Answers are grounded in this paper and cite their sources.
We investigate the impact of a nonstandard time evolution of the dark matter component on current cosmological bounds from cosmic microwave background (CMB) anisotropies. We found that a less than 0.1% variation in the effective dark matter equation of state wdm can drastically change current CMB bounds on the matter density, the Hubble parameter and the age of the Universe. A flat universe without dark energy could provide an excellent fit to current CMB data, providing that wdm~-10^-2.
No takes yet. Share an insight, caveat, or question.
Calabrese et al. (2009) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: