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Persian Astronomy
Persian astronomy or Iranian astronomy refers to the astronomy in ancient Persian history. Pre-Islamic history Ancient Persians celebrated the vernal equinox, summer solstice, autumnal equinox, and winter solstice through a variety of different festivals and traditions. Vernal equinox Nowruz is the day of the vernal equinox and the moment the Sun crosses the celestial equator has been calculated for years. Nowruz was an important day during the Achaemenid period and continued in importance through the Sasanian dynasty. Summer solstice Tirgan is an ancient Iranian festival celebrating the summer solstice. Autumnal equinox Mehregan is an ancient Zoroastrian and Persian festival celebrating the autumnal equinox since at least the 4th century BC. Winter solstice Yaldā Night is an ancient Iranian festival celebrating the winter solstice of the Northern Hemisphere. Star systems Some old Persian names in astronomy have barely survived; the names of the four Royal stars that w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old Persian
Old Persian is one of the two directly attested Old Iranian languages (the other being Avestan) and is the ancestor of Middle Persian (the language of Sasanian Empire). Like other Old Iranian languages, it was known to its native speakers as (Iranian).''cf.'' , p. 2. Old Persian appears primarily in the inscriptions, clay tablets and seals of the Achaemenid era (c. 600 BCE to 300 BCE). Examples of Old Persian have been found in what is now Iran, Romania ( Gherla), Armenia, Bahrain, Iraq, Turkey and Egypt, with the most important attestation by far being the contents of the Behistun Inscription (dated to 525 BCE). Recent research (2007) into the vast Persepolis Fortification Archive at the Oriental Institute at the University of Chicago unearthed Old Persian tablets, which suggest Old Persian was a written language in use for practical recording and not only for royal display. Origin and overview As a written language, Old Persian is attested in royal Achaemenid inscri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artaxerxes II
Arses ( grc-gre, Ἄρσης; 445 – 359/8 BC), known by his regnal name Artaxerxes II ( peo, 𐎠𐎼𐎫𐎧𐏁𐏂 ; grc-gre, Ἀρταξέρξης), was King of Kings of the Achaemenid Empire from 405/4 BC to 358 BC. He was the son and successor of Darius II () and his mother was Parysatis. Soon after his accession, Artaxerxes II faced opposition from his younger brother Cyrus the Younger, who assembled an army composing of troops from his Lydian and Ionian satrapies as well as Greek mercenaries in his bid for the throne. The forces of the brothers clashed at Cunaxa in 401 BC, which resulted in the defeat and death of Cyrus. Following this, Artaxerxes II had to contend with several other revolts; a revolt by Evagoras I () in Cyprus between 391–380 BC, by the Phoenicians in , and most importantly, the revolts by the western satraps (known as the Great Satraps' Revolt) in the 360s and 350s BC, led by distinguished figures such as Datames, Ariobarzanes, and Autophr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth the mass of the Sun. Jupiter is the third brightest natural object in the Earth's night sky after the Moon and Venus, and it has been observed since prehistoric times. It was named after the Roman god Jupiter, the king of the gods. Jupiter is primarily composed of hydrogen, but helium constitutes one-quarter of its mass and one-tenth of its volume. It probably has a rocky core of heavier elements, but, like the other giant planets in the Solar System, it lacks a well-defined solid surface. The ongoing contraction of Jupiter's interior generates more heat than it receives from the Sun. Because of its rapid rotation, the planet's shape is an oblate spheroid: it has a slight but noticeable bulge around the equator. The outer atmosphere i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay Tablet
In the Ancient Near East, clay tablets ( Akkadian ) were used as a writing medium, especially for writing in cuneiform, throughout the Bronze Age and well into the Iron Age. Cuneiform characters were imprinted on a wet clay tablet with a stylus often made of reed (reed pen). Once written upon, many tablets were dried in the sun or air, remaining fragile. Later, these unfired clay tablets could be soaked in water and recycled into new clean tablets. Other tablets, once written, were either deliberately fired in hot kilns, or inadvertently fired when buildings were burnt down by accident or during conflict, making them hard and durable. Collections of these clay documents made up the first archives. They were at the root of the first libraries. Tens of thousands of written tablets, including many fragments, have been found in the Middle East. Surviving tablet-based documents from the Minoan/ Mycenaean civilizations, are mainly those which were used for accounting. Tablets s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Centauri
Alpha Centauri ( Latinized from α Centauri and often abbreviated Alpha Cen or α Cen) is a triple star system in the constellation of Centaurus. It consists of 3 stars: Alpha Centauri A (officially Rigil Kentaurus), Alpha Centauri B (officially Toliman) and Alpha Centauri C (officially Proxima Centauri). Proxima Centauri is also the closest star to the Sun at 4.2465 light-years (1.3020 pc). Alpha Centauri A and B are Sun-like stars ( Class G and K, respectively), and together they form the binary star system Alpha Centauri AB. To the naked eye, the two main components appear to be a single star with an apparent magnitude of −0.27. It is the brightest star in the constellation and the third-brightest in the night sky, outshone only by Sirius and Canopus. Alpha Centauri A has 1.1 times the mass and 1.5 times the luminosity of the Sun, while Alpha Centauri B is smaller and cooler, at 0.9 times the Sun's mass and less than 0.5 times its luminosity. The p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albireo
