Re: [sl4] giant planets ignition - one more existential risk

From: Alexei Turchin (alexeiturchin@gmail.com)
Date: Sat Dec 13 2008 - 15:49:01 MST


And yes, to start detonation of the ocean you need very large fuse -
not ordinary fission bomb as in case of Tellers tube, but a very
powerful hydrogen bomb. For example, to start detonation of 1 to 300
deiterium you need explosion with power of 10**7 megatons (as 1979
artile states) - so the wight of the fuse would be around million
tons.

Of course, it would be very difficult to reate such large bomb in near
future (but not impossible) in case of use of nanomanyfacturing in
space.

But someone could use two stage detonation of the plenet -
1. to find (or create) a small (100 meters in diameter) place with
very high concentration of deiterium inside the planet - like deposit
of mineral on Earth. The 1979 article said that: ".... If thereby
highly enriched in deuterium (10 at. %), thermonuclear detonation of
such layers could be initiated artificially with attainable nuclear
explosives". So 10 per cent concentration would be enogh.
And detonate it this use of common thermonuclear bomb - may be of
several gygatons power.
2. The explosion of this small deposite will give needed 10 **7
megatons which are enogh to fuse detonation wave in large but less
enriched surroundings.

On 12/14/08, Alexei Turchin <alexeiturchin@gmail.com> wrote:
> John, how would you explain that in 1979 scientists returned to the
> question and wrote the article there they said that detonation is
> possible if concentration of deiterium are higer then 1 to 300?
>
> Maybe you remeber Teller''s idea of Simple Super bomb which doesn''t
> work. It was a tube with liqiud deiterium, and it doesn''t want to
> propogate detonation wave. But why?
>
> Because it was too small - and radiation losses take from it much more
> energy than rested in the tube. But this situation is different with
> the case of large ocean, there all emmited energy eventualy is absord
> by surrunding matter.
>
> In fact if Teller Simple Super would have widhth of several hundreds
> meters it would work. But it is inpractical for military purposes.
>
>
>
> On 12/13/08, John K Clark <johnkclark@fastmail.fm> wrote:
> > On Fri, 12 Dec 2008 08:22:03 "Larry"
> > <entropy@farviolet.com> said:
> >
> > > I certainly can't claim to rule it out, it certainly
> > > seems a liquid hydrogen ocean might be able to support a fusion detonation wave.
> >
> >
> > It was ruled out in the late 1940's. It won't even work in a ocean of
> > pure Deuterium and Tritium, and the composition of the gas giant planets
> > are about a billion times less fusion friendly than that. The only way
> > they got it to work in the H bomb is use clever geometry so that one
> > fission bomb compress the fuel and then at just the right instant
> > another fission bomb heats it.
> >
> > Just setting a bomb off in a ocean of fuel will do nothing, that's why
> > it took 7 years after the invention of fission bombs to figure out how
> > to make a H Bomb.
> >
> > John K Clark
> >
> >
> >
> > --
> > John K Clark
> > johnkclark@fastmail.fm
> >
> >
> > --
> > http://www.fastmail.fm - mmm... Fastmail...
> >
> >
>



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