DOCSLIB.ORG

How the Flat Earth Got Round : "An Ancient History” by J

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
How the Flat Earth Got Round : The Geodesy Corner HOW THE FLAT EARTH GOT ROUND : "AN ANCIENT HISTORY” BY J. FERGUSON Long before the start of recorded earth involved the notion that water history, the origins of the earth’s was the key to the universe, and that natural, physical and spiritual proper­ the earth was a flat disk floating on an ties were being studied by ancient infinite ocean. civilizations. A pupil of Thales, a fellow named Several thousand years before the Anaximander, is known to be the first birth of Christ, (2000-4000 BC) it is person to draw a map of the earth as he known that the Babylonian and Egyp­ saw it. He envisioned a cylindrical tian empires were discovering the earth (to explain the change in star bases for mathematical and astronomi­ positions as he travelled) about an east- cal principles. It is a shame that the west axis. He also noted that the stars knowledge of what took place so long rotated about the Pole star, thus com­ ago was merely a memory, and was ing up with the idea that the sky was a recounted only through tales told to the complete sphere. As opposed to Thales, first recorders of history about 1000 Anaximander thought that the fun­ BC. It is not entirely true that the damental element of the universe was science of writing letters and figures a mystical formless mass, although he began in 1000 BC. In fact, around 1650 still believed Thales’ theory that life BC, an Egyptian scribe called Ahmose originated with water. wrote a treatise summarizing the an­ Yet another Greek philosopher, cient Egyptian mathematics, but little Anaximenes, decided that Thales had of the written word has been found the correct notion about the earth as a from before this time. With the virtual flat plane or disk, but he added his idea elimination of the Aegean civilization of a fundamental substance to the in ancient Crete around 1480 BC, the equation. He thought that air was the age of discovery was put on hold until root of the universe, and he would have 700 or 800 BC. At this time, with the a flat earth, surrounded by water, emergence of a "technological revolu­ suspended by compressed air. tion" - the ability to produce metal About the time of the deaths of products - the birth of a new civilization Thales, Anaximander and took place. Once again, the profound Anaximenes, came the birth of yet elementary questions of who and Pythagoras (580 BC). Apart from his what we are came to the fore. teachings of Pythagoreaism, a secre­ At the time of this new Greek era, tive cult with quite odd beliefs, and his there was not an abundance of edu­ work in mathematics, Pythagoras was cated persons capable of the discoveries the first to speculate the earth was a that would follow. Most of the learned sphere. He also postulated on the mo­ were labelled "philosophers", and their tions of the planets, sun and moon, and studies included everything from his beliefs would remain valid until astronomy, medicine, astrology and Kepler revolutionized orbital theories philosophy to cult rituals and pagan in the late 16th century AD. Carrying worship. on the rationalist thinking of Thales, One of the first philosophers to go on Hecataeus, a contemporary of record with a version of what the earth Pythagoras, built upon the map- looked like was the Greek Thales (b. making work of Anaximander. He took 625 BC). It is thought that much of his the world as it was then known, and work in lunar and solar motion was divided it into a north half and a south based on knowledge he had gained half, with Europe and Asia repre­ from travels to ancient Babylonia and senting the respective halves. In this Egypt. However, his own beliefs of the depiction, the Mediterranean Sea 8 The Ontario Land Surveyor, Summer 1990 HOW THE FLAT EARTH GOT ROUND "AN ANCIENT HISTORY” cont’d formed the dividing line and - as was from all points on its surface. At the cluded Europe and Britain, Asia and common at the time - the focal point. same time as Aristotle was India, and Africa south to about the Again, the "world" was surrounded by revolutionizing science, the Greek Arabian Gulf. In addition, all this land a vast body of water which he labelled geographer Dicaearchus described his was, according to Eratoshenes, sur­ Oceanus. version of the world, and was the first rounded by one interconnected ocean, Over the next hundred or so years, to consider the map of the world as part a theory which would not be proved navigators, astronomers and of a sphere. He built upon the dis­ until Magellan circumnavigated the philosophers from the Greek and coveries of some of the explorers of the world in the early 16th century. Phoenician civilizations followed with time, and was able to describe a line of The age of more