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In cosmology dark energy and dark matter are included in the CDM model, but they are still completely unknown. On the other hand the trans-Planckian problem leads to unlikely high photon energies for black holes. We introduce a model with quantized black hole matter. This minimizes the trans- Planckian problem extremely and leads to a scalar field in the oscillating universe model. We show that the scalar field has the same characteristics as a vacuum energy field and leads to the same Casimir effect. Shortly after the beginning of the big bounce this field decays locally and leads to the production of dark matter. In this model no inflation theory is needed. We emphasize that this model is mainly a phenomenological approach with the aim of new impetus to the discussion.

The present paper embraces mainly the three-year period of 1966 to 1968 when the invariant integral of fracture mechanics appeared and became popular, and the last two years of 2015 to 2016 when the neoclassic cosmology based on the invariant integral came up. A mention is given to the previous works of Euler, Cauchy, Maxwell, Nother, Gunther and Eshelby who dealt with invariant integrals in mathematics, hydrodynamics, electrodynamics, and the theory of dislocations. A brief review is given of the creation of the invariant integral of fracture mechanics under static and dynamic conditions for a solid continuum including elastic, plastic and viscoelastic materials, as well as of some of its most important applications, ramifications and generalizations for other physical fields. The initial phase of the expansion and revolution of the large-scale universe is studied in the framework of the neoclassic approach, including the Big Bang and the Dark Energy; it is shown that the spheroidal shape of the universe assumed at the Big Bang retains its eccentricity constant in the initial phase. The assumption of a superphoton as a primordial universe was analyzed.

The high-energy limit of Quantum Chromodynamics is generated by the contraction of its gauge groups. Contraction parameters are taken identical with those of the Electroweak Model and tend to zero when energy increases. At the infinite energy limit all quarks lose masses and have only one color degree of freedom. The limit model represents the development of Quantum Chromodynamics in the early Universe from the Big Bang up to the end of several milliseconds.

We argue that the modified Landau–Raychaudhuri equations should first be analysed in a large class of spacetimes and in dependence on various equations of states, before endorsing any conclusion about (non)singular Big Bang. From the corrected entropy-area law in a large class of metrics, the generalized uncertainty principle (GUP) and the modified dispersion relation (MDR) approaches, and various equations of states, the modified Friedmann equations are derived. They are applied on Landau–Raychaudhuri equations in emergence of cosmic space framework from fixed point method. We show that any conclusion about (non)singular Big Bang is simply badly model-dependent, especially when utilizing GUP and MDR approaches, which can not replace a good theory for quantum gravity. We conclude that the various quantum gravity approaches, metrics and equations of state lead to different modifications in Friedmann and Landau–Raychaudhuri equations and thus to different (non)singular solutions for Big Bang theory.

We consider the model of evolution of the Universe where the Big Bang is regarded as an explosion of a photon superstar. The inflationary epoch is not necessary in the model. The model describes the fundamental phenomena observed: the Universe is expanding at an increasing rate, it is homogeneous and isotropic and contains no antimatter, and its metrics is almost flat.

The discovery of the Standard Model Higgs boson opens up a range of speculative cosmological scenarios, from the formation of structure in the early universe immediately after the big bang, to relics from the electroweak phase transition one nanosecond after the big bang, on to the end of the present-day universe through vacuum decay. Higgs physics is wide-ranging, and gives an impetus to go beyond the Standard Models of particle physics and cosmology to explore the physics of ultra-high energies and quantum gravity., Comment: 15 pages, 7 figures

All measurements are comparisons. The only physically accessible degrees of freedom (DOFs) are dimensionless ratios. The objective description of the universe as a whole thus predicts only how these ratios change collectively as one of them is changed. Here we develop a description for classical Bianchi IX cosmology implementing these relational principles. The objective evolution decouples from the volume and its expansion degree of freedom. We use the relational description to investigate both vacuum dominated and quiescent Bianchi IX cosmologies. In the vacuum dominated case the relational dynamical system predicts an infinite amount of change of the relational DOFs, in accordance with the well known chaotic behaviour of Bianchi IX. In the quiescent case the relational dynamical system evolves uniquely though the point where the decoupled scale DOFs predict the big bang/crunch. This is a non-trivial prediction of the relational description; the big bang/crunch is not the end of physics – it is instead a regular point of the relational evolution. Describing our solutions as spacetimes that satisfy Einstein's equations, we find that the relational dynamical system predicts two singular solutions of GR that are connected at the hypersurface of the singularity such that relational DOFs are continuous and the orientation of the spatial frame is inverted.

