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• Heteromeles commented on In which I am crabby about viral archery videos.
  You just pointed out the good reason to colonize planets, or at least dwarf planets that are big enough to have some sort of differentiation, if not plate tectonics and life. These processes are really, really good at concentrating elements into easily minable ores. Small asteroids have a lot in common with landfills, in that they're a bunch of well-sorted elements that take a lot of refining to make anything useful. As for low-energy concentrating, I'd find an organism (probably a bacterium or possibly a plant) that concentrated uranium, grind up the asteroid, and feed it into a bioreactor. That's...
• gasdive (he, him, ia) commented on In which I am crabby about viral archery videos.
  Hi Heteromeles, I'm a huge space fanboy, but I don't think I can make a case for colonising planets based on Uranium mining. The concentration of U into the crust seems to depend on plate tectonics. There's none on Mars. Venus seems to have (or had) a form of plate tectonics and may have concentrated U in the crust but has no weathering that would lead to ore deposits. There's also the matter of delta V for return of uranium from the surface of Venus to Earth. Despite my incredible mistake in maths in the previous post, it's still pretty...
• Nojay commented on In which I am crabby about viral archery videos.
  I was sort of assuming that in 500 years time there are no other "primary" energy sources left as the ones we use now involve mostly involve fossil carbon. Either we stop committing slow suicide by not extracting and burning the last remnants of fossil carbon or we just run out of anything that can be extracted with less energy that it will take to get it out of the ground and to its destination (Energy Return Over Energy Investment or EROEI). At this point only nuclear electricity is a "primary" energy source that has to fill in for everything...
• gasdive (he, him, ia) commented on In which I am crabby about viral archery videos.
  I'd have to agree with Nojay. If you have to make everything out of electricity, you're going to need a lot of it. Right now electricity is one of the end products, but lots of things get powered directly. This will be pretty much the reverse. I think we both felt that would roughly even out....
• J Thomas commented on In which I am crabby about viral archery videos.
  I'm on the fence about electricity from fission. First off, the arguments that population will keep expanding and energy use per capita will keep expanding so we have to be able to meet those energy goals is bogus. Population will not keep expanding. The question is whether we can keep it from crashing to a new, much-lower carrying capacity, and whether we can avoid extinction in the next thousand years or so. We will not keep increasing energy use because without new technology we don't yet know how to get, we can't. There is lots of uranium. As soon as...