Limits of Observation and Pseudoempirical Arguments in Ptolemy’S Harmonics and Almagest
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1 Timeline 2 Geocentric Model
Ancient Astronomy Many ancient cultures were interested in the night sky • Calenders • Prediction of seasons • Navigation 1 Timeline Astronomy timeline • ∼ 3000 B.C. Stonehenge • 2136 B.C. First record of solar eclipse by Chinese astronomers • 613 B.C. First record of Halley’s comet by Zuo Zhuan (China) • ∼ 270 B.C. Aristarchus proposes Earth goes around Sun (not a popular idea at the time) • ∼ 240 B.C. Eratosthenes estimates Earth’s circumference • ∼ 130 B.C. Hipparchus develops first accurate star map (one of the first to use R.A. and Dec) 2 Geocentric model The Geocentric Model • Greek philosopher Aristotle (384-322 B.C.) • Uniform circular motion • Earth at center of Universe Retrograde Motion • General motion of planets east- ward • Short periods of westward motion of planets • Then continuation eastward How did the early Greek philosophers make retrograde motion consistent with uniform circular motion? 3 Ptolemy Ptolemy’s Geocentric Model • Planet moves around a small circle called an epicycle • Center of epicycle moves along a larger cir- cle called a deferent • Center of deferent is at center of Earth (sort of) Ptolemy’s Geocentric Model • Ptolemy invented the device called the eccentric • The eccentric is the center of the deferent • Sometimes the eccentric was slightly off center from the center of the Earth Ptolemy’s Geocentric Model • Uniform circular motion could not account for speed of the planets thus Ptolemy used a device called the equant • The equant was placed the same distance from the eccentric as the Earth, but on the -
Mathematical Discourse in Philosophical Authors: Examples from Theon of Smyrna and Cleomedes on Mathematical Astronomy
Mathematical discourse in philosophical authors: Examples from Theon of Smyrna and Cleomedes on mathematical astronomy Nathan Sidoli Introduction Ancient philosophers and other intellectuals often mention the work of mathematicians, al- though the latter rarely return the favor.1 The most obvious reason for this stems from the im- personal nature of mathematical discourse, which tends to eschew any discussion of personal, or lived, experience. There seems to be more at stake than this, however, because when math- ematicians do mention names they almost always belong to the small group of people who are known to us as mathematicians, or who are known to us through their mathematical works.2 In order to be accepted as a member of the group of mathematicians, one must not only have mastered various technical concepts and methods, but must also have learned how to express oneself in a stylized form of Greek prose that has often struck the uninitiated as peculiar.3 Be- cause of the specialized nature of this type of intellectual activity, in order to gain real mastery it was probably necessary to have studied it from youth, or to have had the time to apply oneself uninterruptedly.4 Hence, the private nature of ancient education meant that there were many educated individuals who had not mastered, or perhaps even been much exposed to, aspects of ancient mathematical thought and practice that we would regard as rather elementary (Cribiore 2001; Sidoli 2015). Starting from at least the late Hellenistic period, and especially during the Imperial and Late- Ancient periods, some authors sought to address this situation in a variety of different ways— such as discussing technical topics in more elementary modes, rewriting mathematical argu- ments so as to be intelligible to a broader audience, or incorporating mathematical material di- rectly into philosophical curricula. -
Implementing Eratosthenes' Discovery in the Classroom: Educational
Implementing Eratosthenes’ Discovery in the Classroom: Educational Difficulties Needing Attention Nicolas Decamp, C. de Hosson To cite this version: Nicolas Decamp, C. de Hosson. Implementing Eratosthenes’ Discovery in the Classroom: Educational Difficulties Needing Attention. Science and Education, Springer Verlag, 2012, 21 (6), pp.911-920. 10.1007/s11191-010-9286-3. hal-01663445 HAL Id: hal-01663445 https://hal.archives-ouvertes.fr/hal-01663445 Submitted on 18 Dec 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Sci & Educ DOI 10.1007/s11191-010-9286-3 Implementing Eratosthenes’ Discovery in the Classroom: Educational Difficulties Needing Attention Nicolas De´camp • Ce´cile de Hosson Ó Springer Science+Business Media B.V. 2010 Abstract This paper presents a critical analysis of the accepted educational use of the method performed by Eratosthenes to measure the circumference of Earth which is often considered as a relevant means of dealing with issues related to the nature of science and its history. This method relies on a number of assumptions among which the parallelism of sun rays. The assumption of sun rays parallelism (if it is accurate) does not appear spontaneous for students who consider sun rays to be divergent. -
Ptolemy's Almagest
