Sharp Earth
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Riordan Proterozoic Archean Phanerozoic Tectonics Hadean Pannotia Geologic Organisms
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga
Orogeny in Northern Hemisphere. Start of Kaikoura Orogeny forming Southern Alps in New Zealand. Widespread forests slowly draw in massive amounts of CO2, gradually lowering the level of atmospheric CO2 from 650 ppmv down to around 100 ppmv during the Miocene. Modern bird and mammal families become recognizable. The last of the primitive whales go extinct. Grasses become ubiquitous. Ancestor of apes, including humans. Afro-Arabia collides with Eurasia, fully forming the Alpide Belt and closing the Tethys Ocean, while allowing a faunal interchange. At the same time, Afro-Arabia splits into Africa and West Asia.
The invention of a geographic coordinate system is generally credited to Eratosthenes of Cyrene, who composed his now-lost Geography at the Library of Alexandria in the 3rd century BC. A century later, Hipparchus of Nicaea improved on this system by determining latitude from stellar measurements rather than solar altitude and determining longitude by timings of lunar eclipses, rather than dead reckoning. In the 1st or 2nd century, Marinus of Tyre compiled an extensive gazetteer and mathematically plotted world map using coordinates measured east from a prime meridian at the westernmost known land, designated the Fortunate Isles, off the coast of western Africa around the Canary or Cape Verde Islands, and measured north or south of the island of Rhodes off Asia Minor. Ptolemy credited him with the full adoption of longitude and latitude, rather than measuring latitude in terms of the length of the midsummer day.
From crater counts on other From crater counts on other celestial bodies, it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 Ga, and concluded around 3.8 Ga, at the end of the Hadean. In addition, volcanism was severe due to the large heat flow and geothermal gradient. Nevertheless, detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, suggesting that the Earth already had oceans or seas at that time.By the beginning of the Archean, the Earth had cooled significantly. Present life forms could not have survived at Earth's surface, because the Archean atmosphere lacked oxygen hence had no ozone layer to block ultraviolet light. Nevertheless, it is believed that primordial life began to evolve by the early Archean, with candidate fossils dated to around 3.5 Ga. Some scientists even speculate that life could have begun during the early Hadean, as far back as 4.4 Ga, surviving the possible Late Heavy Bombardment period in hydrothermal vents below the Earth's surface. Celestial bodies, it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 Ga, and concluded around 3.8 Ga, at the end of the Hadean. In addition, volcanism was severe due to the large heat flow and geothermal gradient. Nevertheless, detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, suggesting that the Earth already had oceans or seas at that time.By the beginning of the Archean, the Earth had cooled significantly. Present life forms could not have survived at Earth's surface, because the Archean atmosphere lacked oxygen hence had no ozone layer to block ultraviolet light. Nevertheless, it is believed that primordial life began to evolve by the early Archean, with candidate fossils dated to around 3.5 Ga. Some scientists even speculate that life could have begun during the early Hadean, as far back as 4.4 Ga, surviving the possible Late Heavy Bombardment period in hydrothermal vents below the Earth's surface.
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A timespan in the glacial history of the Alps. It started approximately one million years ago and ended about 370 000 years ago. Some sources put the end at 480 000 years ago. Deep sea core samples have identified approximately 5 glacial cycles of varying intensity during Gunz.
Moderate, cooling climate. Archaic mammals (e.g. creodonts, miacoids, "condylarths" etc.) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. Primitive whales and sea cows diversify after returning to water. Birds continue to diversify. First kelp, diprotodonts, bears and simians. The multituberculates and leptictidans go extinct by the end of the epoch. Reglaciation of Antarctica and formation of its ice cap; End of Laramide and Sevier Orogenies of the Rocky Mountains in North America. Hellenic Orogeny begins in Greece and Aegean Sea.
