Light is the most important part of our lives. Louise Riofrio, while working as a Scientist at NASA, made the biggest discovery of the century--the Speed of Light is changing. Starting when a child's eyes first open she describes how we learn about the world through light in our first few months of life, then how we discovered that Earth is round, and how we found we are part of a solar system and a galaxy. The Speed of Light takes you around the world from the Mediterranean to Hawaii in 100 illustrations showing where discoveries were made. This new edition shows how the size of the Universe is related to the cells of our bodies, a new discovery even closer to human life. The Speed of Light is your guide to the Universe.