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- Lawrence M . Krauss, Brian C. Chaboyer
- Science
- 2003

Recent observations of stellar globular clusters in the Milky Way Galaxy, combined with revised ranges of parameters in stellar evolution codes and new estimates of the earliest epoch of globular cluster formation, result in a 95% confidence level lower limit on the age of the Universe of 11.2 billion years. This age is inconsistent with the expansion age… (More)

SUMMARY A diverse set of observations now compellingly suggest that Universe possesses a nonzero cosmological constant. In the context of quantum-field theory a cosmological constant corresponds to the energy density of the vacuum, and the wanted value for the cosmological constant corresponds to a very tiny vacuum energy density. We discuss future… (More)

We review five independent techniques which are used to set the distance scale to globular clusters, including subdwarf main sequence fitting utilizing the recent Hipparcos parallax catalogue. These data together all indicate that globular clusters are farther away than previously believed, implying a reduction in age estimates. We now adopt a best fit… (More)

The flat matter dominated Universe that dominated cosmological model building for much of the past 20 years does not correspond to the Universe in which we live. This has profound implications both for our understanding of dark matter, and also for our understanding of the future of the Universe. I review recent developments here and present best fits for… (More)

The lower limit on the age of the universe derived from globular cluster dating techniques, which previously strongly motivated a non-zero cosmological constant, has now been dramatically reduced, allowing consistency for a flat matter dominated universe with a Hubble Constant, H0 ≤ 66kms−1Mpc−1. The case for an open universe versus a flat universe with… (More)

- Craig J. Copi, Adam N. Davis, Lawrence M . Krauss
- Physical review letters
- 2004

Big bang nucleosynthesis can provide, via constraints on the expansion rate at that time, limits on possible variations in Newton's constant, G. The original analyses were performed before an independent measurement of the baryon-to-photon ratio from the cosmic microwave background was available. Combining this with recent measurements of the primordial… (More)

- Lawrence M . Krauss
- Science
- 1990

We describe in detail how perturbations due to the planets can cause a subpopulation of WIMPs captured by scattering in surface layers of the Sun to evolve to have orbits that no longer intersect the Sun. We argue that such WIMPs, if their orbit has a semi-major axis less than 1/2 of Jupiter’s, can persist in the solar system for cosmological timescales.… (More)

We investigate the redshift accuracy of Type Ia supernova and cluster number count surveys required for the redshift uncertainties not to contribute appreciably to the dark energy parameter error budget. For the Supernova/ Acceleration Probe experiment, we find that without the assistance of ground-based measurements individual supernova redshifts would… (More)

A charge operator is constructed for a quantum field theory with an abelian discrete gauge symmetry, and a non–local order parameter is formulated that specifies how the gauge symmetry is realized. If the discrete gauge symmetry is manifest, then the charge inside a large region can be detected at the boundary of the region, even in a theory with no… (More)