unit 3 astronomy and ancient civilizations€¦ · stonehenge ancient stone structure in england...
TRANSCRIPT
Unit 3
Astronomy and Ancient Civilizations
Agriculture is the key…
�Agriculture is the key to modern civilization
�Without agriculture
�Still hunting and gathering
�No large societies
�No governments
�No cities, factories, technology…
Astronomy allowed prediction of seasons
�People noticed that the sun rose in certain star
patterns at certain times of the year
Astronomy is the key to agriculture
�Astronomy allowed for the prediction of seasons
�Ability to predict seasons allowed agriculture to replace hunting and gathering
Astronomy
Therefore
�Astronomy is the key to modern civilization
Astronomy and ancient cultures
�Ancient cultures had commonalities with astronomy
�Religion
�Navigation
�Time-keeping
Time keeping
�Determining the dates of the solstices and equinoxes was key to early agriculture
�Allowed prediction of seasons
�Allowed for planning of planting and harvesting
�Could determine holidays
Solstices and Equinoxes
Ancient calendars
�Were big structures to monitor the path of the sun and other bodies
Stonehenge
�Ancient stone structure in England
�Used to
�Determine exact day of summer and winter
solstice
�Track path of sun throughout the year
Machu Pichu
� Incan city, believed to be estate of the emperor
�Solar observatory / Sun temple
Stone Calendars
�These sites were built to track the date (calendars)
�Why stone?
�Permanence
�Accuracy
Later calendars…
�By the time of the Greeks, mechanical calendars and calculators were being built
�Used for navigation and astrology
Antikythera Mechanism�Discovered in 1901in an ancient shipwreck
�Built around 150-100 BCE
�Could calculate position of moon, planets and stars for a given date
Chinese contributions�Left detailed records of stellar observations
�Still studied today
�More complete than Western records
Star Catalogs
�An ordered listing of astronomical objects
�Chinese and other ancient civilizations
Babylonian Contributions
�Named many zodiac constellations
Greek Contributions
�Models of the solar system
�Names of many constellations
�Use of mathematics in astronomy
Orbits of the planets
� Planets closer to
Sun than Earth:
� Inferior orbits
� Planets further from
Sun than Earth:
�Superior orbits
Figuring out that Earth is round
�Things going away disappear from bottom up
�Observing shadow of Earth eclipsing the moon
�Stars in North were more overhead when travelling North, less overhead when travelling South
Eratosthenes
�Determined the size of the Earth
Calculating the Earth's Circumference
Heliocentric system
�Sun centered
�First proposed by Aristarchus
Geocentric system
�Earth centered
�Proposed by Aristotle
Prograde Motion
�moving in the same direction as everything else
Retrograde Motion
�moving in the opposite direction to something else
The motion of Mars
Ptolemy
�Proposed a workable geocentric solar system
The Ptolemaic Solar System
Defferents
Epicycles
Why was Ptolemy accepted
�Could prove it mathematically
�Church said it was so