# The cosmological constant is back

@article{Krauss1995TheCC, title={The cosmological constant is back}, author={Lawrence Krauss and Michael S. Turner}, journal={General Relativity and Gravitation}, year={1995}, volume={27}, pages={1137-1144} }

A diverse set of observations now compellingly suggest that the 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 favored value for the cosmological constant corresponds to a very tiny vacuum energy density. We discuss future observational tests for a cosmological constant as well as the fundamental theoretical challenges — and opportunities — that this poses for particle…

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