The Remarkable Science of Ancient Astronomy

276 Pages·2016·17.96 MB·English

Topic Subtopic
Science & Mathematics Astronomy
The Remarkable Science
of Ancient Astronomy
Course Guidebook
Professor Bradley E. Schaefer
Louisiana State University
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Bradley E. Schaefer,
Ph.D.
Distinguished Professor and Alumni
Professor of Physics and Astronomy
Louisiana State University
radley E. Schaefer is Distinguished Professor and Alumni Professor
B
in the Department of Physics and Astronomy at Louisiana State
University. He earned his undergraduate degree in Physics in 1978
and his Ph.D. in Physics in 1983, both from the Massachusetts Institute
of Technology. Professor Schaefer worked for 11 years at NASA’s Goddard
Space Flight Center and then was a professor at Yale University with a joint
appointment in the Departments of Astronomy and Physics. At Louisiana
State University, Professor Schaefer has won campus-wide teaching
awards, including the Alumni Professorship and the Distinguished Faculty
Award, which are given for excellence in teaching. Professor Schaefer has
218 publications in refereed journals.
Starting in the mid-1990s, Professor Schaefer became one of the
members of the Supernova Cosmology Project, led by Saul Perlmutter of
the Lawrence Berkeley National Laboratory. This group found that the
expansion rate of the whole universe is accelerating. The implication of
this startling result is that some unknown dark energy is powering this
acceleration and that this mysterious quantity makes up around 68% of
all the mass-energy of our universe. This was published in a paper in 1999,
with Perlmutter as first author. As one of the discoverers of dark energy,
Professor Schaefer received a share of the $500,000 Gruber Cosmology
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The Remarkable Science of Ancient Astronomy
Prize in 2007 as well as a share of the $3,000,000 Breakthrough Prize in
Fundamental Physics in 2015. In 2011, Perlmutter won the Nobel Prize in
Physics for the discovery work in the 1999 paper.
Professor Schaefer has written 31 refereed articles on the history of
astronomy in journals. In addition, he has written 27 feature articles for
the popular magazine Sky & Telescope, many of them featuring results
presented in this course. Professor Schaefer is on the editorial boards
for both Archaeoastronomy and the Journal for the History of Astronomy
and has served on the editorial board for Culture and Cosmos. In 2004, he
presented the keynote speech for the Oxford VII conference, the interna-
tional quadrennial meeting for archaeoastronomy.
Professor Schaefer has worked on the astrohistory of many topics,
including the canon of Sherlock Holmes, The Hobbit, the Great Escape of
World War II, the so-called Chinese astronomical jade disks, the origin
of the star and crescent symbol, the Voynich manuscript, the heliacal rise
of Sirius, and the Crab supernova as possibly recorded in Europe. He also
has done extensive work on the visibility of celestial objects, including the
green flash, earthshine during solar eclipses, mountain shadows, the black
drop during transits of Venus, and the astrophysics of suntanning.
In 1981, Professor Schaefer invented and started the annual MIT Mystery
Hunt and then ran the first 4 hunts. After he left MIT with his Ph.D., the
tradition was kept alive, and it has grown tremendously. The hunt is a
simple search for an Indian Head penny hidden around campus. The clues
are a vastly wide array of incredibly difficult puzzles and enigmas. The
MIT Mystery Hunt was soon copied on many other university campuses
and then by megacorporations, and hunts like it are now called by the
generic name of puzzlehunts. ■
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Table of Contents
INTRODUCTION
Professor Biography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Course Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
GUIDES
LECTURE 1
Stonehenge and Archaeoastronomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
LECTURE 2
The Real Stonehenge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
LECTURE 3
Alignments at Maes Howe and Newgrange . . . . . . . . . . . . . . . . . . . . . 22
LECTURE 4
Astronomy of Egypt’s Great Pyramid . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
LECTURE 5
Chaco Canyon and Anasazi Astronomy . . . . . . . . . . . . . . . . . . . . . . . . . 43
LECTURE 6
Ancient Cosmologies and Worldviews . . . . . . . . . . . . . . . . . . . . . . . . . . 53
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The Remarkable Science of Ancient Astronomy
LECTURE 7
Meteorite Worship and Start of the Iron Age . . . . . . . . . . . . . . . . . . . . 62
LECTURE 8
Eclipses, Comets, and Omens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
LECTURE 9
The Star of Bethlehem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
LECTURE 10
Origins of Western Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
LECTURE 11
Chinese and Other Non-Western Constellations . . . . . . . . . . . . . . . . . 98
LECTURE 12
Origins and Influence of Astrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
LECTURE 13
Tracking Planet Positions and Conjunctions . . . . . . . . . . . . . . . . . . . . 119
LECTURE 14