This paper posits that the Big Bang was started by the creation of the reverse Higgs field as the massless particle-generating field derived from the absorption of the interuniversal void outside of the universe in the reversible multiverse. The interuniversal void surrounding every universe is to prevent the collision of expanding universes which have the inexhaustible resources of space-time to expand. The collision of expanding universes is permanently irreversible, forbidden in the reversible multiverse. To prevent the collision, the interuniversal void detaches the incoming mass-energy in the interuniversal void to keep expanding universes apart without collision. Inside of the universe, the absorbed interuniversal void with the property of the detachment of mass-energy was transformed into the reverse Higgs field that detached adjacent mass-energy in the universe, resulting in the conversion of rest mass (massive particles) into kinetic energy (massless particles) starting the Big Bang. During the Big Bang, the creation of the reverse Higgs field was followed by the conversion of massless particles except photons into massive particles through the absorption of the Higgs bosons. The absorption of the interuniversal void with zero vacuum energy also started the inflation by converting the high vacuum energy universe into the zero vacuum energy universe. The inflation followed by the Big Bang is a part of the reversible cyclic universe which explains the four force fields (the strong force, gravity, the electromagnetic force, and the weak force) and dark energy. During the Big Bang, the Higgs field and the reverse Higgs field produced the digital space structure consisting of attachment space (the Higgs field) denoted as 1 and detachment space (the reverse Higgs field) denoted as 0.

The favored Big Bang concept is that the original symmetry was skewed, the universe now being all matter, all antimatter having annihilated. -The mechanism of matter/antimatter annihilation is analyzed. A total annihilation of original antimatter could not have occurred; the skewing is unnecessary; and the universe must contain equally both forms of matter. -Current detection of cosmic matter/antimatter annihilations is Gamma Ray Bursts [GRB's]. However, the conviction that the universe is now all matter with no antimatter has left that possibility rejected and uninvestigated and left standing the massive supernovae core collapse hypothesis for GRB's. -It has recently been reported that the rate of GRB's increases with red shift z for z = 0 to 4 as (1 + z)^1.5. The indication is that the rate increases significantly with time into the past at least back to z = 4 [and probably back to the Big Bang]. -That finding is inconsistent with the massive supernovae core collapse hypothesis for GRB's and supports GRB's being cosmic matter/antimatter annihilations., 10 pages, recommend classifications: Astro-Physics & Space Physics, see http://www.the-origin.org for related info. Change is minor correction and minor annotation

We discuss scientific realism from the perspective of modern cosmology, especially primordial cosmology: i.e. the cosmological investigation of the very early universe. We first (Section 2) state our allegiance to scientific realism, and discuss what insights about it cosmology might yield, as against "just" supplying scientific claims that philosophers can then evaluate. In particular, we discuss: the idea of laws of cosmology, and limitations on ascertaining the global structure of spacetime. Then we review some of what is now known about the early universe (Section 3): meaning, roughly, from a thousandth of a second after the Big Bang onwards(!). The rest of the paper takes up two issues about primordial cosmology, i.e. the very early universe, where "very early" means, roughly, much earlier (logarithmically) than one second after the Big Bang: say, less than 10^{-11} seconds. Both issues illustrate that familiar philosophical threat to scientific realism, the under-determination of theory by data---on a cosmic scale. The first issue (Section 4) concerns the difficulty of observationally probing the very early universe. More specifically, the difficulty is to ascertain details of the putative inflationary epoch. The second issue (Section 5) concerns difficulties about confirming a cosmological theory that postulates a multiverse, i.e. a set of domains (universes) each of whose inhabitants (if any) cannot directly observe, or otherwise causally interact with, other domains. This again concerns inflation, since many inflationary models postulate a multiverse. For all these issues, it will be clear that much remains unsettled, as regards both physics and philosophy. But we will maintain that these remaining controversies do not threaten scientific realism.

