scholarly journals Astromechanics of Dual Universe: A New Possible Explanation for the Universe Unsolved Problems

Author(s):  
Mohammed B. Al-Fadhli

The necessity of the dark energy and dark matter in the present universe could be a consequence of the antimatter elimination assumption in the early universe. Current cosmological models that rely on the dark side have left many unsolved mysteries, remarkably: tension in Hubble parameter measurements, the accelerated expansion, the fast orbital speed of stars, the dark flow observations, cosmic horizon, space flatness, absent of the antimatter, etc. On the other hand, General Relativity (GR) has relied on the spacetime to demonstrate the movement of matter due to a local curvature caused by the presence of matter. Founded on this, I trace the evolution of the spacetime worldlines based on the evolution of the universe spatial scale factor and its evolution time in polar coordinates in order to construct a potential spatial curvature over the temporal dimension or a global spacetime curvature. The mathematical derivations of a positively curved universe governed by only gravity revealed two opposite solutions of the worldline evolution. This possibly implies that the matter and antimatter could be evolving in opposite directions as distinct sides of the universe. By implementing the derived model, we find a decelerated phase of spatial expansion during the first 10 Gyr, that is followed by a second phase of an accelerated expansion; potentially matching the tension in Hubble parameter measurements. In addition, the model predicts a final time-reversal phase of spatial contraction, due to rapid surge in density i.e. reversal entropy, leading to a Big Crunch of a cyclic universe. The predicted density is 1.14. Other predictions are (1) an evolvable curved spacetime at the decelerated phase that is transformed to flatness at the accelerated phase with internal voids which could continuously increase the matter and antimatter densities elsewhere in both sides. (2) the spatial curvature through time dimension along spacetime worldlines was found to increase galaxy orbital speed and (3) a calculable flow rate of the matter side towards the antimatter side at the accelerated phase; conceivably explaining the dark flow observation. These findings may indicate the existence of the antimatter as a distinct side, which influences the evolution of the universe instead of the dark energy or dark matter. These theoretical outcomes and predictions are promising, which can be verified, fine-tuned or disproved using astrometric data in future works.

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Tong-Jie Zhang ◽  
Cong Ma ◽  
Tian Lan

This paper is a review on the observational Hubble parameter data that have gained increasing attention in recent years for their illuminating power on the dark side of the universe: the dark matter, dark energy, and the dark age. Currently, there are two major methods of independent observationalH(z)measurement, which we summarize as the “differential age method” and the “radial BAO size method.” Starting with fundamental cosmological notions such as the spacetime coordinates in an expanding universe, we present the basic principles behind the two methods. We further review the two methods in greater detail, including the source of errors. We show how the observationalH(z)data present itself as a useful tool in the study of cosmological models and parameter constraint, and we also discuss several issues associated with their applications. Finally, we point the reader to a future prospect of upcoming observation programs that will lead to some major improvements in the quality of observationalH(z)data.


2021 ◽  
Author(s):  
Ekrem Aydiner ◽  
Isil Basaran-Oz ◽  
Tekin Dereli ◽  
Mustafa Sarisaman

