## Age of the UniverseA variety of reasonably independent methods for determining the age of the universe are available, but none of course are a direct measurement: each rely on certain modeling assumptions. Data in the figure below are only representative of the numerous results in the literature. Many published results have centered on the use of stellar evolution theory, finding the oldest stars (generally in metal poor globular clusters) to obtain a lower limit on the age, and then assuming a cluster formation time in order to achieve an estimate of t Ages obtained through the use of cosmological models are represented by the CMB results of Boomerang, WMAP and Planck, as well as an early result from the Supernova Cosmology Project (Perlmutter et al. 1999). The SNIa result comes from application of the FLRW magnitude-redshift relation to derive 2-d confidence regions within the Ω
PNG (480 x 507 px) 11Kb PNG (1024 x 1081 px) 27Kb PNG (2048 x 2162 px) 60Kb PDF 56Kb (Vector Art) SVG 69Kb (Vector Art) EPS 287Kb (Vector Art) Lower limits on the age of our universe, t
_{0}, may be obtained by estimating the ages of the oldest observable objects. Ages determined in this fashion tend to rely on stellar evolution theory, rather than an assumption of a cosmological model such as ΛCDM. Two representative values are shown, based on cool white dwarfs and the oldest stars in globular clusters, but note that results obtained in this fashion have produced a range of estimates between roughly 12-16 Gyr (Spergel et al. 2003). Within Big Bang cosmologies, t_{0} refers to the time interval since the Big Bang up through the present. The computed value is somewhat dependent of the exact cosmological model assumptions. Within the standard ΛCDM model framework, CMB measurements, combined with BAO and SNIa measurements of the expansion rate, are presently in agreement and tightly constrained. The gray vertical line, representing the weighted average of WMAP and Planck data points, is positioned at t_{0} = 13.785 Gyr.Contributed by the NASA / LAMBDA Archive Team. |