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Thread: Nuclear explosions

  1. #1 Nuclear explosions 
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    You know when a nuclear bomb, particularly hydrogen, detonates and you see the mushroom cloud of fire? What is that fire made of and where did it come from? Think about it...how could so much fire come out of such a small amount of material? Is it only superheated gamma radiation?
    And if so, wouldn't that defy the standard model of nuclear fusion, in terms of what sort of particles are created?


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    Moderator Moderator AlexP's Avatar
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    I would think that it could just be the atmospheric air burning when exposed to the mass amount of energy released by the bomb. I don't know that that's what it is for a fact, but it seems entirely reasonable to me.


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    It's plasma, isn't it? Super-heated air and whatnot....
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    I hope you are aware that a mushroom cloud is not unique to a nuclear blast. It can arise from a very large explosion of any sort and can appear over erupting volcanoes.

    Basically it is caused by a rising hot column of debris. The material rises, expanding, until it is about the density of the atmosphere. Then it spreads out. There is no need to consider a nuclear blast as being something special; any massive release of energy will cause the same results.
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    Forum Radioactive Isotope mitchellmckain's Avatar
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    Quote Originally Posted by SteveF
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    I hope you are aware that a mushroom cloud is not unique to a nuclear blast. It can arise from a very large explosion of any sort and can appear over erupting volcanoes.

    Basically it is caused by a rising hot column of debris. The material rises, expanding, until it is about the density of the atmosphere. Then it spreads out. There is no need to consider a nuclear blast as being something special; any massive release of energy will cause the same results.
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    Yes but beneath this is the question about how the high energy radiation produced the the nuclear reaction becomes such a broad range of energy including heat and the shock wave that makes the mushroom cloud.

    It is well known that such nuclear blasts are the source of a dangerous quantity of high frequency radiation, giving a lethal dose to anyone within range. But consider why such radiation is so dangerous. It has a tendency of hitting things and blasting them apart. This means that close to the chain reaction this radiation will hit everything and turn it into a super-heated plasma. It is only the very small fraction of this high frequency radiation that misses everything in order to reach you within the danger zone in order to blast apart enough of your cellular structure to give you radiation poisoining.

    Thus although a large meteorite will produce a mushroom cloud as well, since its energy did not start out as high frequency radiation, the energy across the electromagnetic spectrum will be a black body distribution depending only on the temperature at the core of the blast and thus will have very little of this harmful radiation by comparison. I think however that a higher velocity metorite will produce a higher temperature core and thus a higher proportion of dangerous radiation.
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    Quote Originally Posted by mitchellmckain
    Quote Originally Posted by SteveF
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    I hope you are aware that a mushroom cloud is not unique to a nuclear blast. It can arise from a very large explosion of any sort and can appear over erupting volcanoes.

    Basically it is caused by a rising hot column of debris. The material rises, expanding, until it is about the density of the atmosphere. Then it spreads out. There is no need to consider a nuclear blast as being something special; any massive release of energy will cause the same results.
    *
    Yes but beneath this is the question about how the high energy radiation produced the the nuclear reaction becomes such a broad range of energy including heat and the shock wave that makes the mushroom cloud.

    It is well known that such nuclear blasts are the source of a dangerous quantity of high frequency radiation, giving a lethal dose to anyone within range. But consider why such radiation is so dangerous. It has a tendency of hitting things and blasting them apart. This means that close to the chain reaction this radiation will hit everything and turn it into a super-heated plasma. It is only the very small fraction of this high frequency radiation that misses everything in order to reach you within the danger zone in order to blast apart enough of your cellular structure to give you radiation poisoining.

    Thus although a large meteorite will produce a mushroom cloud as well, since its energy did not start out as high frequency radiation, the energy across the electromagnetic spectrum will be a black body distribution depending only on the temperature at the core of the blast and thus will have very little of this harmful radiation by comparison. I think however that a higher velocity metorite will produce a higher temperature core and thus a higher proportion of dangerous radiation.
    Most of the energy produced by a fusion bomb is carried off by the products created during the reaction(the new formed nucleus and some neutrons) as kinetic energy.

    Gamma ray are produced, but they do not account for the majority of the energy released.
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    Does the radiation that is absorbed by the air have a place in the EM spectrum or is it beyond what we can study and therefore record?
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

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    All radiation* has a place in the EM spectrum.

    There is nothing unique or mysterious about a nuclear explosion. Its physics is well understood.

    *Alpha and beta "radiation" is not EM at all but particles.



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    Forum Radioactive Isotope mitchellmckain's Avatar
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    Quote Originally Posted by Janus
    Most of the energy produced by a fusion bomb is carried off by the products created during the reaction(the new formed nucleus and some neutrons) as kinetic energy.

    Gamma ray are produced, but they do not account for the majority of the energy released.
    That makes sense, especially the neutrons, since these are the cause of the chain reaction in a fission bomb (or in the detonator of a fusion bomb). High gamma ray production is a more likely result of an antimatter bomb. As far as I can tell, high velocity neutrons don't have anywhere near the range of gamma radiation for these are far more likely to hit things and slow down than is gamma radiation, which like x-rays tend to pass through just about everything. I would however discount the other fission products because conservation of momentum would suggest that these would come out of the explosion with a considerably lower velocity and thus with a considerably lower kinetic energy.

    So in conclusion, my previous comments were misleading and although possibly a good description of an antimatter bomb, was not such a good description of what happens in the case of either a fission bomb or a fusion bomb. In the fission bomb it would be primarily collisions by neutrons that create the plasma and in the fusion bomb there would also be a lot of collisions by alpha particles (helium nuclei) as the dominant energy source. The fusion bomb would also have to produce a fair amount of beta particles (positions) which would annihilate on collision to produce a good deal of high frequency EM radiation.
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