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Author Topic: Is nuclear fission occurring in the Earth's core?  (Read 8672 times)

Offline wanhafizi

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Hi there,

Considering that the core of the earth is very hot and dense, is it possible that a nuclear fission to happen there?

thanks

[MOD EDIT - please phrase post titles as questions]
« Last Edit: 19/06/2009 09:15:40 by chris »


 

Offline neilep

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #1 on: 15/06/2009 10:28:54 »
Hi wanhafizi,

I think nucelar fission would only happen if the earth was a lot denser and bigger and would therefore then become a star. So, in other words, I think it's not possible for fission to happen in the centre of the earth.  effectively, the earth is just not massive enough.

I am hopeful a more scientific explanation will follow.
 

Offline JimBob

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #2 on: 15/06/2009 19:28:58 »
No one really knows and I have not seen any data supporting OR opposing this idea. I do know that the temperature in the core is much hotter than in the Sun. What the possibility calculations are I do not have a clue. 
 

Offline Flyberius

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #3 on: 15/06/2009 19:56:47 »
No one really knows and I have not seen any data supporting OR opposing this idea. I do know that the temperature in the core is much hotter than in the Sun. What the possibility calculations are I do not have a clue. 

I can see that the core of earth could be hotter than the surface and lower regions of the sun but are you saying that the core of earth is hotter than the nuclear death ball at the center of the sun.

Again drawing from a book I read recently, 13 things that don't make sense, I heard that some nuclear reactions were taking place in springs on earth and causing a heating effect as radioactive ores were sloshed past each other.  Remember there is schmexy fusion and its badly dressed and somewhat easy cousin, fission.
« Last Edit: 15/06/2009 19:58:25 by Flyberius »
 

Offline LeeE

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #4 on: 15/06/2009 23:47:11 »
Did the questioner mean to ask if fusion was occurring in the Earth's core?

I'm sure that fission is happening there, seeing as that's where most of the dense materials ended up.  The radioactive materials, both in the Earth's crust and in its core, will have been fissioning since they were produced in the ancestral nova.
 

Offline wanhafizi

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #5 on: 16/06/2009 01:29:02 »
...I do know that the temperature in the core is much hotter than in the Sun...

Wow, that's interesting...
 

Offline wanhafizi

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #6 on: 16/06/2009 02:04:44 »
Did the questioner mean to ask if fusion was occurring in the Earth's core?

I'm sure that fission is happening there, seeing as that's where most of the dense materials ended up.  The radioactive materials, both in the Earth's crust and in its core, will have been fissioning since they were produced in the ancestral nova.

Well, maybe we can discuss both events, fission & fusion.
 

Offline frethack

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #7 on: 16/06/2009 03:57:44 »
As far as core heat, if I remember correctly, some estimates put it at about 9000 C, which is hotter than the photosphere of the sun (the surface).  The core of the the sun burns at tens of millions of degrees centigrade, and the corona (the solar atmosphere...which we live in) is a few million degrees near the photosphere and cools as you get further away.  It is a matter of debate as to why the corona is so much hotter than the photosphere.   Ill have to check this again, but I think I remember it having to do with light bouncing around the suns interior, taking more than a million years to reach the suns surface, and then suddenly and energetically breaking free into space (a bit like the added speed from compression as a bullet exits the tapered barrel of a gun)

As far as core composition, current teaching allows the possibility for relatively small amounts of uranium, thorium, and potassium, which would mean that fission occurs in the core, but Im not sure how compelling the evidence is.
 

Offline Bass

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #8 on: 16/06/2009 06:21:46 »
Depends on how you define "fission".  Spontaneous fission, or radioactive decay, certainly takes place in earth's interior- and can provide the necessary heat at calculated elemental abundances.  Are radioactive elements concentrated enough in the inner earth to cause nuclear fission chain reactions? 

Possibly. 

High uranium concentrations in the crust have been known to create fission chain reactions (however, the uranium may have been concentrated by secondary processes).
 

Offline Ophiolite

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #9 on: 16/06/2009 06:52:17 »
Some points.
1. Fusion, the merging of atomic nuclei, the process that powers the sun and other stars cannot be occuring in the core of the Earth for the reasons noted by others above: the pressure/temperature are far too low.

2. Solar temperatures:
Core   15.7 x 10^6 K
Photosphere 6,400 K

Why is the Corona hotter? "Two main groups of DC(direct current)and AC(alternating current)models involve as a primary energy source chromo-spheric foot point motion or upward leaking Alfven waves, which are dissipated in the corona by magnetic reconnection, current cascades, MHD turbulence, Alfven resonance, resonant absorption,or phasemixing."
So there you go. ;)

3. Fission, the splitting of atomic nuclei, probably occurs in the core because of the presence of a small quantity of naturally radioactive elements. (Bass and LeeE have already pointed this out.) However the conventional view is that the principal radioactive elements (uranium, thorium and pottasium) are lithophiles. This means they are chemically predisposed to concentrate in silicate minerals and so are found primarily in the mantle and crust.

4. A contrary view is that uranium has concentrated in the core and fission in the form of a self sustaining nuclear reactor is ongoing there. Wikipedia is a good starting point to learn more about this.

Edit: I omitted a reference for the quote in point 2. This is from the Acadmic Press Encyclopedia of the Solar System.
« Last Edit: 16/06/2009 06:55:17 by Ophiolite »
 

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Re: Is nuclear fission occurring in the Earth's core?
« Reply #9 on: 16/06/2009 06:52:17 »

 

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