Darren New <dne### [at] sanrrcom> wrote:
> Saying we're not inside a black hole implies we know what happens inside 
> a black hole.

  If we were inside a black hole, GR would be wrong, because GR predicts
certain things about the inside of a black hole (such as all space-time
geodesics going to the singularity), and this is clearly not the case
in our observable universe.

  Given that it's GR which predicts the existence of black holes, and
saying that we may be inside a black hole, which means that GR doesn't
apply after all, it would be a statement that defeats itself: If GR doesn't
apply, then how can be was we are inside a black hole, which is a consequence
of GR?

> Plus, a sufficiently large black hole can have a 
> surprising amount of livable space inside.

  But according to the GR equations everything inside the event horizon
of the black hole would inevitably crunch into the singularity. There's
no avoiding it. Inside the event horizon moving in time is equivalent to
moving in space, and all the timelines go to the singularity. Even if a
force was applied to an object to try to keep it away from the singularity
it wouldn't help, because the object travels in time.

  Source:
http://en.wikipedia.org/wiki/Schwarzschild_metric#Singularities_and_black_holes

  Basically what you are saying is that GR applies inside the event
horizon as if there was no event horizon and no singularity, which is,
of course, contradictory.

  Of course this is how I understand it. I wouldn't be surprised if I'm
wrong. There are many features of GR which I have had and still have
difficulties in understanding (the most recent case being the concept of
the cosmological horizon, which to me seemed impossible at first).

> How do you know everything doesn't go to a singularity in the future? 
> That would be the "big crunch" theory, which I understand scientists 
> believe is true if the universe contains enough mass to be finite in size.

  If all geodesics and timelines point towards the singularity, how can
anything go away from the singularity?

  Anyways, the current consensus, based on measurements, seems to be that
the universe is not only expanding, but is doing so at an accelerated rate.
It seems that there will not be a big crunch. The big rip seems more likely.

-- 
                                                          - Warp

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