Chain reaction based planet detonation - hypothesis

[trackball]

It's well established by now that the Death Star superlaser operates by direct energy transfer. By this I mean it transfers energy, in the form of a coherent beam, to the target planet in excess of the planet's gravitational binding energy. This overwhelms the forces holding the planet together resulting in a catastrophic breakdown; in laymen's terms, it blows up.

We also know that the Species 8472 ships have not demonstrated that they have enough power to duplicate this effect, but by combining their efforts in a "planet buster" formation they can somehow cause a planet to explode. It is generally accepted that for lack of the necessary power to do this via direct energy transfer, Species 8472 must create a chain reaction of some sort in the planet to facilitate the explosion. So far, the nature of this chain reaction remains unknown.

I propose the following:

Earth's crust, which has a total mass of 1.55E23kg, contains 4PPM uranium and 12PPM thorium by mass. The radioactive decay of these elements accounts for a good deal of the warmth of the planet over and above that which is provided by the sun. Almost all of the uranium is in the form of the non-fissile isotope U238 and almost all of the thorium is the likewise non-fissile isotope Th232. Being non-fissile, these isotopes decay radioactively but will not cause a runaway chain reaction.

However, experiments in creating "breeder reactors" have shown that U238 can, through neutron absorption followed by two stages of beta decay, become Pu239. Likewise Th232 can be transformed into U233. Both Pu239 and U233 are fissile and can be used to create atomic bombs.

Beta decay is the result of weak nuclear forces, which are carried by W+, W-, and Z bosons. If the Species 8472 ships are firing these bosons into the planet, they may be causing breeder reactions in the Th232 and U238, transforming them into Pu239 and U233. Effectively, they are turning the planet into a huge fission bomb. If this process can be done quickly enough, large uranium and thorium ore deposits in the crust, previously harmless, can become supercritical masses of Pu239 and U233, which would subsequently explode.

The Nagasaki bomb, which used 15kg of Pu239, had a yield of 8.4E13J. The Hiroshima bomb, which used 64.1kg of U235, had a yield of 6.28E13J (I do not know the yield of U233, so I have to use the U235 number). The gravitational binding energy of Earth is 2.4E32J.

The total amount of uranium in the Earth's crust is 6.2E17kg and the mass of thorium in the Earth's crust is 1.86E18 kg. If all this uranium and thorium were to become Pu239 and U233, exploding at similar efficiency to the Nagasaki and Hiroshima bombs, respectively, it might have a total yield of 3.472E30J + 1.822E30J = 5.294E30J, insufficient by a factor of 45 to overcome the gravitational binding energy of an Earth-sized planet.

Crap.

Well I crunched all these numbers so I'll post it anyway. In any case, that 5.294E30J is all taking place in the crust, which would implode the core, doing God-knows-what to it (maybe setting off fusion reactions which would finish off the planet?). Also, there is more uranium and thorium in the mantle and core which I did not take into account here.

Please note that I fully admit that this is a ridiculous simplification of an incredibly complex problem. The actual yield would depend on the rate of fissile material production due to beta decay, the number of deposits and their densities, the amount of pressure the ore deposits are under, and dozens of other factors I am not qualified to even begin to go over. These numbers are only to give a rough idea of what might be possible.

[Darth Wong]

It's well established by now that the Death Star superlaser operates by direct energy transfer. By this I mean it transfers energy, in the form of a coherent beam, to the target planet in excess of the planet's gravitational binding energy. This overwhelms the forces holding the planet together resulting in a catastrophic breakdown; in laymen's terms, it blows up.

We also know that the Species 8472 ships have not demonstrated that they have enough power to duplicate this effect, but by combining their efforts in a "planet buster" formation they can somehow cause a planet to explode. It is generally accepted that for lack of the necessary power to do this via direct energy transfer, Species 8472 must create a chain reaction of some sort in the planet to facilitate the explosion. So far, the nature of this chain reaction remains unknown.

