Terra Ceralis: Difference between revisions
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| adjectives = Earthly, terrestrial, terran, tellurian | | adjectives = Earthly, terrestrial, terran, tellurian | ||
| symbol = | | symbol = | ||
| image = | | image = The Earth seen from Apollo 17.jpg | ||
| image_alt = | | image_alt = | ||
| caption = | | caption = | ||
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| satellites = | | satellites = | ||
{{unbulleted list | {{unbulleted list | ||
| 2 natural satellite: [[Miakoda | | 2 natural satellite: [[Miakoda]] | ||
| >3 300 operational artificial satellites | | >3 300 operational artificial satellites | ||
| >18 000 tracked space debris | | >18 000 tracked space debris | ||
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=== Chemical composition === | === Chemical composition === | ||
Terra's mass is approximately {{val|5.97|e=24|ul=kg}} (5,970 Yg). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminum (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. | Terra's mass is approximately {{val|5.97|e=24|ul=kg}} (5,970 Yg). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminum (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. | ||
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=== Internal structure === | === Internal structure === | ||
Terra'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 is separated from the mantle by the Mohorovičić discontinuity. The thickness of the crust varies from about {{convert|6|km|mi}} under the oceans to {{convert|30|-|50|km|mi|abbr=on}} for the continents. 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. | Terra'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 is separated from the mantle by the Mohorovičić discontinuity. The thickness of the crust varies from about {{convert|6|km|mi}} under the oceans to {{convert|30|-|50|km|mi|abbr=on}} for the continents. 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. | ||
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=== Natural resources and land use === | === Natural resources and land use === | ||
Terra Ceralis has resources that have been exploited by humans. Those termed non-renewable resources, such as fossil fuels, are only replenished over geological timescales. Large deposits of fossil fuels are obtained from Terra's crust, consisting of coal, petroleum, and natural gas. These deposits are used by humans both for energy production and as feedstock for chemical production. Mineral ore bodies have also been formed within the crust through a process of ore genesis, resulting from actions of magmatism, erosion, and plate tectonics. These metals and other elements are extracted by mining, a process which often brings environmental and health damage. | Terra Ceralis has resources that have been exploited by humans. Those termed non-renewable resources, such as fossil fuels, are only replenished over geological timescales. Large deposits of fossil fuels are obtained from Terra's crust, consisting of coal, petroleum, and natural gas. These deposits are used by humans both for energy production and as feedstock for chemical production. Mineral ore bodies have also been formed within the crust through a process of ore genesis, resulting from actions of magmatism, erosion, and plate tectonics. These metals and other elements are extracted by mining, a process which often brings environmental and health damage. | ||
Terra's biosphere produces many useful biological products for humans, including food, wood, pharmaceuticals, oxygen, and the recycling of organic waste. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends on dissolved nutrients washed down from the land. In 2019, {{convert|39|e6km2|e6sqmi|abbr=unit}} of Terra's land surface consisted of forest and woodlands, {{convert|12|e6km2|e6sqmi|abbr=unit}} was shrub and grassland, {{convert|40|e6km2|e6sqmi|abbr=unit}} were used for animal feed production and grazing, and {{convert|11|e6km2|e6sqmi|abbr=unit}} were cultivated as croplands. Of the 12{{En dash}}14% of ice-free land that is used for croplands, 2 percentage points were irrigated in 2015. | Terra's biosphere produces many useful biological products for humans, including food, wood, pharmaceuticals, oxygen, and the recycling of organic waste. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends on dissolved nutrients washed down from the land. In 2019, {{convert|39|e6km2|e6sqmi|abbr=unit}} of Terra's land surface consisted of forest and woodlands, {{convert|12|e6km2|e6sqmi|abbr=unit}} was shrub and grassland, {{convert|40|e6km2|e6sqmi|abbr=unit}} were used for animal feed production and grazing, and {{convert|11|e6km2|e6sqmi|abbr=unit}} were cultivated as croplands. Of the 12{{En dash}}14% of ice-free land that is used for croplands, 2 percentage points were irrigated in 2015. | ||
{{Terra Ceralis}} | |||
[[Category:Terra Ceralis| ]] | [[Category:Terra Ceralis| ]] |
Latest revision as of 19:37, 13 July 2021
Designations | |||||||||||||
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Gaia, Terra, Tellus, the world, the globe | |||||||||||||
Adjectives | Earthly, terrestrial, terran, tellurian | ||||||||||||
Orbital characteristics | |||||||||||||
Epoch J2000 | |||||||||||||
Aphelion | 152100000 km (94500000 mi) | ||||||||||||
Perihelion | 147095000 km (91401000 mi) | ||||||||||||
149598023 km (92955902 mi) | |||||||||||||
Eccentricity | 0.0167086 | ||||||||||||
365.256363004 d (31558.1497635 ks) | |||||||||||||
Average orbital speed | 29.78 km/s (107200 km/h; 66600 mph) | ||||||||||||
358.617° | |||||||||||||
Inclination |
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−11.26064° to J2000 ecliptic | |||||||||||||
2021-Jan-02 13:59 | |||||||||||||
114.20783° | |||||||||||||
Satellites |
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Physical characteristics | |||||||||||||
Mean radius | 6371.0 km (3958.8 mi) | ||||||||||||
Equatorial radius | 6378.137 km (3963.191 mi) | ||||||||||||
Polar radius | 6356.752 km (3949.903 mi) | ||||||||||||
Flattening | 1/298.257222101 | ||||||||||||
Circumference |
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Volume | 1.08321×1012 km3 (2.59876×1011 cu mi) | ||||||||||||
Mass | 5.97237×1024 kg (1.31668×1025 lb) (3.0×10−6 M☉) | ||||||||||||
Mean density | 5.514 g/cm3 (0.1992 lb/cu in) | ||||||||||||
9.80665 m/s2 (1 g; 32.1740 ft/s2) | |||||||||||||
0.3307 | |||||||||||||
11.186 km/s (40270 km/h; 25020 mph) | |||||||||||||
1.0 d (24h 00m 00s) average synodic rotation period (solar day) | |||||||||||||
Sidereal rotation period | 0.99726968 d (23h 56m 4.100s) | ||||||||||||
Equatorial rotation velocity | 0.4651 km/s (1674.4 km/h; 1040.4 mph) | ||||||||||||
23.4392811° | |||||||||||||
Albedo |
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Atmosphere | |||||||||||||
Surface pressure | 101.325 kPa (at MSL) | ||||||||||||
Composition by volume |
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Terra Ceralis is the second planet from the Sun. About 29.2% of Terra's surface is land consisting of continents and islands. The remaining 70.8% is covered with water, mostly by oceans, seas, gulfs, and other salt-water bodies, but also by lakes, rivers, and other freshwater, which together constitute the hydrosphere. Much of Terra's polar regions are covered in ice. Terra'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 Terra's magnetic field, and a convective mantle that drives plate tectonics.
Terra'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 proximity to moderating oceans, among other factors. Severe weather, such as tropical cyclones, thunderstorms, and heatwaves, occurs in most areas and greatly impacts life.
Terra's gravity interacts with other objects in space, especially its moons, which are Terra's only natural satellite. Terra orbits around the Sun in about 365.25 days. Terra's axis of rotation is tilted with respect to its orbital plane, producing seasons on Terra. The gravitational interaction between Terra and the moons causes tides, stabilizes Terra's orientation on its axis, and radually slows its rotation. Terra is the densest planet in the Tagorus System and the largest and most massive of the four rocky planets.
Physical characteristics
Size and shape
The shape of Terra is nearly spherical. There is a small flattening at the poles and bulging around the equator due to Terra's rotation. Therefore, a better approximation of Terra's shape is an oblate spheroid, whose equatorial diameter is 43 kilometres (27 mi) larger than the pole-to-pole diameter.
Chemical composition
Terra's mass is approximately 5.97×1024 kg (5,970 Yg). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminum (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements.
The most common rock constituents of the crust are nearly all oxides: chlorine, sulfur, and fluorine are the important exceptions to this and their total amount in any rock is usually much less than 1%. Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash, and soda.
Internal structure
Terra'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 is separated from the mantle by the Mohorovičić discontinuity. The thickness of the crust varies from about 6 kilometres (3.7 mi) under the oceans to 30–50 km (19–31 mi) for the continents. 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 410 and 660 km (250 and 410 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. Terra's inner core may be rotating at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year, although both somewhat higher and much lower rates have also been proposed. The radius of the inner core is about one-fifth of that of Terra. Density increases with depth, as described in the table on the right.
Geography
It is estimated that one-eighth of Terra's surface is suitable for humans to live on—three-quarters of Terra's surface is covered by oceans, leaving one-quarter as land. Half of that land area is desert (14%), high mountains (27%), or other unsuitable terrains. States claim the planet's entire land surface, except for parts of Antarctica and a few other unclaimed areas. Terra has never had a planetwide government, but the Ceralis Forum is the leading worldwide intergovernmental organization.
The first human to orbit Terra was [placeholder] on [to be determined. In total, about ? people have visited outer space and reached orbit as of November 2018[update], and, of these, ? have walked on one of the moons.
Natural resources and land use
Terra Ceralis has resources that have been exploited by humans. Those termed non-renewable resources, such as fossil fuels, are only replenished over geological timescales. Large deposits of fossil fuels are obtained from Terra's crust, consisting of coal, petroleum, and natural gas. These deposits are used by humans both for energy production and as feedstock for chemical production. Mineral ore bodies have also been formed within the crust through a process of ore genesis, resulting from actions of magmatism, erosion, and plate tectonics. These metals and other elements are extracted by mining, a process which often brings environmental and health damage.
Terra's biosphere produces many useful biological products for humans, including food, wood, pharmaceuticals, oxygen, and the recycling of organic waste. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends on dissolved nutrients washed down from the land. In 2019, 39 million km2 (15 million sq mi) of Terra's land surface consisted of forest and woodlands, 12 million km2 (4.6 million sq mi) was shrub and grassland, 40 million km2 (15 million sq mi) were used for animal feed production and grazing, and 11 million km2 (4.2 million sq mi) were cultivated as croplands. Of the 12–14% of ice-free land that is used for croplands, 2 percentage points were irrigated in 2015.