1. What is the solar system?

2. Georgia Performance Standards:
S4E2: Students will model the position and motion of the Earth in the Solar System and will explain the role of relative position and motion in determining sequence of the phases of the moon.
a. explain the day/night cycle of the Earth using a model
b. explain the sequence of the phases of the moon
c. demonstrate the revolution of the Earth around the sun and the Earth’s tilt to explain seasonal changes.
d. demonstrate the relative sizes and order from the Sun of the planets in the Solar System

3. The sun and planets
The solar system is made up of the Sun, orbiting planets, their moons, and other objects traveling around the Sun.
Our solar system contains one sun and eight planets.

4. The sun The Sun is the nearest star to Earth.
The Sun is a huge sphere of hot gases that gives off heat and light.
At night, you can see other stars.

5. Planets
A planet is a large body of rock or gas in space that moves around (orbits) a star.
A planet does not produce its own light.
Planets and moons travel in an oval shaped orbit around the sun (or planet).

6. moons A moon is a small, rounded body in orbit around a planet.
A moon does not produce its own light. It reflects light from the sun.
Like planets, moons do not produce their own light. Moons reflect light from the Sun. Most planets have at least one moon.

7. Planets in motion
As it orbits the Sun, each planet spins. Each planet spins at its own rate. For Earth, one rotation takes 24 hours.
The length of time a planet needs to orbit the sun is called a year.
The farther a planet is from the Sun, the longer its year.
Earth’s day is 24 hours. A “day” on Jupiter is just 10 Earth hours long, but on Venus, a “day” is 243 Earth years.
A year on Earth is 365 days. Mercury’s year is 88 Earth days. Neptune’s year takes 165 Earth years.

8. review What objects make up our solar system?
What is one way that planets and moons are similar?