2.1 · What Is in the Solar System

From Ohio 5th Grade Science Power Workbook · Chapter 2 · Lesson 2.1.

Big idea: The solar system is the sun and everything that orbits it.

Learning goals: Name the kinds of things that orbit the sun

Explain what sits at the center of the solar system

The sun is at the center

Our solar system is the sun and every object that travels around it. The sun is a star, and it holds the whole system together.

Planets travel around the sun. Some planets have moons that travel around them. Asteroids, meteoroids, comets and dwarf planets travel around the sun too.

Orbit means to travel around

When one object travels around another, we say it orbits it. Earth orbits the sun. Earth's moon orbits Earth.

Everything in the solar system is in motion. Nothing sits still.

Worked examples

Question: A student says, “The solar system is just the sun and the planets.” What is missing from that description?

Steps: Check what the word solar system includes. It is the sun and everything that orbits it.

List what else orbits the sun. Moons travel with their planets, and asteroids, meteoroids, comets and dwarf planets orbit the sun as well.

So the description leaves out every object that is not a planet.

Answer: It leaves out moons, which orbit the planets, and asteroids, meteoroids, comets and dwarf planets, which orbit the sun.

Common mistakes

Earth is not the center of the solar system

It is easy to think Earth is in the middle, because from here the sun looks like it moves across the sky.

The sun is at the center. Earth is one of the planets orbiting it. The sun only looks like it moves because Earth is turning.

Check your thinking: Ask what is orbiting what. Earth orbits the sun, so the sun is in the middle.

Ohio connection

Two Ohio astronauts

Neil Armstrong grew up in Wapakoneta, Ohio, and John Glenn came from Cambridge, Ohio. Both left Earth and looked back at it from space.

There is a museum named after Armstrong in Wapakoneta you can visit, and NASA's Glenn Research Center sits just outside Cleveland.

Think: Why would seeing Earth from space help someone understand that Earth is a planet?

Remember

Sun in the middle, everything else going around

Picture one drawing: a big circle in the center, and rings of objects going around it. If your drawing has Earth in the middle, it is upside down.

Practice tip

Remember: Ohio asks what orbits what.

Tip: A question on this topic may give you a list of objects and ask which ones orbit the sun. Moons are the exception: a moon orbits a planet.

Written practice

Describe what makes up our solar system. Include at least three different kinds of objects besides the sun.

Sample response: The solar system is the sun and everything that orbits it. It includes planets, moons that orbit those planets, asteroids and comets.

Scoring guide: 1 point: says the solar system is the sun and the objects that orbit it.

1 point: names at least three of planets, moons, asteroids, meteoroids, comets, dwarf planets.

Ohio assesses the solar system as the sun plus every orbiting body, so a full answer names several kinds.