<p>The conventional explanation for the Earth's magnetic field is that some combination of differential rotation and/or convection occurs in the Earth's outer core, primarily in molten iron-nickel (+ sulphur, hydrogen etc.), which acts as a kind of dynamo. Whilst we can't prove it by direct observation, this seems an eminently plausible mechanism. If this is true, then the heat of the core will eventually dissipate, resulting in freezing of the core and cessation of the Earth's magnetic field. The existing heat is partly primordial and partly radiogenic from the decay of U, Th and K, and will take <em>many</em> billions of years to dissipate. </p>

<p>The georeactor hypothesis requires a critical mass of uranium at the centre of the Earth to start up and maintain a nuclear reaction. There are two reasons why this hypothesis is seldom taken seriously except by Herndon himself. Firstly, in order for uranium to reach criticality it has to be a very high concentration of uranium. There is no known concentration mechanism which could achieve this in the Earth's core, whereas there are many reasons to believe that the uranium would be dispersed or 'poisoned' by lead and other heavy metals. Whilst the pressure at the Earth's core would be immense, gravitational separation, i.e. density fractionation, would be almost non-existent. Secondly, if this hypothesis was correct we would expect to see a huge flux of anti-neutrinos in such detectors as the super Kamiokande. We don't. So I'm not losing any sleep at the prospect of the Earth losing it's magnetism within the next billion years. </p>

CC BY-SA 3.0
2016-12-28T01:14:08.110Z
2016-12-28T01:14:08.110Z
Gordon Stanger
<p>I heard about the georeactor hypothesis (Herndon, 1993), which claims that there is a natural atomic fission reactor in the Earth's core giving rise to the geomagnetic field. Further, Herndon claims that this reactor will shut down, causing Earth's magnetic field to disappear at some time between a hundred years to a billion years from now. Is this possible?</p>

<hr>

<p><strong>References</strong></p>

<p>Herndon, J. M. (1993). Feasibility of a nuclear fission reactor at the center of the Earth as the energy source for the geomagnetic field. <em>Journal of geomagnetism and geoelectricity</em>, 45(5), 423-437. <a href="http://www.nuclearplanet.com/Herndon%20JGG93.pdf" rel="noreferrer">Link</a></p>

