Science in Prehistory

1
Science in Prehistory

• Mankind has had a long fascination with the
  heavens the motion of stars, Sun, Moon,
  planets, comets, meteorites, aurora, even
  observation of supernovae.
• Stonehenge
• (Salisbury Plain, UK)
• 2500BC

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STONEHENGE (Salisbury Plain, UK) built over 17
centuries from2800BC to 1100 BC. With the
biggest stones being laid about 2450BC.Stone
configuration correlated to winter and summer
solstices.
3
Newgrange(County Meath Ireland)3000BC
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Newgrange Passage Tomb

• Central Chamber
• Illuminated
• Around the Winter Solstice.

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Stonehenge and Newgrange Conclusions

• An Awareness of the repeatable motions of the
  Sun and Moon
• Despite popularised controversies, Stonehenge is
  not regarded as the birthplace of predictive
  astronomy.
• In comparison to their contemporary Egyptian
  culture, we know very little of the Neolithic and
  early Bronze Age peoples of Northern Europe.

6
Egyptians Observation of the Sun and Moon
Motions.

• Monitoring seasonal variation for agriculture
• Nile Flooded when sun rose near the star Sirius
  (the Dog star, in the Canis Major
  constellation brightest star in the sky).
• Link lunar and solar birth and death to
  religious festivals and an elaborate mythology.

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Babylonian Era

• Monitored the movement of the Sun, Moon and
  Venus.
• Note special events eclipses and comets
• Prediction requires mathematics and record
  keeping! (necessitates a long-lived, stable
  culture)

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Numbers and Early Calendars

• Early Egyptians and Babylonians had 360 days in
  a solar year.
• Origin of 360? in a circle.
• Egyptians divided the day into 24 hours.
• Babylonians developed a base 60 number system.
• Origin of 60 seconds and 60 minutes
• Egyptians introduced Leap years.
• Formalised by Julius Caesar (46 BC)

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Gregorian Calendar (1582 AD)

• Introduced by Pope Gregory XIII
• The precession of the equinoxes (due to earths
  wobble on its axis) results in seasons drifting
  over 26,000 year cycle.
• Gregorian Calendar maintains the seasons in the
  proper months of the year.

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Gregorian Calendar

• 1 extra day in every 4 years (leap year) is too
  much!
• Leap year at the close of the century omitted,
  unless year a multiple of 400!
• i.e 1600, 2000 leap years
• 1700, 1800, 1900 not leap years

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Aristotle (384-332 BC) and Ptolemy (150AD)

• In Greek period, there were a variety of views on
  the nature of reality
• Earth, Fire, Air, Water
• Aristotles view spherical, stationary Earth
  dominated.
• Developed to its full by Ptolemy in the
  Almagest (Arabic for the greatest).

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7 Wanderers 7 Day Week

• Wanderer is the Greek meaning of planets
• Wanderers in the Zodiac
• Sun, Moon, Mercury, Venus, Mars, Saturn and
  Jupiter
• (Latinised names)

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Greek, Islamic and Chinese Cultures Monitored the
Heavens

• Greek Philosophers formalised Geocentric solar
  system
• Islamic Astronomers developed new tools,
  e.g. Astrolabe
• Chinese observed the supernova of 1054 AD

14
Native Americans also Observed the Motion of Key
Stars

• Big Horn Medicine Wheel, Wyoming.
• Spokes are aligned to the rising and setting of
  the Sun and certain stars.