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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.
This is interesting stuff. I've always read that scientists thought that the core was made out of iron (Fe). If this new revelation is true then the density of the center of the core may be much higher than previously thought. What does that mean for the rest of the core? The density must be lower than previously thought???
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.
When did the Earth's magnetic field suddenly become such a "big mystery"?
Also, when did natural radioactive decay become a definition of a reactor?
Next thing ya know, we'll be discussing who invented the telephone!
So the earth is sort of like a giant shed in your mother's backyard?
"And like that
Combine that with the exploded planet hypothesis and you got yourself a great book.
The question is just how much of a chain reaction there is. I guess traditionally, the assumption was "not much". But it seems quite plausible that uranium might concentrate and actually start a significant chain reaction.
Anyone want to take bets on how long until some boy scout tries to make a planet in his mother's potting shed?
--Dan
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.
As usual, the pop science publications do this little justice. The primary literature is published by the Proceedings of the National Academy of Sciences and is published online at: http://www.pnas.org/cgi/content/full/98/20/11085 and certainly makes the case sound more convincing.
The article at EV world doesn't didn't, to my dismay, discuss the electro-magnetic implications at all. It sounded like a stretch to me to conflate geomagnetism with a nuclear process.
Yes, they do: Also, re 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.
There is such a mechanism. Everyone agrees that the core is iron. How did that happen, when the Earth coalesced from random rocky materials? The same way. If iron, why not uranium? From the article:
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.
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.
There is such a mechanism. Everyone agrees that the core is iron. How did that happen, when the Earth coalesced from random rocky materials? The same way. If iron, why not uranium?
Iron is plentiful. Enough of it was present for gross gravitational effects to be enough to separate it from lighter ores within solution.
Uranium is far, far less plentiful, and so would tend to remain dissolved.
There are no "grains" to migrate, as you suggest - uranium would be mixed in as impurities on an atomic level, literally dissolved in other metals and metal oxides.
That would kind of put a new variable into the Drake equation.
Either that, or give plot ideas to Isaac Asimov. Damn Spacers.
Reactor at Earth's Core
:-P
. ..
To power the PC that we are, you know... Um. It's past 2000, WHERE'S THE QUESTION TO THE ANSWER OF LIFE??!!
--pi
42+3.1415926535897932384626433832795028841971..
"In a reactor deep inside the Earth, one would expect fission products, having an average density about 60% that of actinides, to diffuse radially outward as the fuel reconcentrates radially inward because of gravity."
But at the center of the earth gravity is a much weaker force. I would guess that at the center of the earth, there would be no gravity, and the area around the center of the earth would have negligible gravity; sort of like how we see astronauts and satellites "floating" in orbit, but in reality most are in a slowly decaying orbit. The formula for calculating gravity & acceleration inside the earth is given at: http://www.syvum.com/physics/gravitation/gravitati on2.html,
though even with these formulas my math skills are not sufficient
for me to answer my one last question:
Is there a point just outside the center of the earth where gravity would actually pull you *UP*, since the bulk of the earth's mass lays above you? If so, then the denser fuel elements in this reactor would be pulled outward forming a layer enclosing it's byproducts in the center, rather then the opposite as they state in their theory.