2. Inquiry Imagine what would it have been like to see a solar eclipse in ancient times? Imagine what would it have been like to see a solar eclipse in ancient times? What would those people have wondered? What would those people have wondered? Describe a conversation between two young people viewing an eclipse in the year 500 B.C.E. Describe a conversation between two young people viewing an eclipse in the year 500 B.C.E.

3. The Sun-Eating Dragon

4. Sun Gods Ra and Surya

5. Stonehenge

6. Solar Eclipse

8. May 10 1994

9. Solar Eclipses visible in USA August 21, 2017 April 8, 2024** **How old will you be?

10. UNIVERSAL GRAVITATION FROM ARISTOTLE TO EINSTEIN

11. ARISTOTLE 384-322 BC Nature is made up of 4 elements plus the quintessence Air Earth Fire Water Quintessence-celestial realm Taught that objects have natural tendency to be at rest at the center of the Earth.

12. PTOLEMY 87-170 AD Wrote the Almagest which detailed a Universe that was highly complex Wrote of a geocentric Universe which consisted of known planets, moon, sun, and the stars. Used ideas of epicycles, deferents, and equaints to describe the orbits in his model

13. COPERNICUS 1473-1543 Polish priest that taught of a heliocentric Universe Explained retrograde motion of Mars, and motion of the inferior (inner) planets Strongly opposed by Catholic church which supported Ptolemaic system of the Universe

14. Brahe/Kepler Tycho Brahe (1546-1601) –Danish astronomer that tirelessly observed the heavens, and collected immense amounts of data on their motions. Johannes Kepler (1571-1630) –1 st model utilized 5 regular solids –Hired as mathematical assistant to Brahe –Developed model of solar system now known as Kepler’s 3 Laws

15. Kepler’s 1 st Law of Planetary Motion Planets move in ellipses with the Sun at one focus

16. How to Make an Ellipse

17. Kepler’s 2 nd Law of Planetary Motion Planets sweep out equal areas in equal times. Note: Orbit shown is highly eccentric

18. Planets Greatest Speed Planets Least Speed

19. Kepler’s 3 rd Law of Planetary Motion The Ratio of the Squares of their Orbital Periods are equal to the Ratio of the Cubes of the Mean Radii of their Orbits. = Constant (T venus ) 2 (R venus ) 3 = (T mars ) 2 (R mars ) 3 (T mars ) 2 (R mars ) 3

20. GALILEO 1564-1642 Constructed the first telescope that was used to view the moon and planets Believed in and taught the Copernican heliocentric Universe Was sentenced to house arrest by the Pope for espousing that view May be considered the first physicist and the creator of the scientific method

21. ISAAC NEWTON 1643-1727 Inspired while at Woolesthorpe during the black plague epidemic Mythological apple fell on his head while viewing the moon Kept ideas in desk drawer for 20 years

22. UNIVERSAL GRAVITATION The force of gravity is directly proportional to the product of the two masses, and inversely proportional to the square of the distance between their centers. The law is universal to all masses and works throughout the Universe

23. Universal Law of Gravitation

24. HENRY CAVENDISH 1731-1810 Determined experimentally the value of Newton’s Universal Gravitational constant –G = 6.67 x 10 -11 N· m 2 /kg 2 Cavendish indirectly measured the mass of the earth

26. UNIVERSAL LAW OF GRAVITATION

27. ALBERT EINSTEIN 1879-1955 Space as we know it really consists of 4 dimensions combined, which he coined space-time. The gravitational effect on objects (planets, stars, etc.) is caused by a large mass warping space-time.

28. Space-time Planet or Star

29. THE WARPING OF SPACE-TIME

30. BLACK HOLES- A star so dense that it infinitely warps space-time to a point, and consequently even light cannot escape. Stephen Hawking

31. Acceleration due to gravity

32. Gravity Fields g g g

34. Centripetal Force as Gravity

35. Orbital Velocity

39. Escape Velocity

41. To go where no man has gone…