What do charge oscillations in conductors and expansion of the physical Universe have in common?  More than meets the eye!  This Editor's Suggestion, https://link.aps.org/doi/10.1103/PhysRevB.100.140301, shows  that a collection of identical charged particles in the presence of a uniform compensating background charge can evolve as if they were part of an expanding or contracting homogeneous and isotropic Universe with the "wrong" sign of interaction: while gravity is attractive, the charges repel each other.  Otherwise, the equations of motion are exactly the cosmological equations of the general theory of relativity.