If there’s no such thing as absolute distance, then how can you say that a metre bar (and the metre) is larger than it used to be?
If distance is relative, and matter isn’t expanding relative to anything else, then matter isn’t expanding.
We ultimately define distance in terms of c, and the fundamental forces agree with this. We do not observe atoms expanding, but we do observe the space between galaxies expanding. Presumably the space we occupy is also expanding, but it’s such a small effect as to be irrelevant.
Back to my original question, is the boundary between irrelevantly small and detectable above or below the galactic scale?
I think the trouble is also partly based around thinking of then universe as a volume, which implies a centre. And that’s where this analogy falls apart.
Because everything is expanding from everything, there is no centre. YOU are always centre. So you are “expanding” but you don’t change volume.
This is why I keep saying space isn’t getting bigger, distance is.
It’s not that a sheet of paper becoming bigger so the grid paper becomes larger,. It’s changing it’s distance of something, not it’s size and shape.
We don’t observe galaxies getting bigger. We observe them constantly moving away from us. Even. When they’re moving to us, but it’s done at a slower pace than expected. The further away you are, the faster you move away. And it’s a universal constant of 73km/s/Mpsc.
Notice that is a speed per distance. It’s not saying space is getting bigger, it’s saying things are moving faster away from you the further you go away.
The universe isn’t expanding like a loaf of bread because it has a volume. It’s expanding from one volume to another. Where the universe doesn’t.
If there’s no such thing as absolute distance, then how can you say that a metre bar (and the metre) is larger than it used to be?
If distance is relative, and matter isn’t expanding relative to anything else, then matter isn’t expanding.
We ultimately define distance in terms of c, and the fundamental forces agree with this. We do not observe atoms expanding, but we do observe the space between galaxies expanding. Presumably the space we occupy is also expanding, but it’s such a small effect as to be irrelevant.
Back to my original question, is the boundary between irrelevantly small and detectable above or below the galactic scale?
I think the trouble is also partly based around thinking of then universe as a volume, which implies a centre. And that’s where this analogy falls apart.
Because everything is expanding from everything, there is no centre. YOU are always centre. So you are “expanding” but you don’t change volume.
This is why I keep saying space isn’t getting bigger, distance is.
It’s not that a sheet of paper becoming bigger so the grid paper becomes larger,. It’s changing it’s distance of something, not it’s size and shape.
We don’t observe galaxies getting bigger. We observe them constantly moving away from us. Even. When they’re moving to us, but it’s done at a slower pace than expected. The further away you are, the faster you move away. And it’s a universal constant of 73km/s/Mpsc.
Notice that is a speed per distance. It’s not saying space is getting bigger, it’s saying things are moving faster away from you the further you go away.
The universe isn’t expanding like a loaf of bread because it has a volume. It’s expanding from one volume to another. Where the universe doesn’t.