Re: Nanotech
That’s exactly my point: if nanotech performs as advertised by its starriest-eyed advocates, then interstellar colonization can be done with small payloads and energy is cheap enough that they can be launched easily. That is a very big “if,” and not one we can shrug off or assume in advance as the underlying principle of all our models.
What if nanotech turns out to have many of the same limits as its closest natural analogue, biological cells? Biotech is great for doing chemistry, but not so great for assembling industrial machinery (like large solar arrays) in a hostile environment.
As for the “nuclear cars and basement reactors” being out of the picture because of politics and not engineering, that’s… really quite impressively not true, I think. Fission reactors create neutrons that slip through most materials like a ghost and can riddle you with radiation unless you stand far away or have excellent shielding. Radioactive thermal generators require synthetic or refined isotopes that are expensive by nature because they have to be [i]made[/i], atom by atom… and they’re still quite radioactive if they’re hot enough to be a useful power source.
The real problem isn’t the atomic power source itself, it’s the shielding you need to keep it from giving you cancer. There’s no easy way to miniaturize that, because neutron capture cross-sections play no favorites and can’t be tinkered with.
This stuff is not a toy, and there are very good reasons of engineering why it never made the leap from industrial equipment to household use, except in the smallest and most trivial scales (such as americium in smoke detectors). It’s not just about politics.
Re: Nanotech That’s exactly my point: if nanotech performs as advertised by its starriest-eyed advocates, then interstellar colonization can be done with small payloads and energy is cheap enough that they can be launched easily. That is a very big “if,” and not one we can shrug off or assume in advance as the underlying principle of all our models.
What if nanotech turns out to have many of the same limits as its closest natural analogue, biological cells? Biotech is great for doing chemistry, but not so great for assembling industrial machinery (like large solar arrays) in a hostile environment.
As for the “nuclear cars and basement reactors” being out of the picture because of politics and not engineering, that’s… really quite impressively not true, I think. Fission reactors create neutrons that slip through most materials like a ghost and can riddle you with radiation unless you stand far away or have excellent shielding. Radioactive thermal generators require synthetic or refined isotopes that are expensive by nature because they have to be [i]made[/i], atom by atom… and they’re still quite radioactive if they’re hot enough to be a useful power source.
The real problem isn’t the atomic power source itself, it’s the shielding you need to keep it from giving you cancer. There’s no easy way to miniaturize that, because neutron capture cross-sections play no favorites and can’t be tinkered with.
This stuff is not a toy, and there are very good reasons of engineering why it never made the leap from industrial equipment to household use, except in the smallest and most trivial scales (such as americium in smoke detectors). It’s not just about politics.