WHAT HAPPENED BEFORE THE BIG BANG? A physics professor offers a theory about the ultimate origin of the universe—and challenges the concept of a multiverse, string theory, and more.In the beginning was the Big Bang: an unimaginably hot fire almost 14 billion years ago in which the first elements were forged. The physical theory of the hot nascent universe—the Big Bang—was one of the most consequential developments in 20th-century science. And yet it leaves...

Inflationary Cosmology is an advanced graduate-level textbook, covering in detail the physics of inflation in the early universe, with a special focus on the physics of the curvature perturbation — the primordial seed for the formation of structure in the universe — generated by quantum vacuum fluctuations during inflation. The book covers in detail perturbation theory in General Relativity and semiclassical quantization of perturbations in inflation, and observational constraints on infla...

In the beginning was the Big Bang: an unimaginably hot fire almost fourteen billion years ago in which the first elements were forged. The physical theory of the hot nascent universe—the Big Bang—was one of the most consequential developments in twentieth-century science. And yet it leaves many questions unanswered: Why is the universe so big? Why is it so old? What is the origin of structure in the cosmos? In An Infinity of Worlds, physicist Will Kinney explains a more recent the...