The expansion of the universe and the principles of special relativity are not contradictory. In fact, the theory of general relativity, which extends and encompasses special relativity, provides a framework for understanding the expansion of the universe.
According to general relativity, the fabric of spacetime itself can stretch and expand. The expansion of the universe is described by the Hubble's law, which states that galaxies are moving away from each other, and the rate of their separation is proportional to their distance. This expansion is not due to galaxies moving through space but rather the expansion of space itself.
Special relativity deals with objects moving within spacetime, considering their relative velocities and the effects of time dilation and length contraction. However, special relativity does not account for the large-scale dynamics of the entire universe.
On cosmological scales, general relativity provides a description of the expansion of the universe. It incorporates the notion that space itself can expand, allowing galaxies and clusters of galaxies to move apart. This expansion is not constrained by the speed of light limit in special relativity because it is the very fabric of spacetime that is stretching.
It's important to note that the expansion of the universe is not the result of objects moving through space at speeds greater than light. Instead, it is the expansion of the space between objects. The expansion rate of the universe, known as the Hubble constant, has been measured and is found to be accelerating. This acceleration is attributed to a mysterious form of energy called dark energy, which is thought to permeate space and drive the accelerated expansion.
In summary, while special relativity sets a limit on the speed at which objects can move through space, the expansion of the universe is a different phenomenon, governed by the principles of general relativity and the dynamics of spacetime itself.