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B Matter and The Big Bang

  1. Oct 31, 2017 #1

    ISamson

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    Hello.
    I mean no challenge against current existing theories.
    I wanted to ask, how does the Big Bang model explain the creation of all the existing matter in the Universe? I read that the BB created matter but how how could matter be created? I think it should have been either infinitely concentrated in a point, or be just born from something. If it was infinitely concentrated in a point, then where did all that matter come from? It is said that the BB was the beginning of time, so...
    I don't understand this.
    Were all the subatomic particles that we know of in the Standard Model created at one single point in time, the BB? How did all of them come in existence? How did they form?
    https://en.wikipedia.org/wiki/Big_Bang
    I have seen some threads on similar discussions, but to be honest I did not understand much from them...
    Can anyone please help me with my misunderstanding?
    Thank you for taking time to consider all these questions!:smile:

    P.S. This post is full of questions, but this is a very interesting topic and I am just a middle schooler...:)
     
  2. jcsd
  3. Oct 31, 2017 #2

    phinds

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    I recommend Stephen Weinberg's "The First Three Minutes". It's fairly short and an easy read.

    You need to let go of this "everything was at a point" thing. It was a point in TIME, not a point in space. The big bang happened everywhere, not at a point in space. If it had happened at a point in space, it would have been, as pop-sci presentations would have you believe, an "explosion" and there would be a center. There is not. I recommend the link in my signature.
     
  4. Oct 31, 2017 #3

    ISamson

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    @phinds but would the universe have to be expanding from a point, the point of the BB?
    Thank you for the response.
     
  5. Oct 31, 2017 #4

    phinds

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    Yes, a point in TIME, not a point in space.
     
  6. Oct 31, 2017 #5
    That's not very clear to novices, since they have been instructed that space and time are indubitably woven into the fabric of... spacetime.

    Anyway this must be the millionth time this topic has been raised on here, and will no doubt be locked like all the others. Kudos I suppose to the mods for rehashing the same old 'answers', and not exploding in a veritable fireball of incandescent frustration.
     
  7. Oct 31, 2017 #6

    kimbyd

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    If you want a full description, Phinds' suggestion is a good one. Here's a super short version, in two points:

    1. Energy is not conserved in an expanding universe. This is highly counter-intuitive. But it is what General Relativity tells us. General Relativity follows a more complicated conservation law that includes energy, momentum, pressure, and twisting forces. The conservation of this more complicated structure forces energy to change over time following very precise rules based upon the interaction between energy and these other properties (momentum, pressure, twisting forces).
    2. Using a particular definition of energy*, in the most common model (cosmic inflation) extremely early universe energy grew extremely rapidly. Then that energy was converted to matter and radiation, and the energy dropped over time very early-on as the universe cooled. But lots of matter that came from that initial energy production remained.

    * The particular definition in this case is the "total energy in a finite co-moving volume". It increases at an exceedingly rapid pace during inflation. It decreases when radiation is the dominant energy density.
     
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