Austin Joyce, a physicist at the University of Chicago, speaks at the kick-off conference for the new MPG-IAS-NTU Center, held in Wolfensohn Hall at the Institute for Advanced Study. His talk addresses how quantum field theory, built originally to describe particle interactions in flat spacetime, applies to the actual expanding, curved universe we inhabit. He works through the complications that arise once gravity and cosmological expansion enter the picture, touching on effective field theory methods and the kinds of observable signatures that cosmological and particle experiments might detect. The talk is pitched at a technical physics audience, assuming familiarity with field theory formalism, and situates the discussion within current research questions about inflation, vacuum structure, and the boundaries of standard QFT techniques when applied beyond idealized laboratory settings. It serves as a research-level survey rather than an introductory overview.