Ancient Timekeeping and Calendars . . . . . . . . . . . . . . . . . . . . . . . . . . 128
LECTURE 15
The Lunar Crescent and the Islamic Calendar . . . . . . . . . . . . . . . . . . . 138
LECTURE 16
Ancient Navigation: Polynesian to Viking . . . . . . . . . . . . . . . . . . . . . . . 147
LECTURE 17
Breakthroughs of Early Greek Astronomy . . . . . . . . . . . . . . . . . . . . . . 158
LECTURE 18
The Genius of Hipparchus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
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Table of Contents
LECTURE 19
Revealing the Antikythera Mechanism . . . . . . . . . . . . . . . . . . . . . . . . .174
LECTURE 20
How the Antikythera Mechanism Worked . . . . . . . . . . . . . . . . . . . . . . 184
LECTURE 21
Achievements and Legacy of Ptolemy . . . . . . . . . . . . . . . . . . . . . . . . . 193
LECTURE 22
Star Catalogs from around the World . . . . . . . . . . . . . . . . . . . . . . . . . . 202
LECTURE 23
How Ancient Astronomy Ended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
LECTURE 24
Ancient Astronomy and Modern Astrophysics . . . . . . . . . . . . . . . . . . 222
SUPPLEMENTAL MATERIAL
List of Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Timeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Image Credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
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The Remarkable Science of Ancient Astronomy
vi
The Remarkable
Science of Ancient
Astronomy
his introductory astronomy course covers the science of the skies,
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how ancient astronomers used the skies, and how the skies interact
with all humans on many levels. The course will cover the entire
world from many thousands of years B.C. up until the end of ancient
astronomy around 1600 A.D., with a concentration from 3000 B.C. to 200
A.D.
The course starts with Stonehenge, that great monument with wonderful
circles of standing stones an hour’s drive west of London, with its famous
alignment toward the midsummer sunrise over the Heelstone. Actually, the
evidence makes a good case that it is really pointing at the midwinter sunset
in the opposite direction. Stonehenge is just the most spectacular example
of many stone circles and temples and burials throughout Eurasia from the
Late Stone Age and the Bronze Age, many with intentional astronomical
alignments. In the same tradition are the pyramids of ancient Egypt, with
the Great Pyramid aligned north-south to the remarkable accuracy of 1/20°,
as an expression of their directional symbolism (with east for birth, west
for death, and the never-setting stars in the north for immortality).
Starting around 600 B.C., the basic suite of Stone Age astronomy started
changing rapidly with many remarkable discoveries. In breaking the super-
natural away from the sky, the early Greeks started explaining eclipses,
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The Remarkable Science of Ancient Astronomy
knowing the shape and size of our Earth, and crafting a worldview of
the Earth’s place in the universe. Around 130 B.C., the great Greek
astronomer Hipparchus discovered precession (where the stars appear to
move), quantified the skies with his now-lost star catalog, and developed
a detailed solar and lunar model. Around the same time, an anonymous
Babylonian scribe was studying the motions of the planet Jupiter, and he
invented what can only be called part of calculus. Also around that time,
a remarkably complex analog computer was made from bronze gears and
was used to calculate calendars and planet positions and predict eclipses
and the Olympic Games. Around 2000 years ago, the Maya, Indians,
Babylonians, Greeks, and Chinese all measured various planet periods to
accuracies of parts per million.
The regular task of ancient astronomers around the world was to use the
skies to make tools for common and everyday needs. The ancient needs
for timekeeping were many, and a wide variety of methods and mecha-
nisms were devised, all pointing back to the Sun and stars for definition,
measure, and calibration. These include the use of gnomons all around
the world, the sundial throughout Eurasia, the timings of star rise for the
36 Egyptian decans, and the position of the Dipper stars around the pole
throughout the Northern Hemisphere. Ancient astronomers were always
the keepers of the calendars, with these determining the dates of festivals
and holy days as well as predicting the times to plant and harvest crops.
For direction finding, only the Sun and stars could be used, with the Arabs
making the sophisticated technology of the astrolabe. For navigation past
the simple strategy of following the coastline, the basis was direction
finding and latitude sailing, with the Polynesian and Viking sailors
enabling their magnificent voyaging only by fine-tuning with the Sun
and stars. All old cultures also took frequent practical use of the skies as
a source of celestial omens, including astrology, which guided the actions
of kings and commoners. Perhaps the most famous example of this is the
Star of Bethlehem, a celestial omen pointing to the birth of a very great
king in Judea; surprisingly, the real historical origin of this sign in the sky
was only recently discovered.
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