Various versions of standard Big Bang Model (BBM) including the current LCDM cosmology require an “inflationary” phase for the nascent universe ( Δ t ∼ 10 - 32 s) during which the size of the universe blows up by a factor of ∼ 10 78 . However, the so-called R h = ct cosmology (Melia, 2013a) claims that the isotropy and homogeneity of the present universe can be understood without assuming any inflationary phase. To this effect, Melia and his coworkers have often invoked “Weyl’s Postulate” and “Birkhoff’s Theorem” to qualitatively argue for this novel model. On the other hand, here, we explore for a cogent analytical basis of the R h = ct proposal which is claimed to have such a profound implication. First we show that (i) if the spatial flatness of the BBM would be presumed, R h = ct cosmology may indeed follow. To further explore this issue without prior assumption of flatness (ii) we equate the twin expressions for the Energy Complex (EC) associated with BBM computed by using the same Einstein pseudo-tensor and quasi-Cartesian coordinates (Mitra, 2013b). This exercise surprisingly shows that BBM has tacit and latent self-consistency constraints: it is spatially flat and its scale factor a ( t ) ∝ t . Accordingly, it seems that, there is no scope for the other models including inflationary and cyclic ones. The real lumpy universe may be too complex for the simplistic Big Bang model.

We discuss problems arising in three very different physical processes: an electron scattering on a nucleus, an experiment with delayed choice, and the cosmological Big Bang. We describe the role of soft and supersoft photons in solutions of the arising problems.

Autistics and the plane of complex numbers suggest that if the accelerating expansion of our universe and the anti-universe succeeded a coasting expansion 8.8 billion years after the Big Bang, an accelerating contraction will start in 3.8 billion years. Mirroring the expansion phase, a coasting contraction of the two universes in cosmic space will come up in 12.6 billion years. The end of the fourth section of 8.8 billion years will host two Big Crunches, two White Holes, and a new Big Bounce. The reason for that paradox solves the “cosmological constant problem” and joins general relativity to particle physics. The z-plane and autism can also help us cross science with the arts and religion; retain the search for truth, beauty, and goodness by our descendants; and reach the message of progress buried in the Ark of the Covenant, the Great Pyramid, and Giza’s Sphinx: A selfish brain hides a selfless heart.

The theory of gravitational waves in the frame of non-local quantum hydrodynamics (NLQH) is considered. From calculations follow that NLQH equations for “empty” space have the traveling wave solutions belonging in particular to the soliton class. The possible influence and reaction of the background microwave radiation is taken into account. These results lead to the principal correction of the inflation theory and serve as the explanation for the recent discovery of the universe’s cosmic microwave background anomalies. The simple analytical particular cases and numerical calculations are delivered. Proposal for astronomers—to find in the center domain of the hefty cold spot the smallest hot spot as the origin of the initial burst—Big Bang.

International audience; The predictions of general relativity have been verified by now in a variety of different situations, setting strong constraints on any alternative theory of gravity. Nonetheless, there are strong indications that general relativity has to be regarded as an approximation of a more complete theory. Indeed theorists have long been looking for ways to connect general relativity, which describes the cosmos and the infinitely large, to quantum physics, which has been remarkably successful in explaining the infinitely small world of elementary particles. These two worlds, however, come closer and closer to each other as we go back in time all the way up to the big bang. Actually, modern cosmology has changed completely the old big bang paradigm: we now have to talk about (at least) two (big?) bangs. If we know quite something about the one closer to us, at the end of inflation, we are much more ignorant about the one that may have preceded inflation and possibly marked the beginning of time. No one doubts that quantum mechanics plays an essential role in answering these questions: unfortunately a unified theory of gravity and quantum mechanics is still under construction. Finding such a synthesis and confirming it experimentally will no doubt be one of the biggest challenges of this century’s physics.

We examine the cosmological sector of a gauge theory of gravity based on the SO(4,2) conformal group of Minkowski space. We allow for conventional matter coupled to the spacetime metric as well as matter coupled to the field that gauges special conformal transformations. An effective cosmological constant is generated dynamically via solution of the equations of motion, and this allows us to recover the late time acceleration of the universe. Furthermore, gravitational fields sourced by ordinary cosmological matter (i.e. dust and radiation) are significantly weakened in the very early universe, which has the effect of replacing the big bang with a big bounce. Finally, we find that this bounce is followed by a period of nearly-exponential slow roll inflation that can last long enough to explain the large scale homogeneity of the cosmic microwave background., 8 pages, 3 figures, references added, version matches the one published in PRD

Supernovae and gamma-ray bursts are the most powerful explosions in observed Universe. This educational review tells about supernovae and their applications in cosmology. It is explained how to understand the production of light in the most luminous events with minimum required energy of explosion. These most luminous phenomena can serve as primary cosmological distance indicators. Comparing the observed distance dependence on red shift with theoretical models one can extract information on evolution of the Universe from Big Bang until our epoch.

