1. The
Solar
System

2. Solar System Formation

3. Your Parents’ Solar System

4. 21st Century Solar System

5. The 21st Century Solar System
Sun
Terrestrial Planets
Asteroid Belt
Jovian Planets
Kuiper Belt
Oort Cloud

6. The Solar System: List of Ingredients
Sun
Jupiter
Other planets
Everything else
Percent of total mass
99.8%
0.1%
0.05%

7. The Sun A middle-aged, average star: Shines because it is hot:
Mostly Hydrogen & Helium
99.8% of the Solar System
~4.6 billion years old
Shines because it is hot:
Surface Temp ~6000 C
Mostly Visible, UV & IR light
Kept hot by nuclear fusion in its core:
Builds Helium from Hydrogen fusion.
Will shine for ~12 billion years

8. The Sun dominates the Solar System

9. Terrestrial Planets Mercury, Venus, Earth & Mars Rocky Planets:
“Earth-Like” Rocky Planets
Largest is Earth
Only in the inner solar system (0.4 to 1.5 AU)
Rocky Planets:
Solid Surfaces
Mostly Silicates and Iron
High Density: (rock & metal)
Earth, Venus, & Mars have atmospheres

10. The Terrestrial Planets
Mercury
(0.055 M)
Venus
(0.82 M)
Earth
(1 M)
Mars
(0.11 M)

11. The Jovian Planets Jupiter, Saturn, Uranus & Neptune
Largest Planets: at least 15 times mass of Earth.
Only in the outer solar system (5 to 30 AU)
No solid surfaces (mostly atmosphere)
Low density
Gas Giants: (Jupiter & Saturn)
Thick H/He atmosphere, liquid hydrogen mantle, ice core
Ice Giants: (Uranus & Neptune)
Ice/rock core & mantle, thin H/He atmosphere

12. The Jovian Planets Jupiter (318 M) Saturn (95 M) Uranus (15 M)
Neptune
(17 M)

14. Dwarf Planets Defined by the IAU in 2006 Dwarf Planets:
Ceres: first of the Asteroids, discovered in 1801
Pluto: trans-Neptunian object discovered in 1930
Eris: trans-Neptunian object discovered in 2005
Haumea (trans-Neptunian, suspected)
Makemake (trans-Neptunian, suspected)

15. Dwarf Planets

16. The Giant Moons
Moon: any natural satellite orbiting a planet or dwarf planet
Giant Moons:
Earth: The Moon (Luna)
Jupiter: Io, Europa, Ganymede, & Callisto
Saturn: Titan
Neptune: Triton
Many smaller moons, both rocky & icy.
Only Mercury & Venus have no moons.

17. The Giant Moons

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

19. Kuiper Belt Class of icy bodies orbiting beyond Neptune. Examples:
Found only in the outer Solar System (>30AU)
Densities of 1.2 to 2 g/cc (mostly ices)
Examples:
Pluto & Eris (icy dwarf planets)
Kuiper Belt Objects (30-50AU)
Charon, Pluto’s large moon
Sedna & Quaor: distant large icy bodies

20. Kuiper Belt

21. Oort Cloud Spherical cloud of comets.
Extends out to almost 50,000 AU (1 light-year)
May contain trillions of comets
The outer edge is the farthest reach of the Sun’s gravitational pull.
There are no confirmed observations – its existence is theoretical only.

22. Oort Cloud

23. The Leftovers (small bodies)
Asteroids:
Made of rock & metal (density 2-3 g/cc)
Sizes: Few 100km to large boulders
Most are found in the Main Belt ( AU)
Meteoroids:
Bits of rock and metal
Sizes: grains of sand to boulders
Comets:
Composite rock & ice “dirty snowballs”
Longs tails of gas & dust are swept off them when they pass near the Sun.

24. Asteroids
951 Gaspra
243 Ida
253 Mathilde

25. Meteor burning up in the
atmosphere.

26. Comet P/Halley
Comet P/Wilt

29. Is Pluto a Planet? What to consider? Size? Shape? Orbit?
What is it made of?

30. IAU Definition of a Planet
In 2006, the International Astronomical Union (IAU) came up with the following definition of a planet:
orbits the Sun
has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium shape (i.e., it is spherical),
has cleared the neighborhood around its orbit,
is not a satellite

31. IAU Definition of a Dwarf Planet
In 2006, the International Astronomical Union (IAU) came up with the following definition of a dwarf planet:
orbits the Sun
has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium shape (i.e., it is spherical),
has not cleared the neighborhood around its orbit,
is not a satellite