modern theories of slightly different versions of the earth’s latitude from east to west. This line the earth’s size and shape began again form and size. Some were of the "flat showed how all points on the line saw in earnest in the 13th and 14th cen­ earth" school, while others followed the noonday sun at equal angles from turies, at which time many new, per­ Pythagoras’s spherical theories. It was the zenith. haps more scientific, discoveries were also through this period, especially in Elaborating upon the work of made. However, to talk about the Greece, that moral philosphy was Dicaearchus, was a Greek geographer developments from this era to the taking over from natural philosopy, or and explorer called Pytheas (b. 300 present would take a great deal more science, as the accepted area of inter­ BC). He was able to determine latitude space, of which I have no more. est. With the teachings of philosophers of his home town, and was the first to Thus, the earth had at last become such as Socrates and Plato, the study point out that tides could be the result round, and man and woman alike could of the natural earth took a back seat for of influence by the moon. Although live comfortably in the knowledge that a while. It was not until some two these ideas are entirely commonplace they would not fall off, dare they jour­ hundred years after Hecataeus that a in the modern world, one must remem­ ney too far. But didn’t someone just ask new map of the earth was drawn by a ber the difficulty these ancient scien­ me if I wanted to join the Flat Earth Greek astronomer name Eudoxus (b. tists had in actually proving their Society .... 408 BC). In his works he also created a theories, let alone getting anyone to Next time in the Geodesy Corner - map of the stars, with divisions of the believe them. The Connection between Datums and sky in terms of degrees of latitude and By the time the Greek Eratoshenes Ellipsoids. longitude. As we know now, these came on the scene, the idea of a spheri­ would later be applied to the earth’s cal earth was becoming accepted by surface. scholars. Eratoshenes is generally REFERENCES: Among his many postulates and dis­ regarded as being one of the fathers of 1. Asimov, Issac. Asimov’s Biographical En­ coveries, one of the most important geodesy, and among his many dis­ cyclopedia of Science and Technology. theories the great Greek philosopher coveries, it is his historical measure­ ISBN 0-385-17771-2. Aristotle (b. 384 BC) proposed, was the ment of the latitude between 2. Vanicek, Petr and Edward J. Krakiwsky. reasoning behind a spherical earth. He Alexandria and Aswan that made him 1982. Geodesy: The Concepts. ISBN 0-444- suggested that, since stars in the south most famous. This measurement deter­ 86149-1. New York: North-Holland disappear, and stars in the north ap­ mined the radius of the earth to be 6267 Publishing Company. pear as one travels northward, the kilometres - not bad for using range 3. The History of Science and Technology - A earth must be round. If it were flat, he poles and angles to the sun. At this Narrative Chronology. ISBN 0-87196-475- said, all stars would be equally visible point in history, Eratoshenes’ world in­ 9, Vol 1. WELCOME TO OUR NEW ’REGISTERED’ MEMBERS AS OF JULY 1990 : 62 The Ontario Land Surveyor, Summer 1990 9.
Load more

Recommended publications
  • Models for Earth and Maps
    Earth Models and Maps James R. Clynch, Naval Postgraduate School, 2002 I. Earth Models Maps are just a model of the world, or a small part of it. This is true if the model is a globe of the entire world, a paper chart of a harbor or a digital database of streets in San Francisco. A model of the earth is needed to convert measurements made on the curved earth to maps or databases. Each model has advantages and disadvantages. Each is usually in error at some level of accuracy. Some of these error are due to the nature of the model, not the measurements used to make the model. Three are three common models of the earth, the spherical (or globe) model, the ellipsoidal model, and the real earth model. The spherical model is the form encountered in elementary discussions. It is quite good for some approximations. The world is approximately a sphere. The sphere is the shape that minimizes the potential energy of the gravitational attraction of all the little mass elements for each other. The direction of gravity is toward the center of the earth. This is how we define down. It is the direction that a string takes when a weight is at one end - that is a plumb bob. A spirit level will define the horizontal which is perpendicular to up-down. The ellipsoidal model is a better representation of the earth because the earth rotates. This generates other forces on the mass elements and distorts the shape. The minimum energy form is now an ellipse rotated about the polar axis.
