"Billy Brown" <email@example.com> writes:
> Anders Sandberg wrote:
> > Well, an entity composed of multi-million light-year positronium pairs
> > and faint gravity waves, thinking thoughts over eons in a silent and
> > cold universe doesn't strike me as that bizarre. Much weirder things
> > are already happening in mathematics :-) Whether this is implementable
> > is another question, we need something like a billiard ball computer
> > CA example to see if it is feasible according to known laws of
> > physics, and then of course arguments for the practical
> > implementability..
> To make that work you would have to use isolated subatomic particles to
> substitute for the molecules that no longer exist. Now, I'm not going to
> say that an SI couldn't make it work, but from a human perspective it seems
> improbable - it would be like trying to make a gaseous, chemical-based life
> form that could live in deep space without any kind of protective membrane.
It does sound a bit too flimsy, yes. Reminds me a bit of Game of Life machines like the adder or prime calculator - complex patterns that will break down if subjected to too much (i.e. any ) noise. But in a Dysonian asymptotic head death universe noise might indeed be very low. I would really like to see if we could come up with more theoretical applied science designs for intelligent structures that can live in this era, or even in the cold period after the stars.
> > You seem to be assuming that if you remove the big bang model, you
> > will also need to get rid of everything associated with it - including
> > the expansion of the universe, apparently the dynamics of spacetime
> > and everything else done in cosmology.
> No, just one particular feature. The current model holds that there was one
> big bang, which is now over, and no similar event can ever occur again.
OK, that is actually fairly easy to explain. Where would another big bang occur? Note that it was a creation and expansion of spacetime, it didn't occur inside a pre-existing spacetime. So the closest thing to a new big bang would be the budding off of a baby universe, but all models so far suggests that this doesn't change our universe much (some gravity waves from the collapsing navel wormhole). Conservation of energy is locally upheld, so you need some rather extreme changes to our theories in order to get a huge explosion inside our spacetime (baby universe creation and all that of course gets away with their stuff due to the weird properties of global relativity, where energy isn't conserved).
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