1. The Planets

2. Definition of a Planet IAU definition:
1) orbiting a star or stellar remnant
2) enough mass to be rounded by gravity
3) no fusion reaction at core
4) cleared its own orbit of planetessimals

3. Eight Planets
The solar system has eight planets

4. Terrestrial Planets

5. Mercury

6. Mercury Orbital radius: 0.38 AU Orbital period: 0.24 a Composition:
large iron core, rocky mantle
Atmospheric composition:
thin and unstable (low gravity)
Mean surface temperature: 340 K

7. Mercury Mass: 0.06 Earths Satellites: None
Unique features: Fastest orbital period, strong magnetic field

10. Venus

11. Venus Orbital radius: 0.72 AU Orbital period: 0.62 a Composition:
unknown, but similar to Earth
Atmospheric composition:
thick, CO2 and N (93 times thicker than ours)
Mean surface temperature: 735 K

12. Venus Mass: 0.815 Earths Satellites: None Unique features:
heavy volcanism, low magnetic field

14. Earth

15. Earth Orbital radius: 1 AU Orbital period: 1 a Composition:
core, mantle, crust
Atmospheric composition:
just right
Mean surface temperature:

16. Earth
Mass: 1 Earth
Satellites: Luna
Unique features:
I live there

18. Mars

19. Mars Orbital radius: 1.5 AU Orbital period: 1.9 a Composition:
Iron core, silicate mantle, crust
Atmospheric composition:
Thin, CO2 and other gasses
Mean surface temperature: 227 K

20. Mars Satellites: Deimos and Phobos
Unique features: Once had a magnetosphere, red colour caused by iron core, hematite and geological structures suggest there was once liquid water

34. Jupiter

35. Jovian Planets

36. Jupiter Orbital radius: 5.2 AU Orbital period: 11.9 a Composition:
small rocky core surrounded by liquid metallic H
Atmospheric composition:
hydrogen and helium
Mean temperature at 1 bar: 165 K

37. Jupiter Mass: 318 Earths Satellites: 63
Unique features: Largest planet, great red spot, has a ring structure

42. Jovian Satellites 63 moons, including the Galilean moons:
Io  most volcanically active body
Ganymede  largest moon; magnetic field
Europa  covered with ice; possible water
Callisto  heavily cratered; small atmosphere

44. Io

45. Europa

46. Ganymede

47. Callisto

48. Saturn

49. Saturn Orbital radius: 9.5 AU Orbital period: 30 a Composition:
Small rocky core surrounded by liquid H
Atmospheric composition:
Hydrogen and helium
Mean temperature at 1 bar: 134 K

50. Saturn Mass: 95 Earths Satellites: 60
Unique features: Pronounced ring system, less dense than water

52. Hexagonal polar cloud (Voyager)

59. Saturn’s Satellites 60 satellites including:
Titan  dense atmosphere, evidence of liquid water

62. Titan

63. Uranus

64. Uranus Orbital radius: 19 AU Orbital period: 84 a Composition:
icy core
Atmospheric composition:
hydrogen and helium
Mean temperature at 1 bar: 53 K

65. Uranus
Satellites: 27
Unique features: Largest axial tilt (almost on the side … continuous day or night),

69. Uranian Satellites
27 including:
Miranda  water ice surface

71. Miranda

72. Neptune

73. Neptune Orbital radius: 30 AU Orbital period: 165 a Composition:
Icy core
Atmospheric composition:
hydrogen and helium; trace methane
Mean surface temperature: 72 K

74. Neptune Mass: 17 Earths Satellites: 13
Unique features: last planet, blue colour from methane

78. Neptunian Satellites 13 including:
Triton  retrograde synchronous orbit

80. Pluto

81. Pluto

82. HD B