Ptolemy’s Almagest: Fact and Fiction Richard Fitzpatrick Department of Physics, UT Austin Euclid’s Elements and Ptolemy’s Almagest • Ancient Greece -> Two major scientific works: Euclid’s Elements and Ptolemy’s “Almagest”. • Elements -> Compendium of mathematical theorems concerning geometry, proportion, number theory. Still highly regarded. • Almagest -> Comprehensive treatise on ancient Greek astronomy. (Almost) universally disparaged. Popular Modern Criticisms of Ptolemy’s Almagest • Ptolemy’s approach shackled by Aristotelian philosophy -> Earth stationary; celestial bodies move uniformly around circular orbits. • Mental shackles lead directly to introduction of epicycle as kludge to explain retrograde motion without having to admit that Earth moves. • Ptolemy’s model inaccurate. Lead later astronomers to add more and more epicycles to obtain better agreement with observations. • Final model hopelessly unwieldy. Essentially collapsed under own weight, leaving field clear for Copernicus. Geocentric Orbit of Sun SS Sun VE − vernal equinox SPRING SS − summer solstice AE − autumn equinox WS − winter solstice SUMMER93.6 92.8 Earth AE VE AUTUMN89.9 88.9 WINTER WS Successive passages though VE every 365.24 days Geocentric Orbit of Mars Mars E retrograde station direct station W opposition retrograde motion Earth Period between successive oppositions: 780 (+29/−16) days Period between stations and opposition: 36 (+6/−6) days Angular extent of retrograde arc: 15.5 (+3/−5) degrees Immovability of Earth • By time of Aristotle, ancient Greeks knew that Earth is spherical. Also, had good estimate of its radius. • Ancient Greeks calculated that if Earth rotates once every 24 hours then person standing on equator moves west to east at about 1000 mph. -
Astronomy and Hipparchus
CHAPTER 9 Progress in the Sciences: Astronomy and Hipparchus Klaus Geus Introduction Geography in modern times is a term which covers several sub-disciplines like ecology, human geography, economic history, volcanology etc., which all con- cern themselves with “space” or “environment”. In ancient times, the definition of geography was much more limited. Geography aimed at the production of a map of the oikoumene, a geographer was basically a cartographer. The famous scientist Ptolemy defined geography in the first sentence of his Geographical handbook (Geog. 1.1.1) as “imitation through drafting of the entire known part of the earth, including the things which are, generally speaking, connected with it”. In contrast to chorography, geography uses purely “lines and label in order to show the positions of places and general configurations” (Geog. 1.1.5). Therefore, according to Ptolemy, a geographer needs a μέθοδος μαθεματική, abil- ity and competence in mathematical sciences, most prominently astronomy, in order to fulfil his task of drafting a map of the oikoumene. Given this close connection between geography and astronomy, it is not by default that nearly all ancient “geographers” (in the limited sense of the term) stood out also as astronomers and mathematicians: Among them Anaximander, Eudoxus, Eratosthenes, Hipparchus, Poseidonius and Ptolemy are the most illustrious. Apart from certain topics like latitudes, meridians, polar circles etc., ancient geography also took over from astronomy some methods like the determina- tion of the size of the earth or of celestial and terrestrial distances.1 The men- tioned geographers Anaximander, Eudoxus, Hipparchus, Poseidonius and Ptolemy even constructed instruments for measuring, observing and calculat- ing like the gnomon, sundials, skaphe, astrolabe or the meteoroscope.2 1 E.g., Ptolemy (Geog. -
1.1 Eratosthenes Measures the Earth (Copyright: Bryan Dorner All Rights Reserved)
1.1 Eratosthenes Measures the Earth (Copyright: Bryan Dorner all rights reserved) How big is the Earth? The mathematician Eratosthenes (276-195 BCE) lived in the city of Alexandria in northern Egypt near the place where the Nile river empties into the Mediterranean. Eratosthenes was chief librarian at the Alexandria museum and one of the foremost scholars of the day - second only to Archimedes (who many consider one of the two or three best mathematicians ever to have lived). The city of Alexandria had been founded about one hundred years earlier by Alexander the Great whose conquests stretched from Egypt, through Syria, Babylonia, and Persia to northern India and central Asia. As the Greeks were also called Hellenes, the resulting empire was known as the Hellenistic empire and the following period in which Greek culture was dominant is called the Hellenistic age. The Hellenistic age saw a considerable exchange of culture between the conquering Greeks and the civilizations of the lands they controlled. It is from about this period that the predominantly geometric mathematics of the Greeks shows a computational aspect borrowed from the Babylonians. Some of the best mathematics we have inherited comes from just such a blend of contributions from diverse cultures. Eratosthenes is known for his simple but accurate measurement of the size of the earth. The imprint of Babylon (modern Iraq) as well as Greece can be seen in his method. He did not divide the arc of a circle into 360 parts as the Babylonians did, but into 60 equal parts. Still, the use of 60 reveals the influence of the Babylonian number system - the sexagesimal system - which was based on the number 60 in the same way ours is based on the number 10. -