It's not a matter of "not demonstrating" that they have enough power; if the blast met the criteria, then it would be the demonstration we seek. As it is, it certainly demonstrates the power level necessary to create a mass-extinction event. The reason the S8472 blast is obviously a chain reaction is the very long delay before the planet explodes.

Earth's crust, which has a total mass of 1.55E23kg, contains 4PPM uranium and 12PPM thorium by mass. The radioactive decay of these elements accounts for a good deal of the warmth of the planet over and above that which is provided by the sun. Almost all of the uranium is in the form of the non-fissile isotope U238 and almost all of the thorium is the likewise non-fissile isotope Th232. Being non-fissile, these isotopes decay radioactively but will not cause a runaway chain reaction.

However, experiments in creating "breeder reactors" have shown that U238 can, through neutron absorption followed by two stages of beta decay, become Pu239. Likewise Th232 can be transformed into U233. Both Pu239 and U233 are fissile and can be used to create atomic bombs.

Beta decay is the result of weak nuclear forces, which are carried by W+, W-, and Z bosons. If the Species 8472 ships are firing these bosons into the planet, they may be causing breeder reactions in the Th232 and U238, transforming them into Pu239 and U233. Effectively, they are turning the planet into a huge fission bomb. If this process can be done quickly enough, large uranium and thorium ore deposits in the crust, previously harmless, can become supercritical masses of Pu239 and U233, which would subsequently explode.

Don't be ridiculous. The reactant density is many orders of magnitude below what you would need for a spontaneous chain reaction. You do know that this stuff has to be painstakingly purified before it becomes weapons-grade, right? And that the Earth's mass is overwhelmingly composed of materials other than these particular isotopes? Let's not even get into this "magic boson" nonsense.

Well I crunched all these numbers so I'll post it anyway. In any case, that 5.294E30J is all taking place in the crust, which would implode the core, doing God-knows-what to it (maybe setting off fusion reactions which would finish off the planet?). Also, there is more uranium and thorium in the mantle and core which I did not take into account here.

Please note that I fully admit that this is a ridiculous simplification of an incredibly complex problem. The actual yield would depend on the rate of fissile material production due to beta decay, the number of deposits and their densities, the amount of pressure the ore deposits are under, and dozens of other factors I am not qualified to even begin to go over. These numbers are only to give a rough idea of what might be possible.

You are wasting your time. The considerable difficulty of creating and sustaining nuclear reactions even with refined uranium serves as an instant rebuttal to this moronic theory. Neutron radiation is not magic; it has a heating effect on matter because it is not highly penetrative. The notion of scattered bits of uranium starting a chain reaction which then compresses the core of the planet to create fusion is utterly idiotic, particularly when the energy requirements for initiating such a process vastly exceed the energy requirement for destroying the planet through brute force.

[Durandal]

This belongs in PST or STvsSW.

[trackball]

Just an idea. I couldn't think of anything else commonly found in a planet that would be capable of exploding under bizzare circumstances, and I haven't heard any competeing theories. Granted it's got its flaws, but if there are any other theories I'd like to hear them.

This belongs in PST or STvsSW.

I meant to post it in PST. Sorry.

[Durandal]

Just an idea. I couldn't think of anything else commonly found in a planet that would be capable of exploding under bizzare circumstances, and I haven't heard any competeing theories. Granted it's got its flaws, but if there are any other theories I'd like to hear them.

The chain reaction taking place with the S-8472 weapon was very bizarre. They fired for a while, stopped and then about 10 seconds later, the planet exploded.

Your theory of firing bosons at the planet does not explain the heated ejecta spewing out from the planet when the beam impacted. Given the speed at which the ejecta traveled, which was more like a meander, the planet's escape velocity was nowhere near that of Earth's. The ejecta didn't even look to be traveling at more than a few hundred meters per second. That's at least an order of magnitude or two off of 11.2 km/s. If the planet was Earth-sized, its density would be significantly less than Earth's. This in turn means that its binding energy is far less than that of Earth's.