The name Gunz glaciation, Gunzian glaciation or Günz glacial stage (German: Günz-Kaltzeit, also Günz-Glazial, Günz-Komplex and Günz-Eiszeit) goes back to Albrecht Penck and Eduard Brückner, who named this ice age after the River Günz in their multi-volume work, Die Alpen im Eiszeitalter ("The Alps in the Ice Age Period") which was published between 1901 and 1909. Its type region is the Iller-Lech Plateau. It is the oldest glaciation of the Pleistocene in the traditional, quadripartite glacial classification of the Alps. The Günz was thought to follow the Danube-Günz interglacial and was ended by the Günz-Haslach interglacial. The 2016 version of the detailed stratigraphic table by the German Stratigraphic Commission puts the start of Gunz in the late Calabrian (approximately one million years ago, earlier than MIS 19) and shows a continuity of glacial cycles with the following Mindel stage, with the border arbitrarily put at the start of MIS 10 (approximately 374 000 years ago). Gunz corresponds roughly to the Cromerian stage in the glacial history of Northern Europe.[1]
The 2016 version of the detailed stratigraphic table by the German Stratigraphic Commission puts the start of Gunz in the late Calabrian (approximately one million years ago, earlier than MIS 19) and shows a continuity of glacial cycles with the following Mindel stage, with the border arbitrarily put at the start of MIS 10 (approximately 374 000 years ago). Gunz corresponds roughly to the Cromerian stage in the glacial history of Northern Europe. Deep sea core samples have identified approximately 10 marine isotope stages (at least MIS 21 to MIS 11) during Gunz. Thus, there have probably been about 5 glacial cycles of varying intensity during Gunz. During Gunz the 41 000 year glacial cycle of previous stages (Biber and Danube) had been replaced by a dominance of a 100,000-year cycle (Mid-Pleistocene Transition). The most intense glacials of Gunz (MIS 16 and MIS 12) reached similar extents to those of the more recent Riss and Wurm glacials. These have not been easy to identify in the geological record of the Alps, but MIS 16 has been identified with the Don Glaciation of Eastern Europe. The strong glacial MIS 12 has been problematic, and has sometimes been identified with the Mindel glaciation, which would imply an end to Gunz already after MIS 13 (480 000 years ago). There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago. Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods, respectively. The Earth is currently in such an interglacial period of the Quaternary glaciation, with the Last Glacial Period of the Quaternary having ended approximately 11,700 years ago. The current interglacial is known as the Holocene epoch. Based on climate proxies, paleoclimatologists study the different climate states originating from glaciation. The name Gunz glaciation, Gunzian glaciation or Günz glacial stage (German: Günz-Kaltzeit, also Günz-Glazial, Günz-Komplex and Günz-Eiszeit) goes back to Albrecht Penck and Eduard Brückner, who named this ice age after the River Günz in their multi-volume work, Die Alpen im Eiszeitalter ("The Alps in the Ice Age Period") which was published between 1901 and 1909. Its type region is the Iller-Lech Plateau. It is the oldest glaciation of the Pleistocene in the traditional, quadripartite glacial classification of the Alps. The Günz was thought to follow the Danube-Günz interglacial and was ended by the Günz-Haslach interglacial. The 2016 version of the detailed stratigraphic table by the German Stratigraphic Commission puts the start of Gunz in the late Calabrian (approximately one million years ago, earlier than MIS 19) and shows a continuity of glacial cycles with the following Mindel stage, with the border arbitrarily put at the start of MIS 10 (approximately 374 000 years ago). Gunz corresponds roughly to the Cromerian stage in the glacial history of Northern Europe.
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The Araçuaí Belt is the west portion of an orogen that included the West Congo orogen. The rifting and opening of the South Atlantic Ocean divided the orogen into an Africa and a South American part. The Araçuaí Belt lies east of the São Francisco Craton and northeast of the Brasilia
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Mammals are the only living members of Synapsida, one of the two main clades of amniote tetrapods along with Sauropsida (reptiles and birds), whose lineage diverged away from ancestors of mammals over 300 million years ago in the Carboniferous period of the Paleozoic era. Early synapsids were sphenacodonts. The synapsids split into several diverse groups of non-mammalian synapsids — traditionally and incorrectly referred to as "mammal-like reptiles" or by the term "pelycosaurs", and now known as stem mammals or protomammals
In the south, the tourist points are the hydro-mineral spas, such as Caxambu, Lambari, São Lourenço, Poços de Caldas, São Thomé das Letras, Monte Verde (a district of the municipality of Camanducaia) and the national parks of Caparaó and Canastra. The landscape of the state is marked by mountains, valleys, and large areas of fertile lands. In the Serra do Cipó, Sete Lagoas, Cordisburgo and Lagoa Santa, the caves and waterfalls are the attractions. Some of Brazil's most famous caves are located there. With an area of 586,528 square kilometres (226,460 sq mi)—larger than Metropolitan France—it is the fourth largest state in Brazil. The main producer of coffee and milk in the country, Minas Gerais is known for its heritage of architecture and colonial art in historical cities such as São João del-Rei, Congonhas, Ouro Preto, Diamantina, Tiradentes, Mariana, Sabará and Serro.
