5 ms·

We used to think so, yes. But our telescopes have improved a lot since then, and we're now able to see with much more detail, our 3D positioning is better too.

by K0SM0S 7y ago

We used to think so, yes. But our telescopes have improved a lot since then, and we're now able to see with much more detail, our 3D positioning is better too. We've recently observed that the universe, at the largest scales of what's observable to us, looks like this: https://i.stack.imgur.com/lFnDf.jpg https://i.stack.imgur.com/lFnDf.jpg More picture and explanations on this short SE thread: https://physics.stackexchange.com/questions/198138/is-most-of-the-matter-in-the-observable-universe-within-galaxies https://physics.stackexchange.com/questions/198138/is-most-o... I'll let you ponder how much resemblance this bears to other kinds of structures...

Filligree 7y ago
That's a screensaver. You've heard of the simulation hypothesis, I suppose. As untestable as it is... wouldn't it be fun if this comment were literally true?
- mirimir 7y ago
  But if those were neurons and interconnections, wouldn't we expect to see all sorts of structure inside them? I guess that it could all be dark matter, which we can't directly see. And there could also be all sorts of complexity in dark matter.
  - K0SM0S 7y ago
    In these pictures[1], each individual 'dot' is a whole galaxy's worth of dark matter (and here[2] are said galaxies). So you may view galaxies as "neurotransmitters" of the universe, maybe. Or hormones. The big luminous nodes are the neurons, where all 'dark matter synapses' converge. Perhaps what happens when over the short course of a few billion years, some "life" is taken from one node to another, is just a cosmic neuron doing its thing. Perhaps said life is just the equivalent of some positive ion charge, and it ends up blowing up the node into a huge black hole and that's just the universe doing "two minus one" (cataclysmic event = "remove 1" from the neuro-galactic graph, just the time of a thought.) Maybe treants had it right all along. [1]: Finally found a good source. (thanks Filligree for pointing out the screensaver mishap) https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/ https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/ [2]: https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/galseq_D_063.jpg https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/...
mirimir 7y ago
That's what I meant by "foam". And remember that those are ~2D slices. In 3D, there are voids, with thin intervening walls, and stringy stuff where walls intersect. It's dark matter that probably defines that structure. And so that dark matter could be moving, in coherent patterns at extremely large scales. But there's nothing necessarily supraluminal about it. It could just be moving in the same patterns that it did when it was hugely smaller. But then, I have zero clue about how conservation of angular momentum works during inflation. If that were the explanation, we wouldn't expect to see perturbations in cosmic scale motion propagating supraluminally.
- K0SM0S 7y ago
  > That's what I meant by "foam". Oh sorry I didn't catch that (not a native speaker). When thinking of "foam" I see a uniform, homogenous noisy structure and I was pretty sure this was the name given to our former such view of the universe. My bad! (although I'd say, if "foam" is used to described these pictures, it's a pretty bad choice of adjective by scientists imho. "Galactic tissue" or "tissue-like walls" makes more sense to the layman imho). Indeed, it's not "probably" dark matter, it is by the very definition of what we call dark matter. It's important to keep that in mind, when we name unknown phenomena it's just a 'placeholder' so to speak. Like X. So X explains the motion of galaxies, and we intuitively called X dark matter. Assuming there is an X, then there is dark matter (what it actually is is another question, could be "white energy" or fluffly creatures from the 6th dimension for all we know, but we call it dark matter for now). So based on this, I always wonder: is it our observation or maybe interpretation thereof that's flawed? Are there 'effects' that make us see and infer things that are slightly 'off' maybe? (like the discrepancy with dark energy measurements for instance, it appears recently that there might not be accelerating expansion and the increasing redshift is due to errors in our calculations, i.e. we created "dark energy" out of a mistake and now it's possibly going to "disappear" as an idea because it's not needed anymore to explain anything). As for inflation etc. These are also mathematical concepts that fit the observation, the clues; it however might not be the only possible model that works, we also might not have a correct interpretation (layman words) for it. Like we've got QED/QCD and we're still unable to describe in layman terms because it's illogical, paradoxical. Sometimes our idea of "simplest interpretation" is just that, an idea, and reality is a bit more complex, even if the simple equations may work as terms simplify (see how we "add" zero-value or unit-value arguments to some equations in physics to solve the math, it really begs the question if the "thing" you add actually exists, speaks of a real phenomena). I know Einstein was pretty unhappy about the picture painted by Λ... ;-) About supraluminal anything (I assume you mean speed > c), I personally don't think it wise to postulate things that physics rule out explicitely. Inflation doesn't do that though, since it's spacetime expanding and that's not constrained by c. [1]: https://youtu.be/blSTTFS8Uco https://youtu.be/blSTTFS8Uco

by K0SM0S 7y ago

Filligree 7y ago

That's a screensaver. You've heard of the simulation hypothesis, I suppose. As untestable as it is... wouldn't it be fun if this comment were literally true?

