## Universe 4.0 – Part 2: lighting up the Dark Sector

Following on from Part 1, this presentation shows how the exochronous metric is able to mimic the effects of Dark Matter, and in doing so, is able to account for the observed flat galactic rotation curves. I also show that a simple modification to the standard N-body simulation code is able to reproduce the effects previously ascribed to dark matter, in terms of being able to generate large scale structure in the universe.

(Presentation first given to the University of Sussex, Astronomy Seminar, 24th January 2019)

## Universe 4.0 – Part 1: introducing the exochronous metric

This presentation expands on the overview given in “Universe 4.0 – a prospectus”. I review the strengths and weaknesses of the current ΛCDM concordance model, and identify the FLRW metric as the probable cause of many of the issues facing this model. I present an alternative static metric in which all four dimensions are spatial, i.e. there is no time dimension; time being a derived or emergent quantity in this “exochronous” metric. Unlike the original Einstein static metric, this metric results in a solution to the Einstein field equations of General Relativity, without the need to incorporate extraneous factors such as a cosmological constant.

(Presentation first given to the University of Sussex, Astronomy Centre, Large Scale Structure and Gravitational Lensing Team, 24th November 2017)

## Universe 4.0 – a prospectus

Let’s face it, our current cosmological paradigm, the so-called ΛCDM “concordance model” of Universe 3.x (where x≈7), is getting somewhat dated. Arguably, it is no longer fit for purpose. Time then for a rethink, and a vision of what a totally redesigned universe – Universe 4.0 – might look like.

I start with a brief overview of the history of cosmology over the past 4000 years or so, up to the present day, highlighting the common errors of perception that have hindered humankind’s progress in understanding our place in the universe.

The main failings of the current cosmological paradigm are reviewed, concentrating on the coincidences and contradictions presented by the twin concepts of Dark Matter and Dark Energy. A set of criteria are proposed that any new cosmological paradigm should, ideally, fulfil.

I conclude with an illustration of how this might be achieved using an alternative picture of the way time is treated in General Relativity, in the context of a scalar-tensor theory of gravity, and show how this can reproduce the cosmological effects currently ascribed to Dark Energy and Dark Matter.

(Presentation first given to the South Coast Cosmology Meeting, University of Sussex, 9th June 2017.)

## Predicted behaviour of a universe with a low photon-baryon ratio

A fundamental assumption inherent in the standard \(\Lambda\)CDM Hot Big Bang (HBB) model is that matter-antimatter annihilations shortly after the birth of the universe give rise to a vast excess of photons over baryons. Alternative cosmological models imply a much lower photon-baryon ratio, \(\eta_\gamma\). We examine some of the consequences of \(\eta_\gamma\simeq1\) for a number of cosmological processes, within the framework of Machian General Relativity, in which photon energy is an invariant in the cosmological reference frame.

(Presentation given to the 10th International Symposium for the Frontiers of Fundamental and Computational Physics, Perth, Western Australia, 24-26 November 2009)

## The Resonant Universe

A cosmological model based on Machian General Relativity can be shown to result in a universe in which the cosmic scale factor increases linearly as a function of time. This provides a reasonably close fit to the cosmic dynamics inferred from observations of supernova redshifts, but does not fully account for the observed cosmic acceleration. This simple model assumes a universe which begins in a state of static equilibrium between the gravitational and electromagnetic forces. A variant of this cosmological model is proposed, in which the Hubble redshift results not from the kinematics of an expanding universe, but from contraction of the subatomic particles that constitute the universe. Since our standard system of measurement units is based on atomic dimensions and frequencies, this space and time dilation gives rise to an increase in cosmic scale factor over time. Extending the model to cover the more realistic situation in which the universe is created in a state of dynamic equilibrium, and taking into account the fact that the gravitational field propagates at a finite velocity (assumed to be c), results in a more complex dynamical evolution of the scale factor. Specifically, it can be shown that this model predicts a resonant universe in which the rate of increase of the cosmic scale factor undergoes oscillations. Furthermore, the periodicity of these oscillations is determined by a single pure number parameter: the baryon number of the universe. The resultant dynamics of this model are able to account for the apparent acceleration in the rate of expansion of the universe, as implied by the high redshift supernova measurements made in recent years, without the need for a cosmological constant. (Presentation given to Crisis in Cosmology Conference, Port Angeles, WA, September 2008)

## Machian General Relativity

This presentation outlines the main characteristics of Machian General Relatvity, and describes some of the principle implications, including a resolution to the dark energy problem. The presentation was first given at a meeting of the CAPAC group at Imperial College, in June 2001.

## The Quasi Static Universe

Presentation first given to Queen Mary College, London, in July 2001.