Providing explanations, diagrams, and photographs, two physicists reveal how anyone can understand some of the most fundamental questions about the Earth, sun, solar system, and universe.

Get ready for the ultimate astronomy adventure! It's a beautiful evening when Squeak, Orni, and Castor head out for a weekend of camping. But Squeak has a surprise: he's hosting them all in his observatory, high at the top of a tree. The tree house is delightful--and fully equipped for the most incredible discoveries: in the sky and the stars, through the galaxy and beyond.