Starting from the classic Friedmann–Robertson–Walker theory with big bang it is shown that the solutions of the field equations can be extended to negative times. Choosing a new cosmic time scale instead of proper time one achieves complete differentiability of the scale factor and of suitable thermodynamic quantities equivalent to pressure and energy density. Then, the singularity of big bang manifests itself only by the vanishing of the scale factor at time zero. Moreover, all solutions of the field equations are defined for all times from $-\infty$ to $+\infty$. In a separate section, the horizon structure of the extended theory is studied. Some weak assumptions guarantee that there are no horizons. Hence, the horizon problem in a strict sense disappears. An intensive discussion of the results is given at the end of the paper.

School of thought is the theory of creation (theism) and school of thought deals with the random chance of evolution (atheism) about the origin of the universe and origin of the life. In the race of proof of the hypothesis, the theism has no scientific evidence and reliable proof, on the other hand atheism based on the scientific observable evidence. The latest theory of origin of the universe by Big Bang is more believable and supported by some scientific evidence such as Doppler effect on light, Hubble observation and result of the expanding the universe and observation of the cosmic microwave background radiation(CMBR). Paper briefly discussing about the origin of the universe and the Bing Bang. Key words : Big bang; Doppler; Cosmic microwave background radiation(CMBR) The Himalayan Physics Department of Physics, PN Campus, Pokhara Nepal Physical Society, Western Regional Chapter Vol.2, No.2, May, 2011 Page: 67-70 Uploaded Date : 1 August, 2011

The evolution of the Robertson-Walker type universes consisting of radiating perfect fluid distribution coupled with zero-mass scalar field in which the gravitational parameter G varies with cosmic time t are studied. Unified descriptions of the early evolution of the universe consisting of different phases are investigated. The different properties of the cosmological solutions are discussed and the physical behaviour of the model universes during the radiation-dominated era and also during the big bang scenario are studied. Here we obtain models which are geometrically closed and are thereby ever expanding and evolve from rest from a non-singular hot origin with maximum (finite) energy density and temperature and a small minimum (non-zero) gravitational coupling G.

It has been recently shown that, since in general relativity (GR), given one time label t, one can choose any other time label t → t*= f(t), the pressure of a homogeneous and isotropic fluid is intrinsically zero (Mitra, Astrophys. Sp. Sc. 333, 351, 2011). Here we explore the physical reasons for the inevitability of this mathematical result. The essential reason is that the Weyl Postulate assumes that the test particles in a homogeneous and isotropic spacetime undergo pure geodesic motion without any collisions amongst themselves. Such an assumed absence of collisions corresponds to the absence of any intrinsic pressure. Accordingly, the “Big Bang Model” (BBM) which assumes that the cosmic fluid is not only continuous but also homogeneous and isotropic intrinsically corresponds to zero pressure and hence zero temperature. It can be seen that this result also follows from the relevant general relativistic first law of thermodynamics (Mitra, Found. Phys. 41, 1454, 2011). Therefore, the ideal BBM cannot describe the physical universe having pressure, temperature and radiation. Consequently, the physical universe may comprise matter distributed in discrete non-continuous lumpy fashion (as observed) rather than in the form of a homogeneous continuous fluid. The intrinsic absence of pressure in the “Big Bang Model” also rules out the concept of a “Dark Energy”.

What if our universe didn't emerge from nothing, but is a recycled version of one that went before? Anil Ananthaswamy investigates

We give a mathematically exact and physically faithful embedding of curved 4D cosmology in a flat 5D space, thereby enabling visualization of the big bang in a new and informative way. In fact, in unified theories of fields and particles with real extra dimensions, it is possible to dispense with the initial singularity.

A background-independent quantization of Universe near its Big Bang singularity is considered. Several conceptual issues are addressed in Heisenberg picture. (1) The observable spatial-geometry non-covariant characteristics of an empty-space expanding Universe are sampled by (quantized) distances \(Q=Q(t)\) between space-attached observers. (2) In Q(t) one of the Kato’s exceptional-point times \(t=\tau _{(EP)}\) is postulated real-valued. At such an instant the widely accepted “Big Bounce” regularization of the Big Bang singularity gets replaced by the full-fledged quantum degeneracy. Operators \(Q(\tau _{(EP)})\) acquire a non-diagonalizable Jordan-block structure. (3) During our “Eon” (i.e., at all \(t>\tau _{(EP)}\)) the observability status of operators Q(t) is guaranteed by their self-adjoint nature with respect to an ad hoc Hilbert-space metric \(\varTheta (t) \ne I\). (4) In adiabatic approximation the passage of the Universe through its \(t=\tau _{(EP)}\) singularity is interpreted as a quantum phase transition between the preceding and the present Eon.

