# The biggest structures in the universe



## Brian G Turner (Mar 3, 2015)

Or, at the least, the most massive to date, is the Hercules–Corona Borealis Great Wall:
http://en.wikipedia.org/wiki/Hercules–Corona_Borealis_Great_Wall



> The Hercules–Corona Borealis Great Wall (Her–CrB GW) is an immense superstructure of galaxies, or a galaxy filament, that measures about 10 billion light-years across. To date (February 26, 2015), it is the largest and the most massive structure known in the observable universe.



There are other massive structures in the universe, not least Large Quasar Groups:
http://en.wikipedia.org/wiki/Large_quasar_group



> A large quasar group (LQG) is a collection of quasars (a form of supermassive black hole active galactic nuclei) that form what are thought to constitute the largest astronomical structures in the known universe. LQGs are thought to be precursors to the sheets, walls and filaments of galaxies found in the relatively nearby universe.



And there's more information about galactic filaments and other massive structures here:
http://en.wikipedia.org/wiki/Observable_universe#Large-scale_structure







What's especially interesting to read about is how the very existence of these structures - discovered mostly over the past couple of years from sky surveys - challenge our existing ideas of how the universe began. Simply put, these super-massive structures should not exist according to the currently held Big Bang model.


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## K. Riehl (Mar 22, 2015)

I liked this article, 250x larger than what we can see. Whew!
http://www.technologyreview.com/vie...igger-than-visible-universe-say-cosmologists/


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## Brian G Turner (Mar 9, 2016)

Something in New Scientist today about claiming a larger structure:
Billion-light-year galactic wall may be largest object in cosmos

Am I the only one to be reminded of a neural network?


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## SilentRoamer (Mar 9, 2016)

Hey Brian,

These structures don't really challenge currently held theories in Cosmology as I understand it. Leading cosmological models have attributed the large scale superstructures to small variances which are blown up during the superinflationary epoch.

Essentially these large scale structures do not contradict two key factors of modern cosmology models - namely Isotropy and Homogeneity, the reasons being that the potential scale of the Universe (assuming a Euclidean flat finite U) exceeds the sizes of these superstructures by a scale that makes them confirm to Isotropy on the largest scale. Of course if U is infinite then isotropy has little meaning - in fact assuming infinity in a curved U it could be expected there would be huge swathes of Universe that did not appear to be Isotropic but when viewed from a lrger whole are - imagine a space the size of the Hubble volume in an area of the universe with different structural consistency - would it say anything about the infinite as a whole?

There was a similar shout by the scientific community when they discovered the Great Attractor which ended up coming to little.

I totally agree it looks like a large Neural Network, it makes me wonder if intellect is just an emergent property of complex chemistry and then I wonder if this could arise independently of organic neural networks. I have an interesting short I wrote about sentient Nubulae after reading Star Maker but I thought it borrowed to heavily so I never touched it further but this gives me an idea.

Really interesting Brian.


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## J Riff (Mar 9, 2016)

R/C set as wallpaper.....
All in all, yer jest another super-quasar in the wall.


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## Dave (Mar 10, 2016)

SilentRoamer - are you saying that these superstructures are entirely consistent with randomness on a very large scale, and that within any randomness we would expect to see some patterns if we look hard enough - similar to having enough monkeys with typewriters and you will produce Shakespeare? That is just amazing, to have such huge structures produced by chance. We are so small that it is difficult to comprehend it.

Also, if neural-network-like structures were a result of random chance that must increase the chance of intelligent life evolving. It needs to be added to the _Drake_ equation.


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## SilentRoamer (Mar 10, 2016)

Pretty much Dave,

Isotropy as a concept begins to hold less meaning when accounting for an infinite and Euclidean flat unbounded U. Any local region of space (even including something as large as the Hubble Volume) is such a small part of the overall whole that it becomes difficult.

Worth remembering that a spatially infinite U is still temporally finite.

In the far far future Hubble Volumes will naturally shrink due to faster than C expansion (faster than C in the form of scale expansion does not break any laws of relativity). This makes me wonder if in the far future there will be a species looking into the cosmos seeing only their Galaxy as visible light with everything else Redshifted to infinity - I wonder if it would even be possible for them to extrapolate a Big bang. We live in an exciting Universal epoch.

Also I really hate the Monkey analogy for a few reasons but based on statistical probabilities if we were able to turn every single proton in the known universe into a monkey and had it typing since the Big Bang there is still an almost infinitesimally small chance that they would even recreate a single page from ANY book, when dealing with infinities though even a small chance is "almost sure".

On denying infinity:

Even if there was a very small amount of *finite objects *with an accordingly small configuration of states but they existed on an infinite timescale, they would not necessarily repeat the same state. For example, if we take 3 x wheels of equal size, rotating on the same access, one point marked on the same point on each wheel (same point on the circumference) and they all lined up in a straight line, the second wheel rotates twice as fast as the first. If the third wheel spins at 1/ π then the initial configuration of state would never reoccur – even given an infinite amount of spinning (or an infinite timescale).


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