OK, now this baloney is starting to get somewhere. First: which direction convection should happen in Nature?: (A) up to equator, sinks at poles (B) up to poles, sinks at equator? Answer: I claim B should be Nature's choice. The reason is the nonlinear term for interaction between viscosity and gravity. Specifically, gravity is slightly stronger in the polar direction (no centrifugal counterforce). And it also is effectively stronger when acting on hot stuff, because hotter stuff has lower viscosity. So to enjoy the most effective drive for convection, you want to make the hot stuff rise in the polar direction (enjoying the interaction of strong with strong, giving everything a boost) then the cold stuff sinks from the equator. So this effect should bias things to make sure the convection happens predominantly in style (B). This is good since it agrees with my previous post that (B) is the direction that creates a self-reinforcing dynamo, while (A) would experience negative feedback non-dynamo. Great. (Also note, Venus is almost nonrotating which fits with the observation it has almost no magnetic field.) Second. My model sounded great qualitatively, but was yielding way too small magnetic field strength predictions. But now the solution to that puzzle occurs to me. See http://en.wikipedia.org/wiki/Structure_of_the_Earth Inside the earth is a region called the "outer core" (1220 km < r < 3400 km) believed to consist mainly of liquid metal, mainly iron & nickel. All other regions are mainly solid or semisolid/ductile. (Semisolid still has convection via diffusive atomic rearrangements.) So, this has got to be where the magnetic action is. Since liquid, we should get much faster flow speeds (far lower viscosity, by factor of up to 10^25, versus the Mantle), And since metal, much higher electrical conductivity (by factor of 10^7), and since smaller than the earth (outer core has outer radius half that of the whole planet) everything is more concentrated (smaller distances imply greater fields from same-amp currents). In view of all this, there now is probably no problem at all explaining (at least at the low precision level of my crude estimates) how the Earth can have as large a magnetic field as it does. And in case you are worried I'm now predicting way too LARGE a field, no problem, we can weaken it by postulating there's a lot of funny turbulent motion, which cancels out 99% leaving only 1% uncanceled (or pretty much whatever weakening-factor we want can be postulated in this way). So... I now think, yes, this is the explanation for the Earth's magnetic field. How much of this thinking is original? No idea, but probably not a whole lot.