Two interpretations are given for the origin of the name Minas Gerais. It comes from "Minas dos Matos Gerais", the former name of the colonial province ("Mines of the General Woods"). The first interpretation is that the name simply means "General Mines", with the word Gerais serving as an adjective to the mines, which were themselves spread in several spots around a larger region. The second interpretation is that this ignores the two large geographical spaces which conformed the state in its history: the region of the mines (Minas), and the region of the Gerais ("Matos Gerais" or "Campos Gerais", which means something close to "General Fields"). These corresponded to the areas of sertão which were farther and hard to access (with an economy based on farming and agriculture) from the mining spots (whose economic space was urban from its origin). Minas Gerais is in the north of the southeast region of Brazil, which also contains the states of São Paulo, Rio de Janeiro and Espírito Santo. It borders Bahia (north), Goiás (west and northwest), Mato Grosso do Sul (far west), the states of São Paulo and Rio de Janeiro (south) and the state of Espírito Santo (east). It also shares a short boundary with the Federal District (northwest). Minas Gerais is situated between 14°13'58" and 22°54'00" S latitude and between 39°51'32" and 51°02'35" W longitude. It is larger in area than Metropolitan France or Spain. Minas Gerais features some of the longest rivers in Brazil, most notably the São Francisco, the Paraná and to a lesser extent, the Doce river. The state also holds many hydroelectric power plants, including Furnas. Some of the highest peaks in Brazil are in the mountain ranges in the southern part of the state, such as the Mantiqueira Mountains and Serra do Cervo, that mark the border between Minas and its neighbors São Paulo and Rio de Janeiro. The most notable one is the Bandeira peak, the third highest mountain in Brazil at 2,890 m, standing on the border with Espírito Santo state. The state also has huge reserves of iron and sizeable reserves of gold and gemstones, including emerald, topaz and aquamarine mines. Emeralds found in this location are comparable to the best Colombia-origin emeralds, and are most often a bluish-green color.
Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago, the other being Gondwana. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Asia.
Analysis of nuclear DNA sequences indicates that the genetic divergence between African bush and forest elephants dates 2.6 – 5.6 million years ago. The divergence between the Asian elephant and the woolly mammoths is estimated 2.5 – 5.4 million years ago, which strongly supports their status as distinct species. The African forest elephant was found to have a high degree of genetic diversity, perhaps reflecting periodic fragmentation of their habitat during the climatic changes in the Pleistocene.
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African elephants have grey folded skin up to 30 mm (1.2 in) thick that is covered with sparse, bristled dark-brown to black hair. Short tactile hair grows on the trunk, which has two finger-like processes at the tip, whereas Asian elephants only have one. Their large ears help to reduce body heat; flapping them creates air currents and exposes the ears' inner sides where large blood vessels increase heat loss during hot weather. The trunk is a prehensile elongation of its upper lip and nose. This highly sensitive organ is innervated primarily by the trigeminal nerve, and thought to be manipulated by about 40,000–60,000 muscles. Because of this muscular structure, the trunk is so strong that elephants can use it for lifting about 3% of their own body weight. They use it for smelling, touching, feeding, drinking, dusting, producing sounds, loading, defending and attacking. Elephants sometimes swim underwater and use their trunks as snorkels.
