Contrary to popular belief, there is as yet no convincing evidence that the Universe has a density near the critical value required for closure. Indeed, a low-density Universe is favoured by many of the observations. Cosmologists should therefore keep an open mind about this question until it is settled by empirical data. © 1994 Nature Publishing Group.
Coles, P., & Ellis, G. (1994). The case for an open Universe. Nature. https://doi.org/10.1038/370609a0