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.
Einstein-aether theories, popularized by Maurizio Gasperini in papers like Singularity Prevention and Broken Lorentz Symmetry from the 1980s, incorporated an extra element beyond the metric of general relativity. This extra element intuitively represented a universal concept of time.