Unit 1The Terrestrial Planets
2 lessons1 Week
The Terrestrial Planets
 Week 1
Lesson 1
The Terrestrial Planets: Mercury and Venus
In this lesson, you'll learn about the two closest planets to the Sun: Mercury and Venus.
Lesson 2
The Terrestrial Planets: Earth and Mars
In this lesson, you'll learn about the outermost terrestrial planets: Earth and Mars.
Unit 2The Moon
2 lessons2 Weeks
The Moon
 Week 2
Lesson 3
The Moon: Exploration and Geographical Features
In this lesson, you'll learn about some of the missions that have gone to the Moon. You'll also learn about the Moon's three primary surface features.
 Week 3
Lesson 4
The Moon: Phases and Eclipses
In this lesson, you'll about what makes the Moon go through its various phases and also what causes eclipses.
Unit 3The Gas Giants
2 lessons1 Week
The Gas Giants
 Week 4
Lesson 5
The Gas Giants: Jupiter and Saturn
In this lesson, you'll learn about the two largest planets in our Solar System: Jupiter and Saturn.
Lesson 6
The Gas Giants: Uranus and Neptune
In this lesson, you'll learn about Uranus and Neptune, the two farthest planets in our Solar System.
Unit 4Dwarf Planets, Comets, and Asteroids
2 lessons1 Week
Dwarf Planets, Comets, and Asteroids
 Week 5
Lesson 7
Dwarf Planets
In this lesson, you'll be learning about the known dwarf planets in our Solar System.
Lesson 8
Comets and Asteroids
In this lesson, you'll be learning about comets and asteroids.
Unit 5The Sun
2 lessons1 Week
The Sun
 Week 5
Lesson 9
The Sun as a Star
In this lesson, you'll learn about some of the physical characteristics of our Sun that make it a star.
Lesson 10
The Sun in the Sky
In this lesson, you'll learn about how the Sun appears to change throughout the year in Earth's sky.