1. Is Pluto a Planet? Dr John K. Davies UK Astronomy Technology Centre, Royal Observatory, Edinburgh, Scotland

2. Executive Summary

3. The classical solar system

4. Planet Uranus imaged from Voyager 2.

5. Planet Neptune from Voyager 2.

6. Percival Lowell

7. Lowell’s Tomb, shaped like Planet Saturn

8. Clyde Tombaugh and the Pluto Telescope.

9. Discovery of Pluto, 1930

10. Orbits of Pluto and Neptune.

11. Nucleus of Halley’s Comet

12. Pluto is Shrinking

13. Pluto is covered with ice.

14. Pluto and Charon (Gemini Observatory)

15. Pluto should have vanished by now !

16. Mercury and Venus: Planets without Moons

17. 243 Ida and Dactyl Ida: Size about 56 km long. Dactyl: Size about 1.5 km.

18. 45 Eugenia and its moon. Eugenia size ~215km Satellite size ~13 km Period ~4.7 days

19. Pluto has an atmosphere

20. New Horizons Mission-Pluto Flyby, July 2015.

21. Comet Hale-Bopp

22. Comet Orbits Long Period Comet, like Hale-Bopp Short Period Comet. Interstellar comet (never seen)

23. Gerard Kuiper 1905-1973

24. Kenneth Edgeworth. 1880-1973

25. Jane Luu and Dave Jewitt

26. University of Hawaii 2.2m Telescope

27. Discovery of 1992 QB 1

28. The Classical Kuiper Belt

29. The Plutinos

30. 1998 WW31 a Kuiper Belt Object with a satellite

31. Orbital Elements and Stable Regions

32. Some of the the largest known Kuiper Belt Objects Late 2000 Varuna Discovered

33. November 2003 Sedna Announced

34. Sedna: EKO or Oort Cloud Object?

35. Sedna. Planet10?

36. The Discoveries Continue June 2002. Quaour discovered. Late 2004. Orcus (2004 DW 4 ) announced July 2005. Ortiz et al announce ‘discovery’ of 2003 EL 61 July 2005. Brown et al announce, via press release, existence of 2003 UB 313 amidst allegations of ‘hacking’ by Ortiz et al

37. 2003 EL 61 Irregular, rocky object with a glazing of ice. Rotates every 4 hours. Has two satellites.

38. 2003 UB 313 aka ‘Xena’

39. 2003 UB 313 aka Xena

40. 2003 UB 313 aka ‘Xena’

41. What makes a planet? It goes around a star.

42. Io and the Moon are not planets because they don’t go around a star.

43. What makes a planet? It goes around a star. It does not generate heat internally.

44. Jupiter is a planet. since it is not heated by nuclear reactions.

45. What makes a planet? It goes around a star. It does not make heat by nuclear reactions. It is spherical.

46. So MOST asteroids are not planets since they have not collapsed to spherical shapes.

47. What makes a planet? It goes around a star. It does not make heat by nuclear reactions It is (more-or-less) spherical. It is bigger than 1000km in diameter

48. IAU Committees 2003-5: First attempts at planet definition split community almost equally so new panel formed. 2006: Committee Meets in Paris to draft proposal for Prague IAU meeting in August

49. Sunday 13th: Draft IAU resolution sent to press. Allows 12 planets and potential for many more.

50. 3 New Planets

51. Lots of Potential New Planets

52. Thursday 17th: Draft proposal slammed by Div III dynamicists

53. Tuesday 22 nd lunchtime: Further Modified Draft Presented

54. New proposal slammed even harder!

55. Tuesday 22 nd 1800hr: Further modifications seem to be getting closer to consensus

56. Wednesday 23 rd More modifications and coffee break debates over whether a dwarf-planet is the same thing as a “dwarf planet”.

57. Wednesday 23 rd More modifications and coffee break debates over whether a dwarf-planet is the same thing as a “dwarf planet”. and…. If a dwarf planet is a kind of planet or a whole different thing.

58. Thursday 24 th : The final Countdown 5A. A Planet is round, goes around the Sun and dominates its local space. A dwarf planet is round, goes around the Sun, has not cleared its local space and is not a satellite. Everything else is a small solar- system body 5B Change Planet to Classical Planet

59. Thursday 24th: The final Countdown 6A Pluto is a dwarf planet by the above definition and is recognised as the prototype of a new class of trans-Neptunian Objects. 6B This class of dwarf planets will be called Plutonids

60. Thursday 24th: History is Made 5A. A Planet is round, goes around the Sun and dominates its local space.

61. Thursday 24th: History is Made 5A. A Planet is round, goes around the Sun and dominates its local space. 5B Change Planet to Classical Planet

62. Thursday 24th: History is Made 5A. A Planet is round, goes around the Sun and dominates its local space. 5B Change Planet to Classical Planet 6A Pluto is a “dwarf planet” and the prototype of a new class of TNO’s

63. Thursday 24th: History is Made 5A. A Planet is round, goes around the Sun and dominates its local space. 5B Change Planet to Classical Planet 6A Pluto is a “dwarf planet” and the prototype of a new class of TNO’s 6B This class of dwarf planets will be called Plutonoids

64. Mike Brown’s Reaction

65. Some Other Astronomer Reactions

66. The People’s Reaction

67. The Astrologer Reaction. “Scorpio’s can be extremely explosive, and very direct, and this may be the trigger that makes them explode” Milton Black, Australian Astrologer “This is a moment I’ve been waiting for, people are finally talking about Charon” Eric Francis, Minor Planet Astrologer

68. Pluto is a small icy dwarf planet Like Neptune’s moon Triton

69. ..and a member of the Kuiper Belt Pluto

70. Is Pluto a Planet? What do you think?

71. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

72. ATC Clapometer Clap Cheer Standby Mode: Quiet Please

73. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

74. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

75. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

76. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

77. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

78. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

79. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

80. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

81. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

82. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

83. Clap for Yes, Pluto is a Planet Cheer for No, Pluto is NOT a planet Yes No

84. Thanks very much!

85. Bye for now, Drive safely.

86. Is Pluto a Planet? Presented by: John Davies and Suzie Ramsay Howat. Written by: John Davies Thanks to: Jason Cowan, Chad Trujillo, Lowell Observatory archives, NASA, Yerkes Observatory, Dave Jewitt, Jane Luu, Martin Duncan and John Spencer

87. For more information. Published by CUP, get it from Amazon.

88. Mutual Eclipses of Pluto and Charon

89. Comet Ring as predicted by Fred Whipple in 1964, virtually what we today call the Kuiper Belt

90. But 4 of these are no longer in lists of planets published today Ceres Vesta Pallas Juno Sun Venus Earth Mars According to ‘First Steps to Astronomy and Geography’, Hatchard & Son, London, 1828 there are 11 planets. Mercury, Venus, Earth, Mars, Vesta, Juno, Ceres, Pallas, Jupiter, Saturn and Herschel (Uranus)

91. Tradition in Astronomy Constellations Lunar Sea!