1. Planet EarthPart Two: Our Solar System

2. Section 1: Classifications

3. Our Solar System is made up of nine* planets and one sun.

4. Some scientists dispute the number of planets and suggest that Pluto not be classified as a planet, due to its size and lack of control over its orbital path.

5. Does Pluto qualify to be a planet?

6. For an object to be a planet, it needs to meet these three requirements defined by the International Astronomical Union (IAU).

7. It needs to be in orbit around the Sun. Number One

8. Yes, Pluto does orbit around the Sun, so maybe Pluto is a planet?

9. It needs to have enough gravity to pull itself into a spherical shape. Number TWO

10. Yep, that’s a spherical shape! Pluto Basketball

11. It needs to have "cleared the neighborhood" of its orbit. Number Three

12. What does "cleared its neighborhood" mean?

13. As planets form, they become the dominant gravitational body in their orbit in the Solar System.

14. As they interact with other, smaller objects, they either consume them,

15. or sling them away with their gravity.

16. Pluto is only 0.07 times the mass of the other objects in its orbit. The Earth, in comparison, has 1.7 million times the mass of the other objects in its orbit.

17. Any object that doesn't meet this 3rd criteria is considered a dwarf planet. And so, Pluto is a dwarf planet.

18. There are still many objects with similar size and mass to Pluto jostling around in its orbit. And until Pluto crashes into many of them and gains mass, it will remain a dwarf planet.

19. So for the sake of this lesson we will consider Pluto a Dwarf planet.

20. What are the two classifications of planets in our Solar System?

21. Inner vs. OuterorRocky vs. Gas Planets correct!

22. Can anyone name the four Inner or Rocky planets?

23. That’s correct, the Inner or Rocky planets are Mercury, Venus, Earth, and Mars.

24. Can anybody name the five Outer or Gas planets?

25. Correct, the outer planets are Jupiter, Saturn, Uranus, Neptune, and Pluto.

26. Let’s Review! (Section 1) 1.) How many planets are there in our Solar System? 11 10 9 8

27. Let’s Review! (Section 1) 2.) What are the two classifications that we can divide the planets in our Solar System into? Rock and Inner Gas and Outer Inner and Outer Innie and Outtie Rock and Gas

28. Let’s Review! (Section 1) 3.) What are the names of the planets in our Solar System? M___________ f.) S_______________ V___________ g.) U______________ E___________ h.) N______________ M __________ i.) P______________ J____________

29. Let’s Review! (Section 1) 4.) Which planets are the Rocky planets? Earth f.) Neptune Jupiter g.) Pluto Mars h.) Uranus Mercury i.) Venus Saturn

30. Let’s Review! (Section 1) 5.) Which planets are the Gas planets? Earth f.) Neptune Jupiter g.) Pluto Mars h.) Uranus Mercury i.) Venus Saturn

31. Section 2: What’s in a Name?

32. How do planets and their moons get their names? With the exception of Earth, all of the planets in our solar system have names from Greek or Roman mythology.

33. What’s a Myth? “Myth” is a Greek word meaning the telling of a story in order to explain some phenomenon of nature, customs, the origin of the species…

34. Here’s an example of a myth. Some parents tell their children that thunder comes when an angel goes bowling and bowls a strike!

35. Thunder is the sound that follows a flash of lightening, caused by the sudden heating and expansion of air by electrical discharge.

36. The Greeks believed that one of their gods named Zeus, would hurl lightening bolts down from the heavens if he was displeased with something or someone.

37. Myths are just a person’s attempt to explain something that they can’t make any sense of because they don’t have all of the facts and/or technology.

38. Science, facts, and proof take the place of myths for educated people.

39. Let’s Review! (Section 2) 1.) How did the planets and their moons get their names? From America’s Got Talent From Persian and African Mythology From Greek and Russian Mythology From Greek and Roman Mythology

40. Let’s Review! (Section 2) 2.) _________________is a Greek word meaning the telling of a story in order to explain some phenomenon of nature, customs, the origin of the species… proto e.) stellar b) mesa f.) disc c) myth g.) solar d) Ra h.) Zeus

41. Let’s Review! (Section 2) 3.) Myths are just a person’s attempt to explain something that they can’t make any sense of because they don’t ______. have an education know any better have all of the facts and/or technology they can’t read

42. Let’s Review! (Section 2) 4.) What three things take the place of myths for Educated people? gossip e) facts National Enquirer f) fairy tales science g) hear say proof h) Oprah

43. Section 3: The Sun and the Rock Planets

44. The central and largest member of our Solar System, the Sun.

45. Our Sun is the closest star to us.

46. The Sun is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of the total solar system mass.

47. The Sun's interior could hold over 1.3 million Earths.

48. We think of the Earth as a huge place. The dia-meter of the Sun is about 100 times wider than the Earth as can be seen in the diagram at left.

49. Some stars are as small as the Earth while others can be 500 times bigger than our Sun.

50. The astronomical symbol for the Sun is a shield with a dot at the middle. This symbol comes the ancient Egyptian sign for "sun" or "Ra" in the hieroglyphic writing system. The source of this symbol is unknown, but some historians think that the dot might represent a huge central sunspot.