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Old 12-30-2017, 05:39 PM
SamuelA is offline
Join Date: Feb 2017
Posts: 3,903
Originally Posted by k9bfriender View Post
Tell you what, you come up with, from first principles and the knowledge that they would have had in the 30's and early 40's that xenon would be produced by a nuclear reaction of U-235, would act as a neutron poison, and would have a half life of a few hours. Then show, with the same knowledge, that there would not be a build up of other poisons that have much longer half lives that would interfere with a nuclear reaction to the extent of making a reactor essentially impossible to run.

If I had said to someone of your certainty that there may be problems in building a nuclear reactor, would you ask me what laws of physics could exist that could interfere with getting a sustained chain reaction?

It's not the laws of physics, it is how they end up working together to make more complicated things that serve our needs that is the difficulty.

Now, as far as nano-bots, I see any future in that as being modified cells, not tiny robots. Cellular machinery doesn't work like macroscopic machinery works at all, it's not servos and actuators, it is hydrophobic and hydrophilic surfaces interacting (far more complicated than that, but that's a start). That you feel that you can use these properties to make little robots that will do your bidding is not a straightforward proposition. It may be possible, but there is no real roadmap to that, nor any real research that indicates that it is certainly possible, it's more of a maybe.
With chain reactions, no matter how nasty the neutron poisoning happened to be, you could have always increased reactivity to overcome it. Even if you end up with a reactor that is basically just a lump of U-235 gas in a centrifuge at high pressure. The chain reaction is so powerful that you can probably find a way to make it work.

As for nanobots, you're ignoring that we have made prototypes for motors and gears and checked the math on more complex little structures that we can't make yet but they mechanically work.

If you look at nature you see countless sloppy little mechanisms that all definitely work. So you'd have to really feel over-skeptical to think you can't make your own, better mechanisms of the same class of thing that do your bidding.

And I see you just ignored the redirecting the asteroids one because there's no traction there. We already checked the math on that, that works unless the asteroid is extraordinarily large or you have very little time to react.