Philosophy Of The Cosmos - The Expansion Of Space
As I understand it (standard caveat) space continues to expand, so generally speaking, the distance between two points is increasing over time. Further, there is evidence for this in the change in position of the galaxies.
My question is, isn't this expansion going to be more significant at the nuclear level?
If the distance between two galaxies doubles, big deal. But if the distance between two atoms doubles, or the distance between nuclei and electrons doubles, isn't that more significant, in the sense that the trend will ultimately reduce the Universe to sub-atomic particle soup quicker than some of the other scenarios we have discussed?
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Interesting point. It's something we'd have to take into account in calculating what will happen to dispersed subatomic particles. But it's not a problem for subatomic particles in ordinary matter, because the effect you're talking about is swamped by the nuclear and electromagnetic forces acting on them. In ordinary matter, these forces are huge.
The difference for galaxies is that the nuclear forces between galaxies are negligible because of the distances involved, and the electromagnetic forces between galaxies are negligible because galaxies as a whole are electrically neutral, so that leaves gravity as the only force counteracting the expansion of space. And gravity is very weak. So it's in this context that we can see the expansion of space most clearly.