Re: Nanotech Arms Race
Tue, 26 Jan 1999 02:34:56 -0800 (PST)

Spike Jones [] wrote:
>nuclear reactors dont scale down, nor do nuclear
>bombs. a certain critical mass is required. thought experiment: imagine
>a fusion weapon all the way down to two atoms of plutonium 238.

Hate to tell you, but plutionium doesn't fuse, it fissions. Fusion bombs use low-mass atoms like deuterium and tritium. Also, isn't 239 the isotope used in fission bombs?

An equivalent thought experiment for fusion bombs would be to take two atoms of deuterium, and use lasers to push them together at high speed. Do it right, and they will fuse. The lower limits for fusion bombs are technical rather than theoretical.

Michael S. Lorrey [] wrote:
>Lessee, you can make a 10 kiloton weapon these days to fit in a suitcase, lets
>say, generously that that suitcase still weighs in at 100 kilos., so 100
>kilogram devices can produce 10 million kilograms of TNT levels of explosive

Firstly, the US backpack nukes were man-portable, so I'd say 50kg as an upper limit; I have the approximate figures somewhere, but not close to hand. Secondly, they were fission bombs (or possibly fusion-boosted fission) with lots of shielding to protect the user from the radiation from the decaying uranium. Nanofusion bombs shouldn't require anywhere near as much shielding; little to none if you aren't concerned about radiation detectors.

As a rule of thumb, the potential yield of nuclear explosives is about a million times higher than an equivalent mass of chemical explosives; so a well-designed bomb with one gram of fusion fuel should have a yield around a ton... the mass of the laser initiatiors, etc, is another question. So my mosquito estimate was at least an order of magnitude too large, but it should still be able to produce a yield up to hundreds of kilos of TNT.