Solar System Science Digest

Key Concepts

The solar system is a family of objects held together by the Sun’s gravity. Knowing where these objects fit helps you explain space clearly on Florida science tests.

• The Sun is a star at the center of our solar system.
• The eight planets travel in paths called orbits around the Sun.
• Gravity is a pulling force. The Sun’s gravity helps keep planets in orbit.
• Planets do not make their own light. They reflect light from the Sun.
• Moons orbit planets. Earth has one moon.
• Asteroids are rocky objects. Comets are icy objects that can form bright tails near the Sun.
• Stars are huge, hot balls of gas. They are much farther away than planets.

Before you continue: How are a planet, a moon, and a star different?

Key Terms

Solar system - The Sun and all the objects that orbit it.

Star - A huge, hot ball of gas that makes its own light.

Planet - A large, round object that orbits a star.

Moon - A natural object that orbits a planet.

Orbit - The path an object follows around another object.

Gravity - A force that pulls objects toward each other.

Asteroid - A rocky object that travels through space.

Comet - An icy object that may grow a bright tail near the Sun.

Active Recall

Solar system

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Star

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Planet

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Moon

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Orbit

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Gravity

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Asteroid

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Comet

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Worked Examples

1. Which object is at the center of our solar system?

1. Planets orbit the Sun.

2. The Sun is a star.

3. Therefore, the Sun is at the center.

Now you try: Which object gives Earth most of its light and heat?

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2. Earth and its moon

1. Earth is a planet.

2. The Moon travels around Earth.

3. Therefore, the Moon is Earth’s natural satellite, or moon.

Now you try: What does our Moon orbit?

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3. Sort the objects

1. The Sun makes its own light, so it is a star.

2. Mars travels around the Sun, so it is a planet.

3. An asteroid is a rocky space object.

4. A comet is mostly ice and dust.

Now you try: Sort these: Jupiter, a comet, the Sun, and an asteroid.

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Practice Questions

1. (Easy) Circle the star: Earth, Moon, Sun.

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2. (Easy) What force helps keep planets in orbit?

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3. (Medium) Draw an arrow to show the Moon’s orbit around Earth.

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4. (Medium) Explain why Earth is a planet, not a star.

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5. (Hard) Name two objects in the solar system and explain how they move.

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Answer Key

1. Sun.

2. Gravity.

3. The arrow should circle Earth and show the Moon moving around it.

4. Earth orbits the Sun and reflects light; it does not make its own light.

5. Example: Earth orbits the Sun, and the Moon orbits Earth.

Exam Tips & Common Mistakes

• Do not call the Sun a planet. The Sun is a star because it makes its own light.
• Do not say planets make light. Planets reflect light from the Sun....