The Solar System contains the Sun, (at least) eight planets and their moons, and many smaller objects such as dwarf planets, asteroids, and comets.

Planets are heavenly bodies that revolve around the Sun in elliptical orbits. Unlike stars, planets do not emit their own light, but reflect it from the Sun.

Planets can be classified in many ways: by their distance from the Sun, by their orbit relative to the orbit of the Earth, by their composition, their size, etc. In this activity we will see how they are classified in relation to the orbit of our planet.

Introduction

You surely know many facts about the Solar System. Here you can further learn with PETeR, for instance, which planets are visible to the naked eye, how we observe them from Earth, how we can calculate their sizes,…

Download here the INTRODUCTION to this Unit: UNIT 1 – Inner and outer planets

Activities

Would you like to put your knowledge into practice? Follow-up Galileo’s footsteps and discover more about the Solar System and the planets with these activities:

Activity data

Concepts: Planets and Exoplanets. Inner and Outer Planets. Phases in the inner planets. Distances in the sky: angles.

Tools to learn to use: Measurement of distances. Scales.

Estimated time: 4 hours.

Authors: Oswaldo González, Nayra Rodríguez, Alfred Rosenberg, Inés Bonet.

Materials for educators:  Teacher Guide.