Big Bubble theory is a cosmological model where the universe is an expanding bubble in four-dimensional space. Expansion is driven by starlight and gravity acts like surface tension to form a minimal surface. This model is used to derive Minkowski’s spacetime geometrically from four-dimensional Euclidian space. Big Bubble cosmology is consistent with type 1a supernova redshifts without dark energy or expanding spacetime. A different origin for the cosmic microwave background is proposed. The size of the universe is estimated using Hubble’s constant and a doppler shift of the cosmic microwave background. A mechanism for Mach’s principle is described. Big Bubble theory is similar to Einstein’s 1917 cosmological model, which is shown to be a snapshot of a rapidly expanding universe in dynamic equilibrium, rather than a static universe. The orbital speed of stars in spiral galaxies can be reproduced with Newtonian dynamics and without dark matter. A quadratic equation is derived that predicts both faster and slower rotation than purely Kepler orbits, consistent with the behaviour of spiral and elliptical galaxies, and suggesting that spiral galaxies evolve into elliptical galaxies as they age. The Big Bubble physical concept provides a basis for some quantum physics phenomena.