1.
Sun
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The Sun is the star at the center of the Solar System. It is a perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99. 86% of the total mass of the Solar System. About three quarters of the Suns mass consists of hydrogen, the rest is mostly helium, with smaller quantities of heavier elements, including oxygen, carbon, neon. The Sun is a G-type main-sequence star based on its spectral class and it formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into a disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core and it is thought that almost all stars form by this process. The Sun is roughly middle-aged, it has not changed dramatically for more than four billion years and it is calculated that the Sun will become sufficiently large enough to engulf the current orbits of Mercury, Venus, and probably Earth. The enormous effect of the Sun on Earth has been recognized since prehistoric times, the synodic rotation of Earth and its orbit around the Sun are the basis of the solar calendar, which is the predominant calendar in use today. The English proper name Sun developed from Old English sunne and may be related to south, all Germanic terms for the Sun stem from Proto-Germanic *sunnōn. The English weekday name Sunday stems from Old English and is ultimately a result of a Germanic interpretation of Latin dies solis, the Latin name for the Sun, Sol, is not common in general English language use, the adjectival form is the related word solar. The term sol is used by planetary astronomers to refer to the duration of a solar day on another planet. A mean Earth solar day is approximately 24 hours, whereas a mean Martian sol is 24 hours,39 minutes, and 35.244 seconds. From at least the 4th Dynasty of Ancient Egypt, the Sun was worshipped as the god Ra, portrayed as a falcon-headed divinity surmounted by the solar disk, and surrounded by a serpent. In the New Empire period, the Sun became identified with the dung beetle, in the form of the Sun disc Aten, the Sun had a brief resurgence during the Amarna Period when it again became the preeminent, if not only, divinity for the Pharaoh Akhenaton. The Sun is viewed as a goddess in Germanic paganism, Sól/Sunna, in ancient Roman culture, Sunday was the day of the Sun god. It was adopted as the Sabbath day by Christians who did not have a Jewish background, the symbol of light was a pagan device adopted by Christians, and perhaps the most important one that did not come from Jewish traditions
2.
Moon
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The Moon is an astronomical body that orbits planet Earth, being Earths only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, following Jupiters satellite Io, the Moon is second-densest satellite among those whose densities are known. The average distance of the Moon from the Earth is 384,400 km, the Moon is thought to have formed about 4.51 billion years ago, not long after Earth. It is the second-brightest regularly visible celestial object in Earths sky, after the Sun and its surface is actually dark, although compared to the night sky it appears very bright, with a reflectance just slightly higher than that of worn asphalt. Its prominence in the sky and its cycle of phases have made the Moon an important cultural influence since ancient times on language, calendars, art. The Moons gravitational influence produces the ocean tides, body tides, and this matching of apparent visual size will not continue in the far future. The Moons linear distance from Earth is currently increasing at a rate of 3.82 ±0.07 centimetres per year, since the Apollo 17 mission in 1972, the Moon has been visited only by uncrewed spacecraft. The usual English proper name for Earths natural satellite is the Moon, the noun moon is derived from moone, which developed from mone, which is derived from Old English mōna, which ultimately stems from Proto-Germanic *mǣnōn, like all Germanic language cognates. Occasionally, the name Luna is used, in literature, especially science fiction, Luna is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of our moon. The principal modern English adjective pertaining to the Moon is lunar, a less common adjective is selenic, derived from the Ancient Greek Selene, from which is derived the prefix seleno-. Both the Greek Selene and the Roman goddess Diana were alternatively called Cynthia, the names Luna, Cynthia, and Selene are reflected in terminology for lunar orbits in words such as apolune, pericynthion, and selenocentric. The name Diana is connected to dies meaning day, several mechanisms have been proposed for the Moons formation 4.51 billion years ago, and some 60 million years after the origin of the Solar System. These hypotheses also cannot account for the angular momentum of the Earth–Moon system. This hypothesis, although not perfect, perhaps best explains the evidence, eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, and Jeff Taylor challenged fellow lunar scientists, You have eighteen months. Go back to your Apollo data, go back to computer, do whatever you have to. Dont come to our conference unless you have something to say about the Moons birth, at the 1984 conference at Kona, Hawaii, the giant impact hypothesis emerged as the most popular. Afterward there were only two groups, the giant impact camp and the agnostics. Giant impacts are thought to have been common in the early Solar System, computer simulations of a giant impact have produced results that are consistent with the mass of the lunar core and the present angular momentum of the Earth–Moon system
3.
