The expansion of space is not a physical movement of galaxies through space. Rather, it is a change in the fabric of space itself. As the universe expands, the distance between any two points in space increases. This means that even if two galaxies are not moving relative to each other, the distance between them will still increase over time.

The expansion of space is often described as the “fabric of space being stretched.” This is a good analogy, but it is important to remember that space is not a physical object like a piece of cloth. It is a mathematical concept that describes the way that objects are related to each other.

The expansion of space is a very slow process. It is so slow that it is not possible to see galaxies moving away from each other faster than their current expansion rate. However, we can see the effects of the expansion of space by looking at the redshift of distant galaxies. Redshift is a phenomenon that occurs when light from a distant object is stretched, causing the light to shift towards the red end of the spectrum. The amount of redshift is directly proportional to the distance to the object.

The redshift of distant galaxies tells us that the universe is expanding. The more distant a galaxy is, the faster it is moving away from us. This is because the expansion of space is accelerating. The acceleration of the expansion of space is thought to be caused by a mysterious force called dark energy.

Dark energy is one of the most important unsolved mysteries in cosmology. We do not know what dark energy is, but we know that it makes up about 70% of the universe. Dark energy is thought to be responsible for the acceleration of the expansion of space, and it could play a role in the ultimate fate of the universe.