The Remarkable Science of Ancient Astronomy

Course Overview

Discover the ancient sky with an award-winning teacher and noted astronomer. In a world without artificial lights, the night sky is ablaze with stars, whose patterns tell stories you have heard since childhood. The Sun, Moon, and stars are crucial to your daily existence, since they tell the time, direction, and when to plant and harvest. The perfect regularity of the heavens is the only guaranteed part of life and inspires deep religious and philosophical ideas, while unexpected events such as eclipses and comets incite fear.

Experience this ancient outlook with noted astrophysicist and historian of astronomy Professor Bradley Schaefer of Louisiana State University. An award-winning teacher, Dr. Schaefer takes you around the world, exploring the close relationship that people thousands of years ago had with the sky. The Remarkable Science of Ancient Astronomy covers notable sites and phenomena such as Stonehenge, the Great Pyramid, the Star of Bethlehem, the origin of constellations, Polynesian sky navigation, ancient calendars, and more.

Chart the precise alignment of prehistoric monuments with the Sun and stars, learn how to use a medieval astrolabe, and decipher the workings of an astonishing ancient Greek computer called the Antikythera mechanism, which was centuries ahead of its time. Using only their eyes, ancient astronomers got many things right, and their meticulous records have proved invaluable to modern astronomers, helping them calculate the slowing of Earth’s rotation and the expanding stellar cataclysms called supernovae. Ancient astronomers truly laid the foundation for modern science.

Course Structure

01: Stonehenge and Archaeoastronomy

Why were the motions of the Sun, Moon, and stars so important to ancient people? Investigate key astronomical directions noticed by all cultures. Then embark on your study of Stonehenge, seeing how it gave birth to the field of archaeoastronomy and to some very curious modern theories.
Duration: 31 min

02: The Real Stonehenge

In the popular mind, Stonehenge was built as a sophisticated astronomical calculator presided over by priestly astronomers called Druids. But is this view dating from the mid-1960s correct? Address the evidence, and survey the archaeological record to discover the most probable function of Stonehenge.
Duration: 30 min

03: Alignments at Maes Howe and Newgrange

Explore Neolithic tombs and monuments across Europe, discovering an array of alignments toward astronomical events. Start with two sites that are similar to Stonehenge in their clear orientation to the winter solstice: Maes Howe in the Orkney Islands, and Newgrange in Ireland.
Duration: 29 min

04: Astronomy of Egypt’s Great Pyramid

Study the astronomical significance of Egypt’s Great Pyramid. How did its builders achieve such phenomenal accuracy in the pyramid’s alignment to the cardinal directions? Were its air shafts intended to point at stars of special importance? Also evaluate modern claims for the mystical power of pyramids.
Duration: 29 min

05: Chaco Canyon and Anasazi Astronomy

Travel to Chaco Canyon, New Mexico, where the Anasazi culture practiced sky-centered rituals a thousand years ago. Look for evidence of their astronomical knowledge, examine their many “sun daggers,” and probe the controversial pictograph thought to depict the Crab Nebula supernova explosion in 1054 AD.
Duration: 28 min

06: Ancient Cosmologies and Worldviews

Consider the astronomy-based world views of different ancient cultures and how they answered the three big questions: Where did the world come from? What is the nature of the universe? What is its fate? Survey the beliefs of the Greeks, Chinese, Australian aborigines, and other groups, seeking common elements.
Duration: 29 min

07: Meteorite Worship and Start of the Iron Age

Witnessing a meteor fall must have been a strange and awe-inspiring experience for people long ago. Travel around the world to places where meteorites were worshiped and also used as a source of iron, which was rarer than gold before the smelting technology of the Iron Age.Duration: 30 min

08: Eclipses, Comets, and Omens

Since no human can touch the sky, any unexpected celestial event must be a divine omen. Reenter this primordial state of mind, seeing eclipses and comets the way they were perceived before the advent of modern science. In the course of this investigation, discover why comets became more feared than eclipses.
Duration: 29 min

09: The Star of Bethlehem

For centuries, astronomers have struggled to find an explanation for the Star of Bethlehem, recounted in the Gospel of Matthew. Professor Schaefer focuses on a recent theory that has taken scientists and biblical scholars by surprise, due to its success at solving problems that plagued all previous proposals.
Duration: 29 min

10: Origins of Western Constellations

The human propensity for pattern recognition and storytelling has led every culture to invent constellations. Trace the birth of the star groups known in the West, many of which originated in ancient Mesopotamia. At least one constellation is almost certainly more than 14,000 years old and may be humanity’s oldest surviving creative work.
Duration: 32 min