Planet
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The term planet is ancient, with ties to history, astrology, science, mythology, and religion. Several planets in the Solar System can be seen with the naked eye and these were regarded by many early cultures as divine, or as emissaries of deities. As scientific knowledge advanced, human perception of the planets changed, in 2006, the International Astronomical Union officially adopted a resolution defining planets within the Solar System. This definition is controversial because it excludes many objects of mass based on where or what they orbit. The planets were thought by Ptolemy to orbit Earth in deferent, at about the same time, by careful analysis of pre-telescopic observation data collected by Tycho Brahe, Johannes Kepler found the planets orbits were not circular but elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes, and some shared such features as ice caps and seasons. Since the dawn of the Space Age, close observation by space probes has found that Earth and the planets share characteristics such as volcanism, hurricanes, tectonics. Planets are generally divided into two types, large low-density giant planets, and smaller rocky terrestrials. Under IAU definitions, there are eight planets in the Solar System, in order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites, several thousands of planets around other stars have been discovered in the Milky Way. e. in the habitable zone. On December 20,2011, the Kepler Space Telescope team reported the discovery of the first Earth-sized extrasolar planets, Kepler-20e and Kepler-20f, orbiting a Sun-like star, Kepler-20. A2012 study, analyzing gravitational microlensing data, estimates an average of at least 1.6 bound planets for every star in the Milky Way, around one in five Sun-like stars is thought to have an Earth-sized planet in its habitable zone. The idea of planets has evolved over its history, from the lights of antiquity to the earthly objects of the scientific age. The concept has expanded to include not only in the Solar System. The ambiguities inherent in defining planets have led to much scientific controversy, the five classical planets, being visible to the naked eye, have been known since ancient times and have had a significant impact on mythology, religious cosmology, and ancient astronomy. In ancient times, astronomers noted how certain lights moved across the sky, as opposed to the fixed stars, ancient Greeks called these lights πλάνητες ἀστέρες or simply πλανῆται, from which todays word planet was derived. In ancient Greece, China, Babylon, and indeed all pre-modern civilizations, it was almost universally believed that Earth was the center of the Universe and that all the planets circled Earth. The first civilization known to have a theory of the planets were the Babylonians
4.
Alfonso X of Castile
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Alfonso X, called the Wise, was the King of Castile, León and Galicia from 30 May 1252 until his death. During the Imperial election of 1257, a dissident faction chose him to be King of the Romans on 1 April and he renounced his imperial claim in 1275, and in creating an alliance with England in 1254, his claim on Gascony as well. Alfonso X fostered the development of a court that encouraged learning. Jews, Muslims, and Christians had prominent roles in his court, Alfonso was a prolific author of Galician poetry, such as the Cantigas de Santa Maria, which are equally notable for their musical notation as for their literary merit. Alfonsos scientific interests—he is sometimes nicknamed the Astrologer —led him to sponsor the creation of the Alfonsine tables, as a legislator he introduced the first vernacular law code in Spain, the Siete Partidas. He created the Mesta, an association of farmers in the central plain. He fought a war with Portugal, but a less successful one with Granada. The end of his reign was marred by a war with his eldest surviving son, the future Sancho IV. Born in Toledo, Kingdom of Castile, Alfonso was the eldest son of Ferdinand III of Castile and his mother was the paternal cousin of Holy Roman Emperor Frederick II, to whom Alfonso is often compared. His maternal grandparents were Philip of Swabia and Irene Angelina, little is known about his upbringing, but he was most likely raised in Toledo. For the first nine years of his life Alfonso was only heir to Castile until his paternal grandfather king Alfonso IX of Leon died and his father united the kingdoms of Castile and Leon. He began his career as a soldier, under the command of his father, after the election of Theobald I as king of Navarre, his father tried to arrange a marriage for Alfonso with Theobalds daughter, Blanche of Navarre, but the move was unsuccessful. At the same time, he had a relationship with Mayor Guillén de Guzmán. In 1240, he married Mayor Guillén de Guzmán, but the marriage was later annulled, in the same period he conquered several Muslim strongholds in Al-Andalus alongside his father, such as Murcia, Alicante and Cadiz. In 1249, Alfonso married Violante of Aragon, the daughter of King James I of Aragon and Yolande of Hungary, Alfonso succeeded his father as King of Castile and León in 1252. The following year he invaded Portugal, capturing the region of the Algarve, King Afonso III of Portugal had to surrender, but he gained an agreement by which, after he consented to marry Alfonso Xs daughter Beatrice of Castile, the land would be returned to their heirs. In 1263 he returned Algarve to the King of Portugal and signed the Treaty of Badajoz, in 1254 Alfonso X signed a treaty of alliance with the King of England and Duke of Aquitaine, Henry III, supporting him in the war against Louis IX of France. In 1256, at the death of William II of Holland, Alfonsos descent from the Hohenstaufen through his mother, Alfonsos election as King of the Romans by the imperial prince-electors misled him into complicated schemes that involved excessive expense but never succeeded
5.
