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

From: Alexei Turchin (
Date: Fri Dec 12 2008 - 03:35:11 MST

So, if it is not clear, after detonation Jupiter will become a large
cloud of gase with temperature of millions K. The speed of expanding
of this cloud would be arround thousands k/ sec. Of couse it would
cool quikly. But it would be similar to supernova eplosion, just
million times weaker. But it is still enoght to destroy our
On 12/12/08, Alexei Turchin <> wrote:
> Dear William!
> Thank you you for your long post.
> Unfortunately it is misleading, because:
> 1) You think that deiterium can''t partisipate in detonation. But
> science said it can.
> 2) You think that if it detonate Jupiter will become slow burnung
> star. But detonation means explosion, not a slow burning.
> Lets look on the main article on the subject.
> "Necessary conditions for the initiation and propagation of nuclear
> detonation waves in plane atmospheres". Tomas Weaver and A. Wood,
> Physical review 20 – 1 Jule 1979,
> This article was poublished in good scientific journal "Physical
> review" and is continuatuon of famous LA-602 made by Kompton in 1945
> about the possibility that first nuclear explosion would detonate
> Earth''s atmosphera via fusion of nitrogen.
> There it is said: "We, therefore, conclude that
> thermonuclear-detonation waves cannot propagate in the terrestrial
> ocean by any mechanism by an astronomically large margin.
> It is worth noting, in conclusion, that the susceptability to
> thermonuclear detonation of a large body of hydrogenous material is an
> exceedingly sensitive function of its isotopic composition, and,
> specifically, to the deuterium atom fraction, as is implicit in the
> discussion just preceding. If, for instance, the terrestrial oceans
> contained deuterium at any atom fraction greater than 1:300 (instead
> of the actual value of 1: 6000), the ocean could propagate an
> equilibrium thermonuclear-detonation wave at a temperature £2 keV
> (although a fantastic 1030 ergs—2 x 107 MT, or the total amount of
> solar energy incident on the Earth for a two-week period—would be
> required to initiate such a detonation at a deuter¬ium concentration
> of 1: 300). Now a non-neg-ligible fraction of the matter in our own
> galaxy exists at temperatures much less than 300 °K, i.e., the
> gas-giant planets of our stellar system, nebulas, etc. Furthermore,
> it is well known that thermodynamically-governed isotopic
> fractionation ever more strongly favors higher relative concentration
> of deuterium as the temperature decreases, e.g., the D:H concentration
> ratio in the ~102 К Great Nebula in Orion is about 1:200.45 Finally,
> orbital velocities of matter about the galactic center of mass are of
> the order of 3 x 107 cm /sec at our distance from the galactic core.
> It is thus quite conceivable that hydrogenous matter (e.go, CH4, NH3,
> H2O, or just H2) rela¬tively rich in deuterium (1 at. %) could
> accumu¬late at its normal, zero-pressure density in substantial
> thicknesses or planetary surfaces, and such layering might even be a
> fairly common feature of the colder, gas-giant planets. If thereby
> highly enriched in deuterium (£10 at. %), thermo¬nuclear detonation of
> such layers could be initiated artificially with attainable nuclear
> ex¬plosives. Even with deuterium atom fractions approaching 0.3 at. %
> (less than that observed over multiparsec scales in Orion), however,
> such layers might be initiated into propagating thermo¬nuclear
> detonation by the impact of large (diam 102 m), ultra-high velocity
> (^Зх 107 cm/sec) meteors or comets originating from nearer the
> galactic center. Such events, though exceedingly rare, would be
> spectacularly visible on distance scales of many parsecs."
> On 12/12/08, Stuart Armstrong <> wrote:
> > Thanks for an informed post on the subject. It's what was missing in
> > the speculations and counter-speculations.
> >
> >
> > > To fuse, deuterium nuclei have to come together physically in an area the
> > > size of the atomic nucleus. This takes a great deal of pressure and heat.
> > > More likely than two deuterium nuclei fusing is that a deuterium nucleus and
> > > a hydrogen nucleus will fuse to form helium 3. I doubt that the pressures in
> > > a gas giant are anything like high enough to support detonation of the whole
> > > planet. Unlike nuclear fission, where fast neutron cause fission ahead of
> > > the shock front resulting from the release of energy by prior fission events
> > > and thus generate true detonations, fusion requires extremely high pressures
> > > and temperatures such as are found in the centers of stars.
> >
> >
> > ...
> >
> >
> > > Bill
> > >
> > > William P. (Bill) Hall, PhD
> > > Documentation and Knowledge Management Systems Analyst
> >

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