    [Show full text]
  • Anaximander and the Problem of the Earth's Immobility
    Binghamton University The Open Repository @ Binghamton (The ORB) The Society for Ancient Greek Philosophy Newsletter 12-28-1953 Anaximander and the Problem of the Earth's Immobility John Robinson Windham College Follow this and additional works at: https://orb.binghamton.edu/sagp Recommended Citation Robinson, John, "Anaximander and the Problem of the Earth's Immobility" (1953). The Society for Ancient Greek Philosophy Newsletter. 263. https://orb.binghamton.edu/sagp/263 This Article is brought to you for free and open access by The Open Repository @ Binghamton (The ORB). It has been accepted for inclusion in The Society for Ancient Greek Philosophy Newsletter by an authorized administrator of The Open Repository @ Binghamton (The ORB). For more information, please contact [email protected]. JOHN ROBINSON Windham College Anaximander and the Problem of the Earth’s Immobility* N the course of his review of the reasons given by his predecessors for the earth’s immobility, Aristotle states that “some” attribute it I neither to the action of the whirl nor to the air beneath’s hindering its falling : These are the causes with which most thinkers busy themselves. But there are some who say, like Anaximander among the ancients, that it stays where it is because of its “indifference” (όμοιότητα). For what is stationed at the center, and is equably related to the extremes, has no reason to go one way rather than another—either up or down or sideways. And since it is impossible for it to move simultaneously in opposite directions, it necessarily stays where it is.1 The ascription of this curious view to Anaximander appears to have occasioned little uneasiness among modern commentators.
    [Show full text]
  • You Can Only Use a Planar Surface So Far, Before the Equidistance Assumption Creates Large Errors
    You can only use a planar surface so far, before the equidistance assumption creates large errors Distance error from Kiester to Warroad is greater than two football fields in length So we assume a spherical Earth P. Wormer, wikimedia commons Longitudes are great circles, latitudes are small circles (except the Equator, which is a GC) Spherical Geometry Longitude Spherical Geometry Note: The Greek letter l (lambda) is almost always used to specify longitude while f, a, w and c, and other symbols are used to specify latitude Great and Small Circles Great circles splits the Small circles splits the earth into equal halves earth into unequal halves wikipedia geography.name All lines of equal longitude are great circles Equator is the only line of equal latitude that’s a great circle Surface distance measurements should all be along a great circle Caliper Corporation Note that great circle distances appear curved on projected or flat maps Smithsonian In GIS Fundamentals book, Chapter 2 Latitude - angle to a parallel circle, a small circle parallel to the Equatorial great circle Spherical Geometry Three measures: Latitude, Longitude, and Earth Radius + height above/ below the sphere (hp) How do we measure latitude/longitude? Well, now, GNSS, but originally, astronomic measurements: latitude by north star or solar noon angles, at equinox Longitude Measurement Method 1: The Earth rotates 360 degrees in a day, or 15 degrees per hour. If we know the time difference between 2 points, and the longitude of the first point (Greenwich), we can determine the longitude at our current location. Method 2: Create a table of moon-star distances for each day/time of the year at a reference location (Greenwich observatory) Measure the same moon-star distance somewhere else at a standard or known time.
    [Show full text]
  • Paths Between Points on Earth: Great Circles, Geodesics, and Useful Projections
    Paths Between Points on Earth: Great Circles, Geodesics, and Useful Projections I. Historical and Common Navigation Methods There are an infinite number of paths between two points on the earth. For navigation purposes there are only a few historically common choices. 1. Sailing a latitude. Prior to a good method of finding longitude at sea, you sailed north or south until you cane to the latitude of your destination then you sailed due east or west until you reached your goal. Of course if you choose the wrong direction, you can get in big trouble. (This happened in 1707 to a British fleet that sunk when it hit rocks. This started the major British program for a longitude method useful at sea.) In this method the route follows the legs of a right triangle on the sphere. Just as in right triangles on the plane, the hypotenuse is always shorter than the sum of the other two sides. This method is very inefficient, but it was all that worked for open ocean sailing before 1770. 2. Rhumb Line A rhumb line is a line of constant bearing or azimuth. This is not the shortest distance on a long trip, but it is very easy to follow. You just have to know the correct azimuth to use to get between two sites, such as New York and London. You can get this from a straight line on a Mercator projection. This is the reason the Mercator projection was invented. On other projections straight lines are not rhumb lines. 3. Great Circle On a spherical earth, a great circle is the shortest distance between two locations.
