2. Our Solar System Consists of:
Sun
Eight planets and their moons
The dwarf planets
The planets are all unique and differ in terms of
their:
Size (volume)
Surface temperature
Chemical elements (e.g. H2, He, O2 and C)
Gravitational field strength (surface gravity)

3. The planets orbit the sun in the following order: M V E M J S U N P
“My very elderly mother just sent us nine pizzas”

4. The Inner (Terrestrial) Planets
The four planets closest to the sun are: Mercury, Venus, Earth and Mars
Characteristically they are:
Small
High in density
Mainly composed of rocks/metals

5. The Inner (Terrestrial) Planets
Venus
Mercury
Earth
Mars

6. The Outer Planets (Gas Giants)
The four planets farthest from the sun are: Jupiter, Saturn, Uranus & Neptune
Characteristically they are:
Large
Low in density
Mainly composed of gases such as hydrogen and helium
Separated from the inner planets by the asteroid belt.

7. The Outer (Gas Giant) Planets
Jupiter
Saturn
Uranus
Neptune

8. Dwarf Planets
The big difference between a dwarf planet and a regular planet is that:
A dwarf planet’s path around the sun is full of other objects like asteroids and comets whereas a regular planet has a clear path
Pluto
Due to its strange orbit and tiny size astronomers questioned whether it should be considered a planet. A decision was made to reclassify Pluto to a dwarf planet in 2006.

9. Ceres, Eris, MakeMake & Haumea
The Dwarf Planets
Ceres, Eris, MakeMake & Haumea
Ceres (formally an asteroid and still found in the asteroid belt), Eris, MakeMake & Haumea are also dwarf planets. They are different from planets because they are not big enough to clear their orbits and thus orbit with a lot of other debris.
Eris
Ceres
Pluto