Abstract The late time crossover from matter dominated era (represented power-law evolution) to the dark energy dominated era (represented exponential evolution) of the Universe evolution is the major problem in today’s physical cosmology. Unless this critical transition problem is solved, it is not possible to reach a holistic theory of cosmology. To explain this critical transition we propose a new model where the dark matter and dark energy interacting through a potential. Based on the FLRW framework we analytically solve this model and obtain the scale factor a(t). In addition, we numerically compute all cosmological quantities. We find more significant results to enlightening the physical mechanism of the critical transition. Firstly, we show that the scale factor a(t) has a hybrid form as a(t) = a0(t/t0) α e ht/t0 . This is main and important result in the presented work, which clearly indicates that the transition from the power-law to the exponential expansion of the Universe. The numerical results clearly provide that there is a time crossover tc in the scale factor a curve, which indicates the transition from the power-law to the exponential expansion of the Universe. Below t/t0 ≤ tc, matter era dominated hence time evolution of the Universe is given by a(t) ∝ (t/t0) α , on the other hand, above t/t0 > tc, the evolution is represented by a(t) ∝ exp(ht/t0). It is first time, the hybrid result for scale factor is exactly obtained from the presented model without use any approximation. Secondly, we fit the scale factor below and above tc. Surprisingly, we find that the scale factor behaves as a(t) ∝ (t/t0) 2/3 below t/t0 ≤ tc, and as a(t) ∝ exp(ht/t0) which indicates that the Hubble parameter takes the value in the interval of the around H0 = 69.5 and H0 = 73.5 km s−1Mpc−1 depend on the weak and strong interactions between dark components above t/t0 > tc, respectively. These are remarkable that α = 2/3 is completely consistent exact solution of the FLRW and re-scaled Hubble parameter H0 is the observable intervals given by Planck, CMB and SNIa data (or other combinations) for chosen interaction values are purely consistent with cosmological observations. Thirdly, we find from the model the transition point from matter dominated era to the dark energy dominated era in the cosmic time is the t0 = 9.8 Gyear which is consistent with the theoretical solution and observations. Additionally, we numerically obtain and analyse other cosmological quantities such as dimensionless Hubble parameter h, deceleration parameter q, jerk parameter j and EoS parameter w. We show that all cosmological quantities of this model are consistent observational results for the matter and dark energy dominated eras. As a result, we consider late time crossover of the Universe, we propose an interacting dark matter and dark energy model, we show that this model can explain the late time crossover phenomena of the Universe and our solutions are very good consistent with theoretical and observational results. Finally, we state that this work makes essential steps towards solving a critical outstanding problem of the cosmology, and has a potential to creates a paradigm for future studies in this field. Furthermore, the model also sheds light on the interaction mechanism of dark matter and dark energy in the Universe.


2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Aleksander Stachowski ◽  
Marek Szydłowski ◽  
Krzysztof Urbanowski

We consider a cosmology with decaying metastable dark energy and assume that a decay process of this metastable dark energy is a quantum decay process. Such an assumption implies among others that the evolution of the Universe is irreversible and violates the time reversal symmetry. We show that if we replace the cosmological time t appearing in the equation describing the evolution of the Universe by the Hubble cosmological scale time, then we obtain time dependent Λ(t) in the form of the series of even powers of the Hubble parameter H: Λ(t)=Λ(H). Our special attention is focused on radioactive-like exponential form of the decay process of the dark energy and on the consequences of this type decay.


2019 ◽  
Vol 28 (14) ◽  
pp. 1944002 ◽  
Author(s):  
Spyros Basilakos ◽  
Nick E. Mavromatos ◽  
Joan Solà Peracaula

We present a string-based picture of the cosmological evolution in which (CP-violating) gravitational anomalies acting during the inflationary phase of the universe cause the vacuum energy density to “run” with the effective Hubble parameter squared, [Formula: see text], thanks to the axion field of the bosonic string multiplet. This leads to baryogenesis through leptogenesis with massive right-handed neutrinos. The generation of chiral matter after inflation helps in cancelling the anomalies in the observable radiation- and matter-dominated eras. The present era inherits the same “running vacuum” structure triggered during the inflationary time by the axion field. The current dark energy is thus predicted to be mildly dynamical, and dark matter should be made of axions. Paraphrasing Carl Sagan [ https://www.goodreads.com/author/quotes/10538.Carl_Sagan .]: we are all anomalously made from starstuff.


2019 ◽  
Vol 34 (19) ◽  
pp. 1950099 ◽  
Author(s):  
Denitsa Staicova ◽  
Michail Stoilov

We consider the cosmological application of a (variant of) relatively newly proposed model1 unifying inflation, dark energy, dark matter, and the Higgs mechanism. The model was originally defined using additional non-Riemannian measures, but it can be reformulated into effective quintessential model unifying inflation, dark energy and dark matter. Here, we demonstrate numerically that it is capable of describing the entire evolution of the Universe in a seamless way, but this requires some revision of the model setup. The main reason is that there is a strong effective friction in the model, a feature which has been neglected in the pioneer work. This improves the model potential for proper description of the evolution of the Universe, because the friction ensures a finite time inflation with dynamically maintained low-value slow-roll parameters in the realistic scenarios. In addition, the model predicts the existence of a constant scalar field in late Universe.


