid is the surface of gravitational equipotential at mean sea level. Earth's mass is approximately 5. It is composed mostly of iron Due to mass segregation , the core region is estimated to be primarily composed of iron Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical rheological properties.
The outer layer is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. The crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, which is divided into independently moving tectonic plates. Beneath the lithosphere is the asthenosphere , a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at and km and mi below the surface, spanning a transition zone that separates the upper and lower mantle.
Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core. Density increases with depth, as described in the table on the right.
The major heat-producing isotopes within Earth are potassium , uranium , and thorium At approximately 3 Gyr , twice the present-day heat would have been produced, increasing the rates of mantle convection and plate tectonics, and allowing the production of uncommon igneous rocks such as komatiites that are rarely formed today. These plumes can produce hotspots and flood basalts. The final major mode of heat loss is through conduction through the lithosphere, the majority of which occurs under the oceans because the crust there is much thinner than that of the continents.
Earth's mechanically rigid outer layer, the lithosphere, is divided into tectonic plates. These plates are rigid segments that move relative to each other at one of three boundaries types: at convergent boundaries , two plates come together; at divergent boundaries , two plates are pulled apart; and at transform boundaries , two plates slide past one another laterally.
Along these plate boundaries, earthquakes , volcanic activity , mountain-building , and oceanic trench formation can occur. As the tectonic plates migrate, oceanic crust is subducted under the leading edges of the plates at convergent boundaries. At the same time, the upwelling of mantle material at divergent boundaries creates mid-ocean ridges. The combination of these processes recycles the oceanic crust back into the mantle. Due to this recycling, most of the ocean floor is less than Ma old.
The oldest oceanic crust is located in the Western Pacific and is estimated to be Ma old. At the other extreme, the slowest-moving plate is the South American Plate, progressing at a typical rate of The total surface area of Earth is about million km 2 million sq mi. The mean height of land above sea level is about m 2, ft. The continental crust consists of lower density material such as the igneous rocks granite and andesite. Less common is basalt , a denser volcanic rock that is the primary constituent of the ocean floors.
The most abundant silicate minerals on Earth's surface include quartz , feldspars , amphibole , mica , pyroxene and olivine.
Erosion and tectonics , volcanic eruptions , flooding , weathering , glaciation , the growth of coral reefs , and meteorite impacts are among the processes that constantly reshape Earth's surface over geological time. The pedosphere is the outermost layer of Earth's continental surface and is composed of soil and subject to soil formation processes.
The total arable land is The gravity of Earth is the acceleration that is imparted to objects due to the distribution of mass within Earth. Near Earth's surface, gravitational acceleration is approximately 9. Local differences in topography, geology , and deeper tectonic structure cause local and broad, regional differences in Earth's gravitational field, known as gravity anomalies.
The main part of Earth's magnetic field is generated in the core, the site of a dynamo process that converts the kinetic energy of thermally and compositionally driven convection into electrical and magnetic field energy. The field extends outwards from the core, through the mantle, and up to Earth's surface, where it is, approximately, a dipole. The poles of the dipole are located close to Earth's geographic poles.