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Comment by pavel_lishin | Hacker News Reader

> *Ploughshares was an exploration of peaceful uses of nuclear explosives. Turns out they're only really good at digging really gigantic holes that you can't use for 50,000 years.

Seems like it might be handy for moving asteroids around, too.

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Having walked around the crater at the Nevada nuclear test site that was at least one of the 'ploughshares' tests I can assure you that the ground is safe to walk on in a lot less than 50,000 years. In fact it was 'safe' (as in walk around but probably not sleep there) about 3 days after the test. Unlike nuclear plants which vent fission by products as a function of a partially consumed fuel rod, nuclear explosives work really really hard to extract all of the energy out of the material as quickly as possible which leaves behind few by products, and what are left behind are so dispersed as to pose little to no threat to health.

Not so much. There's nothing out there in space for the explosion to push against. You could break them apart, maybe. You could pad the bomb with propellant mass but that won't really work in the case of an asteroid. (It's extremely difficult to direct the energy while capturing enough of it to be useful, so you need small bombs and lots of them. Then you have the ablation problem on the surface of the pushee - ie the asteroid.) Project Orion explored the concept of bomb propulsion at great length.

Two references for you:

Pale Blue Dot, by Carl Sagan, contains a thorough exploration of the technology required to divert earth-bound asteroids, and the consequences of possessing that technology.

Project Orion, by George Dyson, is the definitive history of the 1950's & '60s project to construct a nuclear bomb-powered spacecraft capable of crossing the solar system in months.

The basic idea is to ablate the asteroid to deflect it: https://e-reports-ext.llnl.gov/pdf/343984.pdf http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lare...

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