Now, you might say, "Great! That means that 1E30 J might be able to do the job," but since there's less mass, there is much less fissionable material to be found in the planet, and given its surface appearance, there's no guarantee that it has uranium deposits anything like Earth's. Add in the fact that fission requires a very specific set of circumstances (none of which were present), and the possibility of an induced fission reaction is ruled out. Aside from that, unless S-8472 managed to enrich the uranium already present with their beam, there's utterly no way a significant portion of the planet's mass would fission. I doubt that this is the working mechanism for the beam.

[trackball]

Aside from that, unless S-8472 managed to enrich the uranium already present with their beam, there's utterly no way a significant portion of the planet's mass would fission. I doubt that this is the working mechanism for the beam.

Actually that was the whole point I was trying to make. By somehow artificially inducing beta decay in non-fissile uranium and thorium, you could produce fissile uranium and plutonium. Unfortunately, one of the many flaws in my hypothesis is the unbelievable speed with which this must occur so it doesn't fizzle out prematurely.

[trackball]

Don't be ridiculous. The reactant density is many orders of magnitude below what you would need for a spontaneous chain reaction.

Oh that's right, naturally occuring uranium ore contains far too small amounts of uranium in proportion to the other elements to ever possibly reach a critical mass.

This is a fundamental flaw which cannot be resolved. I utterly and completely retract this hypothesis.

[Howedar]

Good for you. Making stupid theories is perfectly fine and dandy if one can realize and accept that they are stupid. We've all done that.

[trackball]

Good for you. Making stupid theories is perfectly fine and dandy if one can realize and accept that they are stupid. We've all done that.

I honestly can't tell if you're being sarcastic or not.

[Howedar]

Absolutely not.

I'm not sure if I made it clear that I was saying that making stupid theories is okay if you realize that they're stupid eventually. Posting them when you already know they're stupid is, well, stupid.

[Utsanomiko]

Absolutely not.

I'm not sure if I made it clear that I was saying that making stupid theories is okay if you realize that they're stupid eventually. Posting them when you already know they're stupid is, well, stupid.

Psshaw! Where's the dignity in identiftying faults and admitting defeat when you can repeat yourself over and over and hold onto your original claims like a dog with an old rag?

[trackball]

making stupid theories is okay if you realize that they're stupid eventually.

I'm talking about the fact that everyone here seems to be claiming that you know the relative content of Uranium in pitchblende right off the top of your heads. Maybe one or two of you need to know this in your day to day lives but it's not really something most people have to think about very often.

There is no sense of scale around here when it comes to mistakes. I mean honestly, I went and researched beta decay in fission breeder reactors, and when I forget to double-check how dense naturally occurring U238 deposits are you act like I forgot who the president of the United States is.

On a side note, I'd still appreciate it if anyone could point me toward any other theories on this topic, because I can't find any.

[Durandal]

I'm talking about the fact that everyone here seems to be claiming that you know the relative content of Uranium in pitchblende right off the top of your heads. Maybe one or two of you need to know this in your day to day lives but it's not really something most people have to think about very often.

There is no sense of scale around here when it comes to mistakes. I mean honestly, I went and researched beta decay in fission breeder reactors, and when I forget to double-check how dense naturally occurring U238 deposits are you act like I forgot who the president of the United States is.

That's because, on a relative scale, you did commit that kind of a grievous error. You're telling me that you went through all the trouble to research beta decay in fission breeder reactors, and you never once thought to check the conditions necessary in order for fission to occur, much less if those conditions are met in a planet capable of supporting life? You simply assumed that supercritical masses of Pu239 and U233 would be present. That kind of information is available in my sophomore-level physics textbook, and it should be readily available online.

You only studied enough to throw around the term beta decay with only a vague grasp of the concept, and you completely glossed over the necessity of uranium enrichment. You did not comment on the essential element of fission: neutron capture. Where do the neutrons come from? What is the moderator of the reaction? You simply stated that inducing beta decay in U238 and Th232 would be enough. So what do you do with the resulting Pu239 and U233? Let them sit? Granted, U233 is easier to induce fission in than U235, but it won't happen without neutron capture. Again, this information is available both online and in any sophomore-level textbook.

