Sci. 1-1

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Sci. 1-1

• Astronomy- The Original Science
• Pages 4-10

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• A. Astronomy- the study of all physical objects
  beyond Earth

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B. Calendar-a system for organizing time

• Egyptian Stone calendar

• Aztec calendar

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1) Calendars are based on movements of objects in
the sky.
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C. Year- time required for Earth to orbit the sun
once
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D. Month- amount of time required for the moon
to orbit the Earth once
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E. Day- the time required for the earth to rotate
once
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F. Many ancient civilizations developed
calendars- Mayas, Chinese, Egyptians, and Hebrew
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• Our modern calendar was developed
• from the Roman calendar with
• 365 days in a year and 7 days a week.

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• H. Julius Caesar fixed the problem of the seasons
  shifting due to the calendar by adding an extra
  day every 4 years- a leap year.

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• I. Most countries use the Gregorian calendar
  which scientists calculate will be accurate for
  another 3,000 years. It was created to make a
  year more accurate to 365.242 days per year by
  changing how often leap year occurs.

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J. Early Observers
Babylonia
Nabta
Stonehenge
Ancient Arab- astrolabe
Chinese
Mayan Building
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• K. Early Astronomers

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• 1) Claudius Ptolemy- (Greek) Ptolemy thought that
  the Earth was at the center of the universe with
  the sun and other planets revolving around the
  Earth

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• 2) Nicolaus Copernicus- (Polish) thought the sun
  is at the center of the universe and the planets
  orbit around the sun.

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• 3) Tycho Brahe- (Danish)- used a mural which is a
  large quarter-circle on a wall to measure the
  positions of stars and planets.

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• 4) Johannes Kepler- stated that all the planets
  revolve around the sun in elliptical orbits and
  the sun is not in the exact center of the orbits.

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5) Galileo- was the first person to use a
telescope to observe celestial bodies and
discovered sunspots, 4 moons of Jupiter, craters
and mountains on the moon
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• 6) Isaac Newton- explained that planets and
  moons stay in orbit due to gravity.

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L. William Herschel discovered Uranus in 1781.
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M. Edwin Hubble used photography in 1923 to
discover that there are other galaxies.