Final answer:
The density of dark matter is approximately 1 to 2 × 10^-27 kg/m³, or about 10 to 20% of critical density, and together with normal matter, it makes up about 31.5% of the universe's total density.
Step-by-step explanation:
When it comes to understanding the cosmos, one important aspect that intrigues scientists is the density of dark matter. By examining the mass of galaxies and adding estimates of dark matter, scientists have deduced that the average density is approximately 1 to 2 × 10-27 kg/m³, which corresponds to about 10 to 20% of the critical density. These figures, however, are insufficient to halt the cosmic expansion.
According to the standard model of the universe, the combined mass density of ordinary matter and dark matter equals roughly 0.3 times the critical density. Additionally, when analyzing the Planck data, it reveals that ordinary matter constitutes 4.9% of the total density, while dark matter and normal matter together make up 31.5% of the total density. Even though a significant portion of dark matter resides outside the boundaries of galaxies, the total mass attributed to dark matter does not exceed about 30% of the critical density.