1. Is there proof in either the CMB or other observed astronomical phenomena for Big Crunch?
  2. Could there have been a partial Big Crunch maybe like a cluster of Black Holes colluding to create a disappearing zone in the Universe?
  • 2
    $\begingroup$ AFAIK with current and projected space expansion rate, Big Crunch is pretty much a dead idea. Hawking Radiation was an extra nail in its coffin. Supermassive black holes are still a fair game, but with Hawking Radiation they aren't nearly as eternal as they were believed to be, meaning after wiping their part of space clean they'll just evaporate quietly after some time. $\endgroup$
    – SF.
    Feb 9 '16 at 0:00
  • 2
    $\begingroup$ The answer to this and your other question is "not really". The dynamics of the Universe is governed by the density of its various components, which observationally we find not to support these theories, but rather an ever-expanding, accelerating Universe (i.e. no Crunch) which came from a Big Bang (i.e. no Bounce). Other solutions exist as well, e.g. a loitering universe, but our Universe doesn't seem to be such one. $\endgroup$
    – pela
    Feb 9 '16 at 7:32
  • $\begingroup$ @pela The problem isn't just observational, but theoretical as well. An oscillating universe would violate the second law of thermodynamics. $\endgroup$ Oct 4 '16 at 14:15

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