Enhanced Big Rip without Conventional Dark Energy

Abstract

A modified Friedmann equation which arises in an extension of general relativity which accommodates a time-dependent fundamental length $L(t)$ leads to cosmological models where the scale factor diverges with an essential singularity at a finite future time. Such models have no dark energy in the conventional sense of energy possessing a truly simple pressure-energy relationship. Data on supernovae restrict the time from the present until the Rip to be generically longer than the current age of the Universe.

11 pages, 2 figures. Talk at 20th IAP Workshop on Cosmic Microwave Background, l'Institut Astrophysique de Paris, June 28 - July 2, 2004