Dr. N.L. Kachhara
The steady state theory asserts that although the universe is expanding, it nevertheless does not change its outlook over time; it has no beginning and no end. The Theory requires that new matter must be continuously created (mostly as hydrogen) to keep the average density of matter equal over time. The amount required is low and not directly detectable; roughly one solar mass of baryons per cubit megaparsec per year or roughly one hydrogen atom per cubic meter per billion years, with roughly five times as much dark matter. Such a creation rate would, however, produce observable effects on cosmological scales.
Problems with steady-static theory began in the late 1960s, when observations apparently supported the idea that the universe was in fact changing: quasars and radio galaxies were found only at large distances, not in closer galaxies. For most cosmologists the refutation of the steady state theory came with the discovery of the cosmic background radiations in 1965, which was predicted by the Big Bang theory. Within the steady state theory this background radiation is the result of light from ancient stars, which has been scattered by galactic dust. However, this explanation has been unconvincing to most cosmologists as the cosmic microwave background (CMB) is very smooth, making it difficult to explain how it arose from point source and the CMB shows no evidence of features such as polarization, which are normally associated with scattering. Furthermore, its spectrum is so close to that of on ideal black body that it could hardly be formed by the superposition of contributions from dust clumps at different temperatures as well as at different red shifts.
Quasi- Steady State cosmology (QSS) was proposed in 1993 by Fred Hoyle, Geoffrey Burbidge, and Jayant V. Narlikar as a new incarnation of steady state ideas meant to explain additional features unaccounted for in the initial proposal. The theory suggests packets of creation occurring over time within the universe, sometimes referred to as mini bangs, mini-creation events, or little bangs. After the observations of an accelerating universe, further modifications of the model were done.
