1. Solar System

2. Planets
These are the nine planets that we all are aware of.

4. Grouping of Planets
Inner Planets: Mercury, Venus, Earth and Mars and the planets closest to the sun
These four planets are TERRESTRIAL planets
They are small and their densities are high

5. The Planets Mercury - Closest to sun - Smallest planet - No atmosphere
- Large differences in temperature between night and day
Roman god of commerce and messenger of the gods; identified with the Greek Hermes

6. The Planets Venus - similar in size and composition to Earth
- Thick atmosphere of Carbon Dioxide (can reflect sunlight)
- has flat areas, volcanoes, lava flows and rifts
- brightest planet in the sky
Venus was the goddess of love, sex, beauty, and fertility. Roman Venus had many abilities beyond the Greek Aphrodite; she was a goddess of victory, fertility, and even prostitution.

7. The Planets Earth - only life discovered in the universe so far
- only planet with water in three phases
- atmosphere of nitrogen and oxygen
- Shape of surface is constantly changing
The mother goddess was one of the deities who governed the universe before the Titans existed

8. The Planets Mars - Iron in rocks gives it red colour
- surface has large volcanoes and deep craters
- Thin atmosphere of carbon dioxide
- Has two polar ice caps
- Has dust storms that cover whole planet
In early Roman times he was a god of agriculture, but in later religion (when he was identified with the Greek Ares) he was primarily associated with war.

9. Grouping of Planets
Outer Planets: Jupiter, Saturn, Uranus and Neptune are much further away from the sun
These planets are also called the GAS GIANTS
They are large and have low densities because their atmospheres are made up of hydrogen and helium

10. The Planets Jupiter (Greek: Zeus) - largest planet
- “Great Red Spot” is visible from Earth
- spot is a storm of hydrogen and helium gas
- turns on its axis every 10 hours
- has 63 moons

11. The Planets Saturn - Identified by 1000 separate elaborate rings
- Rings are very wide but very thin
- Planet is composed mostly of Helium and Hydrogen
Roman mythology: God of agriculture
Greek: Ruler of the Titans (Kronos)
Cronus was the son of Uranus and Gaea

12. The Planets Uranus - Gets its blue colour from Methane gas atmosphere
- Rotates on its side
- has rings of ice and dust
- has winds that blow up 500 km/h
Greek: God of sky, father of titans; ruler of the universe
Roman: Caelus

13. The Planets Neptune - has a very faint ring system
- composition and colour are similar to Uranus
- has storm spots similar to Jupiter but they appear and disappear more frequently
Neptune was the name that ancient Romans gave to the Greek god of the sea and earthquakes, Poseidon

14. PLUTO Recently demoted from planet to dwarf planet
Pluto has an eccentric orbit and sometimes is closer to the sun than Neptune
Roman god of the underworld and the judge of the dead. Pluto is an alternative name for the Greek god Hades

15. Satellites “Moons” Planet Number of known moons Mercury Venus Earth 1
All planets except Mercury and Venus have one or more objects orbiting around them
Astronomers call these satellites
Planet
Number of known moons
Mercury
Venus
Earth 1
Mars 2
Jupiter 63
Saturn 60
Uranus 27
Neptune 13
Pluto 3