Summary In spite of the paradigmatic status of the Big Bang model of the universe, the genesis of this idea has never been examined in detail. This paper investigates how the Belgian physicist and cosmologist Georges Lemaitre in 1931 arrived at the hypothesis that the universe had begun in a Big Bang, or what he called a ‘primeval atom’. Four years earlier, he had suggested a closed expanding model in which the universe slowly inflated from an equilibrium Einstein state, but in 1931 he advocated an abrupt beginning from an initial, superdense concentration of nuclear matter. Why did Lemaitre believe that the universe had a definite beginning a finite time ago? It turns out that the law of increase of entropy was one motivation, and that the existence of long-lived radioactive substances was another. Contrary to what is often stated, he most likely had the idea of an exploding universe before 1931. Among his chief inspirations to think about the origin of the universe, we draw attention to his persistent f...

We report a new area law in General Relativity. A future holographic screen is a hypersurface foliated by marginally trapped surfaces. We show that their area increases monotonically along the foliation. Future holographic screens can easily be found in collapsing stars and near a big crunch. Past holographic screens exist in any expanding universe and obey a similar theorem, yielding the first rigorous area law in big bang cosmology. Unlike event horizons, these objects can be identified at finite time and without reference to an asymptotic boundary. The Bousso bound is not used, but it naturally suggests a thermodynamic interpretation of our result., Comment: 4 pages, 2 figures; v3: typos fixed

This paper contains a detailed discussion on new cosmic solutions describing the early and late evolution of a universe that is filled with a kind of dark energy that may or may not satisfy the energy conditions. The main distinctive property of the resulting space-times is that they make to appear twice the single singular events predicted by the corresponding quintessential (phantom) models in a manner which can be made symmetric with respect to the origin of cosmic time. Thus, big bang and big rip singularity are shown to take place twice, one on the positive branch of time and the other on the negative one. We have also considered dark energy and phantom energy accretion onto black holes and wormholes in the context of these new cosmic solutions. It is seen that the space-times of these holes would then undergo swelling processes leading to big trip and big hole events taking place on distinct epochs along the evolution of the universe. In this way, the possibility is considered that the past and future be connected in a non-paradoxical manner in the universes described by means of the new symmetric solutions. © 2006 Elsevier B.V. All rights reserved., This work was supported by MEC under Research Project No. FIS2005-01181. The author benefited from discussions with C. Sigüenza, A. Rozas, S. Robles, J.A. Jiménez Madrid, S.D. Vereshchagin and A.V. Astashenok.

We study the accelerating expansion and the induced dark energy of the $5D$ Ricci-flat universe which is characterized by having a big bounce as opposed to a big bang. We show that the arbitrary function $\mu(t)$ contained in the $5D$ solutions can be rewritten in terms of the redshift $z$ as a new arbitrary function $f(z)$, and we find that there is a correspondence between this $f(z)$ and the potential $V(\phi)$ of the 4D quintessence models. Using this correspondence, the arbitrary function $f(z)$ and the $5D$ solution could be specified for a given form of the potential $V(\phi)$., Comment: ws-mpla.cls, 10 pages, 4 figures, to be published in MPLA, one reference added, four eps figures changed

The article discusses common misconceptions about the Big Bang theory and the expansion of the universe. The expansion of the universe may be the most important fact we have ever discovered about our origins. 75 years after its initial discovery, the expansion of the universe is still widely misunderstood. Because expansion is the basis of the big bang model, these misunderstandings are fundamental. Individual galaxies move around at random within clusters, but the clusters of galaxies are essentially at rest. The big bang was not an explosion in space; it was more like an explosion of space. It did not go off at a particular location and spread out from there into some imagined preexisting void. The rate at which the distance between galaxies increases follows a distinctive pattern discovered by American astronomer Edwin Hubble in 1929. According to Hubble's law, the universe does not expand at a single speed. The key to avoiding the misunderstandings is not to take the term "big bang" too literally.

