Dearborn will explore how throughout history, people of many cultures have looked to the sky for knowledge. From it, they learned to navigate the plains and the oceans, as well as to plan and organize their days, months and year. He will explain how some early astronomers developed the ability to predict the motions of planets and when eclipses might appear.

"The practical benefits were so substantial that they associated important cultural beliefs, or myths, with patterns of stars, and looked to the heavens for the fates of individuals and kingdoms," Dearborn said. "In this presentation we will discuss some of the basic observations that allowed shamans to learn and predict the seasons. We will also examine how astronomy was woven into a particular culture, the Inca. In the high Andes, many people saw the sun as a god with the power to make things grow, and the ruling Inca legitimized his Imperial position with a claim of kinship to that celestial bodies."

Today you will learn

  • How was science integrated into ancient civilizations
  • What physical, cultural, and spiritual purposes were addressed through astronomical observation and prediction
  • How the Inca civilization learn about the universe


You will learn how celestial observation was used by ancient cultures to measure time, plant crops, and influence the fate of kingdom.

Student Lecture Notes

You will learn how celestial observation was used by ancient cultures to measure time, plant crops, and influence the fate of kingdom.

Student Lecture Notes


1. List three practical reasons why ancient people would want to know when the solstices will occur.

a. _______________________________________________

b. _______________________________________________

c. _______________________________________________

2. Many ancient cultures supported people who were part astronomer, part doctor, part advisor, and part priest. How were their basic activities like those of modern scientists?


3. What were the pillars around Cuzco and the Island of the Sun used for?


4. What does the distance between these pillars indicate about the Inca solar festivals?


5. What was the significance of the “Island of the Sun” for the Inca people?


6. At Machu Picchu, how did they measure the date of the June solstice?

Speaker Bios

Dr. David Dearborn

Dr. David S. P. Dearborn is a graduate of UCLA (1970) and the University of Texas at Austin (1975). He has held positions at the Copernicus Institute in Warsaw, the Institute of Astronomy in Cambridge, The California Institute of Technology, and Steward Observatory in Tucson. He is currently a research physicist at the Lawrence Livermore National Laboratory.

He was the 1998 Shelby Fellow of the Australian Academy of Science, has received two Pollock awards for studies in the History of astronomy, and three "Weapons Recognition of Excellence" awards from the Department of Energy. These awards recognized his contributions to laser hohlraum development, his work advancing the analysis of radar data, and finally for his efforts on the W87 Life Extension Program. In 2006, he received a DNT acknowledgement for "outstanding contributions of the cross discipline improvement of ICBM accuracy ...", and others (in 2007 and 2008) for "warhead contributions in support of Prompt Global Strike."

His astrophysical research includes publications on observations of isotope ratios in red giants, as well as the discovery of several short period variables. However, most of his astrophysics work involves theoretical studies on the physics of stars, including stellar nucleosynthesis, and astro-particle physics. He is currently involved in Djehuty, a project for the full three-dimensional modeling stars, which recently led to the discovery of a new mixing mechanism that resolves a decades old conflict between predicted and observed abundances.

His work on the astronomy of the Inca includes the discovery of a set of Inca pillars marking the June solar position at the Island of the Sun in Bolivia. This and other Andean work has resulted in a dozen journal publications and a book on the subject. He is a full member of the Institute for Andean Studies, a founding member of the International Society for Archaeoastronomy, and Astronomy in Culture (ISAAC), and until recently was one of four principal editors for the journal Archaeoastronomy, published by the University of Texas Press.

His programmatic work has included the design and testing of both nuclear and conventional explosives. Current responsibilities include generating models and output for the DTRA Red Book, support of the LLNL RV flight-test program, and conventional lethality studies. He has used large lasers for the study of high energy density phenomena, studied non-seismic methods for treaty verification, and designed a shuttle experiment.

His current research on the diversion of asteroids by nuclear explosives mixes his skills in astrophysics and nuclear weapons effects. It began in 2003 for the Planetary Defense Conference, and resulted in publications cited by NASA's 2006 Near-Earth Object Survey and Deflection Study for the congress. Today, this research continues with detailed modeling of the effects of nuclear explosives on asteroids.

Josh Holtzman

Josh Holtzman is a former high-school teacher of physics, earth science, and computer science. He completed his undergraduate work in Oceanography and Limnology at the University of Michigan, and later conducted research into the geochemistry of the Laurentian and East African Great Lakes. After growing restless with his laboratory research, he returned to the University of Michigan to earn a Masters in Education. He began teaching at Monte Vista High School in Danville, California in 1998 He currently works as a consultant developing web-based applications for schools, small businesses, and non-profit organizations. When he is not writing software, he enjoys rock climbing and whitewater kayaking.


  • Capacraymi: "Royal Festival", culminating in the December solstice
  • Chicha: A ritual beverage similar to beer
  • Chulpa: A burial structure
  • Coriconcha: Literally translates to "Golden Enclosure", the temple of the sun, moon, and start
  • Intiraymi: "Solar festival", culminating in the June solstice
  • Intitayta: The Inca sun god
  • Quipu: A knotted string used to record numerical data
  • Solstice: The two times of the year when the sun is at its greatest distance from the celestial equator. The sun is at its highest point in the Northern Hemisphere's sky during the June solstice, and highest in the Southern Hemisphere's sky during the December solstice.
  • Torreon: A Tower