In the late 1970s, cosmologists proposed that our universe began with a period of rapid inflation. In its first fraction of a second, our universe expanded by a factor of 1030—that's one with thirty zeroes after it. In this brief blip of time, our universe grew by a greater percentage than it has in the 14 billion years since. Supported by numerous lines of evidence, this period of inflation is now an accepted part of our standard model of cosmology, but how it happened is far from clear.