Both male and female African elephants have tusks that grow from deciduous teeth called tushes, which are replaced by tusks when calves are about one year old. Tusks are composed of dentin, which forms small diamond-shaped structures in the tusk's center that become larger at its periphery. Tusks are primarily used to dig for roots and strip the bark from trees for food, for fighting each other during mating season, and for defending themselves against predators. The tusks weigh from 23 to 45 kg (51–99 lb) and can be from 1.5 to 2.4 m (5–8 ft) long. They are curved forward and continue to grow throughout the elephant's lifetime. The dental formula of elephants is 1.0.3.30.0.3.3 × 2 = 26. Elephants have four molars; each weighs about 5 kg (11 lb) and measures about 30 cm (12 in) long. As the front pair wears down and drops out in pieces, the back pair moves forward, and two new molars emerge in the back of the mouth. Elephants replace their teeth four to six times in their lifetimes. At around 40 to 60 years of age, the elephant loses the last of its molars and will likely die of starvation which is a common cause of death. African elephants have 24 teeth in total, six on each quadrant of the jaw. The enamel plates of the molars are fewer in number than in Asian elephants. The African bush elephant is the largest terrestrial animal. Cows are 2.2–2.6 m (7.2–8.5 ft) tall at the shoulder and weigh 2,160–3,232 kg (4,762–7,125 lb), while bulls are 3.2–4 m (10–13 ft) tall and weigh 4,700–6,048 kg (10,362–13,334 lb). Its back is concave-shaped, while the back of the African forest elephant is nearly straight. The largest recorded individual stood 3.96 metres (13.0 ft) at the shoulder, and is estimated to have weighed 10,400 kg (22,900 lb)
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A large landmass, sometimes referred to as a supercontinent. It was formed by the accretion of several cratons (a large stable block of the Earth's crust), beginning c. 800 to 650 Ma with the East African Orogeny, the collision of India and Madagascar with East Africa
Minas Gerais is a state in Southeastern Brazil. It ranks as the second most populous, the third by gross domestic product (GDP), and the fourth largest by area in the country. The state's capital and largest city, Belo Horizonte (literally "Beautiful Horizon"), is a major urban and finance center in Latin America, and the sixth largest municipality in Brazil and its metropolitan area is the third largest in Brazil with just over 5.8 million inhabitants, after those of São Paulo and Rio de Janeiro.Nine Brazilian presidents were born in Minas Gerais, the most of any state. The state has 10.1% of the Brazilian population and is responsible for 8.7% of the Brazilian GDP. With an area of 586,528 square kilometres (226,460 sq mi)—larger than Metropolitan France—it is the fourth largest state in Brazil. The main producer of coffee and milk in the country, Minas Gerais is known for its heritage of architecture and colonial art in historical cities such as São João del-Rei, Congonhas, Ouro Preto, Diamantina, Tiradentes, Mariana, Sabará and Serro. In the south, the tourist points are the hydro-mineral spas, such as Caxambu, Lambari, São Lourenço, Poços de Caldas, São Thomé das Letras, Monte Verde (a district of the municipality of Camanducaia) and the national parks of Caparaó and Canastra. The landscape of the state is marked by mountains, valleys, and large areas of fertile lands. In the Serra do Cipó, Sete Lagoas, Cordisburgo and Lagoa Santa, the caves and waterfalls are the attractions. Some of Brazil's most famous caves are located there.
Minas Gerais is a state in Southeastern Brazil. It ranks as the second most populous, the third by gross domestic product (GDP), and the fourth largest by area in the country. The state's capital and largest city, Belo Horizonte (literally "Beautiful Horizon"), is a major urban and finance center in Latin America, and the sixth largest municipality in Brazil and its metropolitan area is the third largest in Brazil with just over 5.8 million inhabitants, after those of São Paulo and Rio de Janeiro.Nine Brazilian presidents were born in Minas Gerais, the most of any state. The state has 10.1% of the Brazilian population and is responsible for 8.7% of the Brazilian GDP. With an area of 586,528 square kilometres (226,460 sq mi)—larger than Metropolitan France—it is the fourth largest state in Brazil. The main producer of coffee and milk in the country, Minas Gerais is known for its heritage of architecture and colonial art in historical cities such as São João del-Rei, Congonhas, Ouro Preto, Diamantina, Tiradentes, Mariana, Sabará and Serro. In the south, the tourist points are the hydro-mineral spas, such as Caxambu, Lambari, São Lourenço, Poços de Caldas, São Thomé das Letras, Monte Verde (a district of the municipality of Camanducaia) and the national parks of Caparaó and Canastra. The landscape of the state is marked by mountains, valleys, and large areas of fertile lands. In the Serra do Cipó, Sete Lagoas, Cordisburgo and Lagoa Santa, the caves and waterfalls are the attractions. Some of Brazil's most famous caves are located there.
