Related papers: Decelerating universes older than their Hubble tim…
We investigate the validity of cosmological models with an oscillating scale factor in relation to late-time cosmological observations. We show that these models not only meet the required late time observational constraints but can also…
Inflationary cosmology predicts that the particle horizon should be generically much bigger than the present-day Hubble radius, $1/H_0$. This implies a special regime of super-Hubble scale energy density fluctuations imprinted on the cosmic…
Observations in the Hubble Deep Fields have been used to study the evolution of galaxy morphology over time. The majority of galaxies with z < 1 are seen to be disk like, whereas most objects with z > 2 appear to be either chaotic or…
A Universe with finite age also has a finite causal scale. Larger scales can not affect our local measurements or modeling, but far away locations could have different cosmological parameters. The size of our causal Universe depends on the…
The effect of the expanding universe on planetary motion is considered to first order in the Hubble constant H. Orbital elements are shown to be unaffected, but there is a small change in the connection between planetary proper time and…
The analysis of the data from the distant supernovae (A.Riess et al, Astron.J. {\bf 116}, 1009, (1988)) for acceleration of the expending Universe from the viewpoint of the gravitation equations proposed by one of the authors (Phys.Lett.…
A recently published paper by Nielsen, Guffanti and Sarkar argues that the evidence for cosmic acceleration is marginal and that a coasting universe - the Milne Universe - fits the same supernovae data in a Hubble diagram nearly as well.…
By coupling observations of type Ia supernovae with results obtained from the best available numerical models we constrain the Hubble constant, independently of any external calibrators. We find an absolute lower limit of Ho > 50 km/s/Mpc.…
A possible slowing down of the cosmic expansion is investigated through a cosmographic approach. By expanding the luminosity distance to fourth order and fitting the SN Ia data from the most recent compilations (Union, Constitution and…
Although big bang cosmology effectively models even the most puzzling observational data, it offers no insight into why the cosmological expansion should occur at all. In this paper it is suggested that a finite Universe poses particular…
We investigate what current cosmological data tells us about the cosmological expansion rate in a model independent way. Specifically, we study if the expansion was decelerating at high redshifts and is accelerating now, without referring…
Taking into account only luminous objects, the kinematics of clusters of galaxies, galaxies and their interior, require a much higher mass than the luminous one to explain the observations. This situation has provoked more than 30 years of…
The cosmological constant, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its…
Over the past decade, supernovae have emerged as some of the most powerful tools for measuring extragalactic distances. A well developed physical understanding of type II supernovae allow them to be used to measure distances independent of…
The recent observations of type Ia supernovae strongly support that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friedmann equation. Instead of a linear…
One of the most important discoveries in modern cosmology is cosmic acceleration. However, we find that today's universe could decelerate in the statistically preferred Chevallier-Polarski-Linder (CPL) scenario over the $\Lambda$CDM model…
The fundamental paradox of the incompatibility of the observed large-scale uniformity of the Universe with the fact that the age of the Universe is finite is overcome by the introduction of an initial a period of superluminal expansion of…
An accurate determination of the Hubble constant remains a puzzle in observational cosmology. The possibility of a new physics has emerged with a significant tension between the current expansion rate of our Universe measured from the…
An impressive bulk of multiple astronomical observations indicates that there are plenty of objects in the universe with the age which cannot be explained by the conventional theory. A model is considered which successfully describes all…
In this article, we introduce an innovative parametric representation of the Hubble parameter, providing a model-independent means to explore the dynamics of an accelerating cosmos. The model's parameters are rigorously constrained through…