How does dark matter relate to the expansion of the universe?

The Newton Law of Gravitation states that the force of gravity weakens as the square of the distance, meaning that the farther away you are, the weaker the force of gravity; conversely, the closer an object is to the center of mass, the faster it moves around it. Using the solar system as an example, the orbital periods of all the planets increase as we move from Mercury towards Neptune. These findings and the observed irregularities in the orbits of objects around galaxies sparked the debate over dark matter.

On a much grander scale, however, this is not the case. What scientists observed was that, in the majority of galaxies, objects at the periphery were moving nearly as fast as those within, suggesting that some sort of force was at work on those objects, a force they named Dark Matter.

The universe is made up of two main components: Dark Matter, which makes up 25% of the total, and Dark Energy, which is mysterious and accounts for the remaining 5% of the universe. The expansion of the universe is caused by Dark Energy. Until recently, scientists thought that the universe would eventually stop expanding and contract again into a singularity, but recent observations have predicted that the universe is expanding continuously due to this mysterious energy, which they have named Dark Energy and which accounts for almost 68% of the universe.

Due to its contribution to the total mass density, dark matter's gravitational pull on the universe influences the dynamics of cosmic expansion that are seen in the universe and influences the rate of expansion.