Einstein-aether theories were popularized by Maurizio Gasperini in a series of papers, such as "Singularity Prevention and Broken Lorentz Symmetry" in the 1980s. In addition to the metric of general relativity these theories also included a scalar field which intuitively corresponded to a universal notion of time. Such a theory will have a preferred reference frame, that in which the universal time is the actual time. The dynamics of the scalar field is identified with that of an aether which is at rest in the preferred frame. This is the origin of the name of the theory, it contains Einstein's gravity plus an aether.