1. Sun
2. planets
3. comets
4. moons
5. Gas Giants
6. rings
7. refractory elements
8. inner planets
9. volatile elements
10. outer planets
11. satellites
12. gravitationally dominant
13. spherical
14. rock and ice
15. tails
16. near sun (3AU)
17. captured asteroids
18. asteroids
19. planetesimals
20. Jupiter
21. Saturn
22. Neptune
23. Uranus
24. Earth
25. Mars
26. Terrestrial
27. Venus
28. Mercury
29. dwarf planets
30. formation of solar system
31. rocky and metallic
32. asertoid belt
33. Mars and Jupiter
34. Kuiper Belt
35. Oort Cloud
36. Pluto
37. Star
38. electromagnetic radiation
39. fusion
40. elements
41. hydrogen
42. hot core
43. radiative zone
44. convective zone
45. photoshere (surface)
46. chromoshpere
47. Corona
48. coronal mass ejections
49. solar wind
50. Aurora Borealis/Australis
51. solar flares
52. surface features
53. solar prominence
54. atmosphere
55. layers
    1. exosphere
    2. ionosphere
    3. stratosphere
    4. troposphere