Our closest solar system is about 10 light years away. It has two main types of planets. Some are rocky and small, like planet Earth, while others are huge balls of gas, like Jupiter. Learn about how astronomers once thought our solar system was the one and only, to how they have now discovered hundreds of stars with planets orbiting them, which means there could be billions of solar systems in outer space! Just maybe, these alien worlds could host life, like our own amazing planet. This book allows students to use observations of the Sun, moon, and stars to describe patterns that can be predicted.