The Cosmic Microwave Background (CMB) anisotropies align with cosmological models that include dark matter.

The Cosmic Microwave Background is the faint afterglow of the Big Bang, a snapshot of the universe when it was only about 380,000 years old. Tiny temperature fluctuations, or anisotropies, in the CMB reveal the initial density variations that eventually grew into the large-scale structures we see today, like galaxies and galaxy clusters. Precise measurements of these fluctuations by missions like WMAP and Planck provide a cosmic blueprint. Cosmological models attempting to explain these CMB patterns require a specific ratio of ordinary matter, dark matter, and dark energy to accurately reproduce the observed peaks and troughs. Without dark matter, the gravitational wells needed to initiate the formation of structures would not have been strong enough, and the universe would look drastically different from what the CMB reveals. The consistency between CMB observations and dark matter models is a powerful confirmation.