Two interpretations are given for the origin of the name Minas Gerais. It comes from "Minas dos Matos Gerais", the former name of the colonial province ("Mines of the General Woods"). The first interpretation is that the name simply means "General Mines", with the word Gerais serving as an adjective to the mines, which were themselves spread in several spots around a larger region. The second interpretation is that this ignores the two large geographical spaces which conformed the state in its history: the region of the mines (Minas), and the region of the Gerais ("Matos Gerais" or "Campos Gerais", which means something close to "General Fields"). These corresponded to the areas of sertão which were farther and hard to access (with an economy based on farming and agriculture) from the mining spots (whose economic space was urban from its origin). Minas Gerais is in the north of the southeast region of Brazil, which also contains the states of São Paulo, Rio de Janeiro and Espírito Santo. It borders Bahia (north), Goiás (west and northwest), Mato Grosso do Sul (far west), the states of São Paulo and Rio de Janeiro (south) and the state of Espírito Santo (east). It also shares a short boundary with the Federal District (northwest). Minas Gerais is situated between 14°13'58" and 22°54'00" S latitude and between 39°51'32" and 51°02'35" W longitude. It is larger in area than Metropolitan France or Spain. Minas Gerais features some of the longest rivers in Brazil, most notably the São Francisco, the Paraná and to a lesser extent, the Doce river. The state also holds many hydroelectric power plants, including Furnas. Some of the highest peaks in Brazil are in the mountain ranges in the southern part of the state, such as the Mantiqueira Mountains and Serra do Cervo, that mark the border between Minas and its neighbors São Paulo and Rio de Janeiro. The most notable one is the Bandeira peak, the third highest mountain in Brazil at 2,890 m, standing on the border with Espírito Santo state. The state also has huge reserves of iron and sizeable reserves of gold and gemstones, including emerald, topaz and aquamarine mines. Emeralds found in this location are comparable to the best Colombia-origin emeralds, and are most often a bluish-green color.
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Continental 🌐 fragments that now make 💥 up part 👀 of Europe
Austrian geologist Eduard Suess proposed that the continents in the Southern Hemisphere were once merged into a larger continent called Gondwana. In 1915 German meteorologist Alfred Wegener proposed the existence of a supercontinent called Pangaea.
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With an area of 586,528 square kilometres (226,460 sq mi)—larger than Metropolitan France—it is the fourth largest state in Brazil. The main producer of coffee and milk in the country, Minas Gerais is known for its heritage of architecture and colonial art in historical cities such as São João del-Rei, Congonhas, Ouro Preto, Diamantina, Tiradentes, Mariana, Sabará and Serro. In the south, the tourist points are the hydro-mineral spas, such as Caxambu, Lambari, São Lourenço, Poços de Caldas, São Thomé das Letras, Monte Verde (a district of the municipality of Camanducaia) and the national parks of Caparaó and Canastra. The landscape of the state is marked by mountains, valleys, and large areas of fertile lands. In the Serra do Cipó, Sete Lagoas, Cordisburgo and Lagoa Santa, the caves and waterfalls are the attractions. Some of Brazil's most famous caves are located there.
It is the fourth largest state in Brazil. The main producer of coffee and milk in the country, known for its heritage of architecture and colonial art in historical cities such as São João del-Rei, Congonhas, Ouro Preto, Diamantina, Tiradentes, Mariana, Sabará and Serro. In the south, the tourist points are the hydro-mineral spas, such as Caxambu, Lambari, São Lourenço, Poços de Caldas, São Thomé das Letras, Monte Verde (a district of the municipality of Camanducaia) and the national parks of Caparaó and Canastra. The landscape of the state is marked by mountains, valleys, and large areas of fertile lands. In the Serra do Cipó, Sete Lagoas, Cordisburgo and Lagoa Santa, the caves and waterfalls are the attractions. Some of Brazil's most famous caves are located there.
