Chapter five of Greene’s Fabric of the Cosmos deals with the flow of time. The book asks the question “Does time really flow?” It certainly seems like times flow from the human perspective, but the book says that there is no compelling evidence to prove that time does flow. The concept of a “now moment” is talked about consistently throughout the chapter. A now moment is everything that happens at exactly this moment. A good question regarding the past is does the past actually exist. If the past does not exist, the chance of time travel in the future is likely impossible. We have learned about the reference to time being a loaf which is cut diagonally at every moment. What would a parallel slice of the loaf then become? Something would have to be constant for the slice to be parallel but I can’t seem to wrap my mind around what that is.