I’m reading about the philosophy of physics (see previous post), so I happen to be thinking of Bohr's wave-particle complimentarity... and resonance:
......An empty bottle, for example, emits a low tone when you blow over it because the tiny vibrations that are the disturbance of the air caused by that blowing all mount up if (and only if) they have a wavelength that fits nicely into the extent of the bottle (much as how, when you give a swing a sequence of little pushes, the swing swings with a larger and larger amplitude). I’m thinking that because the universe has a finite size, so there might be resonance. Maybe the universe is still ringing like a bell from the Big Bang. It is clearly permeated by background radiation (the lingering whisper of that explosion), so maybe there is also resonance. (The universe is growing, so the resonant notes would be lowering their tone.)
......Where is the resonant ringing? Well if the resonance was like a sound wave, we would expect to see bands of denser particles and less dense particles (that being what sound is), those particles being galaxies perhaps, or clusters of galaxies. And if you think of the waves being in spacetime then again, matter would tend to congregate in the troughs. Small ripples move over ocean swells much as they do over calm seas, so we would not necessarily notice anything locally; but such clustering as though in troughs is indeed observed at the largest scales. And most of the wave energy is in those huge swells, which reminds me of the dark matter that, whilst being unobservable (whence the term 'dark'), is thought to make up over 80% of the matter of the universe.
......Galaxies seem to need more mass than we can see, in their stars and dust, to account for how compacted together are those stars and that dust. So my thought is that dark matter might be the energy associated with such huge universal swells. It would be directly unobservable as matter because such swells would be too big to look much like particles to us, much as electrons are too small to look like waves (except when that aspect proves invaluable, e.g. in electron microscopy). Maybe not of course, but I was wondering if any reader knows whether or not the maths of that analogy works out?