The expansion of the universe refers to the ongoing process where space itself is stretching, causing galaxies to move away from each other. This idea stems from observations indicating that galaxies, on average, are moving away from each other at speeds proportional to their distances. This concept is encapsulated within the framework of the Big Bang theory.
The expansion of the universe isn’t galaxies moving through space; rather, it’s space itself stretching, carrying galaxies along with it. This expansion isn’t just happening at the edges of the universe; it’s happening everywhere. This expansion is described by Hubble’s Law, which states that the velocity at which a galaxy is moving away from us is proportional to its distance.
This phenomenon doesn’t mean galaxies are flying apart from a central point; rather, it’s the metric of space itself stretching, resulting in the apparent motion of galaxies away from each other.