CC BY-SA 3.0
2016-12-27T21:29:22.913Z
Isn't the geo-reactor hypothesis about fission being a heat source for the the gas giants? If so, what does that have to do with Earth's magnetic field?
kingledion
CC BY-SA 3.0
2016-12-28T00:07:27.723Z
Hello, and welcome to Stack Exchange. My brief Googling of this theory yielded a number of references to "maverick" and "not well accepted".
Daniel Griscom
CC BY-SA 3.0
2016-12-28T11:24:57.520Z
Regarding the (currently three) close votes: while the "fission reactor at Earth's core" hypothesis is arrant bosh, I don't think that this in itself is a reason to close this question: this is as good a place as any to refute it. Obviously we don't want questions open to refute any old non-notable erroneous claim ("My mate Jeff told me there are marshmallows on Venus!") but I think this one clears the bar: the "fission reactor" bit at least was [published](http://www.nuclearplanet.com/Herndon%20JGG93.pdf) in *J. Geomag. Geoelectr.*, a relatively respectable journal.
Pont
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2016-12-28T18:57:24.030Z
Please add links to your question, so that we don't have to search for it.
Jan Doggen
CC BY-SA 3.0
2016-12-28T19:52:38.900Z
@kingledion I think "georeactor" is a catch-all term for any naturally occurring nuclear reactor in a planetary body. Herndon seems to be proposing that many planets have a georeactor core, and that in Earth's case the geomagnetic field is produced in a proposed "georeactor fission-product sub-shell" rather than (as is commonly accepted) by convection in the liquid outer core.
Pont
CC BY-SA 3.0
2016-12-29T00:23:49.523Z
Related: http://earthscience.stackexchange.com/questions/2950/what-are-the-high-field-strength-and-large-ion-lithophile-hfs-or-hfse-lil-or
David Hammen
CC BY-SA 3.0
2016-12-29T00:25:53.900Z
Related: http://earthscience.stackexchange.com/questions/4798/what-percent-of-the-earths-core-is-uranium
David Hammen
CC BY-SA 3.0
2016-12-29T00:26:08.983Z
Related: http://earthscience.stackexchange.com/questions/8214/why-is-uranium-only-in-the-crust-really/8216
David Hammen
CC BY-SA 3.0
2016-12-29T00:28:01.913Z
I'm voting to close this question as off-topic because this is "pure bosh."
David Hammen
CC BY-SA 3.0
2016-12-29T00:29:37.310Z
@Pont: There is a site on the stackexchange network dedicated to "arrant bosh", http://skeptics.stackexchange.com. This question would be much better suited there.
David Hammen
CC BY-SA 3.0
2016-12-29T00:35:42.377Z
The concept of a georeactor is "arrant bosh" from the perspective of chemistry, which says that uranium is about as lithophilic as an element can get and this is almost absent from the core, and from the perspective of physics which says a uranium georeactor would be emitting neutrinos. Those neutrinos have not been observed.
David Hammen
CC BY-SA 3.0
2016-12-29T05:40:45.767Z
@DavidHammen The skeptic site only cares about loony science, like "the earth is hollow", this one has at least a ring of science to it, so they won't touch it.    I don't think the question is as bad as all that, but it was poorly researched.
userLTK
CC BY-SA 3.0
2016-12-29T08:12:43.433Z
@DavidHammen I think Gordon Stanger's answer, and your comments, demonstrate why this question fits better here than at Skeptics: this site has members with the relevant expertise to refute the claim. It seems a little bizarre to [accept flat earth questions](http://earthscience.stackexchange.com/questions/7056/how-to-quickly-or-easily-prove-the-world-is-spherical) but reject questions on a hypothesis which at least managed to pass peer review in a decent journal.
Pont
CC BY-SA 3.0
2016-12-29T09:38:59.873Z
@Pont - Most geologists, geochemists, and geophysicists view Herndon's nonsense as just shy of loony science. But given that we had a flat earth question here (egads!), I'll make my comment into a question.
David Hammen
CC BY-SA 3.0
2018-02-20T15:58:40.330Z
The neutrino experiments KamLAND and Borexino have conclusively ruled out any possibility of a currently active reactor at the Earth's core (and been able to conclusively attribute a bit over half the geothermal flux to decay activity of uranium and thorium; alas the potassium contribution is inaccessible to those experiments).
dmckee --- ex-moderator kitten
<geothermal-heat><core><geomagnetism><radioactivity><uranium>
Does Earth's magnetic field arise from a fission reactor in its core?
Radja Callier
# Does Earth's magnetic field arise from a fission reactor in its core?

(Asked by: username_0 on 2016-12-27)

I heard about the georeactor hypothesis (Herndon, 1993), which claims that there is a natural atomic fission reactor in the Earth's core giving rise to the geomagnetic field. Further, Herndon claims that this reactor will shut down, causing Earth's magnetic field to disappear at some time between a hundred years to a billion years from now. Is this possible?

---

**References**

Herndon, J. M. (1993). Feasibility of a nuclear fission reactor at the center of the Earth as the energy source for the geomagnetic field. *Journal of geomagnetism and geoelectricity*, 45(5), 423-437. [Link](http://www.nuclearplanet.com/Herndon%20JGG93.pdf)

