Quasi-Steady-State and Related Cosmological Models: A Historical Review

Since the emergence in the late 1960s of the standard hot big-bang theory, cosmology has been dominated by finite-age models. However, the rival view that the universe has existed for an indefinite time has continued to be defended by a minority of researchers. This view has roots far back in history and in the 1950s and 1960s several models were proposed in opposition to the big-bang paradigm. The most important of the alternative models, the steady-state cosmology proposed in 1948, was uniformly expanding rather than exhibiting a cyclical behaviour. In a much revised version it was developed into the quasi-steady-state cosmological model (QSSC) of the 1990s. From a historical point of view, this model, and a few other related models, can be seen as the latest examples of a tradition in cosmological thought that goes back to ancient Greece. The paper describes the background and development of the QSSC model.

💡 Research Summary

The paper offers a comprehensive historical and scientific review of cosmological models that posit an eternal universe, focusing on the development and legacy of the quasi‑steady‑state cosmology (QSSC). It begins by tracing the philosophical roots of an infinite‑time universe back to ancient Greek thought, where thinkers such as Aristotle and the atomists entertained the idea of a cosmos without a beginning or end. The narrative then moves through the Renaissance and the early modern period, noting that the concept of an eternal universe persisted as a minority view even as the dominant paradigm shifted toward finite‑age models.

In the mid‑20th century, a series of “steady‑state” alternatives emerged in response to the growing acceptance of the hot big‑bang theory. The most influential of these was the original steady‑state model proposed in 1948 by Fred Hoyle, Hermann Bondi, and Thomas Gold. This model introduced the continuous creation field (C‑field) to maintain a constant density despite cosmic expansion, embodying the Perfect Cosmological Principle that the universe looks the same at all times and places. Early observational successes of the big‑bang model—most notably the discovery of the cosmic microwave background (CMB) in 1965—posed serious challenges to the steady‑state hypothesis, leading to its decline.

The QSSC, formulated in the 1990s by Hoyle, Geoffrey Burbidge, and Jayant Narlikar, is presented as a revised version of the original steady‑state idea. It retains the C‑field concept but augments it with a cyclic component superimposed on an overall exponential expansion. Mathematically, the scale factor a(t) is expressed as a product of a long‑term exponential term and a short‑period oscillatory term, a(t)=e^{Ht}