Re: Understanding nanotech

Robert J. Bradbury (
Sun, 29 Aug 1999 15:20:14 -0700 (PDT)

On Sun, 29 Aug 1999 wrote:

> Good point: You're not "making" "new energy" in the process of using
> nanotech devices.

Yes, but you could shift local energy densities significantly and that is likely to have a significant weather impact.

> Also, shouldn't the over-all calculation take into account the heat
> "savings" we get from using more efficient industrial and technological
> process?

Yes and no. The survival of humans will be *much* more efficient, since you are harvesting energy from the sun at 20+% (solar cells) instead of 1+% (plants).

However, the calculation assumes that every person on the planet can find *some* use for his 10 kg allocation of robots consuming ~100KW of power. Right now most of the people on the planet don't come close to consuming 100KW. A standard house (with 200 Amp service, probably above average), only pulls 20KW when it is maxed out.

If all of the nanobots are running we are using ~50 times the total current production of power on the planet. So the current fossil/coal/CO2 debate etc. *pales* in comparison to the nanobot power allocation issues. You also have the problem that if you want to use them at the densities that people typically have in cities, then you have a really big heat removal problem.

If you consider the possibility that all of the solar cells are tilt-mirror designs (as in some current view projectors) then you have a means for significantly altering the energy absorption/reflection over *very* large surface areas. Now you have the means to make a significant impact on global weather patterns by controlling local evaporation rates, winds, etc. Now individuals potentially have the power to "steal" their neighbors water, or make it "rain" on their parade). Though I think water resources will not be a big issue post-nanotech, I think people will start to become upset if I decide to move the rain from Seattle to some city in Texas. The power allocation discussions are only going to be a warm up for the weather control discussions (assuming we have computers powerful enough to give us reasonable predictions about how things interact (within the limits of chaos). We will then have the weather "naturalists" picketing international conferences allocating those still-unmananged negative weather side effects equitably between all countries.

Another power-harvesting "style" suggested by Robert is a suspended overhead canopy that only absorbs ~1% of the incident light. It still allows almost all of the plant life underneath to grow but has to be much larger in terms of the infrastructure you use to keep it aloft and repaired (from weather damage), etc.

Another approach, as I believe has been suggested might be energy harvesting "swarms", circulating high in the atmosphere, returning stored energy to the ground periodically.

Whatever way we do the harvesting though, unless we construct many tall skyscrapers that have a very large outward radiating surfaces in the upper atmosphere, or active swarms that pick up a heat load, fly into the upper atmosphere and release it into space or some other process, we are going to be heat constrained on the surface of the planet. Perhaps after Nanomedicine comes out (so everyone has some of the relevant equations), we can start a small working group on whether these things are feasible.

> Seems like reducing whatever current effect human technology has on
> the planet's heat budget would have to be offset against heat created
> by use of nanotech . . . of course, that's subject to the same idea
> contained in the first point, i.e. that the Earth's energy system
> has only one significant real input -- solar energy.

Yes, solar energy is still much larger than all of our puny technological efforts. The ability to relatively easily manipulate it is going to result in some interesting property rights issues (probably akin to the discussions regarding extensions of national rights out to various distances in the oceans).