Apollonius of Pergaconics. Books One - Seven
APOLLONIUS OF PERGACONICS. BOOKS ONE - SEVEN INTRODUCTION A. Apollonius at Perga Apollonius was born at Perga (Περγα) on the Southern coast of Asia Mi- nor, near the modern Turkish city of Bursa. Little is known about his life before he arrived in Alexandria, where he studied. Certain information about Apollonius’ life in Asia Minor can be obtained from his preface to Book 2 of Conics. The name “Apollonius”(Apollonius) means “devoted to Apollo”, similarly to “Artemius” or “Demetrius” meaning “devoted to Artemis or Demeter”. In the mentioned preface Apollonius writes to Eudemus of Pergamum that he sends him one of the books of Conics via his son also named Apollonius. The coincidence shows that this name was traditional in the family, and in all prob- ability Apollonius’ ancestors were priests of Apollo. Asia Minor during many centuries was for Indo-European tribes a bridge to Europe from their pre-fatherland south of the Caspian Sea. The Indo-European nation living in Asia Minor in 2nd and the beginning of the 1st millennia B.C. was usually called Hittites. Hittites are mentioned in the Bible and in Egyptian papyri. A military leader serving under the Biblical king David was the Hittite Uriah. His wife Bath- sheba, after his death, became the wife of king David and the mother of king Solomon. Hittites had a cuneiform writing analogous to the Babylonian one and hi- eroglyphs analogous to Egyptian ones. The Czech historian Bedrich Hrozny (1879-1952) who has deciphered Hittite cuneiform writing had established that the Hittite language belonged to the Western group of Indo-European languages [Hro]. -
9 · the Growth of an Empirical Cartography in Hellenistic Greece
9 · The Growth of an Empirical Cartography in Hellenistic Greece PREPARED BY THE EDITORS FROM MATERIALS SUPPLIED BY GERMAINE AUJAe There is no complete break between the development of That such a change should occur is due both to po cartography in classical and in Hellenistic Greece. In litical and military factors and to cultural developments contrast to many periods in the ancient and medieval within Greek society as a whole. With respect to the world, we are able to reconstruct throughout the Greek latter, we can see how Greek cartography started to be period-and indeed into the Roman-a continuum in influenced by a new infrastructure for learning that had cartographic thought and practice. Certainly the a profound effect on the growth of formalized know achievements of the third century B.C. in Alexandria had ledge in general. Of particular importance for the history been prepared for and made possible by the scientific of the map was the growth of Alexandria as a major progress of the fourth century. Eudoxus, as we have seen, center of learning, far surpassing in this respect the had already formulated the geocentric hypothesis in Macedonian court at Pella. It was at Alexandria that mathematical models; and he had also translated his Euclid's famous school of geometry flourished in the concepts into celestial globes that may be regarded as reign of Ptolemy II Philadelphus (285-246 B.C.). And it anticipating the sphairopoiia. 1 By the beginning of the was at Alexandria that this Ptolemy, son of Ptolemy I Hellenistic period there had been developed not only the Soter, a companion of Alexander, had founded the li various celestial globes, but also systems of concentric brary, soon to become famous throughout the Mediter spheres, together with maps of the inhabited world that ranean world. -
Geminus and the Isia
CORE Metadata, citation and similar papers at core.ac.uk Provided by DSpace at New York University GEMINUS AND THE ISIA ALEXANDER JONES T HE torical Greek interest, scientific including a lost writer treatise onGeminus the foundations wrote of several works of his- mathematics and an extant book on astronomy known as the Isagoge ("Introduction to the Phenomena"). The Isagoge is important to us as a witness to a stage of Greek astronomy that was both less advanced and less homogeneous in method than Ptolemy's. Approximate knowledge of when its author lived would be useful in several respects, for exam- ple in tracing the diffusion of elements originating in Babylonian lunar theory and in Hipparchus' work. Recent scholarship frequently cites Neugebauer's dating of Geminus to about A.D. 50, which has largely superseded the dating to the first half of the first century B.C. that used to be widely accepted.' Both dates derive, oddly enough, from analysis of the same passage in the Isagoge. The purpose of this note is to eluci- date the chronological issues, and to present documentary evidence that decisively establishes the earlier dating. The limits established by ancient citations are not very narrow. Isa- goge 4 mentions Hipparchus as an authority concerning constellations, and though Geminus does not say so, the lengths of the astronomical seasons listed in Isagoge I are the values that Hipparchus had used in deriving a model for the sun's motion. These passages cannot have been written before the 140s B.C. Moreover, Alexander of Aphrodisias (In Arist. -