The gravitational field of matter and that of antimatter could differ. This might be one signature of quantum gravity. We show that primordial Big Bang Nucleosynthesis restricts such a possibility., 11 pages, 3 figures. Reference added

The article focuses on whether the big bang was really the beginning of time. After string theory made its comeback as a theory of gravity in the 1980s, it was applied to black holes and cosmology. Conditions near the zero time of the big bang were so extreme that no one yet knows how to solve the equations. Nevertheless, string theorists have hazarded guesses about the pre-bang universe. Two popular models are floating around. The first, known as the pre-big bang scenario combines T-duality with the better-known symmetry of time reversal, whereby the equations of physics work equally well when applied backward and forward in time. The other leading model for the universe before the bang is the ekpyrotic ("conflagration") scenario. The pre-big bang and ekpyrotic scenarios share some common features. Both begin with a large, cold, nearly empty universe, and both share the problem of making the transition between the pre- and the post-bang phase. Mathematically, the main difference between the scenarios is the behavior of the dilaton field. Like the details of the inflationary phase, those of a possible pre-bangian epoch could have observable consequences, especially for the small variations observed in the cosmic microwave background temperature. Analysis of the microwave background is not the only way to verify these theories. The pre-big bang scenario should also produce a random background of gravitational waves in a range of frequencies that, though irrelevant for the microwave background, should be detectable by future gravitational-wave observatories. Moreover, because the pre-big bang and ekpyrotic scenarios involve changes in the dilaton field, which is coupled to the electromagnetic field, they would both lead to large-scale magnetic field fluctuations. Vestiges of these fluctuations might show up in galactic and intergalactic magnetic fields.

How did the Universe begin? Does time have a beginning and an end? Does space have edges? Einstein's theory of relativity replied to these ancient questions with three startling predictions: that the Universe is expanding from a Big Bang; that black holes so distort space and time that time stops at their edges; and that a dark energy could be pulling space apart, sending galaxies forever beyond the edge of the visible Universe. Observations confirm these remarkable predictions, the last finding only four years ago. Yet Einstein's legacy is incomplete. His theory raises – but cannot answer – three profound questions: What powered the Big Bang? What happens to space, time and matter at the edge of a black hole? and, What is the mysterious dark energy pulling the Universe apart? The Beyond Einstein program within NASA's office of space science aims to answer these questions, employing a series of missions linked by powerful new technologies and complementary approaches to shared science goals. The program also serves as a potent force with which to enhance science education and science literacy.

Despite its great popularity, the Big Bang framework for cosmology faces growing contradictions with observation. The Big Bang theory requires three hypothetical entities-the inflation field, nonbaryonic (dark) matter, and the dark energy field-to overcome gross contradictions of theory and observation. Yet, no evidence has ever confirmed the existence of any of these three hypothetical entities. The predictions of the theory for the abundance of /sup 4/He, /sup 7/Li, and D are more than 7/spl sigma/ from the data for any assumed density of baryons and the probability of the theory fitting the data is less than 10/sup -14/. Observations of voids in the distribution of galaxies that are in excess of 100 Mpc in diameter, combined with observed low streaming velocities of galaxies, imply an age for these structure that is at least triple and more likely six times the hypothesized time since the Big Bang. Big Bang predictions for the anisotropy of the microwave background, which now involve seven or more free parameters, still are excluded by the data at the 2/spl sigma/ level. The observed preferred direction in the background anisotropy completely contradicts Big Bang assumptions. In contrast, the predictions of plasma cosmology have been strengthened by new observations, including evidence for the stellar origin of the light elements, the plasma origin of large-scale structures, and the origin of the cosmic microwave background in a "radio fog" of dense plasma filaments. This review of the evidence shows that the time has come, and indeed has long since come, to abandon the Big Bang as the primary model of cosmology.

The big bounce singularity of a simple 5D cosmological model is studied. Contrary to the standard big bang space-time singularity, this big bounce singularity is found to be an event horizon at which the scale factor and the mass density of the universe are finite, while the pressure undergoes a sudden transition from negative infinity to positive infinity. By using coordinate transformation it is also shown that before the bounce the universe contracts deflationary, and the universe has been existed, according to the proper-time, for an infinitely long time.