Toledo, Spain
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Toledo is a city and municipality located in central Spain, it is the capital of the province of Toledo and the autonomous community of Castile–La Mancha. It was declared a World Heritage Site by UNESCO in 1986 for its cultural and monumental heritage and historical co-existence of Christian, Muslim. Toledo has a history in the production of bladed weapons, which are now popular souvenirs of the city, people who were born or have lived in Toledo include Brunhilda of Austrasia, Al-Zarqali, Garcilaso de la Vega, Eleanor of Toledo, Alfonso X and El Greco. It was also the place of important historic events such as the Visigothic Councils of Toledo, as of 2015, the city has a population of 83,226 and an area of 232.1 km2. The town was granted arms in the 16th century, which by special royal privilege was based on the royal of arms of Spain, Toledo is mentioned by the Roman historian Livy as urbs parva, sed loco munita. At that time, Toletum was a city of the Carpetani tribe and it was incorporated into the Roman Empire as a civitas stipendiaria, that is, a tributary city of non-citizens. It later achieved the status of municipium by Flavian times, with this status, city officials, even of Carpetani origin, obtained Roman citizenship for public service, and the forms of Roman law and politics were increasingly adopted. At approximately this time were constructed in Toletum a Roman circus, city walls, public baths, and a municipal water supply and storage system. The Roman circus in Toledo was one of the largest in Hispania, at 423 metres long and 100 metres wide, chariot races were held on special holidays and were also commissioned by private citizens to celebrate career achievements. A fragmentary stone inscription records circus games paid for by a citizen of unknown name to celebrate his achieving the sevirate, archaeologists have also identified portions of a special seat of the sort used by the city elites to attend circus games, called a sella curulis. The circus could hold up to 15000 spectators, during Roman times, Toledo was never a provincial capital nor a conventus iuridicus. It started to gain importance in late antiquity, there are indications that large private houses within the city walls were enlarged, while several large villas were built north of the city through the third and fourth centuries. Games were held in the circus into the fourth and early fifth centuries C. E. also an indication of active city life. A church council was held in Toledo in the year 400 to discuss the conflict with Priscillianism, a second council of Toledo was held in 527. The Visigothic king Theudis was in Toledo in 546, where he promulgated a law and this is strong though not certain evidence that Toledo was the chief residence for Theudis. King Athanagild died in Toledo, probably in 568 and this changed with Liuvigild, who brought the peninsula under his control. The Visigoths ruled from Toledo until the Moors conquered the Iberian peninsula in the years of 8th century. Today the historic center is pierced of basements, passages, wells, baths, a series of church councils was held in Toledo under the Visigoths
6.
