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Tunguska Event
The Tunguska event (occasionally also called the Tunguska incident) was an approximately 12-megaton explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of June 30, 1908. The explosion over the sparsely populated Eastern Siberian Taiga flattened an estimated 80 million trees over an area of of forest, and eyewitness reports suggest that at least three people may have died in the event. The explosion is generally attributed to a meteor air burst: the atmospheric explosion of a stony asteroid about in size. The supposed asteroid approached from the east-southeast, and likely with a relatively high speed of about (~ Ma 80). It is classified as an impact event, even though no impact crater has been found; the object is thought to have disintegrated at an altitude of rather than having hit the surface of the Earth. The Tunguska event is the largest impact event on Earth in recorded history, thou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonid Kulik
Leonid Alekseyevich Kulik (Russian: Леонид Алексеевич Кулик; 19 August 1883 – 14 or 24 April 1942) was a Soviet mineralogist who is noted for his research into meteorites. He was born in Dorpat, (now Tartu, Tartu County, Estonia), and was educated at the Imperial Forestry Institute in Saint Petersburg and the Kazan University. He served in the Russian military during the Russo-Japanese War, then spent some time in jail for revolutionary political activities. He then served with the Russian military during World War I. Following the war he became an instructor, teaching mineralogy in Tomsk. In 1920 he was offered a job at the Mineralogical Museum in St. Petersburg. In 1927, he led the first Soviet research expedition to investigate the Tunguska event, the largest impact event in recorded history, which had occurred on 30 June 1908. He made a reconnaissance trip to the region, accompanied by Nikolay Ivanovich Fedorov and others, and interviewed local witne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recorded History
Recorded history or written history describes the historical events that have been recorded in a written form or other documented communication which are subsequently evaluated by historians using the historical method. For broader world history, recorded history begins with the accounts of the ancient world around the 4th millennium BC, and it coincides with the invention of writing. For some geographic regions or cultures, written history is limited to a relatively recent period in human history because of the limited use of written records. Moreover, human cultures do not always record all of the information which is considered relevant by later historians, such as the full impact of natural disasters or the names of individuals. Recorded history for particular types of information is therefore limited based on the types of records kept. Because of this, recorded history in different contexts may refer to different periods of time depending on the topic. The interpretation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago and the Russian Far East to the east. The continental landmass is bordered by the Atlantic Ocean and Africa to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two continents is a historical social construct, as many of their borders are over land; thus, in some parts of the world, Eurasia is recognized as the largest of the six, five, or four continents on Earth. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on paleomagnetic data. Eurasia covers around , or around 36.2% of the Earth's total land area. It is also home to the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes such as explosions. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time is called a seismogram. A seismologist is a scientist who does research in seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus (c. 585 BCE), Anaximenes of Miletus (c. 550 BCE), Aristotle (c. 340 BCE), and Zha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Baikal
Lake Baikal (, russian: Oзеро Байкал, Ozero Baykal ); mn, Байгал нуур, Baigal nuur) is a rift lake in Russia. It is situated in southern Siberia, between the federal subjects of Irkutsk Oblast to the northwest and the Republic of Buryatia to the southeast. With of water, Lake Baikal is the world's largest freshwater lake by volume, containing 22–23% of the world's fresh surface water, more than all of the North American Great Lakes combined. It is also the world's deepest lake, with a maximum depth of , and the world's oldest lake, at 25–30 million years. At —slightly larger than Belgium—Lake Baikal is the world's seventh-largest lake by surface area. It is among the world's clearest lakes. Lake Baikal is home to thousands of species of plants and animals, many of them endemic to the region. It is also home to Buryat tribes, who raise goats, camels, cattle, sheep, and horses on the eastern side of the lake, where the mean temperature var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evenkis
