Discover the science behind the incredible space missions that have furthered our knowledge of the universe. Extraordinary images highlight facts about what we have learned about other planets, whether there might be other forms of life out there, and where we intend to explore next. Each title in this series contains a mission activity that poses a challenge for readers to solve. Unlocking the Secrets of the Solar System, How was our Solar System created? Why are the Sun and Moon the same size in the sky? Find out how human and robotic exploration continue to expand our knowledge of space, allowing us to venture farther out into our Solar System. Book jacket.