In a recent paper [Phys. Rev. D{\bf 85}, 023528 (2012)] the authors proposed a generalized Born-Infeld electrodynamics coupled to general relativity which produces a nonsingular bouncing universe. For a magnetic universe the resulting cosmic evolution inevitably interpolates between asymptotic de Sitter states. Here we shall show that (i) the above theory does not have the standard weak field Maxwell limit, (ii) a sudden curvature singularity -- not better than the big bang -- arises, (iii) the speed of sound squared is a negative quantity signaling instability against small perturbations of the background energy density, and that (iv) the conclusion about the inevitability of the asymptotic vacuum regime in a magnetic universe is wrong., 6 pages, 6 eps figures, here we have shown that Born-Infeld magnetic universes either are singular or are unstable against small perturbations of the background energy density or both

The present accelerated expansion of the universe has enriched the list of possible scenarios for its fate, singular or not. In this paper a unifying framework for analyzing such behaviors is proposed, based on generalized power and asymptotic expansions of the barotropic index $w$, or equivalently of the deceleration parameter $q$, in terms of the time coordinate. Besides well known singular and non-singular future behaviors, other types of strong singularities appear around the phantom divide in flat models, with features similar to those of big rip or big bang/crunch, which we have dubbed grand rip and grand bang/crunch respectively, since energy density and pressure diverge faster than $t^{-2}$ in coordinate time. In addition to this, the scale factor does not admit convergent generalized power series around these singularities with a finite number of terms with negative powers., 19 pages, 2 figures. Typos amended

We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze - a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple "crossover model" without a big bang singularity. In the infinite past space-time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy dominated universe., Comment: new material on absence of singularity, 9 pages, 1 figure

The Born-Infeld determinantal gravity has been recently proposed as a way to smooth the Big Bang singularity. This theory is formulated on the Weitzenbock space-time and the teleparallel representation is used instead of the standard Riemannian representation. We find that although this theory is shown to be singularity-free for certain region of the parameter space in which the divergence of the Hubble rate at the high energy regime is substituted by a de-Sitter stage or a bounce in a Friedmann-Lemaitre-Robertson-Walker universe, cosmological singularities such as Big Rip, Big Bang, Big Freeze, and Sudden singularities can emerge in other regions of the configuration space of the theory. We also show that all these singular events exist even though the Universe is filled with a perfect fluid with a constant equation of state., 6 pages, 2 figures, RevTex4-1. A minor change. Version accepted in PRD

The sciences and the humanities, including theology, form an epistemic hierarchy that ensures both constraint and irreducibility. At the same time, theological methodology is analogous to scientific methodology, though with several important differences. This model of interaction between science and theology can be seen illustrated in a consideration of the relation between contemporary cosmology (Big Bang cosmology, cosmic inflation, and quantum cosmology) and Christian systematic and natural theology. In light of developments in cosmology, the question of origins has become theologically less interesting than that of the cosmic evolution of a contingent universe.

Using a combination of algebraic and computer work, we embed the standard spatially flat four-dimensional cosmological models and inflationary models in a flat five-dimensional space and thereby obtain pictures of the big bang. Such embeddings have important implications for astrophysics, notably in regard to particle masses and background radiation. This approach can be extended to superstrings, supergravity, and membrane theory.

We consider the dynamics of a spatially flat universe dominated by a self-interacting nonminimally coupled scalar field. The structure of the phase space and complete phase portraits for the conformal coupling case are given. It is shown that the nonminimal coupling modifies drastically the dynamics of the universe. New cosmological behaviors are identified, including superinflation (H > 0), avoidance of big bang singularities through classical birth of the universe from empty Minkowski space, and spontaneous entry into and exit from inflation. The relevance of this model to the description of quintessence is discussed.

Every open FRW universe can be completely foliated by spacelike slices of finite volume, each intersecting every fundamental worldline. The volumes tend to zero in the past, suggesting a point-like big bang. Embedding diagrams confirm this. How finite slices can contain an infinite amount of matter is explained by time-reversed gravitational collapse.

Cosmology, the study of the universe, has a past, which is reviewed here. The standard model—the Big Bang, or the hot, dense early universe that is still expanding—is based on observations that are basically consistent but which require additional input to improve the agreement. Out of the early universe came the galaxies and stars that shine today. The future of the universe depends on the density of matter: too much mass leads to the Big Crunch; too little leads to eternal expans ion and cooling. The dark-matter problem prevents us from knowing which will be the fate of the universe. Thelimits of what may be called “scientific” are addressed.