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Reactor at Earth's Core?
An anonymous submitter sent in this story suggesting that uranium in the Earth's core may be acting as a giant breeder reactor, generating a large amount of heat and perhaps being responsible for the Earth's magnetic field.
In an article titled No second chance: can Earth explode as a result of Global Warming? by Dr Tom J. Chalko, MSc, PhD, Head of Geophysics Division, Scientific E Research P/L, Melbourne, Australia writes
"It is a well established fact, verified by decades of seismic measurements, that the Earth's inner core is a nearly spherical solid of about 1220 km radius that occupies the central position of our planet. The generally accepted view today is that this solid grew slowly to its current size as a result of the "crystallization" of the surrounding liquid. The "latent heat" of this "crystallization" allegedly explains how the inner core generates heat.
This article considers global hydro-gravitational equilibrium conditions for the Earth's inner core and presents a rigorous and compelling scientific proof that the solid core of our planet could never be smaller or lighter than a certain minimum, otherwise the core would not be able to remain in the center of the planet.
Since the inner core could have only been larger and heavier in the past than it is today - it cannot be the result of any "crystallization". This simple conclusion has astonishing consequences.
Imagine a gigantic object of 1220 km radius that slowly becomes smaller, lighter and gives off heat for millions of years. What could it be? It can only be an object that generates heat by nuclear decay.
The main consequence of the above is that all heat generated inside Earth is of radionic origin. In other words, Earth in its entirety can be considered a nuclear reactor fuelled by spontaneous fission of various isotopes in the super-heavy inner core, as well as their daughter products of decay in the mantle and in the crust.
Life on Earth is possible only because of the efficient cooling of this reactor - a process that is controlled primarily by the atmosphere. Currently this cooling is responsible for a fine thermal balance between the heat from the core reactor, the heat from the Sun and the radiation of heat into space, so that the average temperature on Earth is about 13 deg C.
Since the radionic heat is generated in the entire volume of nuclear fuel (the entire Earth) and cooling can occur only at the surface, the hottest point of the planet should be in its very center.
This article examines the possibility of the "meltdown" of the central part of the inner core due to the reduced cooling capacity of the atmosphere, which traps progressively more solar heat due to the so-called greenhouse effect. Factors that can accelerate the meltdown process, such as an increased solar activity coinciding with increased emissions of greenhouse gasses are discussed.
The most serious consequence of such a "meltdown" could be a gravity-buoyancy based segregation of unstable isotopes in the molten inner core. Such a segregation can "enrich" the nuclear fuel in the core to the point of creating conditions for a chain reaction and a gigantic atomic explosion. Can Earth become another "asteroid belt" in the Solar system?
It is a common knowledge (experiencing seasons) that solar heat is the dominant factor that determines temperatures on the surface of Earth. In the polar regions however, the contribution of solar heat is minimal and this is where the contribution of the heat from the inside of our planet can be seen best. Raising polar ocean temperatures and melting of polar caps should therefore be the first symptoms of overheating of the inner core reactor.
While politicians and businessmen still debate the need for reducing greenhouse emissions and take pride to evade accepting any responsibility, the process of overheating of the inner core reactor has already begun - polar oceans have become warmer and polar caps have begun to melt. Do we have enough imagination, intelligence and integrity to comprehend the danger before the situation becomes irreversible?
Those crazy Aussies ahead of their time!
If we don't fight for ourselves no one will.
Man, is this article bad.
The article proposes a 5-mile sphere of uranium at the Earth's core as the source of Earth's geothermal energy.
Now, the idea of radioactive decay powering the Earth's geothermal heat generation isn't a new one - in fact, it's one of the more plausible models, as it works quite well over a very long time frame and explains the presence of helium in the mantle. However, the uranium, thorium, and other elements involved would be diffused through the core material (i.e. in solution in the liquid outer core, or as dopants in the iron crystal of the inner core). The absolute concentration of uranium in the Earth is very, very low. Without a really strong mechanism operating to separate it out and concentrate it, it's going to remain a trace impurity in other ores, and not a ball at the center of the Earth.
