"Can you point to some of the evidence you used to arrive at the conclusion that the high-tech civ is centered in the core, or that they're gating civilizations entering it?"
A high-tech civilization in the core is IIRC spelled out in A Deepness in the Sky because the planet there comes from the core. On its own that means nothing, but combined with A Fire upon the Deep it means there's more down there than the Upper Beyond realizes.
Gating civilizations entering it is a bit of my own interpolation. One alternative is that powers simply die out after 10 years because there is some reason they need to advance to the next level, but they're locked out by the Zones.
"BOTH the speed of computation AND the laws of physics (whether FTL travel and communication are physically possible)"
My read is that that is cause and effect, though, not two effects. The amount of computation you are allowed is limited; super high tech becomes impossible, then FTL, then our tech, then even any system that performs simple and meaningful mechanical computations. Even a car engine can be viewed as performing computations to stay running.
This is a particularly sci-fi element. I don't think it's immediately obvious how to separate the universe into "meaningful" computation and the sort of computation a stationary rock is "performing" as its atoms jiggle around, such that one can distinguish at the level of the laws of physics themselves between a rock and a car engine or other simple mechanical device. Then again, I'm not a superintelligent civilization with nearly unbounded resources and deeper access to the laws of physics than I have. (Arguably, under the circumstances, it could simply be an enormous computation of its own, in which they aren't doing it via clever rewrites of the universe, but basically by executive fiat, or, to put it another way, the standard may literally be "I know it when I see it" for some sufficiently intelligent "judge", rather than any sort of physical law.)
> This is a particularly sci-fi element. I don't think it's immediately obvious how to separate the universe into "meaningful" computation and the sort of computation a stationary rock is "performing" as its atoms jiggle around, such that one can distinguish at the level of the laws of physics themselves between a rock and a car engine or other simple mechanical device.
It sounds like what you’re asking boils down to “is entropy a real thing, or is it subjective / relative to our purposes and measurements.” And that the Zones essentially work by enforcing an “entropy quota” on things according to where they are in the galaxy- things in the Slow Zones must be very high-entropy (and somehow are forced to become so if they weren’t before) and things in the Transcend can be low-entropy in ways we couldn’t currently imagine.
IIRC the planet comes from the direction of the core, which the protagonists assume implies from the core... but it could have just been travelling through it, no?
As for the FTL limit, I always thought the causality is the reverse - that compute power that the Beyond has is because their computers run on the same physics that allows FTL travel.
If FTL was driven solely by compute, then you'd never have a clear boundary in the first place - just shorter and shorter hyperspace jumps, perhaps until the point where they become infeasible (because the amount of time it takes to make one, including compute, is more than just travelling there). But the way the book describes it, the boundary is qualitative, and FTL drives plainly don't activate once in the Slow Zone. Ditto for FTL comms.
Yes, that was my take too. "OnOff’s eccentric orbit had at least passed through those unseen depths." -- but the irony of the end of the book is that they're going to be going entirely the wrong way. The ellipse that describes its orbit is eccentric -- that means it can touch both points near the center of the galaxy and points outside the Slow Zone.
A high-tech civilization in the core is IIRC spelled out in A Deepness in the Sky because the planet there comes from the core. On its own that means nothing, but combined with A Fire upon the Deep it means there's more down there than the Upper Beyond realizes.
Gating civilizations entering it is a bit of my own interpolation. One alternative is that powers simply die out after 10 years because there is some reason they need to advance to the next level, but they're locked out by the Zones.
"BOTH the speed of computation AND the laws of physics (whether FTL travel and communication are physically possible)"
My read is that that is cause and effect, though, not two effects. The amount of computation you are allowed is limited; super high tech becomes impossible, then FTL, then our tech, then even any system that performs simple and meaningful mechanical computations. Even a car engine can be viewed as performing computations to stay running.
This is a particularly sci-fi element. I don't think it's immediately obvious how to separate the universe into "meaningful" computation and the sort of computation a stationary rock is "performing" as its atoms jiggle around, such that one can distinguish at the level of the laws of physics themselves between a rock and a car engine or other simple mechanical device. Then again, I'm not a superintelligent civilization with nearly unbounded resources and deeper access to the laws of physics than I have. (Arguably, under the circumstances, it could simply be an enormous computation of its own, in which they aren't doing it via clever rewrites of the universe, but basically by executive fiat, or, to put it another way, the standard may literally be "I know it when I see it" for some sufficiently intelligent "judge", rather than any sort of physical law.)