On a side note, I'd still appreciate it if anyone could point me toward any other theories on this topic, because I can't find any.

There really aren't. We kind of shrug our shoulders and say, "Well they obviously didn't do all the work, so something else did." We don't have S-8472 bioships and a bunch of planets to blow up in a laboratory setting, so we're pretty much stuck.

[trackball]

All right, I've had more than enough of this. It's obvious that you don't understand what I'm talking about as fully as you believe you do.

First of all, U238 accounts for over 99% of all naturally occurring Uranium in the world. I knew full well that U235, which is the naturally occurring fissile form, is present only in tiny amounts and that's the reason it has to be enriched, to separate it from the U238.

My actual mistake, which is the part that you're not grasping, was in assuming that since there was over 100 times as much naturally occurring U238 as U235, that it wouldn't be hard to find in amounts greater than 15 kg. What I didn't know, and what I had to search long and hard to find out because nobody's interested in U238, was that even U238 is only present in pitchblende in 1 to 4 pounds per ton.

You are also apparently not grasping the whole point of artificially inducing the beta decay, which is to change all the naturally occurring and normally worthless U238 into fissile Pu239. If U238 could be found in amounts as large as I thought it could have, the whole process of creating the beta decay in the first place would have meant that you wouldn't have had to enrich it, because now all of a sudden 99% of the entire world's supply of uranium was now fissile plutonium. There would have been no enrichment necessary because there would be nothing to separate it from!

And creating a fission reaction isn't as complicated as you seem to think it is. All you need to do is put enough fissile material in one place. The hard part is enriching it, which was the part that I thought I had solved and is the point you are attacking without understanding it.

And if you actually understood the concepts that you think I only have a vague grasp on, you'd have realized that U238 throws out fast neutrons as it decays naturally, that's where the neutrons are coming from to feed the beta decay. Not to mention that the 0.7% U235 which is present along with the U238 (and not part of the breeder reaction) is throwing out neutrons too. There's plenty of neutrons for everyone, don't crowd, please form a single file line.

And if you don't believe me that all you have to do is pile enough fissile material in one place, look up a little mine at Oklo in Gabon, Africa. 1.8 billion years ago there was enough U235 in that area to create a naturally occurring fission reaction.

So in closing, screw this. There are a lot of highly intelligent people here but, unfortunately, you're a bunch of jerks. I'm sick of trying to gain your acceptance.

[Howedar]

In that case, don't let the door hit you on the way out.

[Darth Wong]

You are also apparently not grasping the whole point of artificially inducing the beta decay, which is to change all the naturally occurring and normally worthless U238 into fissile Pu239. If U238 could be found in amounts as large as I thought it could have, the whole process of creating the beta decay in the first place would have meant that you wouldn't have had to enrich it, because now all of a sudden 99% of the entire world's supply of uranium was now fissile plutonium. There would have been no enrichment necessary because there would be nothing to separate it from!

No, dumb-fuck. The problem is that uranium is not found in pure deposits; it is embedded in something called ORE, where its concentration is far below what is needed to actually create a violent, uncontrolled chain reaction. Do you think they dig into the ground and find big solid gleaming chunks of uranium sitting there?

And creating a fission reaction isn't as complicated as you seem to think it is. All you need to do is put enough fissile material in one place. The hard part is enriching it, which was the part that I thought I had solved and is the point you are attacking without understanding it.

Are you really this fucking stupid? You figure there's trillions of tons of pure uranium sitting in one spot somewhere, and all you have to do is convert the isotopes through your ridiculous magic boson beam?

And if you actually understood the concepts that you think I only have a vague grasp on, you'd have realized that U238 throws out fast neutrons as it decays naturally, that's where the neutrons are coming from to feed the beta decay.

Beta decay is not "fed" by neutrons; it is a radioactive decay process. You are talking about fission induced by neutron capture, and unless you have extreme high-purity fissile material available, you need SLOW neutrons for that, you blithering idiot. It's one thing to say something stupid like what you did, but to go and insult people because you don't like the way they corrected you is beyond the pale.

