Abstract

The modern ether concept is compatible with relativity, quantum mechanics, and non-classical geometrization. Misuse of the term "ether" in anti-Relativity polemics in former times causes many physicists to avoid the word and equivalent terms are used instead. The modern concept results from three development programmes. First, there was the evolution of Relativity, Relativistic Cosmology and Geometrodynamics which discarded the early 20th C passive, rigid, ether in favour of geometrized space-time. A non-classical ether, defined as field or space-time, was accepted by Einstein in his later years. This had two main aspects: static (or geometric) and dynamic (or frame-space perspective). Second, there was a Lorentzian programme, which provided a quasi-classical exposition of Relativity in terms of moving rod and clock readings. The Einstein-Minkowski and the Lorentzian programmes can be reconciled. The third development programme is associated with Quantum Mechanics and studies of the physical vacuum. A group of analogues based on the vortex sponge promises to unify these programmes of interpretation. The modern ether, from the smallest scale point of view, resembles a "sea of information", which demands new techniques for interpreting it, drawn from information science, computer science, and communications theory.