Universe Expansion

Discussion in 'Pseudoscience' started by hansda, Aug 24, 2017.

  1. RADII Registered Senior Member

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    Yes. Look @ the link, constructed from the measurements I described.
     
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  3. hansda Valued Senior Member

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    I saw the link but there is no explanation. Only a diagram.
     
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  5. RADII Registered Senior Member

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    I don't know what to do for you! If you can't comprehend that, I don't know how to further explain that is the current shape of the observable Universe as we know it, based on accumulated measurement. It looks like foam.
     
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  7. NotEinstein Registered Senior Member

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    Small correction: it's the matter in the universe in that picture, and that is indeed organized "like foam". The shape of the observable Universe is (almost perfectly) spherical.
     
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  8. James R Just this guy, you know? Staff Member

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    I wrote that the big bang happened everywhere at once. That is, all the matter and energy in our observable universe was once confined to a small volume of space, all of which expanded rapidly in the "big bang".

    A common picture that is used is this: picture a loaf of raisin bread baking in the oven. As the loaf bakes, any two raisins in the bread move further apart. In this analogy the raisins represent galaxies and the bread is the observable universe. The expansion of the loaf is not centred around any particular raisin. Also, note that we're dealing with the bulk of the bread here and are not concerned with the "edges" of the loaf, where bread gives way to the air "outside" the loaf. If it helps, imagine an expanding loaf that is actually infinite in size to start with. Raisins still move apart over time, but there are no "edges".
     
  9. Write4U Valued Senior Member

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    Does that not beg the question; if the universe is edgeless, how do we know how big the universe is and is expanding, according to the standard model?
     
  10. origin Trump is the best argument against a democracy. Valued Senior Member

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    We know it is expanding because we can measure the expansion, it has nothing to do with an edge. We know the size based on the furthest objects we can see.
     
    Last edited: Sep 13, 2017
  11. sweetpea Registered Senior Member

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    773
    IMO
    It seems observations to date have shown no reason to assume homogeneity and isotropy does not extend beyond the observable universe (OU). And to explain that ( within our OU) requires a model which includes the metric expansion of space. In other words, the cosmological principle holds in any model until observations show otherwise. In an infinite universe a 'multiverse model' may be needed if observations (if possible ??) show otherwise. Again until then, the cosmological principle holds.
    And, remembering that every point in our observable universe is the centre of its own observable universe, think of those galaxies on the border of our OU...
    http://www.astro.ucla.edu/~wright/infpoint.html
     
    Last edited: Sep 13, 2017
  12. NotEinstein Registered Senior Member

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    Not only that, but it used to be even more isotropic in the past. For example, the CMB shows only fluctuations of less than 0.1%. The closer you get to the big bang moment, the more true the cosmological principle becomes.
     
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  13. hansda Valued Senior Member

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    Does it mean that, a small volume of space(in which all matter and energy of our observable universe was once confined) was already in existence before "big bang"?
     
  14. hansda Valued Senior Member

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    Thanks for your correction. So we can say that universe-polygon shape is nearly spherical. As the universe expands, this polygon will also expand.
     
    Last edited: Sep 13, 2017
  15. James R Just this guy, you know? Staff Member

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    We know the universe is expanding because we see all the galaxies moving away from us, and they obey the Hubble law.
    We know the size of the observable universe. We can't know the size of the entire universe, of course, because we can't see it. it might even be infinite.
     
  16. origin Trump is the best argument against a democracy. Valued Senior Member

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    I should have said observable universe. Other evidence such as CMBR and that the early galaxies were different than the current galaxies suggest that the universe is not infinite and what we see is essentially the whole universe.
     
  17. DaveC426913 Valued Senior Member

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    The conclusion you draw yourself:
    "Thus our universe is expanding into nothing. We can say, our universe is expanding into Big Vacuum or Big Void which basically is nothing."
    is entirely wrong.

    The universe is not expanding into nothing, be that a big vacuum or a big void.
     
  18. NotEinstein Registered Senior Member

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    But DaveC426913, you don't understand. See, hansda has a TOE, which (apparently) is completely incompatible with GR!

    Please Register or Log in to view the hidden image!

     
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  19. hansda Valued Senior Member

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    My TOE is based on Law of Inertia. So, it is in the realm of Newtonian Model. The way Newtonian Model and GR are related, same way my TOE can be related with GR.
     
  20. NotEinstein Registered Senior Member

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    In that case, please derive the Einstein field equations from your TOE (perhaps in a new thread?).
     
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  21. RADII Registered Senior Member

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    102
    Wait one: my impression is that the [observable] universe is assumed to be anisotropic & inhomogeneous. This is what WMAP & the mapping of the CMBR has revealed, right?
     
  22. James R Just this guy, you know? Staff Member

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    To a good approximation, the early universe was isotropic and homogeneous. However, if it was perfectly homogeneous then we wouldn't have stars and galaxies and things today. Instead, what WMAP etc. has confirmed is that there were small fluctuations from the average density in different regions of space.
     
  23. sweetpea Registered Senior Member

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    http://www.ctc.cam.ac.uk/outreach/origins/inflation_zero.php
    An airy fairy aside...
    I sometimes have this idea that even an infinite multiverse could still be considered homogeneous when thought of on a large enough perspective. Think reallly big here.
    Different 'universes' i.e. different constant values ( even new constants), and perhaps varying in number of dimensions. The order doesn't have to be the same in each direction, but examples of each type of universe will be found in any direction you 'look' in an infinite universe.
     
    Last edited: Oct 3, 2017

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