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True map of universe from computer simulation with CMB initial state

  1. Aug 16, 2014 #1
    Do you think we will ever be able to create a simplified computer simulation of the universe using the cosmic microwave background as the initial state that would generate the true locations of galaxies or at least galaxy clusters, and then be able to find our own galaxy or galaxy cluster within this simulation?

    I assume the model would have to make a great number of simplications while still preserving the true location of formed galaxies.

    What are the biggest bottlenecks?
    1. computation complexity?
    2. not enough detail in the cosmic microwave background map?
    3. finding our own galaxy once the simulation runs?

  2. jcsd
  3. Aug 16, 2014 #2
    Hi David, welcome here. Well my view is that the Universe is too random to repeatedly predict any relatively tiny event like a Galaxy cluster. Also I am not sure if the fluctuations we can see in the CMBR can be proven to correspond to matter we can still see forming part of any galaxy clusters. Lets see what the experts say about this.
    Last edited: Aug 16, 2014
  4. Aug 16, 2014 #3


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    4. The light of the plasma that eventually became our galaxy now being part of the CMB of observers 42 billion light years away, having passed our progenitor atoms some 13.8 billion years ago.
    IOW: you cannot see your own past, you always see light from somewhere else. There are no mirrors in the universe.

    The CMB we see now has nothing to do with galaxy formation at our position. Simulations use only its statistical properties to derive their starting conditions, not its actual shape. It would not be sufficient as starting condition for a 3D simulation anyway, as it is a 2D surface, not a 3D space.
  5. Aug 16, 2014 #4
    Thanks Ich. So from what I understand, even if we were able to overcome the computational burden, we do not have enough information for the initail state to generate a true map of our region. Our initial state cannot be implied from any other data that we currently have.
  6. Aug 16, 2014 #5


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    What we see is an enormous uniformity in the CMB, even though it started from totally different regions of the universe. So it is a reasonable assumption that the universe of our past also looked somewhat similar. The simulation use random starting conditions with the constraing that they'd give rise to a similar looking CMB. If everything works correctly, you get a random universe that looks somewhat similar to our own.
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