#1 - Caution doesn’t solve problems, it finds solutions if they exist. You can’t use caution to ignore air resistance when building a rocket. (Though collapse is not necessarily expected—there’s plenty of interstellar dust).
#4 - I didn’t know about Landauer’s principle, though going by what I’m reading, you’re mistaken on its interpretation—it takes ‘next to nothing’ times the part of the computation you throw out, not the part you read out, where the part you throw out increases proportional to the negentropy you’re getting. No free lunch, still, but one whose price is deferable to the moment you run out of storage space.
That would make it possible for dark matter to be part of a computation that hasn’t been read out yet, though not necessarily a major part: I’m not sure the below reasoning is correct, but The Landauer limit with the current 2.7K universe as heat bath is 0.16 meV per bit. This means that the ‘free’ computational cycle you get from the fact that you only need to pay at the end would, to a maximally efficient builder, reward them with 0.16 meV extra for every piece of matter that can hold one bit. We don’t yet have a lower bound for the neutrino mass, but the upper bound is 120 meV. If the upper bound is true, that would mean you would have to cram 10^3 bits in a neutrino before using it as storage nets you more than burning it for energy (by chucking it into an evaporating black hole).
I don’t have data for #2 and #3 at hand. It’s the scientific consensus, for what that’s worth.
1-3: You are certainly right that cold and homogenous black matter is the scientific consensus right now (at least if by consensus we mean « most experts would either think that’s true or admit there is no data strong enough to convince most experts it’s wrong »).
The point I’m trying to make is: as soon as we say « computronium » we are outside of normal science. In normal science, you don’t suppose matter can choose to deploy itself like a solar sail and use that to progressively reach outside regions of the galaxy where dangerous SN are less frequent. You suppose if it exists it has no aim, then find the best non-weird model that fits the data.
In other words, I don’t think we can assume that the scientific consensus is automatically 10^4 or 10^8 strong evidence for « how sure are we that black matters is not a kind of matter that astrophysicist usually don’t botter to consider? », especially when the scientific consensus also includes « we need to keep spending ressources on figuring out what black matter is ». You do agree that’s also the scientific consensus, right? (And not just to keep labs open, but really to add data and visit and revisit new and old models because we’re still not sure what it is)
4: in the theory of purely reversible computation, the size of what you read dictates the size you must throw out. Your computation is however more sounded than the theory of pure reversible computation, because pure reversible computation may well be as impossible as perfectly analog computation. Now, suppose all black matters emits 0,16 mev/bit. How much computation per second and kilo would let the thermal radiation largely below our ability to detect it?
#1 - Caution doesn’t solve problems, it finds solutions if they exist. You can’t use caution to ignore air resistance when building a rocket. (Though collapse is not necessarily expected—there’s plenty of interstellar dust).
#4 - I didn’t know about Landauer’s principle, though going by what I’m reading, you’re mistaken on its interpretation—it takes ‘next to nothing’ times the part of the computation you throw out, not the part you read out, where the part you throw out increases proportional to the negentropy you’re getting. No free lunch, still, but one whose price is deferable to the moment you run out of storage space.
That would make it possible for dark matter to be part of a computation that hasn’t been read out yet, though not necessarily a major part: I’m not sure the below reasoning is correct, but The Landauer limit with the current 2.7K universe as heat bath is 0.16 meV per bit. This means that the ‘free’ computational cycle you get from the fact that you only need to pay at the end would, to a maximally efficient builder, reward them with 0.16 meV extra for every piece of matter that can hold one bit. We don’t yet have a lower bound for the neutrino mass, but the upper bound is 120 meV. If the upper bound is true, that would mean you would have to cram 10^3 bits in a neutrino before using it as storage nets you more than burning it for energy (by chucking it into an evaporating black hole).
I don’t have data for #2 and #3 at hand. It’s the scientific consensus, for what that’s worth.
1-3: You are certainly right that cold and homogenous black matter is the scientific consensus right now (at least if by consensus we mean « most experts would either think that’s true or admit there is no data strong enough to convince most experts it’s wrong »).
The point I’m trying to make is: as soon as we say « computronium » we are outside of normal science. In normal science, you don’t suppose matter can choose to deploy itself like a solar sail and use that to progressively reach outside regions of the galaxy where dangerous SN are less frequent. You suppose if it exists it has no aim, then find the best non-weird model that fits the data.
In other words, I don’t think we can assume that the scientific consensus is automatically 10^4 or 10^8 strong evidence for « how sure are we that black matters is not a kind of matter that astrophysicist usually don’t botter to consider? », especially when the scientific consensus also includes « we need to keep spending ressources on figuring out what black matter is ». You do agree that’s also the scientific consensus, right? (And not just to keep labs open, but really to add data and visit and revisit new and old models because we’re still not sure what it is)
4: in the theory of purely reversible computation, the size of what you read dictates the size you must throw out. Your computation is however more sounded than the theory of pure reversible computation, because pure reversible computation may well be as impossible as perfectly analog computation. Now, suppose all black matters emits 0,16 mev/bit. How much computation per second and kilo would let the thermal radiation largely below our ability to detect it?