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The article seems to assume that the universe is fractal, but Wikipedia can't seem to make up its mind whether fractal cosmologies are fringe ideas or not. It's

by wbhart 9y ago

The article seems to assume that the universe is fractal, but Wikipedia can't seem to make up its mind whether fractal cosmologies are fringe ideas or not. It's certainly far outside the consensus.

cbennett 9y ago
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://en.wikipedia.org/wiki/Primordial_fluctuations https://arxiv.org/abs/astro-ph/0003124 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-theory.html 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.
- posterboy 9y ago
  > 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.
  - llamaz 9y ago
    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.
    - posterboy 9y ago
      ... 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?).
      - llamaz 9y ago
        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).
        posterboy 9y ago
        innerrestin but hard to believe to be a settled matter
canoebuilder 9y ago
How about a fractal of fractals? Your circulatory system is a fractal for similar reasons that trees are fractals for similar reasons that watersheds are fractals. Fractal structures are probably the rule rather than the exception for basic reasons of space and energy efficiency. Here's another interesting fractal thought, where is the universe? In your head, or outside of it, or both? So the neuronal structure representing the universe in your head is at least in some ways similar to the objective outside universe, if there is such a thing, and if there is such a thing then that neuronal structure in your head is also in(and of) that objective universe while also being similar to it. A good term for fractals is self-similar. Self-similarity all the way down. I am a strange loop. - Douglas Hofstadter It's in you, and you're in it. - Alan Watts
- notduncansmith 9y ago
  Explains why computer science is such an interesting field. It's the study of universes, which happens to yield a remarkable number of insights into our own. If you consider the Curry-Howard correspondence in connection with Gödel's Incompleteness Theorems, the fractal nature of the universe seems inevitable.
  - yorwba 9y ago
    The Curry-Howard correspondence in connection with Gödel's Incompleteness Theorems only gets me to "For some types, there is no program of that type, but also no way to show that there is no such program." What does that have to do with fractals or the physical universe?
    - posterboy 9y ago
      Isn't that backwards? Why care about type without a corresponding programm? The systematic problem with higher order incompleteness is propositions fro syntactic argument, without consideration for semantics.
      - yorwba 9y ago
contingencies 9y ago
https://xkcd.com/1867/ https://xkcd.com/1867/

by wbhart 9y ago

The article seems to assume that the universe is fractal, but Wikipedia can't seem to make up its mind whether fractal cosmologies are fringe ideas or not. It's certainly far outside the consensus.

cbennett 9y ago

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://en.wikipedia.org/wiki/Primordial_fluctuations https://arxiv.org/abs/astro-ph/0003124 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-theory.html 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.

posterboy 9y ago
> 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.
- llamaz 9y ago
  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.
  - posterboy 9y ago
    ... 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?).
    - llamaz 9y ago
      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).
      - posterboy 9y ago
        innerrestin but hard to believe to be a settled matter

canoebuilder 9y ago

How about a fractal of fractals? Your circulatory system is a fractal for similar reasons that trees are fractals for similar reasons that watersheds are fractals. Fractal structures are probably the rule rather than the exception for basic reasons of space and energy efficiency. Here's another interesting fractal thought, where is the universe? In your head, or outside of it, or both? So the neuronal structure representing the universe in your head is at least in some ways similar to the objective outside universe, if there is such a thing, and if there is such a thing then that neuronal structure in your head is also in(and of) that objective universe while also being similar to it. A good term for fractals is self-similar. Self-similarity all the way down. I am a strange loop. - Douglas Hofstadter It's in you, and you're in it. - Alan Watts

notduncansmith 9y ago
Explains why computer science is such an interesting field. It's the study of universes, which happens to yield a remarkable number of insights into our own. If you consider the Curry-Howard correspondence in connection with Gödel's Incompleteness Theorems, the fractal nature of the universe seems inevitable.
- yorwba 9y ago
  The Curry-Howard correspondence in connection with Gödel's Incompleteness Theorems only gets me to "For some types, there is no program of that type, but also no way to show that there is no such program." What does that have to do with fractals or the physical universe?
  - posterboy 9y ago
    Isn't that backwards? Why care about type without a corresponding programm? The systematic problem with higher order incompleteness is propositions fro syntactic argument, without consideration for semantics.
    - yorwba 9y ago

contingencies 9y ago

https://xkcd.com/1867/ https://xkcd.com/1867/