    [Show full text]
  • The Shape of the Earth
    The Shape of the Earth Produced for the Cosmology and Cultures Project of the OBU Planetarium by Kerry Magruder August, 2005 2 Credits Written & Produced by: Kerry Magruder Nicole Oresme: Kerry Magruder Students: Rachel Magruder, Hannah Magruder, Kevin Kemp, Chris Kemp, Kara Kemp Idiot Professor: Phil Kemp Andrew Dickson White: Phil Kemp Cicero, Aquinas: J Harvey NASA writer: Sylvia Patterson Jeffrey Burton Russell: Candace Magruder Images courtesy: History of Science Collections, University of Oklahoma Libraries Digital photography and processing by: Hannah Magruder Soundtrack composed and produced by: Eric Barfield Special thanks to... Jeffrey Burton Russell, Mike Keas, JoAnn Palmeri, Hannah Magruder, Rachel Magruder, Susanna Magruder, Candace Magruder Produced with a grant from the American Council of Learned Societies 3 1. Contents 1. Contents________________________________________________3 2. Introduction_____________________________________________ 4 A. Summary____________________________________________ 4 B. Synopsis____________________________________________ 5 C. Instructor Notes_______________________________________6 3. Before the Show_________________________________________ 7 A. Video: A Private Universe______________________________ 7 B. Pre-Test_____________________________________________ 8 4. Production Script_________________________________________9 A. Production Notes______________________________________9 B. Theater Preparation___________________________________10 C. Script______________________________________________
    [Show full text]
  • 307 Lesson 21: Eratosthenes' Measurement of the Earth the Most
    307 Lesson 21: Eratosthenes’ Measurement of the Earth The most important parallel of latitude is the equator; it is the only parallel of latitude that is a great circle. However, in the previous lesson we learned about four other parallels of latitude which are of great importance because of the relative geometry of the Earth and the Sun. These are the Tropics of Cancer and Capricorn and the Arctic and Antarctic Circles. We briefly review the basic facts about these four parallels. At each moment on the day of the summer solstice, there is a single point on the surface of the Earth that is closet to the Sun. As the Earth rotates through the day of the summer solstice, this closest point to the Sun moves around the surface of the Earth and traces a parallel of latitude called the Tropic of Cancer. Another description of the Tropic of Cancer is that it is the set of all points on the Earth’s surface where the Sun is directly overhead at solar noon on the day of the summer solstice. The latitude coordinate of the Tropic of Cancer equals the measure of the angle that the Earth’s axis makes with the perpendicular to the ecliptic plane: approximately 23.5º N. On the day of the summer solstice, as the Earth rotates about its axis, the terminator (the division between daytime and nighttime) moves, and its northernmost point traces out a parallel of latitude called the Arctic Circle. Similarly, as the Earth rotates, the southernmost point of the terminator traces out a parallel of latitude called the Antarctic Circle.
    [Show full text]
  • Astronomy Through the Ages 1 Early History and Greek Astronomy
    Astronomy Through the Ages 1 Early History and Greek Astronomy ASTR 101 9/26/2018 1 Early History • Astronomy is often described as the oldest of the natural sciences. – Humans attempts to understand and make sense of the sky predates antiquity. – Religious, mythological and astrological beliefs and practices of pre-historical societies related to celestial objects and events can be seen from many artifacts that have survived to date. The Blanchard Bone, depicting a series of moon phases (France. 25,000 - 32,000 BCE) Stonehenge The Mayan observatory at Chichen Itza, seemed to have built to observe Venus and the Sun. The pyramid is aligned to solar equinox 2 Babylonian and ancient Egyptian astronomy (left) Mul Apin tablet(1100 BCE): Describing the appearance of different constellations and stars: Astronomical ceiling. 1470BCE Egyptian tomb (right) Babylonian clay tablets listing observation of Venus painting with constellations, planets, lunar th c. 7 century BCE. www.mesopotamia.co.uk/astronomer/explore/mulapin1.html cycle and stars depicted. • Astronomy and mathematics were in an advance state in the Babylonian civilization: • They kept records of position of the stars and planets and eclipses Many constellations visible from the northern hemisphere, and the zodiac are of Babylonian/Sumerian origin. • They used a number system with base 60 (sexadesimal), and a year of 360 days. • Circle 360 degrees, 60 minutes and 60 seconds descend from the Babylonian sexadesimal number system. • Egyptian astronomy mostly carried out by priest astronomers was largely concerned with time reckoning. Its main lasting contribution was the civil calendar of 365 days, with 12 months 3 • Unable to comprehend their underlying causes, early cultures resort to mysticism and religion for answers.
