Bigger Rip with no dark energy

By studying a modified Friedmann equation which arises in an extension of general relativity which accommodates a time-dependent fundamental length L(t), we consider 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 simple pressure–energy relationship. Data on supernovae restrict the time from the present until the Rip to be longer than the current age of the Universe.