mirimir 7y ago
But if those were neurons and interconnections, wouldn't we expect to see all sorts of structure inside them? I guess that it could all be dark matter, which we can't directly see. And there could also be all sorts of complexity in dark matter.
- K0SM0S 7y ago
  In these pictures[1], each individual 'dot' is a whole galaxy's worth of dark matter (and here[2] are said galaxies). So you may view galaxies as "neurotransmitters" of the universe, maybe. Or hormones. The big luminous nodes are the neurons, where all 'dark matter synapses' converge. Perhaps what happens when over the short course of a few billion years, some "life" is taken from one node to another, is just a cosmic neuron doing its thing. Perhaps said life is just the equivalent of some positive ion charge, and it ends up blowing up the node into a huge black hole and that's just the universe doing "two minus one" (cataclysmic event = "remove 1" from the neuro-galactic graph, just the time of a thought.) Maybe treants had it right all along. [1]: Finally found a good source. (thanks Filligree for pointing out the screensaver mishap) https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/ https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/ [2]: https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/galseq_D_063.jpg https://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/...

mirimir 7y ago

That's what I meant by "foam". And remember that those are ~2D slices. In 3D, there are voids, with thin intervening walls, and stringy stuff where walls intersect. It's dark matter that probably defines that structure. And so that dark matter could be moving, in coherent patterns at extremely large scales. But there's nothing necessarily supraluminal about it. It could just be moving in the same patterns that it did when it was hugely smaller. But then, I have zero clue about how conservation of angular momentum works during inflation. If that were the explanation, we wouldn't expect to see perturbations in cosmic scale motion propagating supraluminally.

K0SM0S 7y ago
> That's what I meant by "foam". Oh sorry I didn't catch that (not a native speaker). When thinking of "foam" I see a uniform, homogenous noisy structure and I was pretty sure this was the name given to our former such view of the universe. My bad! (although I'd say, if "foam" is used to described these pictures, it's a pretty bad choice of adjective by scientists imho. "Galactic tissue" or "tissue-like walls" makes more sense to the layman imho). Indeed, it's not "probably" dark matter, it is by the very definition of what we call dark matter. It's important to keep that in mind, when we name unknown phenomena it's just a 'placeholder' so to speak. Like X. So X explains the motion of galaxies, and we intuitively called X dark matter. Assuming there is an X, then there is dark matter (what it actually is is another question, could be "white energy" or fluffly creatures from the 6th dimension for all we know, but we call it dark matter for now). So based on this, I always wonder: is it our observation or maybe interpretation thereof that's flawed? Are there 'effects' that make us see and infer things that are slightly 'off' maybe? (like the discrepancy with dark energy measurements for instance, it appears recently that there might not be accelerating expansion and the increasing redshift is due to errors in our calculations, i.e. we created "dark energy" out of a mistake and now it's possibly going to "disappear" as an idea because it's not needed anymore to explain anything). As for inflation etc. These are also mathematical concepts that fit the observation, the clues; it however might not be the only possible model that works, we also might not have a correct interpretation (layman words) for it. Like we've got QED/QCD and we're still unable to describe in layman terms because it's illogical, paradoxical. Sometimes our idea of "simplest interpretation" is just that, an idea, and reality is a bit more complex, even if the simple equations may work as terms simplify (see how we "add" zero-value or unit-value arguments to some equations in physics to solve the math, it really begs the question if the "thing" you add actually exists, speaks of a real phenomena). I know Einstein was pretty unhappy about the picture painted by Λ... ;-) About supraluminal anything (I assume you mean speed > c), I personally don't think it wise to postulate things that physics rule out explicitely. Inflation doesn't do that though, since it's spacetime expanding and that's not constrained by c. [1]: https://youtu.be/blSTTFS8Uco https://youtu.be/blSTTFS8Uco