**Tags:** geothermal-heat, core, geomagnetism, radioactivity, uranium

> **Comments:**
> **username_1**: Isn't the geo-reactor hypothesis about fission being a heat source for the the gas giants? If so, what does that have to do with Earth's magnetic field?  
> **username_2**: Hello, and welcome to Stack Exchange. My brief Googling of this theory yielded a number of references to "maverick" and "not well accepted".  
> **username_3**: Regarding the (currently three) close votes: while the "fission reactor at Earth's core" hypothesis is arrant bosh, I don't think that this in itself is a reason to close this question: this is as good a place as any to refute it. Obviously we don't want questions open to refute any old non-notable erroneous claim ("My mate Jeff told me there are marshmallows on Venus!") but I think this one clears the bar: the "fission reactor" bit at least was [published](http://www.nuclearplanet.com/Herndon%20JGG93.pdf) in *J. Geomag. Geoelectr.*, a relatively respectable journal.  
> **username_4**: Please add links to your question, so that we don't have to search for it.  
> **username_3**: @username_1 I think "georeactor" is a catch-all term for any naturally occurring nuclear reactor in a planetary body. Herndon seems to be proposing that many planets have a georeactor core, and that in Earth's case the geomagnetic field is produced in a proposed "georeactor fission-product sub-shell" rather than (as is commonly accepted) by convection in the liquid outer core.  
> **username_5**: Related: http://earthscience.stackexchange.com/questions/2950/what-are-the-high-field-strength-and-large-ion-lithophile-hfs-or-hfse-lil-or  
> **username_5**: Related: http://earthscience.stackexchange.com/questions/4798/what-percent-of-the-earths-core-is-uranium  
> **username_5**: Related: http://earthscience.stackexchange.com/questions/8214/why-is-uranium-only-in-the-crust-really/8216  
> **username_5**: I'm voting to close this question as off-topic because this is "pure bosh."  
> **username_5**: @username_3: There is a site on the stackexchange network dedicated to "arrant bosh", http://skeptics.stackexchange.com. This question would be much better suited there.  
> **username_5**: The concept of a georeactor is "arrant bosh" from the perspective of chemistry, which says that uranium is about as lithophilic as an element can get and this is almost absent from the core, and from the perspective of physics which says a uranium georeactor would be emitting neutrinos. Those neutrinos have not been observed.  
> **username_6**: @username_5 The skeptic site only cares about loony science, like "the earth is hollow", this one has at least a ring of science to it, so they won't touch it.    I don't think the question is as bad as all that, but it was poorly researched.  
> **username_3**: @username_5 I think username_8 username_8's answer, and your comments, demonstrate why this question fits better here than at Skeptics: this site has members with the relevant expertise to refute the claim. It seems a little bizarre to [accept flat earth questions](http://earthscience.stackexchange.com/questions/7056/how-to-quickly-or-easily-prove-the-world-is-spherical) but reject questions on a hypothesis which at least managed to pass peer review in a decent journal.  
> **username_5**: @username_3 - Most geologists, geochemists, and geophysicists view Herndon's nonsense as just shy of loony science. But given that we had a flat earth question here (egads!), I'll make my comment into a question.  
> **username_7**: The neutrino experiments KamLAND and Borexino have conclusively ruled out any possibility of a currently active reactor at the Earth's core (and been able to conclusively attribute a bit over half the geothermal flux to decay activity of uranium and thorium; alas the potassium contribution is inaccessible to those experiments).  

---

## 1 answers

### Answer by username_8 on 2016-12-28. Score: 14

The conventional explanation for the Earth's magnetic field is that some combination of differential rotation and/or convection occurs in the Earth's outer core, primarily in molten iron-nickel (+ sulphur, hydrogen etc.), which acts as a kind of dynamo. Whilst we can't prove it by direct observation, this seems an eminently plausible mechanism. If this is true, then the heat of the core will eventually dissipate, resulting in freezing of the core and cessation of the Earth's magnetic field. The existing heat is partly primordial and partly radiogenic from the decay of U, Th and K, and will take *many* billions of years to dissipate.

The georeactor hypothesis requires a critical mass of uranium at the centre of the Earth to start up and maintain a nuclear reaction. There are two reasons why this hypothesis is seldom taken seriously except by Herndon himself. Firstly, in order for uranium to reach criticality it has to be a very high concentration of uranium. There is no known concentration mechanism which could achieve this in the Earth's core, whereas there are many reasons to believe that the uranium would be dispersed or 'poisoned' by lead and other heavy metals. Whilst the pressure at the Earth's core would be immense, gravitational separation, i.e. density fractionation, would be almost non-existent. Secondly, if this hypothesis was correct we would expect to see a huge flux of anti-neutrinos in such detectors as the super Kamiokande. We don't. So I'm not losing any sleep at the prospect of the Earth losing it's magnetism within the next billion years.


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