During television's early days, a popular commercial featured a child asking, "Why's the sky blue, daddy?" The father assured the child the answer could be found in the encyclopedia the ad was selling. Today's scientists still gaze at the skies with childlike wonder. But the questions they ask are far from childlike: What does it mean when we say the universe is curved? Why is the cosmos expanding at a constantly accelerating rate? How are the forces affecting the stars and planets related to those affecting the tiniest sub-atomic particles within a single atom? In God's Equation, Amir Aczel explains how physicists, astronomers and cosmologists are trying to find the answers in Einstein's theories, non-Euclidean geometry and advanced mathematics. The story begins with Einstein's general theory of relativity, which proposed that the universe is curved, that gravity is not a force, as Newton believed, but a curved field created by the presence of mass, and that the presence of mass will make light bend. In 1919, studies of a total solar eclipse showed that starlight did, in fact, bend around the sun. The headlines that followed this discovery turned Einstein into the world's first "media star" and its most famous scientist since Newton. More importantly, it set the direction for most of the twentieth century's research into physics, astronomy and cosmology, and influenced everything from the development of nuclear energy to quantum theory and mathematics.

Einstein himself spent the rest of his life looking for a "unified field theory," literally a "theory of everything" that would explain both the very small (the world of sub-atomic particles and quantum theory) and the very large (the expanding universe). He called his search an attempt to understand "God's thoughts" when the cosmos was created. The equation in that theory would be the human approximation of "God's Equation