Toledo School of Translators
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The School went through two distinct periods separated by a transitional phase. The first was led by Archbishop Raymond of Toledo in the 12th century, under King Alfonso X of Castile during the 13th century, the translators no longer worked with Latin as the final language, but translated into a revised version of Castilian. This resulted in establishing the foundations of the modern Spanish language, traditionally Toledo was a center of multilingual culture and had prior importance as a center of learning and translation, beginning in its era under Muslim rule. This era saw the development of a community of Arabic-speaking Christians, known as. But translating efforts were not methodically organized until Toledo was reconquered by Christian forces in 1085 and they translated many works, usually from Arabic into Castilian, and then from Castilian into Latin, as it was the official church language. In some cases, the translator could work directly from Arabic into Latin or Greek, as a result, the library of the cathedral, which had been refitted under Raymonds orders, became a translations center of a scale and importance not matched in the history of western culture. Gerard of Cremona was the most productive of the Toledo translators at the time and he came to Toledo in 1167 in search of Ptolemys Almagest. Since he did not know Arabic when he arrived, he relied on Jews and Mozarabs for translation, another important translator was John of Seville. Together with Dominicus Gundissalinus during the days of the School. He also translated many astrology treatises from al-Fargani, Abu Mashar, al-Kindi, Aḥmad ibn Yusuf, al-Battani, Thābit ibn Qurra, al-Qabisi, etc. In philosophy he produced Latin translations of Ibn Sina, Costa ben Lucas De differentia spiritus et animae, Al-Farabi, Ibn Gabirol, Al-Ghazali, overall hes known for his intelligent syntheses, combined with his own observations and interpretations, particularly in astrology. Rudolf of Bruges, a Flemish astronomer and translator from Arabic to Latin, was a pupil of Hermann of Carinthia. He translated into Latin the Liber de compositione astrolabii, a work of Islamic science on the astrolabe, by Maslamah Ibn Ahmad al-Majriti. Dominicus Gundissalinus is considered to be the first appointed director of the Toledo School of Translators, at the beginning, Gundissalinus only translated from Greek into Latin or Castilian, as he did not have sufficient knowledge of Arabic. He depended on John of Seville for all translations in that language, later in his career Gundissalinus mastered Arabic sufficiently to translate it by himself. Unlike his colleagues, he focused exclusively on philosophy, translating Greek and Arabic works, among his important translations is Fons Vitæ, by the Jewish philosopher ibn Gabirol. At one time it was thought to be the work of the Christian scholastic Avicebron, Gundissalinus also translated several works of the major Muslim philosophers Avicenna and al-Ghazâlî. He is known for frequently eliminating passages and adding his own commentaries, michael Scot, a Scotsman who studied at Oxford University and in Paris before settling in Toledo, also worked as a translator during this period
7.
Astronomy in the medieval Islamic world
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Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age, and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa and these included Greek, Sassanid, and Indian works in particular, which were translated and built upon. Islamic astronomy also had an influence on Chinese astronomy and Malian astronomy, a significant number of stars in the sky, such as Aldebaran, Altair and Deneb, and astronomical terms such as alidade, azimuth, and nadir, are still referred to by their Arabic names. A large corpus of literature from Islamic astronomy remains today, numbering approximately 10,000 manuscripts scattered throughout the world, even so, a reasonably accurate picture of Islamic activity in the field of astronomy can be reconstructed. These observations were based on the rising and setting of stars. Anwa continued to be developed after Islamization by the Arabs, where Islamic astronomers added mathematical methods to their empirical observations, according to David King, after the rise of Islam, the religious obligation to determine the qibla and prayer times inspired more progress in astronomy for centuries. The first astronomical texts that were translated into Arabic were of Indian and Persian origin, another text translated was the Zij al-Shah, a collection of astronomical tables compiled in Sasanid Persia over two centuries. Fragments of texts during this period indicate that Arabs adopted the function in place of the chords of arc used in Greek trigonometry. The House of Wisdom was an established in Baghdad under Abbasid caliph Al-Mamun in the early 9th century. From this time, independent investigation into the Ptolemaic system became possible, Astronomical research was greatly supported by the Abbasid caliph al-Mamun through The House of Wisdom. Baghdad and Damascus became the centers of such activity, the caliphs not only supported this work financially, but endowed the work with formal prestige. The first major Muslim work of astronomy was Zij al-Sindh by al-Khwarizmi in 830, the work contains tables for the movements of the sun, the moon and the five planets known at the time. The work is significant as it introduced Ptolemaic concepts into Islamic sciences and this work also marks the turning point in Islamic astronomy. Hitherto, Muslim astronomers had adopted a primarily research approach to the field, translating works of others, al-Khwarizmis work marked the beginning of nontraditional methods of study and calculations. In 850, al-Farghani wrote Kitab fi Jawani, the book primarily gave a summary of Ptolemic cosmography. However, it also corrected Ptolemy based on findings of earlier Arab astronomers, al-Farghani gave revised values for the obliquity of the ecliptic, the precessional movement of the apogees of the sun and the moon, and the circumference of the earth. The book was circulated through the Muslim world, and even translated into Latin. The period when a distinctive Islamic system of astronomy flourished, the period began as the Muslim astronomers began questioning the framework of the Ptolemaic system of astronomy
8.
