1. Preface/Review – What We Already Know about the Solar System

2. 5 Dwarf Planets (so far…)
The New Solar System
8 Planets
Eris
5 Dwarf Planets (so far…)

3. [ Note: Any good hypothesis has to explain ALL of the known facts !! ]

4. The planets are relatively isolated from each
The planets are relatively isolated from each other and are spaced at regular intervals.

5. 2) All of the planets orbit in the same flat plane (Solar System is disk-shaped.)
3) The planets revolve in the same direction that the sun rotates on its axis.

6. The planets’ orbits are elliptical, but nearly circular (except for Mercury, Pluto & Eris).
Inner Planets
Outer Planets

7. 5) The sun’s rate of rotation is slower than expected.

8. The planets of the solar system contain large quantities of rare, heavy elements such as: Gold (Au) , Uranium (U),
Lead (Pb) and Platinum (Pt).

9. 7) The 4 inner planets are rocky, small and very dense, with solid surfaces and thin
atmospheres of heavier gases such as
CO2, N2 and O2. They have weak or no magnetic field and no rings.

10. 8) There is a boundary zone in the solar system called the frost line (≈ 4 AU from our sun) where it becomes cold enough for Water (H2O), Ammonia (NH3) and Methane (CH4) to become
ices (i.e. frozen solid).

11. Frost Line
Inside frost line, rocks and minerals can condense, but methane and ammonia stay in the gaseous state.
Outside the frost line, even methane and ammonia condense into liquids and ices.
98 % of the solar nebula is hydrogen and helium gas that don’t EVER condense (always gases).

12. Note: There is an imaginary boundary in the solar nebula called the Frost Line:
Inside the frost line - so warm that only rocks and metal can condense (turn solid).
Outside the frost line - cold enough for H compounds (water, ammonia & methane) to condense (turn into ices).
98 % of the nebula is H and He, which won’t condense anywhere!! (They’re always gases.)
Frost Line

13. Result - the outer planets are mostly frozen ices of water (H2O), ammonia (NH4) and methane (CH4) with just a little bit of rock mixed in, while the inner planets are mostly rock and metal, because it is too warm for the Hydrogen compounds to condense.
Frost Line
Frost Line

14. Frost Line Result - the outer planets are mostly frozen ices of:
water (H2O), ammonia (NH4) and methane (CH4) with just a little bit of rock mixed in, while the inner planets are mostly rock and metal, because it is too warm for the Hydrogen compounds to condense.
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15. The 5 outer planets are gas giants – much larger with thick atmospheres of lighter gases such as H2, He, NH3, CH4 and other hydrocarbons - but much less dense.
They have strong magnetic fields and well-developed ring systems.

16. 10) Asteroids are very old and exhibit properties not found in either Inner or Outer Planets.

17. 11) The Kuiper Belt is a collection of asteroid-sized icy bodies and dwarf planet Pluto.

18. Chapter 12, Sec. 2 Birth of a Planet - Review
From the Big Bang to Heavy Elements
Subatomic particles formed in the first second after the Big Bang.
Subatomic particles combined to form H and He atoms in just 380,000 years.

19. Figure 12.4b

20. Chapter 12, Sec. 2 Birth of a Planet - Review
From the Big Bang to Heavy Elements
H and He gas clouds formed the first stars and galaxies over the next billion years.
The Milky Way Galaxy formed about 10 billion years ago (bya).

21. Figure 12.4c

22. Chapter 12, Sec. 2 Birth of a Planet - Review
From the Big Bang to Heavy Elements
Nuclear reactions inside stars form elements up to and including Iron (26Fe56).

23. Chapter 12, Sec. 2 Birth of a Planet - Review
From the Big Bang to Heavy Elements
Elements larger than Iron were produced by supernovas, which then
splattered these elements
into the nebular clouds
of the surrounding
galaxy.

24. Figure 12.4d