12. Mercury My Venus Very Earth Energetic Mars Mother Jupiter Just Saturn Served Uranus Us Neptune Nine Pluto Pizzas

13. Your Parents’ Solar System

14. Facts Are Not Knowledge Memorization, not understanding Factoids Highlights differences Little or no relevance Little or no “big picture”

15. The 21st Century Solar System Sun Rocky Planets Asteroid Belt Giant Planets Kuiper Belt Oort Cloud

16. Families of the Solar System Classes of similar objects Size Composition Orbit size Orbit shape Orbit inclination Moons Rings

20. Hollywood’s View of the Asteroid Belt

21. 960 million miles Hundreds of thousands of asteroids … … about a million miles apart! Scientific View of the Asteroid Belt

22. Sizes of the Giant Planets and Earth

23. Kuiper Belt

26. Oort Cloud Billions of icy minor planets – comet nuclei Roughly spherical out to 50,000 AU Predicted by Jan Oort Explains long-period comets

28. Sedna

29. Sedna Orbit 76 – 840 AU Very red color Outer Kuiper Belt? Inner Oort Cloud? Planet at 70 AU?

31. Families of the Solar System Classification Structure of the solar system Similar objects lie in similar regions Clues to solar system formation and evolution

32. Rocky Planets Giant Planets

33. Sun Rocky Planets Asteroid Belt Giant Planets Kuiper Belt Oort Cloud

34. Sun Mercury Venus Earth Mars Asteroid Belt Jupiter Saturn Uranus Neptune Kuiper Belt Oort Cloud

35. Science May View Established Models As Basic Justified Standards Until New Knowledge Bears Out Changes

36. Sometimes My Very Energetic Mother Also Boils Jumbo Shrimp Using Nine Kettles Bubbling Over Coals

37. The Inevitable Question …

38. Why is Pluto No Longer a Planet?

39. Planet Pluto January 23, 1930 January 29, 1930

40. The Incredible Shrinking Planet Lowell’s Planet X – 7 times Earth 1940’s – 1 times Earth 1980 – 0.1 times Earth 1985 – 0.002 times Earth

42. Double Take: Charon 1978 – James Christy (USNO) observations to refine Pluto’s orbit Notices elongated images, deduces moon 1985 – Charon occults Pluto, confirms existence Refined sizes and masses – tiny

43. Pluto/Charon

45. Umbriel Mimas Ariel Iapetus Hygeia Miranda Proteus Pallas Tethys Dione Vesta Oberon Ceres Charon Rhea Titania Enceladus Io Mercury Europa Moon Triton Titan Ganymede Callisto Pluto

46. Kuiper Belt 1930 – Leonard mentions possibility of trans-Plutonian objects 1943 – Kenneth Edgeworth postulates objects beyond Pluto 1951 – Gerard Kuiper predicts that a massive Pluto would disperse small objects into a belt 1980 – Fernandez predicts ‘comet belt’ that resembles what was eventually found

47. Kuiper Belt Objects 1992 – Jewitt & Luu find QB1 Distance of 42 AU First (third?) object discovered in the Kuiper Belt

49. Kuiper Belt

50. More and more KBOs Large searches for KBOs ensued Hundreds discovered within a decade Over 1200 discovered so far Over 70,000 predicted diameters > 100 km orbits 30-50 AU

51. Pluto Defenders Pluto is different from the KBOs Pluto is bigger than the KBOs Pluto has a moon, Charon Wrong!

52. Pluto/Charon orbits within Kuiper Belt

54. KBO Size Comparison

55. Sidebar: Is the Moon a Moon? Earth Moon

56. Binary KBOs About 10% of KBOs are binaries

57. Eris & Dysnomia (2003 UB313)

58. Easterbunny Eris & Dysnomia Santa & Rudolph

59. Pluto vs the Kuiper Belt Orbit similar to KBOs Size similar to KBOs KBO companions common Composition similar to KBOs

60. Pluto vs the Kuiper Belt Orbit similar to KBOs Size similar to KBOs KBO companions common Composition similar to KBOs Pluto has found its family!!

61. IAU Definition – August 2006 IAU defines “planet” Orbits the Sun Upper mass limit not massive enough to produce fusion Deuterium fusion occurs at about 15x Jupiter’s mass Lower mass limit Massive enough for gravity to make it spherical About 500 miles in diameter Dominates its orbit Dwarf planets meet 1, 2, 3, but not 4

63. Other Planetary Systems? Solar system alone is category of one ???

69. Beta Pictoris

70. We Are Not Alone Lots of dust disks found Proplyds – proto-planetary disks Kuiper Belt sized and larger Some substructure seen

71. Planets around Other Stars Cannot see directly (yet) Detect via gravitational pull on star Wobble Periodic shift of spectral lines Monitor for many years (several orbits) Giant planets detectable

72. Planets around Other Stars Current count (May 2006) 162 planetary systems 188 planets 19 multiple planet systems At least 15% of sun-like stars have planets