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We have studied approx 4.6% of normal/ordinary matter in the universe and everything till now we observed are a part of this 4.6%

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I always have doubt. this 4.6% include all the matters and energies apart from dark matter and dark energy

4.6% Includes

  1. Normal matter
  2. Normal energies (Cosmic, Mass-energy, photon, etc)
  3. Anti-matter
  4. exotic matter
  5. virtual particles
Rajeev Ranjan Sharma
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    Search terms: “radiation era,” “matter era.” – rob Jan 15 '22 at 18:43
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    @rob So at the radiation era there is no matter? – Rajeev Ranjan Sharma Jan 16 '22 at 05:58
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    There was still matter during the radiation-dominated era, just like there is still matter and radiation during the current dark-energy-dominated era. A search for those terms will take you to one of a number of histories whose discussions will illuminate your question. – rob Jan 16 '22 at 06:25
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    @rob at different time period of universe we observed different dominated era. So, every fundamental matter, energies and force convert into another and vise versa. Eg, normal matter can convert to dark matter? – Rajeev Ranjan Sharma Jan 16 '22 at 16:46

1 Answers1

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Yes, this 4.6% includes everything we know about except dark matter and dark energy. So it includes atoms, baryons, leptons, neutrinos, antimatter, cosmic rays, and the mass-energy from virtual particles as well (much of the mass of the proton and of atoms comes from that). Depending on your definition of "exotic matter", that's either hypothetical and so everybody's guess, or things like positronium which isn't stable but would be part of those 4.6%, or could be a term for dark matter, in which case it would be part of, well, dark matter.

rfl
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    Exotic matter : https://en.wikipedia.org/wiki/Exotic_matter – Rajeev Ranjan Sharma Jan 16 '22 at 05:57
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    So this mean our whole universe is made of up approx 2.3% of matter because till now we have not detected antimatter naturally in our universe and we assume it lies outside of our universe or in other dimension.

    Volume of matter = volume of anti-matter

     – Rajeev Ranjan Sharma Jan 16 '22 at 06:43
  • As you can see from that wikipedia article, exotic matter is just a catch-all phrase for stuff that folks thought up but for which no evidence whatsoever exists. Like, pink elephants. – rfl Jan 16 '22 at 15:55
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    No, in this context, antimatter is just matter too. Plus, the amount of antimatter in our universe is negligible. It is hardly meaningful to contemplate what would be "outside" our universe when "universe" already means "everything that is accessible to us". Also, "other dimensions" are entirely hypothetical. – rfl Jan 16 '22 at 15:57
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    Exotic matter is not a hypothetical. we already have synthetic exotic matter Positronium. or it something different? https://physics.stackexchange.com/questions/689057/what-kind-of-matter-is-positronium – Rajeev Ranjan Sharma Jan 16 '22 at 16:41
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    Semantics. Depends on the field. Nuclear physics might think of positronium as being exotic, dark matter particle physicists might not. Point being: Positronium would be part of those 4.6% as well, though of course it isn't stable. – rfl Jan 16 '22 at 20:53
  • I got your point. Different branch can label different to same particle. Like @Árpád Szendrei described about quarkonium based on your answer. https://physics.stackexchange.com/a/689321/325462 – Rajeev Ranjan Sharma Jan 18 '22 at 07:39