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Eratosthenes
Eratosthenes of Cyrene (; grc-gre, Ἐρατοσθένης ; – ) was a Greek polymath: a mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. His work is comparable to what is now known as the study of geography, and he introduced some of the terminology still used today. He is best known for being the first person known to calculate the circumference of the Earth, which he did by using the extensive survey results he could access in his role at the Library; his calculation was remarkably accurate. He was also the first to calculate Earth's axial tilt, which has also proved to have remarkable accuracy. He created the first global projection of the world, incorporating parallels and meridians based on the available geographic knowledge of his era. Eratosthenes was the founder of scientific chronology; he used Egyptian and Persian records to estimate the dates of the main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ἐρατοσθένης
Eratosthenes of Cyrene (; grc-gre, Ἐρατοσθένης ; – ) was a Greek polymath: a mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. His work is comparable to what is now known as the study of geography, and he introduced some of the terminology still used today. He is best known for being the first person known to calculate the circumference of the Earth, which he did by using the extensive survey results he could access in his role at the Library; his calculation was remarkably accurate. He was also the first to calculate Earth's axial tilt, which has also proved to have remarkable accuracy. He created the first global projection of the world, incorporating parallels and meridians based on the available geographic knowledge of his era. Eratosthenes was the founder of scientific chronology; he used Egyptian and Persian records to estimate the dates of the ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumference Of The Earth
Earth's circumference is the distance around Earth. Measured around the Equator, it is . Measured around the poles, the circumference is . Measurement of Earth's circumference has been important to navigation since ancient times. The first known scientific measurement and calculation was done by Eratosthenes, who achieved a great degree of precision in his computation. Treating the Earth as a sphere, its circumference would be its single most important measurement. Earth deviates from spherical by about 0.3%, as characterized by flattening. In modern times, Earth's circumference has been used to define fundamental units of measurement of length: the nautical mile in the seventeenth century and the metre in the eighteenth. Earth's polar circumference is very near to 21,600 nautical miles because the nautical mile was intended to express one minute of latitude (see meridian arc), which is 21,600 partitions of the polar circumference (that is 60 minutes × 360 degrees). The p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philipp Daniel Lippert
Philipp is both a surname and a given name. Notable people with the name include: "Philipp" has also been a shortened version of Philippson, a German language, German surname especially prevalent amongst German Jews and Dutch Jews. Surname * Adolf Philipp (1864–1936), German/American actor, composer and playwright * David Philipp, biologist * David Philipp (footballer) (born 2000), German footballer * Elke Philipp (born 1964), German Paralympic equestrian * Elliot Philipp (1915–2010), British gynaecologist and obstetrician * Franz Philipp (1890–1972), German church musician and composer * Julius Philipp (1878–1944), German metal trader * Lutz Philipp (1940–2012), German long-distance runner * Oscar Philipp (1882–1965), German and British metal trader * Paul Philipp (born 1950), Luxembourgian football player and manager * Peter Philipp (1971–2014), German writer and comedian * Robert Philipp (1895–1981), American Impressionist painter Given name * Philipp Bönig ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circle Of Latitude
A circle of latitude or line of latitude on Earth is an abstract east–west small circle connecting all locations around Earth (ignoring elevation) at a given latitude coordinate line. Circles of latitude are often called parallels because they are Parallel (geometry), parallel to each other; that is, planes that contain any of these circles never Intersection, intersect each other. A location's position along a circle of latitude is given by its longitude. Circles of latitude are unlike circles of longitude, which are all great circles with the centre of Earth in the middle, as the circles of latitude get smaller as the distance from the Equator increases. Their length can be calculated by a common sine or cosine function. The 60th parallel north or 60th parallel south, south is half as long as the Equator (disregarding Earth's minor flattening by 0.335%). On the Mercator projection or on the Gall-Peters projection, a circle of latitude is perpendicular to all meridian (geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tocra
Tocra, Taucheira or Tukrah, is a town on the coast of the Marj District in the Cyrenaica region of northeastern Libya, founded by Cyrene. It lay 200 stadia west of Ptolemais. Today it is a coastal town west of Marj. History Founded by the Greeks and considered by some to be part of the Pentapolis of Cyrenaica, at a later period it became a Roman colony (Tab. Peut.), and was fortified by Justinian I. (Procop. ''de Aed.'' vi. 3.) Taucheira was particularly noted for the worship of Cybele, in honour of whom an annual festival was celebrated. (Synes. Ep. 3.) In the city fortifications from the Hellenistic, Roman and Byzantine periods have been found. Name Taucheira, Teucheira, Tauchira or Teuchira (Greek: , ,). Under the Ptolemies it obtained the name of Arsinoe (Arsinoë) (Greek: ), after Arsinoe II of Egypt, named by her brother and husband, Ptolemy Philadelphus. Later it became known as Tocra or Tukrah or Tokara, and then Al Quriyah or El Agouriya in Arabic. It is the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentapolis (North Africa)