Two interpretations are given for the origin of the name Minas Gerais. It comes from "Minas dos Matos Gerais", the former name of the colonial province ("Mines of the General Woods"). The first interpretation is that the name simply means "General Mines", with the word Gerais serving as an adjective to the mines, which were themselves spread in several spots around a larger region. The second interpretation is that this ignores the two large geographical spaces which conformed the state in its history: the region of the mines (Minas), and the region of the Gerais ("Matos Gerais" or "Campos Gerais", which means something close to "General Fields"). These corresponded to the areas of sertão which were farther and hard to access (with an economy based on farming and agriculture) from the mining spots (whose economic space was urban from its origin). Minas Gerais is in the north of the southeast region of Brazil, which also contains the states of São Paulo, Rio de Janeiro and Espírito Santo. It borders Bahia (north), Goiás (west and northwest), Mato Grosso do Sul (far west), the states of São Paulo and Rio de Janeiro (south) and the state of Espírito Santo (east). It also shares a short boundary with the Federal District (northwest). Minas Gerais is situated between 14°13'58" and 22°54'00" S latitude and between 39°51'32" and 51°02'35" W longitude. It is larger in area than Metropolitan France or Spain. Minas Gerais features some of the longest rivers in Brazil, most notably the São Francisco, the Paraná and to a lesser extent, the Doce river. The state also holds many hydroelectric power plants, including Furnas. Some of the highest peaks in Brazil are in the mountain ranges in the southern part of the state, such as the Mantiqueira Mountains and Serra do Cervo, that mark the border between Minas and its neighbors São Paulo and Rio de Janeiro. The most notable one is the Bandeira peak, the third highest mountain in Brazil at 2,890 m, standing on the border with Espírito Santo state. The state also has huge reserves of iron and sizeable reserves of gold and gemstones, including emerald, topaz and aquamarine mines. Emeralds found in this location are comparable to the best Colombia-origin emeralds, and are most often a bluish-green color.
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Sharp Earth enables disparate language groups -Latin, Arabic, Indic, Japanese, Greek, Thai, English and various indigenous languages - to appear graphically harmonious while remaining legible and true to their origins.
From crater counts on other celestial bodies, it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 Ga, and concluded around 3.8 Ga, at the end of the Hadean. In addition, volcanism was severe due to the large heat flow and geothermal gradient. Nevertheless, detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, suggesting that the Earth already had oceans or seas at that time.By the beginning of the Archean, the Earth had cooled significantly. From crater counts on other celestial bodies, it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 Ga, and concluded around 3.8 Ga, at the end of the Hadean. In addition, volcanism was severe due to the large heat flow and geothermal gradient. Nevertheless, detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, suggesting that the Earth already had oceans or seas at that time.By the beginning of the Archean, the Earth had cooled significantly. Present
Z liczby kraterów na innych ciałach niebieskich wnioskuje się, że okres intensywnych uderzeń meteorytów, zwany późnym ciężkim bombardowaniem, rozpoczął się około 4,1 Ga i zakończył około 3,8 Ga na końcu Hadeanu. Ponadto wulkanizm był poważny ze względu na duży przepływ ciepła i gradient geotermalny. Niemniej jednak detrytyczne kryształy cyrkonu datowane na 4,4 Ga wykazują dowody na kontakt z ciekłą wodą, co sugeruje, że na Ziemi istniały już wówczas oceany lub morza. Na początku archaiku Ziemia znacznie się ochłodziła. Z liczby kraterów na innych ciałach niebieskich wnioskuje się, że okres intensywnych uderzeń meteorytów, zwany późnym ciężkim bombardowaniem, rozpoczął się około 4,1 Ga i zakończył około 3,8 Ga na końcu Hadeanu. Ponadto wulkanizm był poważny ze względu na duży przepływ ciepła i gradient geotermalny. Niemniej jednak detrytyczne kryształy cyrkonu datowane na 4,4 Ga wykazują dowody na kontakt z ciekłą wodą, co sugeruje, że na Ziemi istniały już wówczas oceany lub morza. Na początku archaiku Ziemia znacznie się ochłodziła. Obecny
На основании подсчета кратеров на других небесных телах можно сделать вывод, что период интенсивных ударов метеоритов, названный Поздней тяжелой бомбардировкой, начался около 4,1 млрд лет назад и завершился около 3,8 млрд лет назад, в конце Гадея. Кроме того, вулканизм был сильным из-за большого теплового потока и геотермического градиента. Тем не менее, обломочные кристаллы циркона, датированные 4,4 млрд лет, свидетельствуют о контакте с жидкой водой, что позволяет предположить, что на Земле в то время уже были океаны или моря. К началу архея Земля значительно остыла. На основании подсчета кратеров на других небесных телах можно сделать вывод, что период интенсивных ударов метеоритов, названный Поздней тяжелой бомбардировкой, начался около 4,1 млрд лет назад и завершился около 3,8 млрд лет назад, в конце Гадея. Кроме того, вулканизм был сильным из-за большого теплового потока и геотермического градиента. Тем не менее, обломочные кристаллы циркона, датированные 4,4 млрд лет, свидетельствуют о контакте с жидкой водой, что позволяет предположить, что на Земле в то время уже были океаны или моря. К началу архея Земля значительно остыла.
