Hmm, so thinking about this more, I think that Holevo's theorem can probably be interpreted in a way that much more substantially restricts what one would need to know about the other n bits in order to simulate them, especially since one is apparently simulating not just bits but qubits. But I don't really have a good understanding of this sort of thing at all. Maybe someone who knows more can comment?
Another issue which backs up simulation being easier- if one cares primarily about life forms one doesn't need a detailed simulation then of the inside of planets and stars. The exact quantum state of every iron atom in the core of the planet for example shouldn't matter that much. So if one is mainly simulating the surface of a single planet in full detail, or even just the surfaces of a bunch of planets, that's a lot less computation.
One other issue is that I'm not sure you can have simulations run that much faster than your own physical reality (again assuming that the simulated universe uses the same basic physics as the underlying universe). See for example this paper which shows that most classical algorithms don't get major speedup from a quantum computer beyond a constant factor. That constant factor could be big, but this is a pretty strong result even before one is talking about general quantum algorithms. Of course, if the external world didn't quite work the same (say different constants for things like the speed of light) this might not be much of an issue at all.
Here.
Long story short, it's an attempt to justify the planetarium hypothesis as a solution to the Fermi paradox. The first half is a discussion of how it and things like it are relevant to the intended purview of the blog, and the second half is the meat of the post. You'll probably want to just eat the meat, which I think is relevant to the interests of many LessWrong folk.
The blog is Computational Theology. It's new. I'll be the primary poster, but others are sought. I'll likely introduce the blog and more completely describe it in its own discussion post when more posts are up, hopefully including a few from people besides me, and when the archive will give a more informative indication of what to expect from the blog. Despite theism's suspect reputation here at LessWrong I suspect many of the future posts will be of interest to this audience anyway, especially for those of you who take interest in discussion of the singularity. The blog will even occasionally touch on rationality proper. So you might want to store the fact of the blog's existence somewhere deep in the back of your head. A link to the blog's main page can be found on my LessWrong user page if you forget the url.
I'd appreciate it if comments about the substance of the post were made on the blog post itself, but if you want to discuss the content here on LessWrong then that's okay too. Any meta-level comments about presentation, typos, or the post's relevance to LessWrong, should probably be put as comments on this discussion post. Thanks all!