Not to mention that the 0.7% U235 which is present along with the U238 (and not part of the breeder reaction) is throwing out neutrons too. There's plenty of neutrons for everyone, don't crowd, please form a single file line.

Did you ever think to ask yourself why they have to use a neutron moderator in a fission reactor?

And if you don't believe me that all you have to do is pile enough fissile material in one place, look up a little mine at Oklo in Gabon, Africa. 1.8 billion years ago there was enough U235 in that area to create a naturally occurring fission reaction.

At such low rates that all it did was create a mild heating effect, dumb-ass. The rates necessary to create a violent, uncontrolled chain-reaction are orders of magnitude higher.

So in closing, screw this. There are a lot of highly intelligent people here but, unfortunately, you're a bunch of jerks. I'm sick of trying to gain your acceptance.

You haven't been trying to gain anyone's acceptance; you've been trying to impress people by bluffing things you obviously don't understand. There's a big difference.

[Durandal]

All right, I've had more than enough of this. It's obvious that you don't understand what I'm talking about as fully as you believe you do.

First of all, U238 accounts for over 99% of all naturally occurring Uranium in the world. I knew full well that U235, which is the naturally occurring fissile form, is present only in tiny amounts and that's the reason it has to be enriched, to separate it from the U238.

My actual mistake, which is the part that you're not grasping, was in assuming that since there was over 100 times as much naturally occurring U238 as U235, that it wouldn't be hard to find in amounts greater than 15 kg. What I didn't know, and what I had to search long and hard to find out because nobody's interested in U238, was that even U238 is only present in pitchblende in 1 to 4 pounds per ton.

You are also apparently not grasping the whole point of artificially inducing the beta decay, which is to change all the naturally occurring and normally worthless U238 into fissile Pu239. If U238 could be found in amounts as large as I thought it could have, the whole process of creating the beta decay in the first place would have meant that you wouldn't have had to enrich it, because now all of a sudden 99% of the entire world's supply of uranium was now fissile plutonium. There would have been no enrichment necessary because there would be nothing to separate it from!

So where does 99% come from? I understand your mechanism now, but you've missed several key components. You have some wiggle room, given that the planet in question is clearly nothing like Earth in composition. Then again, S-8472 destroyed 13 other planets. Either they picked their targets very carefully (not too far a stretch) or their chain reaction is fucked up.

And creating a fission reaction isn't as complicated as you seem to think it is. All you need to do is put enough fissile material in one place. The hard part is enriching it, which was the part that I thought I had solved and is the point you are attacking without understanding it.

No, you need a moderator. Cramming U235 into one place will result in some fission, but a moderator is used to increase the number of collisions and the energy output.

And if you actually understood the concepts that you think I only have a vague grasp on, you'd have realized that U238 throws out fast neutrons as it decays naturally, that's where the neutrons are coming from to feed the beta decay. Not to mention that the 0.7% U235 which is present along with the U238 (and not part of the breeder reaction) is throwing out neutrons too. There's plenty of neutrons for everyone, don't crowd, please form a single file line.

And if you understood those concepts, you'd know that fast neutrons are bad for fission. The probability of a neutron colliding with a nucleus is inversely proportional to the neutron's kinetic energy. Where's your moderator?

And if you don't believe me that all you have to do is pile enough fissile material in one place, look up a little mine at Oklo in Gabon, Africa. 1.8 billion years ago there was enough U235 in that area to create a naturally occurring fission reaction.

The only reason this was possible was because ground water seeped through and served as a moderator, the part of my post which you didn't respond to. What moderates your fission reactions? Hopes and dreams?

So in closing, screw this. There are a lot of highly intelligent people here but, unfortunately, you're a bunch of jerks. I'm sick of trying to gain your acceptance.

Look, I think that we got started off on the wrong foot. You mean well, but struggling to gain acceptance is just something we don't like here. We like people being themselves, not people who try to fit in with the "in crowd."

[Ender]

The knowledge of fission trackball is displaying in this thread makes me want o cry