Ian Graham 
What Do We Know About the Solar System? [PDF ebook] 

How do we know Earth isn’t flat? What are the benefits of space exploration, and is it good value? How and why do scientists study the Universe? This series answers questions like these, while tackling key curriculum topics relating to Earth, Space, and the Universe. The series encourages critical thinking to support the modern science curriculum and includes features on "space science in the home" and "what it means for us", showing the relevance of space science to our everyday lives.