We discuss the cosmological degeneracy between the age of the Universe, the Hubble parameter and the effective number of relativistic particles Neff . We show that independent determinations of the Hubble parameter H(z) such as those recently provided by [1], combined with other cosmological data sets can provide the most stringent constraints on Neff , yielding Neff = 3.7 +1.1 −1.2 at 95% conf...

A favored interpretation of recent microlensing measurements towards the Large Magellanic Cloud implies that a large fraction (i.e. 10–50%) of the mass of the galactic dark halo is composed of white dwarfs. However, a ground based search by Liebert, Dahn & Monet (1988; LDM) and a recent search of the Hubble Deep Field by Flynn, Gould & Bahcall(1996) did not detect a substantial dark halo popula...

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 Ω mat = ρ mat /ρ C takes on all values between zero and infinity in conformal gravity, nonetheless it is of order one (but not identically equal to one) for half a Hubble time to thus naturally expl...

It is shown that density fluctuations obey a scaling law in an open Friedmann universe. In a flat universe, the fluctuations are not scale-invariant. We compute the growth rate of adiabatic scale-invariant density fluctuations in flat, open and inflationary universes. We find that, given a sufficiently long time, the density perturbations decay away in the Einstein-de-Sitter universe. On the co...

We have reanalyzed the age of the universe problem under the assumption that the lower limit on the age of the globular clusters is 11Gyr, as predicted by the recent Hipparcos data. We find that the globular cluster and the expansion ages in a standard λ = 0 universe are consistent only if the present value H0 of the Hubble constant is ≤ 60kmsMpc. If H0 > 60kms Mpc some kind of modification of ...

A new model of the observed universe, using solutions to the full Einstein equations, is developed from the hypothesis that our observable universe is an underdense bubble, with an internally inhomogeneous fractal bubble distribution of bound matter systems, in a spatially flat bulk universe. It is argued on the basis of primordial inflation and resulting structure formation, that the clocks of...