First cosmology computer simulations

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Discussion Overview

The discussion centers on the early cosmological computer simulations and their implications for understanding large-scale structure (LSS) in the universe, particularly in relation to dark matter (DM). Participants explore the limitations of these simulations, the historical context of dark matter, and the characteristics of voids in cosmic structure.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants note that the first cosmological simulations lacked dark matter and only modeled gas dynamics, resulting in a uniform space devoid of structure.
  • Others argue that dark matter was conceptualized prior to these simulations, based on observations of galaxy rotation curves rather than cosmological simulations.
  • One participant suggests that the absence of dark matter in early simulations aligns with the observed voids in the universe, implying a level of understanding regarding these regions.
  • Another participant challenges the interpretation of voids and dark matter, questioning whether the absence of dark matter in voids is widely accepted or controversial.
  • It is mentioned that dark matter is often viewed as the framework for structure formation, complicating assessments of its distribution in low-density regions like voids.

Areas of Agreement / Disagreement

Participants express differing views on the role of dark matter in early simulations and its implications for understanding voids and large-scale structure. There is no consensus on the interpretation of these simulations or the status of dark matter in voids.

Contextual Notes

Limitations include the historical context of dark matter's conception, the specific conditions under which early simulations were conducted, and the unresolved nature of dark matter's distribution in voids.

TEFLing
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I understand that the first cosmological computer simulations

Did not have DM

Only gas dynamics on expanding grids

And, that those sims produced no structure of any kind

No LSS

Only vast expanses of nearly uniform space plasma

Devoid of any clumps

Essentially reminiscent of the real actual voids

Which fill about 3/4ths of the volume of space

So simply stated, the first earliest computer simulations

Accurately reproduced VOIDS ...
In some sense they were 75% accurate...

But they never produced the large scale STRUCTURE

Particularly important to people upon this planet?

Hence the motivation for " something extra" ( people inserted DM ) to cause clumping into galaxies and clusters etc??
 
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The concept of dark matter is older than the first proper simulations, and it was based on galaxy rotation curves, not on cosmology and structure formation.

Sure, if you have some type of matter you cannot see you want to check if simulations work out without this type - and as you see, they do not. With dark matter, they work out nicely.
 
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Fritz Zwickey and Vera Rubin?

they noticed that unseen mass seems to "plague" the matter we see ( bright stars ), in the sense of being near and amidst and around "light matter" ( as it were )

like nemesis planets or stars orbiting beyond Pluto, or something like that ( please see link below )

As for the VOIDS ( only ) they are well described by the first simulations...

perhaps implying that we can claim the voids to be "well understood"...

i.e. no DM, only huge regions of diffuse space plasma?
 
It sounds like you are making a case against DM based on cherry picked popular sources. That doesn't impress.
 
say again?

is it true, that nobody ever argues, for the presence of DM, out in the VOIDS comprising deep intergalactic space ( size scale ~100 Mpc or something like that ) ?

no DM in voids is non-controversial, yes? To be distinguished from the ~25% of space harboring LSS?
 
DM is generally considered the 'scaffolding' upon which structures are formed. Have you seen the cosmic web portrayals based on Herschel space observatory, or 2df galaxy redshift surveys? Given dark matter is only detectable, at present, based on gravitational effects, and since voids are, by definition, matter deficient, it is understandably difficult to assess dark matter distribution in such regions.
 

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