1. The History Of Astronomy

2. Since time immemorial, people have looked up at the skies and wondered what meaning it holds…

3. Every known culture has its own constellations and stories that attempt to explain how the stars came to be…

4. Humans have taken their notions of time from the movements of the Earth and moon in space.

5. Stonehenge Constructed: 3000 – 1800 B.C.
Stonehenge aligns with locations of sunset, sunrise, moonset and moonrise at the summer and winter solstices. It was probably used as a calendar.

6. The Ancient Egyptians based their calendar on the appearance of the brightest star in the sky: Sirius

7. Many other cultures have done the same. E. g
Many other cultures have done the same. E.g., Caracol (Maya culture, approx. A.C.E. 1000)

8. Babylonians (3000 BC)
We still use many of their names for the stars and also their Constellations, although renamed from Greco-Roman Mythology.
They also made up the signs of the zodiac which we still use today. Many people still believe in their ideas about Astrology.

9. Aristotle
Aristotle (384 BC – 322 BC), a famous Greek writer, philosopher, and physicist, was one of the 1st to attempt to develop a rational understanding of the universe.

10. Aristotle’s Ideas Geocentric Theory
– Earth is the Center of the Solar System and everything else (planets, sun, and stars) revolves around it
-- All stars are fixed points which rotate on a single sphere.
There are only a few basic Substances:
1. Earthly Realm – Air, Earth, Fire, and Water 2. Heavenly Realm – Quintessence (Not found on Earth)
Believed Earth is round BUT not be moving!

11. Aristotle’s Model of the Solar System

13. Eratosthenes ( B.C.)
1st person able to measure the circumference of the Earth (came within a couple thousand miles of actual value)
- used geometry and ratios to determine the size of Earth
Ptolemy (90 – 168 AD)
worked out a complex system of Epicycles and perfect circles for the orbits of planets, sun, and moon around Earth

14. Geocentric Model
Ptolemy’s

15. Answer in Your Journal in Complete Sentences that restate the questions:
When did people start to look up at the sky and ask why?
How can the skies be used to mark time?
What were Aristotle’s ideas about the universe?
Getting philosophical: Do we look at the stars because we are human, or are we human because we look at the stars…..?