The Bridge V Learning Edition 1 ; our solar system | Page 17

Introduction
The Solar System, in which we live, consists of the Sun as its central star, eight planets with their
moons and several dwarf planets. Together with hundreds of thousands of asteroids (boulders)
and comets, these celestial bodies orbit the Sun.
The Earth is a very special planet among these celestial bodies. It is our home! In order to
understand its uniqueness, children need to compare the Earth to the other planets in the Solar
System. As the Earth is located about 150 million kilometres from the Sun, the temperature is
exactly right for liquid water to be present on the surface, unlike on most other planets. This
proved crucial for the development of life!
The Solar System as a whole is part of the Milky Way system, a collection of about 200 billion
stars that are arranged in a spiral, along with gas and dust. Billions of these stars have planets
and these, in turn, have moons. This suggests that we are probably not alone in the Milky Way,
but the distances between the stars are so big that a visit to another world would be very difficult.
Credit: Wikimedia Common / Nick Risinger
Credit: NASA / JPL