ANCIENT ASTRONOMY

What is Astronomy?• Astronomy is the science of the stars,

planets and other celestial bodies as well as the universe as a whole.

• Astronomy stretches back over 6000 years, making it the oldest science by far.

• The development of astronomy has been intertwined with the development of civilization through timekeeping, navigation, religion and curiosity.

Time Keeping• The 24-hour day is based on the time it takes

the sun to circle the sky.• The length of a month is from the lunar cycle

(from new moon to full moon and back).• The calendar year is the cycle of the seasons

(caused by the axial tilt of the Earth). • Days of the week are named after the seven

naked-eye objects that appear to move among the constellations: the Sun, the Moon, Mars, Mercury, Jupiter, Venus, Saturn.

• Shadows during the day were used to time keep (sun dial)

NavigationSeafaring Polynesians 1000BCE

– Use the Sun during the day.– Use the Stars during night.

• In the Northern Hemisphere: Ursa Major (Big Dipper) used to find Polaris (the North Star)

• In the Southern Hemisphere: No bright star in the Southern Hemisphere equivalent to Polaris. The Southern Cross constellation can be used to find South.

Religion• Babylonians thought that celestial gods ruled the

sky.• Greeks and Romans adopted those gods.• Egyptian deity Ra, the Sun God, was swallowed

every evening by Nut, the Sky Goddess.• Sumerians thought every evening the Sun was

captured by a magical boatman.• African tribes had a variety of beliefs about the

sky.• Mayans worshiped the god of Sun, Moon, etc.