Nicolaus Copernicus
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Copernicus was born and died in Royal Prussia, a region that had been part of the Kingdom of Poland since 1466. A polyglot and polymath, he obtained a doctorate in law and was also a mathematician, astronomer, physician, classics scholar, translator, governor, diplomat. In 1517 he derived a quantity theory of money – a key concept in economics –, Nicolaus Copernicus was born on 19 February 1473 in the city of Toruń, in the province of Royal Prussia, in the Crown of the Kingdom of Poland. His father was a merchant from Kraków and his mother was the daughter of a wealthy Toruń merchant, Nicolaus was the youngest of four children. His brother Andreas became an Augustinian canon at Frombork and his sister Barbara, named after her mother, became a Benedictine nun and, in her final years, prioress of a convent in Chełmno, she died after 1517. His sister Katharina married the businessman and Toruń city councilor Barthel Gertner and left five children, Copernicus fathers family can be traced to a village in Silesia near Nysa. The villages name has been variously spelled Kopernik, Copernik, Copernic, Kopernic, Coprirnik, in the 14th century, members of the family began moving to various other Silesian cities, to the Polish capital, Kraków, and to Toruń. The father, Mikołaj the Elder, likely the son of Jan, Nicolaus was named after his father, who appears in records for the first time as a well-to-do merchant who dealt in copper, selling it mostly in Danzig. He moved from Kraków to Toruń around 1458, Nicolaus father was actively engaged in the politics of the day and supported Poland and the cities against the Teutonic Order. In 1454 he mediated negotiations between Polands Cardinal Zbigniew Oleśnicki and the Prussian cities for repayment of war loans, Copernicuss father married Barbara Watzenrode, the astronomers mother, between 1461 and 1464. The Modlibógs were a prominent Polish family who had been known in Polands history since 1271. The Watzenrode family, like the Kopernik family, had come from Silesia from near Świdnica and they soon became one of the wealthiest and most influential patrician families. Lucas Watzenrode the Elder, a merchant and in 1439–62 president of the judicial bench, was a decided opponent of the Teutonic Knights. In 1453 he was the delegate from Toruń at the Grudziądz conference that planned the uprising against them, Lucas Watzenrode the Younger, the astronomers maternal uncle and patron, was educated at the University of Kraków and at the universities of Cologne and Bologna. He was an opponent of the Teutonic Order, and its Grand Master once referred to him as the devil incarnate. In 1489 Watzenrode was elected Bishop of Warmia against the preference of King Casimir IV, as a result, Watzenrode quarreled with the king until Casimir IVs death three years later. Watzenrode was then able to close relations with three successive Polish monarchs, John I Albert, Alexander Jagiellon, and Sigismund I the Old. He was a friend and key advisor to each ruler, Watzenrode came to be considered the most powerful man in Warmia, and his wealth, connections and influence allowed him to secure Copernicus education and career as a canon at Frombork Cathedral
9.