11: Chinese and Other Non-Western Constellations

Study the constellation patterns of ancient China, which influenced those of India and Arabia. Professor Schaefer dates the origin of the Chinese star groups called lunar lodges, and he samples southern constellations conceived by cultures in South America and Australia.
Duration: 30 min

12: Origins and Influence of Astrology

Astrology grew up hand in hand with astronomy. Focus on the different astrological traditions in Mesopotamia, China, India, and Mexico. Also trace the spread of astrology through the Mediterranean world. As an example, study the auspicious horoscope of Octavian, who became Emperor Augustus.
Duration: 31 min

13: Tracking Planet Positions and Conjunctions

Until the invention of the telescope in 1610, astronomy was mostly the study of the sky positions of the Sun, Moon, and planets. Learn the extraordinary precision attained by ancient astronomers in their observations. Discover why they prized this knowledge, and also uncover a lost great discovery of the Babylonians.
Duration: 31 min

14: Ancient Timekeeping and Calendars

For ancient people, keeping track of the time of day and year required a detailed understanding of the motions of the Sun, Moon, and stars. See how different cultures solved this problem. Also learn how to use a handy astronomical measuring device called the astrolabe.
Duration: 31 min

15: The Lunar Crescent and the Islamic Calendar

Delve into the surprisingly tricky problem of deciding when a lunar month begins—usually determined by the first sighting of a crescent Moon after new Moon. Professor Schaefer describes his algorithm for calculating this event and then applies it to dating the crucifixion of Jesus.
Duration: 29 min

16: Ancient Navigation: Polynesian to Viking

In the era before compasses and GPS, precise direction-finding was possible only through knowledge of the sky. Learn how the Polynesians found islands across thousands of miles of open ocean, and how the Vikings solved the very different challenge of navigating the North Atlantic.
Duration: 29 min

17: Breakthroughs of Early Greek Astronomy

Between 600 and 200 BC, Greek astronomers went from being flat-Earthers to full proto-scientists with reasonable models and distances for the Solar System. How and why did this revolution happen? Focus on the achievements of Thales, Aristarchus, Eratosthenes, and Aristotle.
Duration: 31 min

18: The Genius of Hipparchus

Considered the greatest astronomer of the ancient world, Hipparchus created a thousand-star catalog and discovered precession, the eons-slow rotation of the fixed stars around the ecliptic. Did this remarkable discovery give birth to the Mithraic religion, which rivaled Christianity?
Duration: 31 min

19: Revealing the Antikythera Mechanism

In 1901, divers off a Greek island discovered a corroded bronze artifact composed of interlocking gears. Later analysis and X-ray imaging show it is an astonishingly versatile astronomical computer. Professor Schaefer identifies a probable date when it was built and two likely candidates for its brilliant designer.
Duration: 29 min

20: How the Antikythera Mechanism Worked

Learn to operate the Antikythera mechanism, the glory of ancient astronomy. Modern models show how a simple turn of the crank could reveal the day of the year, phase of the Moon, possible eclipse dates, the cycles of ancient games, and other information. Probe the historical impact of this device.
Duration: 28 min

21: Achievements and Legacy of Ptolemy

Ptolemy has been called the greatest astronomer of antiquity. But was he? Evaluate his reputation by focusing on his star catalog, celestial coordinate system, and magnitude scale. Then gauge the extent of his influence over later astronomers, which lasted over a thousand years.
Duration: 30 min

22: Star Catalogs from around the World

The genius of Greek astronomy is epitomized by the star catalogs of Hipparchus and Ptolemy. Professor Schaefer recounts his exciting discovery of a star chart apparently influenced by Hipparchus’s lost catalog. Close by comparing Greek star catalogs with those of China and the Arab world.
Duration: 30 min

23: How Ancient Astronomy Ended

Review the state of astronomy in 1500. Then chart the revolution sparked by Copernicus’s heliocentric theory of the Sun and planets. Learn how Copernicus was the last of the ancient astronomers, succeeded by the founders of modern science, including Tycho, Kepler, and Galileo.
Duration: 30 min

24: Ancient Astronomy and Modern Astrophysics

Finish the course by seeing how ancient records of eclipses and supernova explosions have refined our modern understanding of Earth-Moon dynamics and stellar processes—proving that today’s cutting-edge astrophysicists owe a great debt to astronomers who watched the skies long ago.
Duration: 32 min