What would the universe look like without dark matter?

In summary, without dark matter, the universe would have a much simpler and less structured appearance. Galaxies would not have the same gravitational forces that hold them together, and thus would not have their characteristic spiral or elliptical shapes. The speed at which stars and galaxies move would also be greatly affected, potentially leading to a more chaotic and unpredictable universe. Additionally, the formation of large-scale structures such as galaxy clusters would be hindered without the presence of dark matter. Overall, the absence of dark matter would drastically change the appearance and behavior of the universe as we know it.
  • #1
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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  • #2
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.
 
  • #3
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.
 
  • #4
Ranku said:
With only visible matter, radiation, and cosmological constant present.
Still not sufficient. You need to specify proportions.
 
  • #5
Orodruin said:
Still not sufficient. You need to specify proportions.
I guess the present proportion would be visible matter 5 % and dark energy 95 %.
 
  • #6
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1. What is dark matter and why is it important in our understanding of the universe?

Dark matter is a hypothetical form of matter that is believed to make up about 85% of the total mass of the universe. It does not emit or absorb light, making it invisible to telescopes and other instruments. Its existence is inferred through its gravitational effects on visible matter. Without dark matter, our current understanding of the universe and its structure would be incomplete.

2. What evidence supports the idea of a universe without dark matter?

There is currently no direct evidence for a universe without dark matter. However, some scientists have proposed alternative theories, such as modified gravity, to explain the observed phenomena that are typically attributed to dark matter. These theories have not been widely accepted and do not fully explain all of the evidence for dark matter.

3. How would a universe without dark matter differ from our current understanding?

If dark matter did not exist, the gravitational effects it has on visible matter would not be present. This would result in a different distribution of matter and different structures in the universe, such as galaxies and galaxy clusters. Additionally, the current understanding of the expansion of the universe and the formation of large-scale structures would need to be revised.

4. What are some potential implications of a universe without dark matter?

If dark matter did not exist, it would have significant implications for our understanding of gravity and the laws of physics. It could also have implications for the search for dark matter particles, as well as the development of theories and models to explain the structure and evolution of the universe.

5. How could we test the idea of a universe without dark matter?

Scientists are continuously conducting experiments and observations to search for evidence of dark matter. If a universe without dark matter were to be proven, it would require significant revisions to our current understanding of the universe. This could potentially be achieved through further studies of the behavior of gravity on large scales and the development of new theories and models to explain the observed phenomena.

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