The Evenks (also spelled Ewenki or Evenki based on their endonym )Autonym: (); russian: Эвенки (); (); formerly known as Tungus or Tunguz; mn, Хамниган () or Aiwenji () are a Tungusic people of North Asia. In Russia, the Evenks are recognised as one of the indigenous peoples of the Russian North, with a population of 38,396 ( 2010 census). In China, the Evenki form one of the 56 ethnic groups officially recognised by the People's Republic of China, with a population of 30,875 ( 2010 census). There are 537 Evenks in Mongolia (2015 census), called ''Khamnigan'' in the Mongolian language. Origin The Evenks or Ewenki are sometimes conjectured to be connected to the Shiwei people who inhabited the Greater Khingan Range in the 5th to 9th centuries, although the native land of the majority of Evenki people is in the vast regions of Siberia between Lake Baikal and the Amur River. The Ewenki language forms the northern branch of the Manchu- Tungusic language group a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soviet Calendar
The Soviet calendar was a modified Gregorian calendar that was used in Soviet Russia between 1918 and 1940. Several variations were used during that time. The Gregorian calendar, under the name "Western European calendar", was implemented in Soviet Russia in February 1918 by dropping the Julian dates of . As many as nine national holidays (paid days of rest) were implemented in the following decade, but four were eliminated or merged on , leaving only five national holidays: 22January, 1–2May, and 7–8November until 1951, when 22January reverted to a normal day. During the summer of 1929, five-day continuous work weeks were implemented in factories, government offices, and commercial enterprises, but not collective farms. One of the five days was randomly assigned to each worker as their day of rest, without regard to the rest days assigned to their family members or friends. These five-day work weeks continued throughout the Gregorian year, interrupted only by the five natio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Calendar
The Julian calendar, proposed by Roman consul Julius Caesar in 46 BC, was a reform of the Roman calendar. It took effect on , by edict. It was designed with the aid of Greek mathematicians and astronomers such as Sosigenes of Alexandria. The calendar became the predominant calendar in the Roman Empire and subsequently most of the Western world for more than 1,600 years until 1582, when Pope Gregory XIII promulgated a minor modification to reduce the average length of the year from 365.25 days to 365.2425 days and thus corrected the Julian calendar's drift against the solar year. Worldwide adoption of this revised calendar, which became known as the Gregorian calendar, took place over the subsequent centuries, first in Catholic countries and subsequently in Protestant countries of the Western Christian world. The Julian calendar is still used in parts of the Eastern Orthodox Church and in parts of Oriental Orthodoxy as well as by the Berbers. The Julian calenda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adoption Of The Gregorian Calendar
The adoption of the Gregorian Calendar was an event in the early modern history of most cultures and societies, marking a change from their traditional (or "old style") dating system to the modern (or "new style") dating system the Gregorian calendar that is widely used around the world today. Some states adopted the new calendar from 1582, some did not do so before the early twentieth century, and others did so at various dates between. A number of jurisdictions continue to use a different civil calendar. For many the new style calendar is only used for civil purposes and the old style calendar remains used in religious contexts. Today, the Gregorian calendar is the world's most widely used civil calendar. During and for some time after the change between systems, it has been common to use the terms "Old Style" and "New Style" when giving dates, to indicate which calendar was used to reckon them. The Gregorian calendar was decreed in 1582 by the papal bull by Pope Gregory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Impact Avoidance
Asteroid impact avoidance comprises the methods by which near-Earth objects (NEO) on a potential collision course with Earth could be diverted away, preventing destructive impact events. An impact by a sufficiently large asteroid or other NEOs would cause, depending on its impact location, massive tsunamis or multiple firestorms, and an impact winter caused by the sunlight-blocking effect of large quantities of pulverized rock dust and other debris placed into the stratosphere. A collision 66 million years ago between the Earth and an object approximately wide is thought to have produced the Chicxulub crater and triggered the Cretaceous–Paleogene extinction event that is understood by the scientific community to have caused the extinction of all non-avian dinosaurs. While the chances of a major collision are low in the near term, it is a near-certainty that one will happen eventually unless defensive measures are taken. Astronomical events—such as the Shoemaker-Levy 9 imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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