Από τις μετρήσεις κρατήρων σε άλλα ουράνια σώματα, συνάγεται ότι μια περίοδος έντονων κρούσεων μετεωριτών, που ονομάζεται Ύστερος Βαρύς Βομβαρδισμός, ξεκίνησε περίπου στα 4,1 Ga και ολοκληρώθηκε γύρω στα 3,8 Ga, στο τέλος του Αδαίου. Επιπλέον, ο ηφαιστειασμός ήταν σοβαρός λόγω της μεγάλης ροής θερμότητας και της γεωθερμικής κλίσης. Παρόλα αυτά, κρύσταλλοι ζιρκονίου που χρονολογούνται στο 4,4 Ga δείχνουν στοιχεία επαφής με υγρό νερό, υποδηλώνοντας ότι η Γη είχε ήδη ωκεανούς ή θάλασσες εκείνη την εποχή. Από την αρχή του Αρχαίου, η Γη είχε κρυώσει σημαντικά. Από τις μετρήσεις κρατήρων σε άλλα ουράνια σώματα, συνάγεται ότι μια περίοδος έντονων κρούσεων μετεωριτών, που ονομάζεται Ύστερος Βαρύς Βομβαρδισμός, ξεκίνησε περίπου στα 4,1 Ga και ολοκληρώθηκε γύρω στα 3,8 Ga, στο τέλος του Αδαίου. Επιπλέον, ο ηφαιστειασμός ήταν σοβαρός λόγω της μεγάλης ροής θερμότητας και της γεωθερμικής κλίσης. Παρόλα αυτά, κρύσταλλοι ζιρκονίου που χρονολογούνται στο 4,4 Ga δείχνουν στοιχεία επαφής με υγρό νερό, υποδηλώνοντας ότι η Γη είχε ήδη ωκεανούς ή θάλασσες εκείνη την εποχή. Από την αρχή του Αρχαίου, η Γη είχε κρυώσει σημαντικά. Παρόν
จากการนับปล่องภูเขาไฟบนเทห์ฟากฟ้าอื่นๆ สรุปได้ว่าช่วงที่อุกกาบาตพุ่งชนอย่างรุนแรง เรียกว่า การทิ้งระเบิดหนักตอนปลาย (Late Heavy Bombardment) เริ่มต้นประมาณ 4.1 Ga และสรุปที่ประมาณ 3.8 Ga ที่ปลายสุดของฮาเดียน นอกจากนี้ ภูเขาไฟยังมีความรุนแรงเนื่องจากมีความร้อนไหลเข้ามามากและการไล่ระดับความร้อนใต้พิภพ อย่างไรก็ตาม ผลึกเพทายที่เสียหายซึ่งมีอายุถึง 4.4 Ga แสดงหลักฐานของการสัมผัสกับน้ำของเหลว ซึ่งบ่งบอกว่าโลกมีมหาสมุทรหรือทะเลอยู่แล้วในขณะนั้น เมื่อถึงจุดเริ่มต้นของ Archean โลกก็เย็นลงอย่างเห็นได้ชัด ปัจจุบัน จากการนับปล่องภูเขาไฟบนเทห์ฟากฟ้าอื่นๆ สรุปได้ว่าช่วงที่อุกกาบาตพุ่งชนอย่างรุนแรง เรียกว่า การทิ้งระเบิดหนักตอนปลาย (Late Heavy Bombardment) เริ่มต้นประมาณ 4.1 Ga และสรุปที่ประมาณ 3.8 Ga ที่ปลายสุดของฮาเดียน นอกจากนี้ ภูเขาไฟยังมีความรุนแรงเนื่องจากมีความร้อนไหลเข้ามามากและการไล่ระดับความร้อนใต้พิภพ อย่างไรก็ตาม ผลึกเพทายที่เสียหายซึ่งมีอายุถึง 4.4 Ga แสดงหลักฐานของการสัมผัสกับน้ำของเหลว ซึ่งบ่งบอกว่าโลกมีมหาสมุทรหรือทะเลอยู่แล้วในขณะนั้น เมื่อถึงจุดเริ่มต้นของ Archean โลกก็เย็นลงอย่างเห็นได้ชัด ปัจจุบัน