Albireo is a double star designated Beta Cygni (β Cygni, abbreviated Beta Cyg, β Cyg). The International Astronomical Union uses the name "Albireo" specifically for the brightest star in the system. Although designated ' beta', it is fainter than Gamma Cygni, Delta Cygni, and Epsilon Cygni and is the fifth-brightest point of light in the constellation of Cygnus. Appearing to the naked eye to be a single star of magnitude 3, viewing through even a low-magnification telescope resolves it into its two components. The brighter yellow star, itself a very close binary system, makes a striking colour contrast with its fainter blue companion. Nomenclature ''β Cygni'' ( Latinised to ''Beta Cygni'') is the system's Bayer designation. The brighter of the two components is designated ''β¹ Cygni'' or ''Beta Cygni A'' and the fainter ''β² Cygni'' or ''Beta Cygni B''. The system's traditional name ''Albireo'' is a result of misunderstanding and mistranslation. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcyone (star)
Alcyone , designated η Tauri (Eta Tauri, abbreviated Eta Tau, η Tau), is a star in the constellation of Taurus. Approximately 440 light-years from the Sun, it is the brightest star in the Pleiades open cluster, which is a young cluster, around 100 million years old. There are a number of fainter stars very close to Alcyone, some of which are members of the same cluster. Nomenclature ''Eta Tauri'' is the star's Bayer designation. The name ''Alcyone'' originates in Greek mythology; she is one of the seven daughters of Atlas and Pleione known as the Pleiades. In 2016, the International Astronomical Union (IAU) organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Alcyone'' for this star. It is now so entered in the IAU Catalog of Star Names. In Chinese, (), meaning '' Hairy Head'', refers to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star System
A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or ''galaxy'', although, broadly speaking, they are also star systems. Star systems are not to be confused with planetary systems, which include planets and similar bodies (such as comets). A star system of two stars is known as a ''binary star'', ''binary star system'' or ''physical double star''. If there are no tidal effects, no perturbation from other forces, and no transfer of mass from one star to the other, such a system is stable, and both stars will trace out an elliptical orbit around the barycenter of the system indefinitely. ''(See Two-body problem)''. Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which probably consists of a star and a black hole. Multiple star systems A multiple star system consists of three or more stars that appe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fomalhaut
Fomalhaut is the brightest star in the southern constellation of Piscis Austrinus, the "Southern Fish", and one of the brightest stars in the night sky. It has the Bayer designation Alpha Piscis Austrini, which is Latinized from α Piscis Austrini, and is abbreviated Alpha PsA or α PsA. This is a class A star on the main sequence approximately from the Sun as measured by the Hipparcos astrometry satellite. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. It is classified as a Vega-like star that emits excess infrared radiation, indicating it is surrounded by a circumstellar disk. Fomalhaut, K-type main-sequence star TW Piscis Austrini, and M-type, red dwarf star LP 876-10 constitute a triple system, even though the companions are separated by approximately 8 degrees. Fomalhaut was the first stellar system with an extrasolar planet candidate (designated Fomalhaut b, later ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antares
Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ Scorpii near the center of the constellation. Distinctly reddish when viewed with the naked eye, Antares is a slow irregular variable star that ranges in brightness from an apparent visual magnitude of +0.6 down to +1.6. It is on average the fifteenth-brightest star in the night sky. Classified as spectral type M1.5Iab-Ib, Antares is a red supergiant, a large evolved massive star and one of the largest stars visible to the naked eye. Its exact size remains uncertain, but if placed at the center of the Solar System, it would reach to somewhere between the orbits of Mars and Jupiter. Its mass is calculated to be around 12 times that of the Sun. Antares is the brightest and most evolved stellar member of the nearest OB association ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regulus
Regulus is the brightest object in the constellation Leo and one of the brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Regulus appears singular, but is actually a quadruple star system composed of four stars that are organized into two pairs. The spectroscopic binary Regulus A consists of a blue-white main-sequence star and its companion, which has not yet been directly observed, but is probably a white dwarf. The system lies approximately 79 light years from the Sun. HD 87884 is separated from Regulus by and is itself a close pair. Regulus, along with five slightly dimmer stars ( Zeta Leonis, Mu Leonis, Gamma Leonis, Epsilon Leonis, and Eta Leonis) have collectively been called 'the Sickle', which is an asterism that marks the head of Leo. Nomenclature ''α Leonis'' (Latinized to ''Alpha Leonis'') is the star system's Bayer designation. The traditional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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