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Yu Xi
Yu Xi (虞喜; 307–345 AD), courtesy name Zhongning (仲寧), was a Chinese astronomer, politician, and writer of the Jin dynasty (266–420 AD). He is best known for his discovery of the precession of the equinoxes, independently of the earlier ancient Greek astronomer Hipparchus. He also postulated that the Earth could be spherical in shape instead of being flat and square, long before the idea became widely accepted in Chinese science with the advances in circumnavigation by Europeans from the 16th-20th centuries, especially with their arrival into the capital's imperial court in the 17th century. Background and official career The life and works of Yu Xi are described in his biography found in the ''Book of Jin'', the official history of the Jin dynasty.Knechtges and Chang (2014), p. 2010. He was born in Yuyao, Guiji (modern Shaoxing, Zhejiang province, China). Yu Song, son of Yu Fan, was recorded to be his clan elder. His father Yu Cha (虞察) was a military commander ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yu (Chinese Surname)
Yu is the pinyin romanisation of several Chinese family names. However, in the Wade–Giles romanisation system, Yu is equivalent to You (surname), You in pinyin. "Yu" may represent many different Chinese characters, including #Surname Yu (余), 余, Yu Surname (于), 于, 由, #Prominent people with family name 魚, 魚 (鱼), 漁(渔), 楀, 俞(兪), 喻 (this character is 35th name on the ''Hundred Family Surnames'' poem), 於, 遇, 虞, 郁, 尉, 禹, 游, 尤, 庾, 娛(娱), and Ru (surname), 茹 (Rú). The most common of the Yu surnames are 于, 余, and 俞. In China, 0.62% of the population have the family name 于 in 2002 (about 7.4 million), and this surname is most common in Shandong province and northeastern China. Around 0.41% of the population have the surname 余 in 2002 (over five million), and it is most common in Jiangxi, Zhejiang and Fujian provinces. The 俞 surname represents around 0.12% of China's population. Surname Yu (于) Surname Yu (余) Surname Yu (� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commandery (China)
A commandery ( zh, s=郡, p=jùn) was a historical administrative division of China that was in use from the Eastern Zhou (c. 7th century BCE) until the early Tang dynasty (c. 7th century CE). Several neighboring countries adopted Chinese commanderies as the basis for their own administrative divisions. History and development China Eastern Zhou During the Eastern Zhou's Spring and Autumn period from the 8th to 5th centuries BCE, the larger and more powerful of the Zhou dynasty, Zhou's Chinese feudalism, vassal states—including Qin (state), Qin, Jin (Chinese state), Jin and Wei (state), Wei—began annexing their smaller rivals. These new lands were not part of their original fiefs and were instead organized into Counties of the People's Republic of China#History, counties (''xiàn''). Eventually, commanderies were developed as marchlands between the Warring States period, major realms. Despite having smaller populations and ranking lower on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Astronomy
The history of astronomy focuses on the contributions civilizations have made to further their understanding of the universe beyond earth's atmosphere. Astronomy is one of the oldest natural sciences, achieving a high level of success in the second half of the first millennium. Astronomy has origins in the religious, mythological, cosmological, calendrical, and astrological beliefs and practices of prehistory. Early astronomical records date back to the Babylonians around 1000 BCE. There is also astronomical evidence of interest from early Chinese, Central American and North European cultures. Astronomy was used by early cultures for a variety of reasons. These include timekeeping, navigation, spiritual and religious practices, and agricultural planning. Ancient astronomers used their observations to chart the skies in an effort to learn about the workings of the universe. During the Renaissance Period, revolutionary ideas emerged about astronomy. One such idea was contributed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zhang Heng
Zhang Heng (; AD 78–139), formerly romanization of Chinese, romanized Chang Heng, was a Chinese polymathic scientist and statesman who lived during the Han dynasty#Eastern Han (25–220 AD), Eastern Han dynasty. Educated in the capital cities of Luoyang and Chang'an, he achieved success as an Chinese astronomy, astronomer, Chinese mathematics, mathematician, seismologist, hydraulic engineer, inventor, geographer, History of cartography#China, cartographer, ethnographer, Chinese painting, artist, Chinese poetry, poet, Philosophy, philosopher, politician, and literary scholar. Zhang Heng began his career as a minor civil servant in Nanyang, Henan, Nanyang. Eventually, he became Chief Astronomer, Prefect of the Majors for Official Carriages, and then Palace Attendant at the imperial court. His uncompromising stance on historical and calendrical issues led to his becoming a controversial figure, preventing him from rising to the status of Grand Historian. His political rivalry w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luoxia Hong
Luoxia Hong (, c. 130–70 BCE) was a Chinese astronomer during the Western Han dynasty. A folk astronomer from southwest China, Hong was one of over twenty astronomers who traveled to Chang'an (now Xi'an) to propose a new calendar system for Emperor Wu. It was not uncommon for emperors to introduce new calendars in order to place greater emphasis on heavenly bodies that were seen as particularly astrologically relevant to the particular ruler, but this reform was of such a scale that it was called the "Grand Inception" (太初) in contemporary documents. The calendar made by Hong and his associate Deng Ping was accepted over that of other contestants, including several imperial astronomers. It included 12 months of 29 or 30 days, with an additional month in seven out of 19 years. It also included precise calculations for the movement of the sun, moon, planets, and the time of eclipses, which Hong was able to predict using an equatorial armillary sphere which he significantly impr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static Universe
