According to our current understanding of the universe, the expansion of space itself can cause galaxies, clusters of galaxies, and other cosmic structures to move away from each other. This phenomenon is often referred to as the "expansion of the universe." It is important to note that this expansion does not violate Einstein's theory of relativity or the principle that nothing can travel faster than the speed of light within space.
When we say that the universe is expanding faster than light, it means that the rate at which the space between two distant objects is increasing exceeds the speed of light. However, this does not imply that objects within space are moving through space faster than light.
The key point to understand is that the expansion of the universe is not a motion through space but rather a stretching of space itself. It's comparable to the expansion of a balloon: as the balloon inflates, the dots drawn on it move away from each other, but no dot is actually moving through the surface of the balloon.
In the case of the universe, the expansion of space itself is responsible for the apparent motion of galaxies away from each other. The fabric of space itself is expanding, causing the distances between galaxies to increase over time. Since this expansion happens on a cosmic scale and involves the fabric of space itself, it is not constrained by the limitations of objects moving within space.
In summary, while objects cannot move through space faster than light, the expansion of the universe is a different phenomenon where space itself is stretching, allowing for apparent faster-than-light expansion on large scales.