J. Marvin Herndon claims that the evidence of the georeactor comes from 3He/4He ratios released to the oceans at the mid oceanic ridges. Georeactor-produced 3He/4He ratios are related to the extent of actinide fuel consumption at time of production and are high near the end of the georeactor lifetime. Georeactor numerical simulation results and the observed high 3He/4He ratios measured in Icelandic and Hawaiian oceanic basalts indicate that the demise of the georeactor is approaching. Is Herndon correct in claiming that the 3He and 4He in oceanic basalt are being produced by a georeactor in the Earth's core? If not, what is their origin?

Nuclear georeactor origin of oceanic basalt 3He/4He, evidence, and implications (or as PDF).

  • $\begingroup$ Related: earthscience.stackexchange.com/questions/9360/… $\endgroup$
    – Pont
    Commented Jan 4, 2017 at 18:32
  • $\begingroup$ This is probably not the case for the reasons outlined in the previous question about this topic. Interestingly, what the high 3He levels in some ocean island basalts really suggest is that they are sampling parts of the mantle that have never been degassed - possibly the lower mantle. $\endgroup$
    – bon
    Commented Jan 5, 2017 at 9:54
  • $\begingroup$ I've taken the liberty of editing your question to focus more strongly on the origin of Helium-3 and -4 in oceanic basalt. Your question as originally phrased was identical to your previous question on this topic, which asked about the possibility of a geomagnetic field collapse. If this edit goes against your intentions, feel free to revert it, but bear in mind that your question as originally phrased might be flagged as a duplicate and closed. $\endgroup$
    – Pont
    Commented Jan 6, 2017 at 11:29

1 Answer 1


Are Helium 3 and 4 being produced by earth's core?

tl;dr no.

The paper you are referring to has major flaws in it. Claims that should not be in any respectable scientific journal such as:

...the demise of the georeactor is approaching. Within the present level of uncertainty, one cannot say precisely when georeactor demise will occur, whether in the next century...


At some point in time after the georeactor dies, there will be no geomagnetic field and life on Earth will never be the same.

etc., have no place in a scientific article that is to be taken seriously by anyone. This is scaremongering that belongs in tabloids. This was publish in PNAS which is a reputable venue, so I don't know how it got through. Was this even reviewed? No idea. But let's talk about the actual science presented in the paper.

I'm not an expert on nuclear reactions so I can't comment on that actual model presented in the paper, but I can comment on the assumptions that are simply wrong. His model assumes a certain volume of uranium that exists in the core. Such a "block" of uranium doesn't exist. Uranium doesn't go in the core. He says:

The background as to why a large portion of the Earth's reservoir of uranium is expected to exist in the core, precipitate, and ultimately collect at the center of the Earth has been set forth in refs. 8–11...

But refs 8–10 are actually his own papers. So he made up a theory that uranium goes in the core, completely ignoring years of published experimental work by different groups saying that uranium does not go into any significant amounts in the core, and then bases his story on that. This is wrong. Some related questions:

Why is uranium only in the crust, really?

What percent of the Earth's core is uranium?

Also note the lack of neutrinos, as mentioned by David Hammen in one of the answers, something that should happen if this was true.

So your questions:

Is Herndon correct...

No, he is not.

If not, what is their origin?

Mantle sources with different 3He/4He ratios. There are many reasons for that. Mid ocean ridge basalts are mostly generated by melting of depleted mantle, that is, mantle that was already melted (at least) once. So it will not have too much of primordial 3He in it, and the ratio will be low. Hotspots such as Iceland or Hawaii tap a deeper mantle source that still has 3He in it, so the ratio will be higher. There are other factors that can modify the ratio. Episodes of depletion and recycling, metasomatism (by aqueous fluids or carbonatites, each with their own capability to transport U and Th), and some more than I can't think of at the moment. Anyway, there's no nuclear reactor in the core of the earth and we're not going to die due to its demise because it doesn't exist.

  • 1
    $\begingroup$ Note that the four self-citations are also in respectable journals, and we should assume that they passed peer review (which of course does not mean the hypothesis is correct!). I did a quick literature trawl and haven't yet found any conclusive refutation of the georeactor hypothesis. The closest I've got is a 2011 geoneutrino paper which constrains the power output of a putative georeactor to < 3 TW, which by Herndon's own calculations would give us another billion years before it shuts down. I agree that his doom-mongering does him no favours, though. $\endgroup$
    – Pont
    Commented Jan 7, 2017 at 14:57
  • $\begingroup$ @Pont maybe there are respectable journals, but I personally never heard of them. Maybe he was just submitting the paper to journals, keeping getting rejected, until he found a journal far away from the field enough that the editors and reviewers didn't realise it was complete nonsense? Maybe this is also why it wasn't refuted, because no one in the geoscience field reads those journals. Or maybe people don't care and have better things to do. Writing an answer here in SE takes a few minutes, writing a paper takes much more time than that. $\endgroup$
    – Gimelist
    Commented Jan 7, 2017 at 20:49
  • $\begingroup$ I think most people have heard of PNAS, which published refs 10 and 11. Certainly the papers have been read, because I kept finding neutrino papers like the one I mentioned about (here's another) which cite it in a context of "and here's how our measurements constrain the power output of a putative georeactor". So it appears that at least some of the neutrino crowd are OK with this as a hypothesis. But we know that geophysicists and geochemists disagree on radioisotopes in the core. $\endgroup$
    – Pont
    Commented Jan 8, 2017 at 9:53
  • $\begingroup$ @Pont the papers that you mentioned do not single out the core, they treat the Earth as a whole. That's fine - there's plenty of U K Th in the Earth, just not in the core. The Herndon papers claim that it's in the core and it's about to stop and we're all going to die, despite plenty of evidence to suggest otherwise, evidence that was completely ignored by Herndon. $\endgroup$
    – Gimelist
    Commented Jan 8, 2017 at 10:34
  • $\begingroup$ The first paper: "Finally, the suggestion that there may exist a natural nuclear reactor in the Earth's core... was tested by adding to the fit a reactor spectrum with a varying amplitude." The second: "The KamLAND data, together with the solar ν data, set an upper limit of 6.2 TW (90% C.L.) for a $\bar{ν}_e$ reactor source at the Earth’s center". They are very explicitly addressing the core georeactor hypothesis. $\endgroup$
    – Pont
    Commented Jan 8, 2017 at 10:42

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