A year ago, I asked on the possibility of Teller Nuclear Bombs, where the bomb is hot enough to fuse oxygen and cause a runway reaction that destroys Earth by using the air as "fusion material". This type of world destruction is especially common in WH40k, which we all know as Exterminatus.


Of course, in that thread, it was dismissed as being impossible due to the insanely high temperatures required. As stated on wikipedia regarding the Oxygen-Burning Process, the temperature required for such fusion processes would be around 1 to 2 billion degrees.


But now, I decided to change the rules. I no longer need modern day technology. Assume this is the far future. Feel free to use any unobtainium (Degenerate or Exotic Matter, Micro Black Holes, Cosmic Rays) to see if the bomb has any possibility of coming to be. As long as it is not utter handwavium (Physics-defying matter that isn't even deemed as Dark Matter or Energy), it is all fine.

PS: I would ask this because even with said unobtainium, I do not know what could cause such an event to happen.

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    $\begingroup$ There is no way to have oxygen fusing spontaneously while Earth still exists in any recognizable form. That is to say, any mechanism which produces the conditions where oxygen undergoes nuclear fusion will also completely destroy Earth. Since Earth is already completely destroyed, whether oxygen undergoes nuclear fusion or not is irrelevant. (Ah, and if by WH40K you mean Warhammer 40,000, that's an example of English humor at its finest. Think the first season of Blackadder. It is not intended to be taken seriously.) $\endgroup$
    – AlexP
    Commented Apr 11, 2020 at 14:04
  • $\begingroup$ Exactly, no normal tech can do those stuff. Thus this is why I specified that Unobtainium is free here this time. $\endgroup$ Commented Apr 11, 2020 at 14:07
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    $\begingroup$ I did not say anything about the technology. I said that any technology able to bring about the conditions required for fusing oxygen will also completely destroy Earth before reaching those conditions. $\endgroup$
    – AlexP
    Commented Apr 11, 2020 at 14:18
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    $\begingroup$ Note there is a much simpler way to burn oxygen, fluorine can oxidize oxygen. $\endgroup$
    – John
    Commented Apr 11, 2020 at 14:45
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    $\begingroup$ Wikipedia: "Oxygen in the core ignites in the temperature range of 1.5 to 2.6 billion K and in the density range of 2.6 to 6.7 thousand tonnes per cubic centimeter". Such conditions can exist only in the core of a massive star -- our Sun is much too puny to ever reach such conditions. We are speaking of conditions consistent with the core of star ten times as massive as the Sun. I would say that creating such conditions is incompatible with the continued existence of Earth as a tiny ball of iron. $\endgroup$
    – AlexP
    Commented Apr 11, 2020 at 14:56

1 Answer 1


Assuming you could raised the temperature of the whole atmosphere to a point where Oxygen could fuse, that would be pointing a LOT of energy at the Earth. The average mass of a molecule in earth's atmosphere is about 28.77099 amu. Assuming 77%N2, 20%O2, 2%H2O, and 1%CO2. Which should be close enough. If you want to raise the temperature of the whole atmosphere to 2 billion degrees Kelvin then the average Kinetic Energy of those particles would be about $$ \bar{E_{k}} = \frac{3K}{2N_{A}}T = 2.0709 \times 10^{-23} T = 4.142 \times 10^{-23}J/particle $$ The number of particles in the atmosphere is about: $$ n = \frac{m_{atm}}{\bar{m}_{p}} = 10^{44} particles$$ So the total energy your weapon would impart to the earth would have to be at least: $$ E_{weapon}\geq \bar{E_{k}} \cdot n = 4.142 \times 10^{21}J$$ The gravitational binding energy of the earth is about $ 2 \times 10^{23} J $ which isn't a huge difference, whatever was left of the earth after you used your weapon would be at the very least a good deal smaller than it is now.

If you wanted ALL of the Oxygen to fuse you would need a fair amount more energy than that so... come up with another way to ignite the atmosphere.


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