The universe is expanding, causing galaxies to move away from each other, but this expansion does not affect smaller systems of particles due to the dominance of local forces such as gravity and electromagnetic forces. While dark energy is theorized to drive the accelerated expansion of the universe on a cosmic scale, it does not influence the interactions between closely spaced particles. The distinction between intergalactic space, which is homogeneous, and local space, which is not, is crucial in understanding how expansion operates differently at various scales.
PREREQUISITESAstronomers, physicists, cosmologists, and anyone interested in the fundamental forces governing the universe's expansion and the interactions of particles within it.
There is no "force" driving the expansion, nor is dark energy needed. Dark energy is thought to drive the recent accelerated expansion of the universe.anorlunda said:Dark energy forces act on the universe at very large time scales and make it expand.
At short distances, gravity, electrical and other atomic forces are much stronger and they overwhelm the dark energy force.
Therefore, things far apart expand, things close together don't.
But there is a difference between intergalactic space and local space: the former is homogeneous and the latter is not. The geometry of space dictates the cosmology.ggolu2 said:Space is expanding and there is no difference between intergalactic space and space in which we are present right. So why would you not agree on the fact that we are also 'expanding'?