**SUM – Model of a Stationary Background Universe behind our Cosmos**

**Peter Ostermann**

Physical Contributions 2009-2013, ISBN 978-3-941550-25-4, Hardcover, 256 S., 48,00 € *

Given there has been something where a big-bang origin of our evolutionary cosmos took place: What is the relativistic line element describing the energy density and pressure of such a pre-existing universal background? The simplest conceivable ansatz leads to a Stationary-Universe Model (SUM), which instead of the ‘Steady-state Theory’ is shown to be an arguable alternative to the Cosmological Concordance Model (CCM) commonly accepted today.

The SUM stands out with redshift values statistically independent of time, a significant Hubble parameter is proved in contrast to the conventional one. It requires a negative gravitational ‘dark’ pressure of –1/3 the critical density. Intrinsic limitations of proper length and time are derived, which cause a struggle of local SRT (quantum mechanics) and universal GRT (gravitation). Using one macroscopic constant *H* in addition to *c* and *G* only, the model describes a background free of coincidences or horizon problems.

While the CCM’s key parameter Omega_Lambda seems essentially determined by SUM ‘boundary’ conditions, there is a chance of having already observed parts of a stationary universe. With no need for ‘dark energy’, this alternative explains straightforwardly the SNe-Ia data on universal scales.

Besides its currently assumed parts, a non-lensing homogeneous background of matter might fill the gap to critical density. A mathematical solution is derived for a perfect black-body spectrum composed of redshifted microwave radiation emitted from ‘dark’ sources within the universe, thus the CMB might exist as a special part of the extragalactic background light.

Given the law of entropy restricted to evolutionary processes, an open concept implies a ‘chaotic’ quasi-inflation background, embedding ‘local-bang’ cosmoses therein. The SUM is shown to be the only arguable solution of Einstein’s original equations without cosmological constant.

In addition to the main text of the book there are several associated articles appended, which treat important insights and aspects in more detail. This may be not unnecessary since particularly the interpretation of general relativity is found to need some revision today. - For physicists and cosmologists.