George Levy writes:
> An RAC/CSO may be physically realizable using a black hole. Just fly near a
> black hole and drop a computer into it, preferably one that runs Microsoft
> software. As it falls down you'll observe a CSO. Or leave the computer behind
> and YOU take the plunge. As you get nearer the BH the computer will look like
> an RAC. Of course this doesn't take into account quantum effects.
This doesn't quite work. From the outside, you do observe the computer
effectively slow to a halt (actually it stops emitting light altogether)
as it falls in, but after all there's no trick to making computers that
halt. What you want is to *be* the CSO, so that you see an infinite amount
of computation elsewhere.
In the case of an infalling observer, he does not see the universe go
through an infinite amount of time. The problem is that he passes the
event horizon at the speed of light, doppler shifting the rest of the
universe and slowing its observed speed. The net result is that he only
sees a finite amount of events pass in the outside world as he falls in.
If you could build a solid shell around the event horizon and lower
yourself arbitrarily close to it (not falling in), you could be a CSO,
but you can't do that. No material is strong enough to let you get
arbitrarily close to the event horizon. So you cannot see an infinite
amount of computation done outside, unless you have an infinitely strong
material (the observer would also have to be infinitely small).