    [Show full text]
  • Sunlight and Seasons
    Project ATMOSPHERE This guide is one of a series produced by Project ATMOSPHERE, an initiative of the American Meteorological Society. Project ATMOSPHERE has created and trained a network of resource agents who provide nationwide leadership in precollege atmospheric environment education. To support these agents in their teacher training, Project ATMOSPHERE develops and produces teacher’s guides and other educational materials. For further information, and additional background on the American Meteorological Society’s Education Program, please contact: American Meteorological Society Education Program 1200 New York Ave., NW, Ste. 500 Washington, DC 20005-3928 www.ametsoc.org/amsedu This material is based upon work initially supported by the National Science Foundation under Grant No. TPE-9340055. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the National Science Foundation. © 2012 American Meteorological Society (Permission is hereby granted for the reproduction of materials contained in this publication for non-commercial use in schools on the condition their source is acknowledged.) 2 Foreword This guide has been prepared to introduce fundamental understandings about the guide topic. This guide is organized as follows: Introduction This is a narrative summary of background information to introduce the topic. Basic Understandings Basic understandings are statements of principles, concepts, and information. The basic understandings represent material to be mastered by the learner, and can be especially helpful in devising learning activities in writing learning objectives and test items. They are numbered so they can be keyed with activities, objectives and test items. Activities These are related investigations.
    [Show full text]
  • GEOMETRIC ANALYSIS of an OBSERVER on a SPHERICAL EARTH and an AIRCRAFT OR SATELLITE Michael Geyer
    GEOMETRIC ANALYSIS OF AN OBSERVER ON A SPHERICAL EARTH AND AN AIRCRAFT OR SATELLITE Michael Geyer S π/2 - α - θ d h α N U Re Re θ O Federico Rostagno Michael Geyer Peter Mercator nosco.com Project Memorandum — September 2013 DOT-VNTSC-FAA-13-08 Prepared for: Federal Aviation Administration Wake Turbulence Research Program DOT/RITA Volpe Center TABLE OF CONTENTS 1. INTRODUCTION...................................................................................................... 1 1.1 Basic Problem and Solution Approach........................................................................................1 1.2 Vertical Plane Formulation ..........................................................................................................2 1.3 Spherical Surface Formulation ....................................................................................................3 1.4 Limitations and Applicability of Analysis...................................................................................4 1.5 Recommended Approach to Finding a Solution.........................................................................5 1.6 Outline of this Document ..............................................................................................................6 2. MATHEMATICS AND PHYSICS BASICS ............................................................... 8 2.1 Exact and Approximate Solutions to Common Equations ........................................................8 2.1.1 The Law of Sines for Plane Triangles.........................................................................................8
    [Show full text]
  • The Copernican Revolution
    Lecture 4: The Copernican Revolution Astronomy 141 – Winter 2012 The lecture will discuss the Copernican Revolution. Modern science was born out of an effort over many centuries to understand the motions of celestial bodies. Two competing models were proposed: Geocentric (earth-centered) and Heliocentric (Sun-centered). The final success of the heliocentric model relied on crucial philosophical insights and technological advances. The motions of celestial bodies visible to the naked eye are mostly regular and repeatable. The stars rise in the east and set in the west daily The Sun rises & sets daily, and makes an eastward circuit relative to the stars once a year. The Moon rises & sets daily, and makes an eastward circuit relative to the stars once a month. Planetary motions are much more complex, showing occasional retrograde motion. Planets rise and set daily, and move generally eastward relative to the stars at varying speeds. Mars during 2005/6 Retrograde But, they occasionally stop, move westward (or retrograde), then stop again and resume moving eastward. For 2000 years, a geocentric model for the universe was widely assumed. Stars affixed to a Celestial Sphere Moon, Sun, planets, between the Earth & stars Spherical Earth at center of the Universe Aristotle (384-322 BC) argued for a geocentric model on physical grounds. Earth was fixed and unmoving at the center because it is was too big to move, including rotation. The Sun, Moon, Planets and Stars are afixed to crystalline spheres in uniform circular motion. The combination of perfect motions produces the net retrograde and non-uniform motions observed. The ultimate Geocentric System was formulated Claudius Ptolemy around 150 AD.
