EXPANSION OF THE UNIVERSE

The expansion of the universe is the increase in distance between any two gravitationally unbound parts of the observable universe with time. It is an intrinsic expansion whereby the scale of space changes. The universe does not expand "into" anything and does not require space to exist "outside" it. This expansion involves neither space nor objects in space "moving" in a traditional sense, but rather it is the metric (which governs the size and geometry of spacetime itself) that changes in scale. While objects within space cannot travel faster than light, this limitation does not apply to the effects of changes in the metric itself. Objects that recede beyond the event horizon will eventually become unobservable, as no new light from them will be capable of overcoming the universe's expansion, limiting the size of our observable universe. If the expansion has certain characteristics, parts of the universe will never be observable, no matter how long the observer waits for the light from those regions to arrive. The most distant galaxies actually move away from us faster than the speed of light. This high-speed galactic exodus breaks no laws of physics, for it is the universe itself that is expanding- the very spacetime fabric upon which all of existence is stitched.