3.  There was 2 reasons the ancient people had an interest in studying the sky: 1. Used the sky to navigate on the sea 2. To know what time of year it was…this was very important for planting crops

5.  Stonehenge which is located in Salisbury Plain in England was built in 2800 B.C.  Researchers believe that it is an ancient astronomical calendar

9.  Heaviest stones weigh up to 50 tons  It is still a mystery as to how primitive man was able to move these heavy stones and form them into a pattern

10.  The ancient Chinese kept excellent records on astronomical events Especially two things: 1. Comets 2. guest stars (stars that appear bright for a short time and then appear to go away (super nova)

11.  1. Geocentric Model- This model supported the belief that the Earth was the center of the Universe.  This belief followed the teaching of Aristotle

13. 2. Ptolemaic Model- this model included part of the geocentric model.  It stated that the Earth was in the center of the universe  But the moons and planets rotated in circles as they went around Earth

15. 3 rd Model- Heliocentric Model- This means Sun centered. Nicholas Copernicus finds a 1000 year old model of the solar system made by Arastarchus  Copernicus will make this idea popular  The Copernican Revolution- was the critical realization that the Earth was not the center of the universe

17.  Galileo was an Italian mathematician and philosopher  He was the first to study the sky with a telescope

18.  Galileo had 4 major discoveries: 1. Saw mountains on moon 2. Saw sunspots on Sun…later made him blind 3. Saw the moons of Jupiter 4. Realized that Venus had phases which meant that it orbited the Sun

19. Galileo took a stand against the Church (which supported the geocentric model).  Galileo supported the heliocentric model  This was a time when the Church burned Bruno (an astronomer) for his beliefs for the sun-centered model.

20.  Galileo made fun of the geocentric model in public  The Church demanded that he retract his statements and placed him under house arrest in 1633.  He spent the rest of his life a prisoner in his own home  The Church officially and publicly forgave Galileo for his crimes in 1992

21.  1 Tycho Brahe- famous for keeping great records of the sky  2. Kepler – worked under Brahe and used Brahe’s records to develop mathematical laws on how the planets move.

22.  He was a British mathematician  He was born on Dec. 25 th …the year Galileo died  Newton’s famous statements… “if have seen far, it is because I have stood on the shoulder of giants”.

24. 3 laws are: 1. A body will stay in motion or at rest unless another force acts upon it. 2. The greater the force acting on the body, the faster it will travel 3. To every action there is an equal and opposite reaction

25.  Newton also discovered that gravity is an attractive force a body has on another body. Escape speed- the speed needed for an object to escape a gravitational field.