Physicists and astronomers have learned a lot about the earliest stages of our universe and how it evolved nearly 14 billion years ago, around the time of the "Big Bang." Several lines of evidence suggest that our universe underwent a very brief period of rapid, violent expansion, doubling in size every trillion-trillion-trillionth of a second, in a period known as "cosmic inflation." Cosmic inflation predicts several features of our universe today, from its shape and overall smoothness across vast distances, to the clumpiness we observe on shorter scales, ranging from the human-sized to the supergalactic. Major clues about this dramatic era of our cosmic history come from tiny, subtle patterns in the early glow from the big bang known as the cosmic microwave background radiation. Recent measurements have confirmed these predictions to high accuracy, yielding new insights into the quantum state of the universe during its earliest moments.