What would the universe look like without dark matter?

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Discussion Overview

The discussion explores the hypothetical scenario of a universe without dark matter, questioning its implications for galaxy formation, the solar system, and the potential for life. Participants examine the necessary conditions and components that would exist in such a universe.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants inquire about the differences in the universe's structure and the formation of galaxies without dark matter.
  • Others argue that simply stating "without dark matter" is insufficient without specifying alternative components that might replace it.
  • A later reply emphasizes the need to clarify the proportions of visible matter, radiation, and cosmological constant in the absence of dark matter.
  • One participant suggests that the current proportions of visible matter and dark energy are approximately 5% and 95%, respectively, but this is presented as a guess rather than a definitive statement.
  • Another participant provides a link to a cosmological calculator as a resource for further exploration of these proportions.

Areas of Agreement / Disagreement

Participants do not reach consensus on the implications of a universe without dark matter, and multiple competing views regarding necessary components and their proportions remain present.

Contextual Notes

Limitations include the lack of clarity on what specific components would replace dark matter and the unresolved nature of the proportions of visible matter and dark energy.

Ranku
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How different would the universe look without dark matter? Would galaxies have formed, allowing for the existence of the solar system and life?
 
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It is not sufficient to just say "without dark matter" because that does not specify what other things (if anything) you put into the Universe instead.
 
Orodruin said:
It is not sufficient to just say "without dark matter" because that does not specify what other things (if anything) you put into the Universe instead.
With only visible matter, radiation, and cosmological constant present.
 
Ranku said:
With only visible matter, radiation, and cosmological constant present.
Still not sufficient. You need to specify proportions.
 
Orodruin said:
Still not sufficient. You need to specify proportions.
I guess the present proportion would be visible matter 5 % and dark energy 95 %.
 

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