2020 ◽  
Vol 35 (20) ◽  
pp. 2050166 ◽  
Author(s):  
A. Pourbagher ◽  
Alireza Amani

In this paper, we first obtain the energy density by the approach of the new agegraphic dark energy model, and then the [Formula: see text] gravity model is studied as an alternative to the dark energy in a viscous fluid by flat-FRW background, in which [Formula: see text] and [Formula: see text] are torsion scalar and boundary term. The Friedmann equations will be obtained in the framework of modified teleparallel gravity by tetrad components. We consider that the universe dominates with components such as matter and dark energy by an interacting model. The Hubble parameter is parameterized by the power-law for the scale factor, and then we fit the corresponding Hubble parameter with observational data constraints. The variation of the equation of state (EoS) for dark energy is plotted as a function of the redshift parameter, and the accelerated expansion of the universe is explored. In what follows, the stability of the model is also studied on the base of the sound speed parameter. Finally, the generalized second law of thermodynamics is investigated by entropies of inside and on the boundary of the apparent horizon in thermodynamics equilibrium.


2016 ◽  
Vol 26 (06) ◽  
pp. 1750049 ◽  
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Ines G. Salako ◽  
Faiza Gulshan

We discuss the cosmological implications of interacting pilgrim dark energy (PDE) models (with Hubble, Granda–Oliveros and generalized ghost cutoffs) with cold dark matter ([Formula: see text]CDM) in fractal cosmology by assuming the flat universe. We observe that the Hubble parameter lies within observational suggested ranges while deceleration parameter represents the accelerated expansion behavior of the universe. The equation of state (EoS) parameter ([Formula: see text]) corresponds to the quintessence region and phantom region for different cases of [Formula: see text]. Further, we can see that [Formula: see text]–[Formula: see text] (where prime indicates the derivative with respect to natural logarithmic of scale factor) plane describes the freezing and thawing regions and also corresponds to [Formula: see text] limit for some cases of [Formula: see text] (PDE parameter). It is also noted that the [Formula: see text]–[Formula: see text] (state-finder parameters) plane corresponds to [Formula: see text] limit and also shows the Chaplygin as well as phantom/quintessence behavior. It is observed that pilgrim dark energy models in fractal cosmology expressed the consistent behavior with recent observational schemes.


2007 ◽  
Vol 16 (10) ◽  
pp. 1641-1651 ◽  
Author(s):  
RAM GOPAL VISHWAKARMA

Dark energy and the accelerated expansion of the universe have been the direct predictions of the distant supernovae Ia observations which are also supported, indirectly, by the observations of the CMB anisotropies, gravitational lensing and the studies of galaxy clusters. Today these results are accommodated in what has become the concordance cosmology: a universe with flat spatial sections t = constant with about 70% of its energy in the form of Einstein's cosmological constant Λ and about 25% in the form of dark matter (made of perhaps weakly-interacting massive particles). Though the composition is weird, the theory has shown remarkable successes at many fronts. However, we find that as more and more supernovae Ia are observed, more accurately and towards higher redshift, the probability that the data are well-explained by the cosmological models decreases alarmingly, finally ruling out the concordance model at more than 95% confidence level. This raises doubts against the "standard candle"-hypothesis of the supernovae Ia and their use in constraining the cosmological models. We need a better understanding of the entire SN Ia phenomenon in order to extract cosmological consequences from them.


2014 ◽  
Vol 11 (02) ◽  
pp. 1460014 ◽  
Author(s):  
Winfried Zimdahl

Interactions inside the cosmological dark sector influence the cosmological dynamics. As a consequence, the future evolution of the Universe may be different from that predicted by the ΛCDM model. We review main features of several recently studied models with nongravitational couplings between dark matter and dark energy.


2005 ◽  
Vol 20 (19) ◽  
pp. 1443-1449 ◽  
Author(s):  
WEI WANG ◽  
YUANXING GUI ◽  
SUHONG ZHANG ◽  
GUANGHAI GUO ◽  
YING SHAO

We assume that dark matter and dark energy satisfy the unified equation of state: p = B(z)ρ, with p = pdE, ρ = ρdm+ρdE, where the pressure of dark matter pdm = 0 has been taken into account. A special function [Formula: see text] is presented, which can well describe the evolution of the universe. In this model, the universe will end up with a Big Rip. By further simple analysis, we know other choices of the function B can also describe the universe but lead to a different doomsday.


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