Actually, the above paragraph assumed that everyone now living would want to upload their minds into computronium. That assumption was way too optimistic. A significant percentage of the world’s population is likely to want to remain in a physical body. This would require us to leave this planet mostly intact. Yes, it would be a terribly inefficient use of matter, from a utilitarian perspective, but it’s a big universe. We can afford to leave this planet to the people who want to remain in a physical body. We can even afford to give them a few other planets too, if they really want. It’s a big universe, plenty of room for everyone. Just so long as they don’t force any other mind to suffer.
You could also almost certainly convert a considerable percentage of the planet’s mass to computronium without impacting the planet’s ability to support life. A planet isn’t a very mass-efficient habitat, and I doubt many people would even notice if most of the core was removed, provided it was replaced with something structurally and electrodynamically equivalent.
If computronium is of density equal to or greater than iron, physics wouldn’t need to be changed. Remove the core, replace it with a roughly spherical wad of perfected brain-matter, plus whatever structural supports are necessary to keep the crust in place, and Newton’s Shell Theorem says gravity would be the same. Add some electromagnets for the poles, and channel waste heat from the mechanisms inside to simulate volcanism where appropriate.
Even if computronium turns out to have lower density than iron, and for whatever reason it’s unacceptable to reduce surface gravity or transplant the luddites to an otherwise earthlike planet of correspondingly greater diameter, some of the core’s mass could be converted and the remainder compressed into a black hole. Again, shell theorem means there’s no difference from the outside.
You could also almost certainly convert a considerable percentage of the planet’s mass to computronium without impacting the planet’s ability to support life. A planet isn’t a very mass-efficient habitat, and I doubt many people would even notice if most of the core was removed, provided it was replaced with something structurally and electrodynamically equivalent.
You need the mass of the core to maintain the gravity. What sort of physics do you have in mind?
If computronium is of density equal to or greater than iron, physics wouldn’t need to be changed. Remove the core, replace it with a roughly spherical wad of perfected brain-matter, plus whatever structural supports are necessary to keep the crust in place, and Newton’s Shell Theorem says gravity would be the same. Add some electromagnets for the poles, and channel waste heat from the mechanisms inside to simulate volcanism where appropriate.
Even if computronium turns out to have lower density than iron, and for whatever reason it’s unacceptable to reduce surface gravity or transplant the luddites to an otherwise earthlike planet of correspondingly greater diameter, some of the core’s mass could be converted and the remainder compressed into a black hole. Again, shell theorem means there’s no difference from the outside.
good point, thanks for mentioning that.
heh, that’s actually what I meant by leaving the planet “mostly intact”, but I should have made that clearer.