We classify the future of the universe for general cosmological models including matter and dark energy. If the equation of state of dark energy is less then −1, the age of the universe becomes finite. We compute the rest of the age of the universe for such universe models. The behaviour of the future growth of matter density perturbation is also studied. We find that the collapse of spherical ...

Webb et al. [2] experimental results on the fine strucutre “constant ” variation with the age of the Universe, is here analized. By using the experimental data on the fine-structure “constant ”’s variation with the age of the Universe, and Dirac’s LNH (Large Number Hypothesis), we find how should vary the total number of nucleons in the Universe, the speed of light, Newton’s gravitational “cons...

In the past 40 years a considerable effort has been focused in determining the age of the Universe at zero redshift using several stellar clocks. In this review I will describe the best theoretical methods to determine the age of the oldest Galactic Globular Clusters (GC). I will also argue that a more accurate age determination may come from passively evolving high-redshift ellipticals. In par...

For the past 15 years most astronomers have assumed that 95% of the Universe was in some mysterious form of cold dark matter. They also assumed that the cosmological constant, ΩΛ, was Einstein’s biggest blunder and could be ignored. However, recent measurements of the cosmic microwave background combined with other cosmological observations strongly suggest that 75% of the Universe is made of c...

The dominant systematic uncertainty in the age determination of galactic globular clusters is depth convection envelope stars. This parameter partially degenerate with metallicity which turn age. However, if metal content, distance and extinction are known, position morphology red giant branch a color-magnitude diagram mostly sensitive to value convective envelope. Therefore, using external, pr...

An overview is presented of the current situation regarding radioactive dating of the matter of which our Galaxy is comprised. A firm lower bound on the age from nuclear chronometers of approximately 9-10 Gyr is entirely consistent with age determinations from globular clusters and white dwarf cooling histories. The reasonable assumption of an approximately uniform nucleosynthesis rate yields a...

The National Academy of Sciences (NAS) sponsored a 2-day colloquium titled ‘‘The Age of the Universe, Dark Matter, and Structure Formation,’’ March 21–23, 1997, at the Arnold and Mabel Beckman Center of the National Academies of Science and Engineering in Irvine, CA. Eighty-eight cosmologists who represented a wide range of individual scientific disciplines attended the colloquium. Also present...