[Public Lecture] Are There Many Universes!?

When you look up at the night sky, an immense universe unfolds before you. Where did this universe come from, and what fate awaits it? What lies "outside" our universe? "Superstring theory" is a leading candidate for a unified description of everything, and the latest developments in theoretical physics that it exemplifies have begun to reveal a universe far stranger than we imagined. This lecture introduces "multiverse cosmology" — the idea that what we once thought of as the entire universe is in fact only one of countless "universes" (a multiverse) governed by entirely different laws. We also discuss how this radical shift in worldview connects to recent and upcoming cosmological observations — in particular the discovery of the mysterious property of spacetime called dark energy, and the experimental search for the "curvature" of our universe — and what they imply for the multiverse picture.