Ancient History of Astronomy

Page
1

Slide 1

Slide 2

• When did mankind first become interested in the science of astronomy? With the advent of modern computer technology (mid-20th century)

• With the development of the theory of relativity (early 20th century)

• With the invention of the telescope (~ A.D. 1600)

• During the times of the ancient greeks (~ 400 – 300 B.C.)

• In the stone and bronze ages (several thousand years B.C.)

Slide 3

Already in the stone and bronze ages, human cultures realized the cyclic nature of motions in the sky.

Monuments dating back to ~ 3000 B.C. show alignments with astronomical significance.

Those monuments were probably used as calendars or even to predict eclipses.

Slide 4

Stonehenge

Slide 5

•Stonehenge Constructed 3000 – 1800 B.C. in Great Britain

• Alignments with locations of sunset, sunrise, moonset and moonrise at summer and winter solstices

• Probably used as calendar

Slide 6

Big Horn Medicine Wheel (Wyoming)

Slide 7

Other Examples around the World

Slide 8

• Why is it so difficult to find out about the state of astronomical knowledge of bronze-age civilizations? Written documents from that time are in a language that we don’t understand.

• There are no written documents documents from that time.

• Different written documents about their astronomical knowledge often contradict each other.

• Due to the Earth’s precession, they had a completely different view of the sky than we have today.

• They didn’t have any astronomical knowledge at all.

Slide 9

Models were based on unproven “first principles”, believed to be “obvious” and were not questioned:

1. Geocentric “Universe”: The Earth is at the Center of the “Universe”.

2. “Perfect Heavens”: The motions of all celestial bodies can be described by motions involving objects of “perfect” shape, i.e., spheres or circles.

Slide 10

Slide 11

Slide 12

Epicycles

Introduced to explain retrograde (westward) motion of planets The ptolemaic system was considered the “standard model” of the Universe until the Copernican Revolution