Astrology
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Astrology is the study of the movements and relative positions of celestial objects as a means for divining information about human affairs and terrestrial events. Throughout most of its history astrology was considered a tradition and was common in academic circles, often in close relation with astronomy, alchemy, meteorology. It was present in political circles, and is mentioned in works of literature, from Dante Alighieri and Geoffrey Chaucer to William Shakespeare, Lope de Vega. Astrology thus lost its academic and theoretical standing, and common belief in it has largely declined, Astrology is now recognized to be pseudoscience. The word astrology comes from the early Latin word astrologia, which derives from the Greek ἀστρολογία—from ἄστρον astron, astrologia later passed into meaning star-divination with astronomia used for the scientific term. Many cultures have attached importance to astronomical events, and the Indians, Chinese, the majority of professional astrologers rely on such systems. Astrology has been dated to at least the 2nd millennium BCE, with roots in systems used to predict seasonal shifts. A form of astrology was practised in the first dynasty of Mesopotamia, Chinese astrology was elaborated in the Zhou dynasty. Hellenistic astrology after 332 BCE mixed Babylonian astrology with Egyptian Decanic astrology in Alexandria, Alexander the Greats conquest of Asia allowed astrology to spread to Ancient Greece and Rome. In Rome, astrology was associated with Chaldean wisdom, after the conquest of Alexandria in the 7th century, astrology was taken up by Islamic scholars, and Hellenistic texts were translated into Arabic and Persian. In the 12th century, Arabic texts were imported to Europe, major astronomers including Tycho Brahe, Johannes Kepler and Galileo practised as court astrologers. Astrological references appear in literature in the works of such as Dante Alighieri and Geoffrey Chaucer. Throughout most of its history, astrology was considered a scholarly tradition and it was accepted in political and academic contexts, and was connected with other studies, such as astronomy, alchemy, meteorology, and medicine. At the end of the 17th century, new concepts in astronomy. Astrology thus lost its academic and theoretical standing, and common belief in astrology has largely declined, Astrology, in its broadest sense, is the search for meaning in the sky. This was a first step towards recording the Moons influence upon tides and rivers, by the 3rd millennium BCE, civilisations had sophisticated awareness of celestial cycles, and may have oriented temples in alignment with heliacal risings of the stars. Scattered evidence suggests that the oldest known references are copies of texts made in the ancient world. The Venus tablet of Ammisaduqa thought to be compiled in Babylon around 1700 BCE, a scroll documenting an early use of electional astrology is doubtfully ascribed to the reign of the Sumerian ruler Gudea of Lagash
10.
Ptolemy
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Claudius Ptolemy was a Greek writer, known as a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in the city of Alexandria in the Roman province of Egypt, wrote in Koine Greek, beyond that, few reliable details of his life are known. His birthplace has been given as Ptolemais Hermiou in the Thebaid in a statement by the 14th-century astronomer Theodore Meliteniotes. This is a very late attestation, however, and there is no reason to suppose that he ever lived elsewhere than Alexandria. Ptolemy wrote several treatises, three of which were of importance to later Byzantine, Islamic and European science. The first is the astronomical treatise now known as the Almagest, although it was entitled the Mathematical Treatise. The second is the Geography, which is a discussion of the geographic knowledge of the Greco-Roman world. The third is the treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day. This is sometimes known as the Apotelesmatika but more known as the Tetrabiblos from the Greek meaning Four Books or by the Latin Quadripartitum. The name Claudius is a Roman nomen, the fact that Ptolemy bore it indicates he lived under the Roman rule of Egypt with the privileges and political rights of Roman citizenship. It would have suited custom if the first of Ptolemys family to become a citizen took the nomen from a Roman called Claudius who was responsible for granting citizenship, if, as was common, this was the emperor, citizenship would have been granted between AD41 and 68. The astronomer would also have had a praenomen, which remains unknown and it occurs once in Greek mythology, and is of Homeric form. All the kings after him, until Egypt became a Roman province in 30 BC, were also Ptolemies, abu Mashar recorded a belief that a different member of this royal line composed the book on astrology and attributed it to Ptolemy. The correct answer is not known”, Ptolemy wrote in Greek and can be shown to have utilized Babylonian astronomical data. He was a Roman citizen, but most scholars conclude that Ptolemy was ethnically Greek and he was often known in later Arabic sources as the Upper Egyptian, suggesting he may have had origins in southern Egypt. Later Arabic astronomers, geographers and physicists referred to him by his name in Arabic, Ptolemys Almagest is the only surviving comprehensive ancient treatise on astronomy. Ptolemy presented his models in convenient tables, which could be used to compute the future or past position of the planets. The Almagest also contains a catalogue, which is a version of a catalogue created by Hipparchus
11.
