1. Astronomy in the Middle Ages to the Modern Era From Copernicus to Galileo to man on the moon

2. Copernicus Began the process of disproving the _________________ theory A _______________ model of the universe offers a much simpler explanation of the universe (remember Occam’s Razor)

3. Heliocentric Model Explains __________________________ Planets will appear to change direction every time Earth _____________________ their orbit Could now determine the distance a planet is from the sun using ____________________ There were still problems with his model because he said the orbits of the planets were ___________________________ His views were _____________ to be accepted

5. Tycho and Kepler Copernicus opened the door to new ideas A cultural renaissance was taking place in Europe The Protestant Reformation had begun The new world was being settled It was an environment ripe for intellectual stimulation

6. Tycho Brahe Believed that God placed the planets in the heavens as a ________ to humankind of events on Earth Made precise measurements with______________ he constructed

7. Tycho Brahe First to show the existence of heavenly bodies ____________ of our solar system Suggested that the heavens were more ________________ than we first believed He had Earth still as the ____________ of the universe with the Sun orbiting around it and the other planets orbiting the Sun

8. Johannes Kepler Explained Brahe’s precise observations in _______________ terms Developed_________ laws that explained most aspects of planetary motion

9. Kepler’s Laws Law of ________________

10. Law of Ellipses Each planet orbits the sun in an _____________________ path Each ellipse has two _________ – one of which is the sun This means the planet is not always the ___________________ from the sun

11. Law of Ellipses ________________ – the point where the planet’s orbit is closest to the sun ________________ – the point where the planet’s orbit is furthest from the sun The distance given is usually the ________________ of the perihelion and the aphelion

12. Law of Equal Areas Describes the ______________ at which planets travel at different points in their orbits Earth’s orbit is _____________ a perfect circle with the sun off center Earth moved ____________ when it was ____________ to the sun

14. Law of Periods Describes the relationship between the ___________________ of a planet from the sun and the orbital period of the planet ___________________ – the time it takes to make one revolution around the sun The cube of the average distance of a planet from the sun (a) is always proportional to the square of the period (p)

15. The Mathematics K X a 3 = p 2 K is a mathematic constant If we measure distance in AU and use earth- years, K = 1 and therefore a 3 = p 2 a = average distance of the object from the Sun p = period

16. Kepler’s Three Laws Describe the essential features of planetary motion around our Sun Were the first laws to describe the heavens correctly Kepler also gave us the word ___________

17. Galileo Galilei Used the newly invented telescope to study the motions of the planets (Note: Galileo ___________ invent the telescope) Proved that the _______________ model was the correct one

18. Galileo Galilei Was the first to use the telescope to study the heavens Observed that the moon was a ____________ Observed _______________ and that they changed from day to day and deduced that the sun _______________ Discovered that Jupiter had _______________ Examined the _________________ and saw that it was made up of millions of stars Observed that Venus went through _______________ just like the Moon

19. Galileo Galilei That fact that Venus had phases left no doubt that it orbited the Sun and put an end to the Geocentric model of the universe The originator of the ______________________ still in use today Was brought up on charges of _____________ against the church (1992 the church admitted it made a mistake)

20. Newton’s Application of Kepler’s Laws Newton wanted to know why the planets moved liked this Newton said that a moving body will only change its motion if an ________________ causes it to do so An outside force must cause it to _______ This force he determined was _________ The gravitational pull of the __________ is what keeps the planets in orbit around it.

21. Isaac Newton and the Birth of Astrophysics Some consider him to be the greatest scientist of all time Studying the moon he came up with the laws of gravity Invented __________________ His laws of gravity and motion were totally accepted for ___________ years

22. The Growth of Astrophysics New Planets were discovered Stars had companions that orbit with them Irregularities in the orbit of Uranus led to the discovery of _________________ Bigger telescopes – Telescopes in space Applying photography Space Exploration