The Fabric of the Cosmos: Space, Time, and the Texture of Reality

by Brian Greene

the size of the universe increased by at least a factor of 1030 during inflation, which means the volume of the universe increased by a factor of at least (10 30)3 = 1090. Consequently, the energy embodied in the inflaton field increased by the same huge factor: as the inflationary phase drew to a close, a mere 10−35 or so seconds after it began, the energy in the inflaton field grew by a factor on the order of 1090, if not more. This means that at the onset of inflation, the inflaton field didn’t need to have much energy, since the enormous expansionit was about to spawn would enormously amplify the energy it carried. A simple calculation shows that a tiny nugget, on the order of 10 −26 centimeters across, filled with a uniform inflaton field—and weighing a mere twenty pounds—would, through the ensuing inflationary expansion, acquire enough energy to account for all we see in the universe today.