I love this series so much for it's simple clarity and because the stories introduce the material in such a way that it's easier to visualize and understand.
In this one, 3 students need to put on a play to avoid losing their drama club. They decide to do the Tale of the Bamboo Cutter, an ancient story about a bamboo cutter who finds a child in bamboo, the child is from the moon. Talking about it, they realize that they need to know a lot more about space so they can update the story and make it their own. The brother of one of the students is a university student studying astrophysics. With his help, and the help of his teacher, they learn a lot more about the universe.
The authors use things like soccer to demonstrate some of the current theories and discuss the history of astrophysics from the time when people thought the earth was the center of a very small universe, to realizing we weren't even the center of our solar system and on to realizing just how vast the universe is.
They explain the measurements used and a little bit about how our current data is being accumulated. They discuss theories as well as what is known and explain how tests and math are validating the theories that scientists currently have about the universe, it's origins, it's possible eventual end, and how it all works. Even talking about the possibility of extra-terrestrial life.
It's a fantastic introduction into basic astrophysics. Not just for kids but also for adults who would like more understanding. I'm not a scientist. Just an occasional dabbler, I watch Nova and read some of the more popular books on the subject. Where these books absolutely shine is how easy it is to apply the material to things you know so that you can learn it in the stories. The further detail in the text sections is then building on what you've learned so you can have a deeper understanding. Because it's engagingly written, these books have a strong appeal both to teens and adults.