Archaeoastronomy

Archaeoastronomy is the study of ancient, essentially prehistoric, astronomical theories and practices through evidence provided by archaeology, the interpretation of ancient artifacts, the written records (if available) and ethnological sources such as tribal legends It is sometimes called ethnoastronomy.

Because in ancient times astronomy was serving the needs of rulers, it was treated as Astrology to some extent for divination purposes, observation and predictions of solar and lunar eclipses were given special attention. The conjunctions of bright planets as well as appearances of comets, meteors and new stars were considered to have divinatory value. Therefore the movements of the Sun, Moon and planets, and rare astronomical phenomena were carefully and systematically observed. Thus a huge body of astronomical phenomena was recorded.

Many ancient peoples – for example the Stone Age populations of the European countries and the Eastern Mediterranean are known to have been fully aware of celestial phenomena, as manifested in the alignments of their megalithic monuments such as Stonehenge, New grange and the dolmens of north-west France. Measurements of the Egyptian pyramids show that they are orientated within a small fraction of a degree in the north–south and east–west directions, and this must have required considerable practical observational skill.

Ancient astronomical observations were not limited to the Old World: for example, Meso-American peoples such as the Maya and the Aztec have left codices and other evidence which reveal knowledge of celestial events and the determination of celestial cycles.

In some ancient civilizations, observation of the Heliacal rising of Sirius provided a reference point that enabled their lunisolar calendar to be corrected to match the true solar year. This was essential to the civilization if the calendar was to be used to decide the proper time for planting crops.

What may be called applied historical astronomy makes use of ancient records to derive data of value to modern astronomical research. For example, ancient observations of eclipses from Babylon, China, Europe and the Islamic world can be used to determine the variation in the Earth’s rotational period over the past 2700 years. In addition, ancient records of the extremely rare outbursts of supernovae, often recorded as ‘guest’ or ‘new’ stars, are invaluable in the study of the development and present day remnants of these events.

Questions to Ponder

• Why is the astronomical importance of the Stonehenge?
• What is the connection between the Egyptian Pyramids and Position of Sirius Star?