    [Show full text]
  • Early Cosmology
    The spherical Earth Greeks knew the Earth was a sphere View of constellations changes from NS Observations of ships sailing over the horizon (mast disappears last) Observations of the Earth’s shadow on the Moon during lunar eclipses The myth of the Flat Earth is a modern misconception about ancient and medieval thought 1 08/14/12Earth’s shadow on the Moon during a lunar eclipse Earth radius ~ 4x Moon radius 08/14/12 2 Distance of Moon From Earth Suggest a method for determining this distance; hint: use the Sun. Twice if you like. Start with: The size of the Earth (radius R) The Sun is very far away You’ve seen lunar eclipses… (Work in your groups of 3) I’ll get you started… Distance of Moon From Earth Moon moves in a large circle of radius R Moon goes around one circle per month T Earth’s shadow is about twice its radius r Time it takes Moon to cross the shadow t (maximally, about 3.6 hours) v = v it’s the same “velocity”! 2πR/T = 2 r/t R/r ~ 1 month / (3 hr * π) Average distance of the Moon ~ 60 Earth radii Aristarchus, 270 BC… But how big is r? Eratosthenes Astronomer/mathematician in Hellenistic Egypt (c.275-195 BC) Calculated circumference of Earth Measured altitude of Sun at two different points on the Earth (Alexandria & Syene about 800 km apart): found 7° difference How did he do it? (What do you do with those numbers?) Multiplied (360°/7°)×800km (distance between the 2 sites) to obtain circumference~40,000km 08/14/12 5 This is a bit oversimplified! Note mountains not shown to scale.
    [Show full text]
  • CSISS Classics
    UC Santa Barbara CSISS Classics Title Claudius Ptolemaeus (Ptolemy): Representation, Understanding, and Mathematical Labeling of the Spherical Earth. CSISS Classics Permalink https://escholarship.org/uc/item/4q10b6qk Author Sprague, Ben Publication Date 2003 eScholarship.org Powered by the California Digital Library University of California CSISS Classics - Claudius Ptolemaeus (Ptolemy): Representation, Understanding, and Mathemati... Claudius Ptolemaeus (Ptolemy): Representation, Understanding, and Mathematical Labeling of the Spherical Earth By Ben Sprague Background Claudius Ptolemaeus, better known as Ptolemy (circa 100–178 AD) made many important contributions to geography and spatial thought. A Greek by descent, he was a native of Alexandria in Egypt, and became known as the most wise and learned man of his time. Although little is known about Ptolemy's life, he wrote on many topics, including geography, astrology, musical theory, optics, physics, and astronomy. Innovation Ptolemy's work in astronomy and geography have made him famous for the ages, despite the fact that many of his theories were in the following centuries proven wrong or changed. Ptolemy collected, analyzed, and presented geographical knowledge so that it could be preserved and perfected by future generations. These ideas include expressing locations by longitude and latitude, representing a spherical earth on a flat surface, and developing the first equal area map projection. Ptolemy's accomplishments reflect his understanding of spatial relationships among places on earth and of the Earth's spatial relationships to other celestial bodies. Ptolemy's most famous written works are the Almagest, a textbook of astronomy in which, among other things, he laid the foundations of modern trigonometry; the Tetrabiblos, a compendium of astrology and geography; and Geographica (his guide to "Geography"), which compiled and summarized much of the geographic information accumulated by the Greeks and Romans up to that time.
    [Show full text]