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I start by defining the cosmological parameters $H_0, \Omega_m$ and $\Omega_\Lambda$. Then I show how the age of the universe depends on them, followed by the evolution of the scale parameter of the universe for various values of the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Palash B. Pal

We compare and combine likelihood functions of the cosmological parameters Omega_m, h and sigma_8, from peculiar velocities, CMB and type Ia supernovae. These three data sets directly probe the mass in the Universe, without the need to…

Astrophysics · Physics 2009-10-31 S. L. Bridle , I. Zehavi , A. Dekel , O. Lahav , M. P. Hobson , A. N. Lasenby

We show that within the cosmology associated with conformal gravity the age of the universe is given as $1/H_0$, to thus overcome the current cosmological age crisis. We show that while the parameter $\Omega_{mat} = \rho_{mat} / \rho_C$…

Astrophysics · Physics 2007-05-23 Philip D. Mannheim

The cosmological parameters that I will emphasize are the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the age of the universe $t_0$, the average matter density $\Omega_m$, the baryonic matter density $\Omega_b$, the neutrino…

Astrophysics · Physics 2007-05-23 Joel R. Primack

The cosmological parameters that I emphasize are the age of the universe $t_0$, the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the average matter density $\Omega_m$, the baryonic matter density $\Omega_b$, the neutrino…

Astrophysics · Physics 2009-10-31 Joel R. Primack

In this paper, time variable cosmological constant, dubbed {\it age cosmological constant}, is investigated motivated by the fact: any cosmological length scale and time scale can introduce a cosmological constant or vacuum energy density…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-28 Lixin Xu , Jianbo Lu , Wenbo Li

Cosmological parameters are constrained by a wide variety of observations. We examine the concordance diagram for modern measurements of the Hubble constant, the shape parameter from large scale structure, the cluster baryon fraction, and…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-22 Stacy McGaugh

We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble…

Astrophysics · Physics 2014-11-18 Daniel G. Figueroa , Licia Verde , Raul Jimenez

We have shown that the varying physical constant model is consistent with the recently published variational approach wherein Einstein equations are modified to include the variation of the speed of light c, gravitational constant G and…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-21 Rajendra P. Gupta

The inflation-free solution of problems of the modern cosmology (horizon, cosmic initial data, Planck era, arrow of time, singularity,homogeneity, and so on) is considered in the conformal-invariant unified theory given in the space with…

General Relativity and Quantum Cosmology · Physics 2014-11-17 V. Pervushin , D. Proskurin

Most cosmological parameter estimations are based on the same set of observations and are therefore not independent. Here, we test the consistency of parameter estimations using a combination of large-scale structure and supernovae data,…

Astrophysics · Physics 2009-11-10 Carolina Odman , Mike Hobson , Anthony Lasenby , Alessandro Melchiorri

The details of the CMB power spectrum are being revealed through the combined efforts of the world's CMBologists. The current data set constrains several cosmological parameters. A combination with other (non-lensing) constraints yields…

Astrophysics · Physics 2007-05-23 Charles H. Lineweaver

The observed value of the cosmological constant corresponds to a time scale that is very close to the current conformal age of the universe. Here we show that this is not a coincidence but is caused by a periodic boundary condition, which…

General Physics · Physics 2019-09-25 Jan Stenflo

The age of the universe in the Big Bang model can be calculated from three parameters: Hubble's constant, h; the mass density of the universe, Omega_m; and the cosmological constant, Omega_lambda. Recent observations of the cosmic microwave…

Astrophysics · Physics 2009-06-16 Charles H. Lineweaver

The first section discusses a recalibration of the luminosity-linewidth technique and its use in a determination of H_0. The recalibration introduces (i) new cluster calibration data, (ii) new corrections for reddening as a function of…

Astrophysics · Physics 2007-05-23 R. Brent Tully

The ages of the oldest stellar objects in our galaxy provide an independent test of the current cosmological model as they give a lower limit to the age of the Universe. Recent accurate parallaxes by the Gaia space mission, accurate…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-01 Raul Jimenez , Andrea Cimatti , Licia Verde , Michele Moresco , Benjamin Wandelt

Determinations of the main cosmological parameters are reviewed and the implications for cold dark matter discussed. There is no longer an age problem for an $\Omega_o = 1, \Lambda = 0$ model and, if anything, there is now an age problem…

Astrophysics · Physics 2007-05-23 M. Rowan-Robinson

Rapid progress has been made recently toward the measurement of cosmological parameters. Still, there are areas remaining where future progress will be relatively slow and difficult, and where further attention is needed. In this review,…

Astrophysics · Physics 2009-10-31 Wendy L. Freedman

The Cosmic Defect theory has been confronted with four observational constraints: primordial nuclear species abundances emerging from the big bang nucleosynthesis; large scale structure formation in the universe; cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 N. Radicella , M. Sereno , A. Tartaglia

I discuss the Hubble parameter $H_0$, the age of the universe $t_0$, the density $\Omega_0$, and the cosmological constant $\Lambda$. To focus the discussion, I concentrate on the issue of the value of the density $\Omega_0$ in currently…

Astrophysics · Physics 2016-08-30 Joel R. Primack
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