| ai.viXra.org > Astrophysics > 2512 |
|
 |
| ai.viXra.org > Astrophysics > 2512 |
|
|
[2] ai.viXra.org:2512.0104 [pdf] submitted on 2025-12-31 20:39:31
Authors: Pavel Holub
Comments: 40 Pages. Copyright © 2025 Pavel Holub. All rights reserved.
This article presents the Spherical Model of the Universe (SMU) as a consistent and testable alternative to the standard cosmological model, $Lambda$CDM [7]. The SMU describes the universe as an inhomogeneous, non-singular, spherically closed, energy-conservative, and cyclic system. The SMU explains the tension between $H_0 approx 73$ and $H_0 approx 67$ [1] as a logical consequence of this structure, rather than a measurement error. It thus shifts the problem from a "measurement error" to a "model error," which strongly supports the necessity of transitioning from the homogeneous $Lambda$CDM to inhomogeneous models such as the SMU. The SMU alternative addresses the difficulties of $Lambda$CDM by returning to Einstein’s original methodological principles. Standard cosmological analysis is burdened by a circular argument ($Lambda$CDM proves itself).The cyclicity of the SMU is enabled by a fundamental principle: the outer event horizon ($Phi$-horizon) is defined by zero gravitational potential ($Phi = 0$), ensuring the energy closure of the system. A key implication of this cyclicity is that it is impossible to distinguish whether our contemporary universe is the initiating phase or the $n$-th cycle of its evolution.The SMU model assumes the existence of a pre-geometric structure that exists independently of matter, energy, and spacetime. In this phase, time, distance, and metric are not defined; there is no expansion or motion in the conventional sense. The structure represents only a set of permitted causal relations, not physical space.
Category: Astrophysics
[1] ai.viXra.org:2512.0077 [pdf] submitted on 2025-12-21 00:13:08
Authors: Hari Kumar Nair
Comments: 49 Pages. DOI: 10.5281/zenodo.17914713
Observations of Type Ia supernovae, the cosmic microwave background, and baryon acoustic oscillations indicate that the Universe is undergoing accelerated expansion. In LambdaCDM, this is attributed to a cosmological constant Lambda. While successful, Lambda lacks a microphysical origin, and alternative dynamical models often treat dark energy as a structureless homogeneous fluid. We explore a concrete alternative hypothesis: that dark energy arises from an ensemble of discrete brane-like objects, "repellons," modelled as closed two-dimensional shells embedded in three-dimensional space. We ground this hypothesis in general relativity using a relativistic thin-shell model, demonstrating how tension-dominated branes can source an effectively repulsive gravitational potential.The repellon brane contributes stress—energy to our spacetime while its interior is not part of the observable Universe. When coarse-grained over cosmological volumes, the ensemble behaves as an effective fluid with equation-of-state parameter omega_R<-1/3, capable of driving late-time acceleration. We retain standard baryons and cold dark matter as the agents of structure formation and halo dynamics, treating repellons purely as a dark-energy sector. Motivated by a simple gravitational-response picture, we further posit a mild anti-correlation between repellon and matter densities, such that repellons preferentially populate underdense regions. Numerical integration of the coupled linear perturbation equations confirms this mechanism, showing that repellons naturally accumulate in voids as matter evacuates. We outline how this void bias could enhance void expansion and modify large-scale flows and late-time ISW correlations relative to LambdaCDM with the same background history. This framework is phenomenological, designed to identify qualitative signatures (specifically in void dynamics) that can guide future perturbative calculations and N-body simulations.
Category: Astrophysics