Geocentric model
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In astronomy, the geocentric model is a superseded description of the universe with the Earth at the center. Under the geocentric model, the Sun, Moon, stars, the geocentric model served as the predominant description of the cosmos in many ancient civilizations, such as those of Aristotle and Ptolemy. Two observations supported the idea that the Earth was the center of the Universe, first, the Sun appears to revolve around the Earth once per day. While the Moon and the planets have their own motions, they appear to revolve around the Earth about once per day. The stars appeared to be on a sphere, rotating once each day along an axis through the north and south geographic poles of the Earth. Second, the Earth does not seem to move from the perspective of an Earth-bound observer, it appears to be solid, stable, Ancient Greek, ancient Roman and medieval philosophers usually combined the geocentric model with a spherical Earth. It is not the same as the older flat Earth model implied in some mythology, the ancient Jewish Babylonian uranography pictured a flat Earth with a dome-shaped rigid canopy named firmament placed over it. The astronomical predictions of Ptolemys geocentric model were used to prepare astrological and astronomical charts for over 1500 years. The geocentric model held sway into the modern age, but from the late 16th century onward, it was gradually superseded by the Heliocentric model of Copernicus, Galileo. There was much resistance to the transition between these two theories, christian theologians were reluctant to reject a theory that agreed with Bible passages. Others felt a new, unknown theory could not subvert an accepted consensus for geocentrism, the geocentric model entered Greek astronomy and philosophy at an early point, it can be found in Pre-Socratic philosophy. In the 6th century BC, Anaximander proposed a cosmology with the Earth shaped like a section of a pillar, the Sun, Moon, and planets were holes in invisible wheels surrounding the Earth, through the holes, humans could see concealed fire. About the same time, the Pythagoreans thought that the Earth was a sphere, later these views were combined, so most educated Greeks from the 4th century BC on thought that the Earth was a sphere at the center of the universe. In the 4th century BC, two influential Greek philosophers, Plato and his student Aristotle, wrote works based on the geocentric model, according to Plato, the Earth was a sphere, stationary at the center of the universe. In his Myth of Er, a section of the Republic, Plato describes the cosmos as the Spindle of Necessity, attended by the Sirens and these spheres, known as crystalline spheres, all moved at different uniform speeds to create the revolution of bodies around the Earth. They were composed of a substance called aether. Aristotle believed that the moon was in the innermost sphere and therefore touches the realm of Earth, causing the dark spots and he further described his system by explaining the natural tendencies of the terrestrial elements, Earth, water, fire, air, as well as celestial aether. His system held that Earth was the heaviest element, with the strongest movement towards the center, the tendency of air and fire, on the other hand, was to move upwards, away from the center, with fire being lighter than air
12.
Johannes Kepler
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Johannes Kepler was a German mathematician, astronomer, and astrologer. A key figure in the 17th-century scientific revolution, he is best known for his laws of motion, based on his works Astronomia nova, Harmonices Mundi. These works also provided one of the foundations for Isaac Newtons theory of universal gravitation, Kepler was a mathematics teacher at a seminary school in Graz, where he became an associate of Prince Hans Ulrich von Eggenberg. Later he became an assistant to the astronomer Tycho Brahe in Prague and he was also a mathematics teacher in Linz, and an adviser to General Wallenstein. Kepler lived in an era when there was no distinction between astronomy and astrology, but there was a strong division between astronomy and physics. Kepler was born on December 27, the feast day of St John the Evangelist,1571 and his grandfather, Sebald Kepler, had been Lord Mayor of the city. By the time Johannes was born, he had two brothers and one sister and the Kepler family fortune was in decline and his father, Heinrich Kepler, earned a precarious living as a mercenary, and he left the family when Johannes was five years old. He was believed to have died in the Eighty Years War in the Netherlands and his mother Katharina Guldenmann, an innkeepers daughter, was a healer and herbalist. Born prematurely, Johannes claimed to have weak and sickly as a child. Nevertheless, he often impressed travelers at his grandfathers inn with his phenomenal mathematical faculty and he was introduced to astronomy at an early age, and developed a love for it that would span his entire life. At age six, he observed the Great Comet of 1577, in 1580, at age nine, he observed another astronomical event, a lunar eclipse, recording that he remembered being called outdoors to see it and that the moon appeared quite red. However, childhood smallpox left him with vision and crippled hands. In 1589, after moving through grammar school, Latin school, there, he studied philosophy under Vitus Müller and theology under Jacob Heerbrand, who also taught Michael Maestlin while he was a student, until he became Chancellor at Tübingen in 1590. He proved himself to be a mathematician and earned a reputation as a skilful astrologer. Under the instruction of Michael Maestlin, Tübingens professor of mathematics from 1583 to 1631 and he became a Copernican at that time. In a student disputation, he defended heliocentrism from both a theoretical and theological perspective, maintaining that the Sun was the source of motive power in the universe. Despite his desire to become a minister, near the end of his studies, Kepler was recommended for a position as teacher of mathematics and he accepted the position in April 1594, at the age of 23. Keplers first major work, Mysterium Cosmographicum, was the first published defense of the Copernican system
