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The galaxies are not randomly distributed. In fact there are correlations between galaxy distributions at various scales that essentialy can be traced to initia

The galaxies are not randomly distributed. In fact there are correlations between galaxy distributions at various scales that essentialy can be traced to initial perturbations that arose after the big bang. Multiple projects are now working on exactly figuring out those correlations as a function of scale.

soheil 6y ago
I understand the galaxies can be traced back to those initial perturbations, but regardless of that, it'd be interesting to see if there are any patterns that can be identified at a large scale and based on similar sky survey images posted here. Are there any projects working on identifying such patterns?
- toufka 6y ago
  WMAP went from the cosmic microwave background downwards. So looking only at the largest structures. The patterns it sees are real, and very cool. https://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy_Probe https://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy...
- raattgift 6y ago
  Yes, there is a pronounced filamentary structure to galaxy clusters. https://en.wikipedia.org/wiki/Galaxy_filament https://en.wikipedia.org/wiki/Galaxy_filament with a concrete rendering at https://en.wikipedia.org/wiki/Void_(astronomy)#/media/File:Structure_of_the_Universe.jpg https://en.wikipedia.org/wiki/Void_(astronomy)#/media/File:S... and some more at https://en.wikipedia.org/wiki/Observable_universe#Walls,_filaments,_nodes,_and_voids https://en.wikipedia.org/wiki/Observable_universe#Walls,_fil... These filamentary luminous matter distributions (and the sparse, dark, cold voids between them) drive our theories of structure formation: https://map.gsfc.nasa.gov/universe/bb_cosmo_struct.html https://map.gsfc.nasa.gov/universe/bb_cosmo_struct.html There are some patterns at scales of up to a few tens of megaparsecs, but beyond that matter is for all practical purposes homogeneous and isotropic: with a good enough (infrared- or radio-) telescope you will observe a galaxy or a precursor along every line of sight unobscured by objects within our own galaxy, and only the reddening and dimming from the metric expansion of space permits any darkness at all in our sky. This is important to the standard mode of cosmology, \Lambda-CDM, which relies on Friedmann equations, which model all the matter content of the entire universe (past and present) as a perfect fluid of uniform dust. Because of the "local" nonuniformities like filaments and voids, grains of dust are thus on the order kilo- to megaparsecs. If we find that there are bigger grains, the standard "concordance cosmology" will have to be adjusted to be concordant with the new large-scale evidence. (There is lots of looking right now, but so far everything points to smoothness at scales much smaller than gigaparsecs, kinda how a sheet of paper looks smooth in your hands, but a tiny piece of it under a light microscope looks very fibrous, and under an electron microscope one might discern the remnants of plant cells, or even see microbes!).

soheil 6y ago

I understand the galaxies can be traced back to those initial perturbations, but regardless of that, it'd be interesting to see if there are any patterns that can be identified at a large scale and based on similar sky survey images posted here. Are there any projects working on identifying such patterns?

toufka 6y ago
WMAP went from the cosmic microwave background downwards. So looking only at the largest structures. The patterns it sees are real, and very cool. https://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy_Probe https://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy...
raattgift 6y ago
Yes, there is a pronounced filamentary structure to galaxy clusters. https://en.wikipedia.org/wiki/Galaxy_filament https://en.wikipedia.org/wiki/Galaxy_filament with a concrete rendering at https://en.wikipedia.org/wiki/Void_(astronomy)#/media/File:Structure_of_the_Universe.jpg https://en.wikipedia.org/wiki/Void_(astronomy)#/media/File:S... and some more at https://en.wikipedia.org/wiki/Observable_universe#Walls,_filaments,_nodes,_and_voids https://en.wikipedia.org/wiki/Observable_universe#Walls,_fil... These filamentary luminous matter distributions (and the sparse, dark, cold voids between them) drive our theories of structure formation: https://map.gsfc.nasa.gov/universe/bb_cosmo_struct.html https://map.gsfc.nasa.gov/universe/bb_cosmo_struct.html There are some patterns at scales of up to a few tens of megaparsecs, but beyond that matter is for all practical purposes homogeneous and isotropic: with a good enough (infrared- or radio-) telescope you will observe a galaxy or a precursor along every line of sight unobscured by objects within our own galaxy, and only the reddening and dimming from the metric expansion of space permits any darkness at all in our sky. This is important to the standard mode of cosmology, \Lambda-CDM, which relies on Friedmann equations, which model all the matter content of the entire universe (past and present) as a perfect fluid of uniform dust. Because of the "local" nonuniformities like filaments and voids, grains of dust are thus on the order kilo- to megaparsecs. If we find that there are bigger grains, the standard "concordance cosmology" will have to be adjusted to be concordant with the new large-scale evidence. (There is lots of looking right now, but so far everything points to smoothness at scales much smaller than gigaparsecs, kinda how a sheet of paper looks smooth in your hands, but a tiny piece of it under a light microscope looks very fibrous, and under an electron microscope one might discern the remnants of plant cells, or even see microbes!).