من خلال تعداد الحفر على الأجرام السماوية الأخرى، يُستنتج أن فترة من التأثيرات النيزكية الشديدة، تسمى القصف الثقيل المتأخر، بدأت حوالي 4.1 مليار سنة، وانتهت حوالي 3.8 مليار سنة، في نهاية العصر الهادياني. بالإضافة إلى ذلك، كانت البراكين شديدة بسبب التدفق الحراري الكبير والتدرج الحراري الأرضي. ومع ذلك، فإن بلورات الزركون الفتاتية التي يرجع تاريخها إلى 4.4 مليار سنة تظهر دليلاً على تعرضها للتلامس مع الماء السائل، مما يشير إلى أن الأرض كانت تحتوي بالفعل على محيطات أو بحار في ذلك الوقت. وبحلول بداية العصر الأركي، كانت الأرض قد بردت بشكل ملحوظ. حاضر من خلال تعداد الحفر على الأجرام السماوية الأخرى، يُستنتج أن فترة من التأثيرات النيزكية الشديدة، تسمى القصف الثقيل المتأخر، بدأت حوالي 4.1 مليار سنة، وانتهت حوالي 3.8 مليار سنة، في نهاية العصر الهادياني. بالإضافة إلى ذلك، كانت البراكين شديدة بسبب التدفق الحراري الكبير والتدرج الحراري الأرضي. ومع ذلك، فإن بلورات الزركون الفتاتية التي يرجع تاريخها إلى 4.4 مليار سنة تظهر دليلاً على تعرضها للتلامس مع الماء السائل، مما يشير إلى أن الأرض كانت تحتوي بالفعل على محيطات أو بحار في ذلك الوقت. وبحلول بداية العصر الأركي، كانت الأرض قد بردت بشكل ملحوظ. حاضر
अन्य खगोलीय पिंडों पर क्रेटर गणना से, यह अनुमान लगाया जाता है कि तीव्र उल्कापिंड प्रभावों की अवधि, जिसे लेट हेवी बॉम्बार्डमेंट कहा जाता है, लगभग 4.1 Ga में शुरू हुई और हेडियन के अंत में 3.8 Ga के आसपास समाप्त हुई। इसके अलावा, बड़े ताप प्रवाह और भूतापीय प्रवणता के कारण ज्वालामुखी गंभीर था। फिर भी, 4.4 Ga के डेट्राइटल जिरकोन क्रिस्टल तरल पानी के संपर्क में आने का प्रमाण दिखाते हैं, जिससे पता चलता है कि उस समय पृथ्वी पर पहले से ही महासागर या समुद्र थे। आर्कियन की शुरुआत तक, पृथ्वी काफी हद तक ठंडी हो गई थी। उपस्थित अन्य खगोलीय पिंडों पर क्रेटर गणना से, यह अनुमान लगाया जाता है कि तीव्र उल्कापिंड प्रभावों की अवधि, जिसे लेट हेवी बॉम्बार्डमेंट कहा जाता है, लगभग 4.1 Ga में शुरू हुई और हेडियन के अंत में 3.8 Ga के आसपास समाप्त हुई। इसके अलावा, बड़े ताप प्रवाह और भूतापीय प्रवणता के कारण ज्वालामुखी गंभीर था। फिर भी, 4.4 Ga के डेट्राइटल जिरकोन क्रिस्टल तरल पानी के संपर्क में आने का प्रमाण दिखाते हैं, जिससे पता चलता है कि उस समय पृथ्वी पर पहले से ही महासागर या समुद्र थे। आर्कियन की शुरुआत तक, पृथ्वी काफी हद तक ठंडी हो गई थी। उपस्थित
古代になり、文字で記録や歴史が残される時代になっても、星の研究はもっぱら肉眼で行われた。しかし文明が発達するとともに、バビロニア・中国・エジプト・ギリシア・インド・中央アメリカなどで天文台が建設され、宇宙の根元についての考察が発展を始めた。ほとんどの初期天文学は、恒星や惑星の位置を記す、現在では位置天文学と呼ばれるものだった。これらの観測から、惑星の挙動に対する最初のアイデアが形成され、宇宙における太陽・月そして地球の根源が哲学的に探求された。「地球は宇宙の中心にあり、太陽・月・星々が周囲を廻っている」と考えられた。この考え方は、クラウディオス・プトレマイオスから名を取って「プトレマイック・システム (Ptolemaic System)」と呼ばれる。