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Are we(universe) real

  1. Sep 30, 2008 #1
    I heard that for one baryon there are 10^9 photons exists in this universe..i want to know how did they calculate? is there any theory which solves baryon asymmetry with satisfaction Or is it still a mystery? why there should be equal number of matter and antimatter? is it to make the total electric charge of universe to zero? if so,then we should also do this for all conservation laws and say that energy,momentum etc..are also zero...and if everything is zero,then how we came to existence and this pushes me to ask a question ARE WE(UNIVERSE) REAL?
  2. jcsd
  3. Sep 30, 2008 #2


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    I can take the philosophical question first. Descartes: "I think, therefore I exist"
  4. Sep 30, 2008 #3
    The baryon asymmetry issue remains unresolved in the strictest sense. We can be pretty confident that http://en.wikipedia.org/wiki/CP-violation" [Broken] has something to do with it. No the baryon asymmetry issue has nothing to do with making the total electric charge of universe to zero. It is a serious question about what changes and don't change (symmetries) under the laws of physics given different kinds of transformations. For instance if you watched a movie that was filmed through a mirror is there any way for you to tell from the movie alone? This mirror is the P, or parity symmetry, refered to in "CP-violations". I'll leave it to you to look into CP-violations and CPT-symmetry if you are so inclined.

    To the philosophical question "ARE WE(UNIVERSE) REAL" sounds as pointless as asking what if it's not. Suppose this universe is a model on someones computer. Perhaps the only thing modeled is our thoughts making our experiences the only thing actually there. Does that make us any less real? malawi_glenn's quote of Descartes remains just as valid no matter how you slice or dice the ontology.
    Last edited by a moderator: May 3, 2017
  5. Sep 30, 2008 #4

    I didnt ask the last question in philosophical background..what i mean is if the total energy of universe is zero then how can we say universe is real..
    Last edited by a moderator: May 3, 2017
  6. Oct 1, 2008 #5
    Ok, I should had realized the implicit ontology from context. However, it remains a purely ontological question and not a physical one. Consider noise cancelation. You can take a sound and create another sound 180 degrees out of phase. When you combine them there is no sound at all. Does that mean the sound wasn't real in the first place? This begs the question of what exactly you mean by real. The fact of the matter is that there can be many physically (empirically) consistant ontologies that appear logically mutually exclusive. This is why modern theory deals in symmetries, not in some ontological notion of realness. Many of the crank ideas in science are built upon some notion of an ultimate ontological truth rather than an actual physical principle. Even in the mainstream the distinction between theoretical constructs and empirical content sometimes gets conflated.
  7. Oct 1, 2008 #6
    ok i accept that we are real...
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