How do we know that the physics we can do in labs here on Earth today is the same physics in galaxies a long time ago and far, far away? Take a collection of your favourite theories - the gravity of Newton, the electromagnetism of Maxwell, the quantum world of Schrödinger and Heisenberg, Einstein's relativity, Fermi's "little one" (neutrino) and the bizzare zoo of sub-atomic particles - how do you know they work on the Moon? On Proxima Centauri (the nearest star - other than the Sun - that we know of)? In the Andromeda galaxy (M31)? How do you know they worked before Chicxulub? before the trilobites? before the solar system formed? I would like to look at some of these questions from the astronomical perspective - how do astronomical observations support the idea that physics hasn't changed over the last ~10 billion years, and that it works just the same in distant quasars as it does here on Earth. Of course, there are plenty of other experiments and observations that show the universality of physics - the ancient nuclear reactor at Oklo for example - and maybe someone else will start a thread in Geology on that.