In cosmology, a static universe (also referred to as stationary, infinite, static infinite or static eternal) is a cosmological model in which the universe is both spatially and temporally infinite, and space is neither expanding nor contracting. Such a universe does not have so-called spatial curvature; that is to say that it is 'flat' or Euclidean. A static infinite universe was first proposed by English astronomer Thomas Digges (1546–1595). In contrast to this model, Albert Einstein proposed a temporally infinite but spatially finite model - ''static eternal universe'' - as his preferred cosmology during 1917, in his paper ''Cosmological Considerations in the General Theory of Relativity''. After the discovery of the redshift-distance relationship (deduced by the inverse correlation of galactic brightness to redshift) by American astronomers Vesto Slipher and Edwin Hubble, the Belgian astrophysicist and priest Georges Lemaître interpreted the redshift as evidence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observable Universe
The observable universe is a Ball (mathematics), spherical region of the universe consisting of all matter that can be observation, observed from Earth; the electromagnetic radiation from these astronomical object, objects has had time to reach the Solar System and Earth since the beginning of the metric expansion of space, cosmological expansion. Assuming the universe is isotropy, isotropic, the distance to the edge of the observable universe is equidistant, the same in every direction. That is, the observable universe is a sphere, spherical region centered on the observer. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth. The word ''observable'' in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether there is anything to be detected. It refers to the physical limit created by the speed of light itself. No signal can travel faster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestial Sphere
In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, which may be centered on Earth or the observer. If centered on the observer, half of the sphere would resemble a hemispherical screen over the observing location. The celestial sphere is a conceptual tool used in spherical astronomy to specify the position of an object in the sky without consideration of its linear distance from the observer. The celestial equator divides the celestial sphere into northern and southern hemispheres. Description Because astronomical objects are at such remote distances, casual observation of the sky offers no information on their actual distances. All celestial objects seem equally far away, as if fixed onto the inside of a sphere with a large but unknown radius, which appears to rotate westwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
March Equinox
The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (or spring equinox) in the Northern Hemisphere and as the autumnal equinox (or fall equinox) in the Southern Hemisphere. On the Gregorian calendar at 0° longitude, the northward equinox can occur as early as 19 March (which happened most recently in 1796, and will happen next in 2044), and it can occur as late as 21 March (which happened most recently in 2007, and will happen next in 2102). For a common year the computed time slippage is about 5 hours 49 minutes ''later'' than the previous year, and for a leap year about 18 hours 11 minutes ''earlier'' than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic
The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the fixed stars, background of stars – specifically the Zodiac constellations. The planets of the Solar System can also be seen along the ecliptic, because their orbital planes are very close to Earth's. The Moon's orbital plane is also similar to Earth's; the ecliptic is so named because the ancients noted that eclipses only occur when the Moon is crossing it. The ecliptic is an important Plane of reference, reference plane and is the basis of the ecliptic coordinate system. Ancient scientists were able to calculate Earth's axial tilt by comparing the ecliptic plane to that of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Astronomy
Ancient Greek astronomy is the astronomy written in the Greek language during classical antiquity. Greek astronomy is understood to include the Ancient Greece, Ancient Greek, Hellenistic period, Hellenistic, Roman Empire, Greco-Roman, and Late antiquity, late antique eras. Ancient Greek astronomy can be divided into three phases, with ''Classical Greek astronomy'' being practiced during the 5th and 4th centuries BC, ''Hellenistic period, Hellenistic astronomy'' from the 3rd century BC until the formation of the Roman Empire in the late 1st century BC, and ''Greco-Roman astronomy'' continuing the tradition in the Roman world. During the Hellenistic era and onwards, Greek astronomy expanded beyond the geographic region of Greece as the Greek language had become the language of scholarship throughout the Hellenistic world, in large part delimited by the boundaries of the Macedonian Empire established by Alexander the Great. The most prominent and influential practitione ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
