1. Not Your Parents’ Solar System! Dr. Frank Summers Space Telescope Science Institute March 28, 2008 It’s

2. Your Ancient Ancestors’ Solar System

6. Claudius Ptolemy 150 – Almagest

7. Earth Moon Mercury Venus Sun Mars Jupiter Saturn

8. Your Parents’ Solar System

9. Nicholas Copernicus 1543 – On the Revolutions of Heavenly Spheres

10. Earth Moon Mercury Venus Sun Mars Jupiter Saturn

11. Sun Mercury Venus Earth / Moon Mars Jupiter Saturn

12. William Herschel 1781 – Discovery of Uranus

13. Urbain Le Verrier & John Couch Adams 1846 – Prediction and discovery of Neptune

14. Clyde Tombaugh 1930 – Discovery of Pluto

15. Your Parents’ Solar System

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

29. Your Parents’ Solar System

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

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

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

36. Hollywood’s View of the Asteroid Belt

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

38. Sizes of the Giant Planets and Earth

39. Kuiper Belt

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

44. Sedna

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

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

48. Rocky PlanetsGiant Planets

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

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

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

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

53. The Inevitable Question …

54. Why is Pluto No Longer a Planet?

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

56. 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

58. 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

59. Pluto/Charon

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

62. 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

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

65. Kuiper Belt

66. 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

67. Pluto Defenders Pluto is different from the KBOs Pluto is bigger than the KBOs Pluto has a moon, Charon

68. Pluto/Charon orbits within Kuiper Belt

70. KBO Size Comparison

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

72. Binary KBOs About 10% of KBOs are binaries

73. Eris & Dysnomia (2003 UB313)

74. Eris & DysnomiaSanta & Rudolph Easterbunny

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

76. 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!!

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

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

86. Beta Pictoris

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

88. 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

89. 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

91. Planets around Other Stars Jupiter mass planets in Mercury orbits Elliptical orbits Multiple Jupiter sized planets Planets around pulsars Smallest (so far) is about 5 Earth masses

92. Planetary System Formation Planetary systems form in a predictable fashion from a spinning circular disk

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

94. So Much to Discover Our solar system is the oddball Need to generalize our formation and evolution scenarios Implications for life in the universe –Lots of planets –Stability of orbits? New era of solar system study