A Flemish Tapestry from the 1500s AD depicting an astronomer and others gazing at the heavens

The Early History of Astronomy

What types of things can you see in the sky with the naked eye?

These are the things ancient cultures could observe, without the aid of technology! (The Sun, Mercury, Venus, Mars, Jupiter, Saturn, Meteors, Comets, and Stars.)

Astronomy is the oldest science. There is evidence of crude astronomy even in prehistoric times.

Early astronomy was about observing the motion of these celestial objects.

How could ancient astronomers tell the difference between stars and planets?

Relatively speaking, stars remain at predictable fixed points in the sky, but planets can move larger distances over a much shorter period of time.

Why is this true?Because the planets are much, much closer to us than the stars!

How did many ancient cultures explain it?Many believed the planets were gods.

For example, Mercury, the Roman God of trade, profit, and commerce, was depicted as a messenger, and called Hermes in Greek mythology.

Why would anybody want to study the lights in the sky?• To attempt to predict things• To make a calendar

What types of things might you be able to predict by carefully watching the sky?• Seasons• Tides

Why do people need a calendar?• To know when to observe a ritual• To anticipate a harvest or planting season

A portion of the ancient Mayan calendar, still in use today by some remote villages in the Guatamalan highlands. The pictures (“glyphs”) represent named days in the calendar’s cycle.

Calendars are usually solar (based on the Sun’s cycle) or lunar (based on the Moon’s cycle).

Some cultures have incorporated elements of both of these types (and other types) into their system.

For example, in our culture, the time periods “day” and “year” are based on the Sun, while the time period “month” is based on the Moon.

Astronomy arose independently in many areas around the Earth:

• Egypt, before 3,000 B.C.• Mesopotamia, before 1,200 B.C.• China, before 600 B.C.• Greece, before 400 B.C.• India, before 1 A.D.

In each area, different cultural patterns, religious beliefs, and political influences developed due to varying interpretations of the meaning of celestial objects & motion.

The pyramids of Giza, Egypt, align with then-pole star Thubus, in Draco

Nabta playa, Egypt, built c. 7,000 B.C., marks the start of summer.

Stonehenge, England, built around 6,000 B.C., marks 1st day of summer.

Newgrange, Ireland, built around 3,000 B.C., tomb marks start of winter.

Newgrange, Ireland, built around 3,000 B.C., tomb marks start of winter.

Newgrange, Ireland, built around 3,000 B.C., tomb marks start of winter.

Newgrange, Ireland, built around 3,000 B.C., tomb marks start of winter.

Moai on Easter Is., c. 700 A.D. Astronomy connection?

Big Horn medicine wheel, Wyoming, c. 1,800 A.D.

All of these are examples of megaliths.

A megalith is a collection of stones, often very large, arranged in such a way as to be used for astronomy, timekeeping, religious practices, etc.

Megaliths are important objects to study in the field of archaeoastronomy.

Archaeoastronomy is the study of how ancient cultures understood and used celestial objects in their societies.