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Hipparchus On Sizes And Distances
''On Sizes and Distances (of the Sun and Moon)'' (Περὶ μεγεθῶν καὶ ἀποστημάτων ��λίου καὶ σελήνης ''Peri megethon kai apostematon'') is a text by the ancient Greek astronomer Hipparchus () in which approximations are made for the radii of the Sun and the Moon as well as their distances from the Earth. It is not extant, but some of its contents have been preserved in the works of Ptolemy and his commentator Pappus of Alexandria. Several modern historians have attempted to reconstruct the methods of Hipparchus using the available texts. Sources Most of what is known about Hipparchus' text comes from two ancient sources: Ptolemy and Pappus. The work is also mentioned by Theon of Smyrna and others, but their accounts have proven less useful in reconstructing the procedures of Hipparchus. Ptolemy In ''Almagest'' V, 11, Ptolemy writes: : Now Hipparchus made such an examination principally from the sun. Since from other properties of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greeks
The Greeks or Hellenes (; el, Έλληνες, ''Éllines'' ) are an ethnic group and nation indigenous to the Eastern Mediterranean and the Black Sea regions, namely Greece, Cyprus, Albania, Italy, Turkey, Egypt, and, to a lesser extent, other countries surrounding the Mediterranean Sea. They also form a significant diaspora (), with Greek communities established around the world.. Greek colonies and communities have been historically established on the shores of the Mediterranean Sea and Black Sea, but the Greek people themselves have always been centered on the Aegean and Ionian seas, where the Greek language has been spoken since the Bronze Age.. Until the early 20th century, Greeks were distributed between the Greek peninsula, the western coast of Asia Minor, the Black Sea coast, Cappadocia in central Anatolia, Egypt, the Balkans, Cyprus, and Constantinople. Many of these regions coincided to a large extent with the borders of the Byzantine Empire of the late 11th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hellespont
The Dardanelles (; tr, Çanakkale Boğazı, lit=Strait of Çanakkale, el, Δαρδανέλλια, translit=Dardanéllia), also known as the Strait of Gallipoli from the Gallipoli peninsula or from Classical Antiquity as the Hellespont (; grc-x-classical, Ἑλλήσποντος, translit=Hellēspontos, lit=Sea of Helle), is a narrow, natural strait and internationally significant waterway in northwestern Turkey that forms part of the continental boundary between Asia and Europe and separates Asian Turkey from European Turkey. Together with the Bosporus, the Dardanelles forms the Turkish Straits. One of the world's narrowest straits used for international navigation, the Dardanelles connects the Sea of Marmara with the Aegean and Mediterranean seas while also allowing passage to the Black Sea by extension via the Bosporus. The Dardanelles is long and wide. It has an average depth of with a maximum depth of at its narrowest point abreast the city of Çanakkale. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Mathematics
Greek mathematics refers to mathematics texts and ideas stemming from the Archaic through the Hellenistic and Roman periods, mostly extant from the 7th century BC to the 4th century AD, around the shores of the Eastern Mediterranean. Greek mathematicians lived in cities spread over the entire Eastern Mediterranean from Italy to North Africa but were united by Greek culture and the Greek language. The word "mathematics" itself derives from the grc, , máthēma , meaning "subject of instruction". The study of mathematics for its own sake and the use of generalized mathematical theories and proofs is an important difference between Greek mathematics and those of preceding civilizations. Origins of Greek mathematics The origin of Greek mathematics is not well documented. The earliest advanced civilizations in Greece and in Europe were the Minoan and later Mycenaean civilizations, both of which flourished during the 2nd millennium BCE. While these civilizations possessed writing a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On The Measure Of The Earth
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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Precession
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis. In the absence of precession, the astronomical body's orbit would show axial parallelism. In particular, axial precession can refer to the gradual shift in the orientation of Earth's axis of rotation in a cycle of approximately 26,000 years.Hohenkerk, C.Y., Yallop, B.D., Smith, C.A., & Sinclair, A.T. "Celestial Reference Systems" in Seidelmann, P.K. (ed.) ''Explanatory Supplement to the Astronomical Almanac''. Sausalito: University Science Books. p. 99. This is similar to the precession of a spinning top, with the axis tracing out a pair of cones joined at their apices. The term "precession" typically refers only to this largest part of the motion; other changes in the alignment of Earth's axis— nutation and polar motion—are much smaller in magnitude. Earth's precession was historically called the precession of the equinoxes, be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On The Sizes And Distances (Aristarchus)
