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Why Does the Universe Expand?

82 points · 77 comments · the__alchemist

  1. chasil · · focus · HN ↗
    I understand that, for a stationary black hole without spin (which does not exist), an object that falls into it will freeze, then the image will redshift until it disappears.

    <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Event_horizon" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Event_horizon

    I also understand that there is a cosmological (event) horizon, where galaxies freeze, then rapidly redshift in the same way. This happens because these distant objects are accelerated away from us faster than light.

    It appears to me that we are seeing black hole event horizons from the outside, and the cosmological event horizon is seen from the inside.

    The similarities do give one pause.

    The mechanisms are different; one is gravity, and the other is dark energy.

    <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Cosmological_horizon" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Cosmological_horizon

    1. pieter3d · · focus · HN ↗
      Maybe dark energy is inside-out gravity
      1. nxpnsv · · focus · HN ↗
        What does that mean?
        1. cobbzilla · · focus · HN ↗
          Not OP, but it’s not incompatible that dark-energy expansion (and ultimate big rip event) in a child universe correlates to the same process as black hole evaporation (and final event) for the originating black hole, if the “black hole universe” theory holds and they remain geometrically connected.
          1. nxpnsv · · focus · HN ↗
            I’ll have to take your word for it, my general relativity isn’t that up to date… thanks for giving me context though!
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