Chapter 2 Observing the Sky: The Birth of Astronomy
Chapter 2 Observing the Sky: The Birth of Astronomy
2.2 Ancient Astronomy Around the World
Learning Objectives
By the end of this section, you will be able to:
- Describe early examples of astronomy around the world
Astronomy around the World
Let us now look briefly back into history. Much of modern Western civilization is derived in one way or another from the ideas of the ancient Greeks and Romans, and this is true in astronomy as well. However, many other ancient cultures also developed sophisticated systems for observing and interpreting the sky.
Ancient Babylonian, Assyrian, and Egyptian astronomers knew the approximate length of the year. The Egyptians of 3000 years ago, for example, adopted a calendar based on a 365-day year. They kept careful track of the rising time of the bright star Sirius in the predawn sky, which has a yearly cycle that corresponded with the flooding of the Nile River.
The Chinese also had a working calendar; they determined the length of the year at about the same time as the Egyptians. The Chinese also recorded comets, bright meteors, and dark spots on the Sun. (Many types of astronomical objects were introduced in Science and the Universe: A Brief Tour. If you are not familiar with terms like comets and meteors, you may want to review that chapter.) Later, Chinese astronomers kept careful records of “guest stars”—those that are normally too faint to see but suddenly flare up to become visible to the unaided eye for a few weeks or months. We still use some of these records in studying stars that exploded a long time ago. They used a lunar-solar calendar. The Calgary, Alberta, Canada section of the Royal Astronomical Society of Canada have produced a bilingual (English-Chinese) handout detailing Chinese New Year and its astronomical connections. http://calgary.rasc.ca/downloads/Chinese_New_Year_bilingual_formatted.pdf
The Mayan culture in Mexico and Central America developed a sophisticated calendar based on the planet Venus, and they made astronomical observations from sites dedicated to this purpose a thousand years ago.
In July 2021 a site in Chile was awarded UNESCO World Heritage status. https://en.wikipedia.org/wiki/Chanquillo. Chanquillo[1][2][3][4][5] or Chankillo[3][6][7][8] is an ancient monumental complex in the Peruvian coastal desert, found in the Casma-Sechin basin in the Ancash Department of Peru. The Thirteen Towers have been interpreted as an astronomical observatory built in the 4th century BC.[6][9] The regularly-spaced thirteen towers of Chankillo were constructed atop the ridge of a low hill running near north to south, forming a “toothed” horizon with narrow gaps at regular intervals. To the east and west investigators designated two possible observation points. From these vantages, the 300m long spread of the towers along the horizon corresponds very closely to the rising and setting positions of the sun over the year. On the winter solstice, the sun would rise behind the leftmost tower of Cha