Secondly, I'm pretty sure that a 5-mile ball would be over the critical mass/volume envelope for an uncontrolled chain reaction of the U-235 and U-233 present in uranium ore. The fact that the Earth hasn't exploded suggests that uranium is not concentrated into a ball. Anyone with the fast-neutron cross section data care to work this out?
Now, on to other questionables.
The Earth's magnetic field is created by movement of the conducting material in the Earth's outer core. The polarity changes in the field are adequately explained by the idea that turbulence destabilizes the dynamo fluid currents every so often. A fascinating article was published about this a while back, but the citation escapes me.
Turbulence happens; it's a known and expected phenomenon. However, the article authours propose no mechanism for their magical solid-state fission reactor to turn on and off every so often to reset the dynamo currents. Thus, I consider the turbulence conjecture the more plausible.
Now, on to Jupiter. While Jupiter undoubtedly also has heavy element fission contributing to its heat, the majority of its heat is expected to come from it essentially continuing to slowly compact itself. The idea is that as hydrogen progresses from gas to liquid to metallic liquid to metallic solid state, it undergoes several exothermic phase transitions (analagous to the heat of condensation for more common substances). This provides a feedback loop that limits the rate of conversion - for example, if a lot of liquid hydrogen starts converting to liquid metallic hydrogen, the boundary layer heats up, which makes it less favourable for the conversion to continue. The rate of conversion for some of these phases is expected to be slow enough for Jupiter not to have reached its final equilibrium composition. If the conversion is still going on, then as it's exothermic, it could indeed explain heat generation in Jupiter.
A similar mechanism involving crystallization of iron was proposed as a source of Earth's geothermal energy, though this is less convincing as the amounts of matter involved are small enough that Earth should have reached equilibrium long ago.
In summary, the "mysteries" that the article attempts to invoke compact reactors to solve are already adequately explained without the need for such an implausible mechanism.
But how do you get the fission products out of a solid chunk of uranium? Solids neither convect nor differntiate.
This theory also doesn't explain why the Sun's magnetic field chances orientation in a 22-year cycle.
I'm not sure about the second point, either. Uranium, as far as I know, chemically reacts with other elements and doesn't necessarily differentiate out of the Earth. If you sliced open Earth, you wouldn't find it layered like an onion, one layer per element. Many of them are chemcially mixed in with the major constituents, like iron.
To add a point: the authors really don't understand energy production or planets (possibly both). Jupiter has to generate about as much energy as it takes in from that Sun. That's or order 10 Watts per square meter, according to my quick calculation. Now, Jupiter's core, IF it has a core at all, is mainly ices. The rocky/metal bit is probably not larger than Earth. So it shouldn't be generating more power than Earth's core. Earth's outward heat flux due to internal heat is 0.01 Watts per square meter. Consider that Jupiter has over 100 times the surface area, and now your core has to be generating 100,000 times the energy that Earth's is, despite being the same size.
Does this sound reasonable?
In one of Stephen Baxter's books, he imagines a nifty successor to the Humvee(Hummer?). It has four electric motors in the HUB of each wheel. I visualize it to be kind of like a giant computer fan, where the motor is wrapped around the axle and instead of fan blades you have a tire attached to it. I always wondered why this slick idea never got more attention. It would have so many advantages. You could replace the entire transmission with wires, witch would improve efficiency dramatically. I would do it this way. Have an ultra-efficient Diesel engine sized to the AVERAGE load of the vehicle. It would only run at one RPM, which makes it easier to make a cleaner and more efficient engine. The engine would turn a high-efficiency DC generator (better than 90%), whose output would be cached in a bank of 2700 Farad ultra-capacitors to handle spikes in demand. (http://www.maxwell.com/ultracapacitors/products/T C2700.html). All this would make the internal combustion engine much more efficient. You could also lose two of the motors and still keep on truckin'.
Smoking is an expensive, slow, and unreliable method of suicide.