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Comment by cbennett | Hacker News Reader

In terms of cosmology, the physically observable universe does have (some) fractal structure or features--, primarily to the existence of multi-scale primordial (quantum) fluctuations. https://en.wikipedia.org/wiki/Primordial_fluctuations https://arxiv.org/abs/astro-ph/0003124

On the other hand, at very large scales the universe is expressly homogenous (smooth) https://www.space.com/17234-universe-fractal-large-scale-the...

W/r to larger and more wide-ranging questions, e.g. if the mutli-verse has some sort of deep fractal meta-structure, and/or the recursion of fundamental quantum computing operations, the jury is still entirely out.

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> On the other hand, at very large scales the universe is expressly homogenous (smooth)

I assume that's because of looking at it through low pass filters, inadvertantly.

As elec. engineers (and c. scientists) one of our only hammers is signals theory and cosmology looks like a nail. But the physicists probably have it right.

... have what right exactly? Pictures (i.e. measurements) of faint celestal bodies are but mushy wish-washed smears of a point is what I'm talking about for example. Quite simply, our band-width is limited by position, the ammount that we can observe is likely just a tiny fraction, the known universe only accounts for ca. 10% of theoretical total energy. In that sense the low energies are likely lost on us, then we actually see through a highpass (redshift?).

I mean that the physicists have accounted for the limited amount of information available and still conclude that the observable universe is not a fractal.

I remember thinking about this in 2011/2012 when it wasn't known (IIRC there was a bet over a bottle of wine between two physicists over this matter). But years later, because a satellite "zoomed out" far enough and sent images back to earth, physicists confirmed that it is very likely that the observable universe is not a fractal (i.e. it's Hausdorff-Besikovitch dimension, which is calculated from measurements, is fractional).

innerrestin but hard to believe to be a settled matter

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