The Equant in India Redux
The equant in India redux Dennis W. Duke The Almagest equant plus epicycle model of planetary motion is arguably the crowning achieve- ment of ancient Greek astronomy. Our understanding of ancient Greek astronomy in the cen- turies preceding the Almagest is far from complete, but apparently the equant at some point in time replaced an eccentric plus epicycle model because it gives a better account of various observed phenomena.1 In the centuries following the Almagest the equant was tinkered with in technical ways, first by multiple Arabic astronomers, and later by Copernicus, in order to bring it closer to Aristotelian expectations, but it was not significantly improved upon until the discov- eries of Kepler in the early 17th century.2 This simple linear history is not, however, the whole story of the equant. Since 2005 it has been known that the standard ancient Hindu planetary models, generally thought for many de- cades to be based on the eccentric plus epicycle model, in fact instead approximate the Almagest equant model.3 This situation presents a dilemma of sorts because there is nothing else in an- cient Hindu astronomy that suggests any connection whatsoever with the Greek astronomy that we find in theAlmagest . In fact, the general feeling, at least among Western scholars, has always been that ancient Hindu astronomy was entirely (or nearly so, since there is also some clearly identifiable Babylonian influence) derived from pre-Almagest Greek astronomy, and therefore offers a view into that otherwise inaccessible time period.4 The goal in this paper is to analyze more thoroughly the relationship between the Almag- est equant and the Hindu planetary models. -
The Almagest
Alma College The Alma, MI 48801 Almagest The bi-weekly newsletter of the Department of Mathematics and Computer Science. Your trusted source for news. Volume 9 No. 4 October 24, 2016 Math & C.S. Colloquium pportionment is a mathematical way to round A integers proportionally. Although well known to determine how many seats each state receives in the U.S. House of Representatives, apportionment methods are also used in the U.S. presidential primaries and the general election. In this talk, Dr. Michael Jones will Why Call it “The Almagest?” examine the geometry of two types of paradoxical behavior ctually, the name of our newsletter was that may occur in these A borrowed from an astronomical handbook settings, using real data when published around 150 A.D. The author was appropriate. We’ll also touch on some recent Claudius Ptolemy, an Egyptian astronomer, mathe- proposed laws and how they would affect the matician, and geographer of Greek descent. paradoxical behavior. Dr. Jones is an Associate Almagest came in thirteen volumes and proclaimed Editor at the American Mathe-matical Society's Mathematical Reviews in Ann Arbor, MI. that the universe was geocentric—the Earth was the middle of the universe. That, however, is not “The Mathematics of Apportionment in what most interests a mathematician about U.S. Presidential Primaries and the Almagest. Of more importance to us is the lost mathematical work that it displays. General Election” Presenter: Dr. Michael Jones Hipparchus was a Greek astronomer and mathema- Date: Tuesday, November 1st tician whose work dates to about three centuries Time: 4:00 prior to Ptolemy’s. -
10 · Greek Cartography in the Early Roman World
10 · Greek Cartography in the Early Roman World PREPARED BY THE EDITORS FROM MATERIALS SUPPLIED BY GERMAINE AUJAe The Roman republic offers a good case for continuing to treat the Greek contribution to mapping as a separate CONTINUITY AND CHANGE IN THEORETICAL strand in the history ofclassical cartography. While there CARTOGRAPHY: POLYBIUS, CRATES, was a considerable blending-and interdependence-of AND HIPPARCHUS Greek and Roman concepts and skills, the fundamental distinction between the often theoretical nature of the Greek contribution and the increasingly practical uses The extent to which a new generation of scholars in the for maps devised by the Romans forms a familiar but second century B.C. was familiar with the texts, maps, satisfactory division for their respective cartographic in and globes of the Hellenistic period is a clear pointer to fluences. Certainly the political expansion of Rome, an uninterrupted continuity of cartographic knowledge. whose domination was rapidly extending over the Med Such knowledge, relating to both terrestrial and celestial iterranean, did not lead to an eclipse of Greek influence. mapping, had been transmitted through a succession of It is true that after the death of Ptolemy III Euergetes in well-defined master-pupil relationships, and the pres 221 B.C. a decline in the cultural supremacy of Alex ervation of texts and three-dimensional models had been andria set in. Intellectual life moved to more energetic aided by the growth of libraries. Yet this evidence should centers such as Pergamum, Rhodes, and above all Rome, not be interpreted to suggest that the Greek contribution but this promoted the diffusion and development of to cartography in the early Roman world was merely a Greek knowledge about maps rather than its extinction.