Boulder Book Store Author Event: Author/Illustrator and former Boulder resident David A. Aguilar will discuss his two new National Geographic books, “ALIEN WORLDS” (ages 8-12) and “SPACE ENCYCLOPEDIA” (ages 8 and up).  In “ALIEN WORLDS” he applies real-world astronomy, biology, geology, chemistry, botany and meteorology to known exoplanets and speculates what sort of exotic life forms might evolve there. “SPACE ENCYCLOPEDIA” presents the latest exciting findins on space exploration and spectacular views of the universe. David is the Director of Science Information at the Harvard-Smithsonian Center for Astrophysics in Cambridge MA.