A pentapolis (from Greek ''penta-'', 'five' and ''polis'', 'city') is a geographic and/or institutional grouping of five cities. Cities in the ancient world probably formed such groups for political, commercial and military reasons, as happened later with the Cinque Ports in England. Significant historical cases * In the biblical Holy Land, describes the region where five cities — Sodom, Gomorrah, Zoara, Admah and Zeboim — united to resist the invasion of Chedorlaomer, and of which four were shortly after destroyed. * The Philistine Pentapolis: Ashkelon, Ashdod, Ekron, Gath, and Gaza, all combined to make Philistia. * The Doric – or Dorian Pentapolis: Kos, on the island of the same name in the Aegean Sea; Cnidus, in Caria on the west coast of Asia Minor; Lindus, Ialysus and Camirus, all three on Rhodes. * The Phrygian Pentapolis: Eucarpia, Hierapolis, Otrus, Bruzus, and Stectorium * The Pontic Pentapolis: Apollonia, Callatis, Mesembria, Odessos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrene (city)
Cyrene ( ) or Kyrene ( ; grc, Κυρήνη, Kyrḗnē, arb, شحات, Shaḥāt), was an ancient Greek and later Roman city near present-day Shahhat, Libya. It was the oldest and most important of the five Greek cities, known as the pentapoleis, in the region. It gave eastern Libya the classical name ''Cyrenaica'' that it has retained to modern times. Located nearby is the ancient Necropolis of Cyrene. The traditional founder of the city was Battus the Lacedemonian, though the exact relationship between the fledgling city and other cities has led historians to question that narrative. Particularly, the idea that Thera was the sole "mother city" is disputed; and the relationship with other cities, such as Sparta and Samnium merchants, is unclear. Cyrene lies in a lush valley in the Jebel Akhdar uplands. The city was named after a spring, Kyre, which the Greeks consecrated to Apollo. It became the seat of the Cyrenaics, a famous school of philosophy in the fourth century BC, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suda
The ''Suda'' or ''Souda'' (; grc-x-medieval, Σοῦδα, Soûda; la, Suidae Lexicon) is a large 10th-century Byzantine encyclopedia of the ancient Mediterranean world, formerly attributed to an author called Soudas (Σούδας) or Souidas (Σουίδας). It is an encyclopedic lexicon, written in Greek, with 30,000 entries, many drawing from ancient sources that have since been lost, and often derived from medieval Christian compilers. Title The derivation is probably from the Byzantine Greek word ''souda'', meaning "fortress" or "stronghold", with the alternate name, ''Suidas'', stemming from an error made by Eustathius, who mistook the title for the author's name. Paul Maas once ironized by suggesting that the title may be connected to the Latin verb ''suda'', the second-person singular imperative of ''sudāre'', meaning "to sweat", but Franz Dölger traced its origins back to Byzantine military lexicon (σοῦδα, "ditch, trench", then "fortress"). Silvio Giuse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twelve Olympians
upright=1.8, Fragment of a relief (1st century BC1st century AD) depicting the twelve Olympians carrying their attributes in procession; from left to right: Hestia (scepter), Hermes (winged cap and staff), Aphrodite (veiled), Ares (helmet and spear), Demeter (scepter and wheat sheaf), Hephaestus (staff), Hera (scepter), Poseidon (trident), Athena (owl and helmet), Zeus (thunderbolt and staff), Artemis (bow and quiver) and Apollo (lyre) from the Walters Art Museum. In ancient Greek religion and Greek mythology, mythology, the twelve Olympians are the major Deity, deities of the Greek mythology, Greek pantheon, commonly considered to be Zeus, Hera, Poseidon, Demeter, Aphrodite, Athena, Ares, Artemis, Apollo, Hephaestus, Hermes, and either Hestia or Dionysus. They were called ''Olympians'' because, according to tradition, they resided on Mount Olympus. Although Hades was a major ancient Greek god and was the brother of the first generation of Olympians (Zeus, Poseidon, Hera, De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prime Number
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, or , involve 5 itself. However, 4 is composite because it is a product (2 × 2) in which both numbers are smaller than 4. Primes are central in number theory because of the fundamental theorem of arithmetic: every natural number greater than 1 is either a prime itself or can be factorized as a product of primes that is unique up to their order. The property of being prime is called primality. A simple but slow method of checking the primality of a given number n, called trial division, tests whether n is a multiple of any integer between 2 and \sqrt. Faster algorithms include the Miller–Rabin primality test, which is fast but has a small chance of error, and the AKS primality test, which always pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sieve Of Eratosthenes
In mathematics, the sieve of Eratosthenes is an ancient algorithm for finding all prime numbers up to any given limit. It does so by iteratively marking as composite (i.e., not prime) the multiples of each prime, starting with the first prime number, 2. The multiples of a given prime are generated as a sequence of numbers starting from that prime, with constant difference between them that is equal to that prime.Horsley, Rev. Samuel, F. R. S., "' or, The Sieve of Eratosthenes. Being an account of his method of finding all the Prime Numbers,''Philosophical Transactions'' (1683–1775), Vol. 62. (1772), pp. 327–347 This is the sieve's key distinction from using trial division to sequentially test each candidate number for divisibility by each prime. Once all the multiples of each discovered prime have been marked as composites, the remaining unmarked numbers are primes. The earliest known reference to the sieve ( grc, κόσκινον Ἐρατοσθένους, ''kóskinon Erat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Number Theory
Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure mathematics devoted primarily to the study of the integers and arithmetic function, integer-valued functions. German mathematician Carl Friedrich Gauss (1777–1855) said, "Mathematics is the queen of the sciences—and number theory is the queen of mathematics."German original: "Die Mathematik ist die Königin der Wissenschaften, und die Arithmetik ist die Königin der Mathematik." Number theorists study prime numbers as well as the properties of mathematical objects made out of integers (for example, rational numbers) or defined as generalizations of the integers (for example, algebraic integers). Integers can be considered either in themselves or as solutions to equations (Diophantine geometry). Questions in number theory are often best understood through the study of Complex analysis, analytical objects (for example, the Riemann zeta function) that encode properties of the integers, primes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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