''On the Sizes and Distances (of the Sun and Moon)'' ( grc, Περὶ μεγεθῶν καὶ ἀποστημάτων ��λίου καὶ σελήνης}) is widely accepted as the only extant work written by Aristarchus of Samos, an ancient Greek astronomer who lived circa 310–230 BCE. This work calculates the sizes of the Sun and Moon, as well as their distances from the Earth in terms of Earth's radius. The book was presumably preserved by students of Pappus of Alexandria's course in mathematics, although there is no evidence of this. The '' editio princeps'' was published by John Wallis in 1688, using several medieval manuscripts compiled by Sir Henry Savile. The earliest Latin translation was made by Giorgio Valla in 1488. There is also 1572 Latin translation and commentaryby Frederico Commandino. Symbols The work's method relied on several observations: * The apparent size of the Sun and the Moon in the sky. * The size of the Earth's shadow in relation to the Moon dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleomedes
Cleomedes ( el, Κλεομήδης) was a Greek astronomer who is known chiefly for his book ''On the Circular Motions of the Celestial Bodies'' (Κυκλικὴ θεωρία μετεώρων), also known as ''The Heavens'' ( la, Caelestia). Placing his work chronologically His birth and death dates are not known—historians have suggested that he wrote his work sometime between the mid-1st century BC and 400 AD. The earlier estimates rely on the fact that Cleomedes refers extensively in his writing to the work of mathematician and astronomer Posidonius of Rhodes (c. 135 – c. 51 BC), and yet seemingly not at all to the work of Ptolemy (c. 100 – c. 170 AD). (Cleomedes also refers to Aristotle (384–322 BC), Pytheas of Massalia (310–306 BC), Aratus (c. 315/310 BC – 240 BC), Eratosthenes (276–195 BC), and Hipparchus (c. 190 – c. 120 BC). These conclusions have been challenged on the grounds that Cleomedes' work was in relatively elementary astronomy, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aristarchus Of Samos
Aristarchus of Samos (; grc-gre, Ἀρίσταρχος ὁ Σάμιος, ''Aristarkhos ho Samios''; ) was an ancient Greek astronomer and mathematician who presented the first known heliocentric model that placed the Sun at the center of the known universe, with the Earth revolving around the Sun once a year and rotating about its axis once a day. He was a student of Strato of Lampsacus, who was the third head of the Peripatetic School in Greece. According to Ptolemy, during Aristarchus' time there, he observed the summer solstice of 280 BCE. Along with his contributions to the heliocentric model, as reported by Vitruvius, he created two separate sundials: one that is a flat disc; and one hemispherical. Aristarchus was influenced by the concept presented by Philolaus of Croton (c. 470 – 385 BCE) of a fire at the center of the universe, but Aristarchus identified the "central fire" with the Sun and he put the other planets in their correct order of distance around t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
İznik
İznik is a town and an administrative district in the Province of Bursa, Turkey. It was historically known as Nicaea ( el, Νίκαια, ''Níkaia''), from which its modern name also derives. The town lies in a fertile basin at the eastern end of Lake İznik, bounded by ranges of hills to the north and south. The town is only southeast of Istanbul but by road it is around the Gulf of İzmit. It is by road from Bursa. The town is situated with its west wall rising from the lake itself, providing both protection from siege from that direction, as well as a source of supplies which would be difficult to cut off. The lake is large enough that it cannot be blockaded from the land easily, and the city was large enough to make any attempt to reach the harbour from shore-based siege weapons very difficult. The city was surrounded on all sides by of walls about high. These were in turn surrounded by a double ditch on the land portions, and also included over 100 towers in various ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography
Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of Earth. The first recorded use of the word γεωγραφία was as a title of a book by Greek scholar Eratosthenes (276–194 BC). Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities—not merely where objects are, but also how they have changed and come to be. While geography is specific to Earth, many concepts can be applied more broadly to other celestial bodies in the field of planetary science. One such concept, the first law of geography, proposed by Waldo Tobler, is "everything is related to everything else, but near things are more related than distant things." Geography has been called "the world discipline" and "the bridge between the human a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabo
Strabo''Strabo'' (meaning "squinty", as in strabismus) was a term employed by the Romans for anyone whose eyes were distorted or deformed. The father of Pompey was called " Pompeius Strabo". A native of Sicily so clear-sighted that he could see things at great distance as if they were nearby was also called "Strabo". (; el, Στράβων ''Strábōn''; 64 or 63 BC 24 AD) was a Greek geographer, philosopher, and historian who lived in Asia Minor during the transitional period of the Roman Republic into the Roman Empire. Life Strabo was born to an affluent family from Amaseia in Pontus (in present-day Turkey) in around 64BC. His family had been involved in politics since at least the reign of Mithridates V. Strabo was related to Dorylaeus on his mother's side. Several other family members, including his paternal grandfather had served Mithridates VI during the Mithridatic Wars. As the war drew to a close, Strabo's grandfather had turned several Pon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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