Stilgar Episode IV: A False Hope
Last Revised: 2000.12.31
Yup, it's another discussion-group troll with a cute alias (and as you might guess, he refuses to divulge his true name or background). This exchange occurred on Brian Young's discussion board. Stilgar starts innocently enough, as many fanatical debaters do, by pretending to be quite reasonable. However, you shouldn't be confused by style over substance: his positions are in fact quite extreme, to the point of being unreasonable. His method is very similar to the methods of guys like Graham Kennedy, who obviously believe that if your style and tone are technical enough, you will come off as a scientific expert. Sadly, this actually does fool some people, but not smart people like us, right? :)
Warning: this thread is not like some of the more childish Hate Mail threads. This guy is wrong but he's not a little brat. So unless you're comfortable with physics, you might not want to peruse this exchange. It's not virulent like the more childish Hate Mail examples, but it's very long and it can get quite dry and technical. I include it not as a form of mockery (although I don't think too much of Stilgar's dogmatic approach) but as an example of what some of the more clever Trekkie debaters tend to sound like.
Update: He recently sent me a bunch of legal threats. I've added them as a separate page.
Does the DS really need to supply all the power needed here, or could the DS "Super Laser" have been simply a specially designed trigger, say in inducing fusion in the hydrogen contained in the planet, sort of like the fission explosion in a modern fusion bomb? What difference would such a scenrio make?
I've heard these claims about the DS initiating fusion or fission before. In order to do that, it would have to create incredible temperatures and pressures all throughout the Earth's mass- how difficult would it be to raise the entire Earth to 50 million K and thousands of bars? Same goes for fission; the DS would have to create a staggering amount of neutron radiation, and somehow pump it through th entire planet's mass. These "cheap way out" methods actually make less sense than simply saying that it's a hypermatter reactor and leaving it at that.
I did some numbers, rather than just speculating (I always do when I try to prove something, and especially when I am removing an existing theory ;) ) I calculated some numbers. The short version is that it would have taken the fusion of less than 0.24% of the hydrogen in the Earth to provide the same amount of energy as is needed to totally overcome its gravitational binding energy. And yes, while iron will not fuse, Earth also contains massive amounts of lighter elements that would undergo fusion under extreme conditions that would have been created by the superlaser providing even more energy. Hence, in the end only a tiny fraction, much less than 1% by weight, of a planet's mass would have to be induced to fusion by the superlaser to release enough energy to overcome the gravitational binding energy of an Earth type planet :) So, I am right.
(Editor's note: this is a common treknobabble tactic: concentrate on the ramifications of the theory rather than the accuracy of the theory. He adds up the total energy that would be released by nuclear fusion in a planet but he completely ignores the question of whether it will happen at all. It's an evasion because he's not addressing the real problem with his idea).
Mike, you are simply using a trekkie style technobabble. By any other name, a rose would smell just the same. We do know that IT IS IMPOSSIBLE to release more energy from any mass than given by Einstein's famous formula, there is no way around that limitation, and there never will be. Period. Mike, you also have no need for self-sustaining fusion, or for a massive one. After all fusion bombs, hydrogen bombs, exist and have been exploded on Earth, and according to you that is not true because it is impossible :) All you need is something in the range of a few hundreds of one percent of an Earth type planet's mass to undergo fusion and you will have energy equivalent to the planet's binding energy. That's all there is to it. No. It is not a trekkie conspiracy, but it is a first year physics textbook scientific fact. However, since you do not want it, I claim the idea, I will write it up for my own page.
Are you suggesting that I don't think H-bombs are possible, or that I don't believe in general relativity? I have made neither claim. I will assume for now that the insult was unintentional, and I will make a few points:
You claim that a tiny fraction of the Earth's hydrogen would have been sufficient in fusion to generate the gravitational binding energy of the planet. However, did you realize that when you create the conditions necessary to produce fusion, you will only produce fusion in a miniscule fraction of the atoms present? That is why the sun doesn't simply explode; even though its core temperature and pressure are 15 million K and 250 billion atmospheres, less than 0.000000000000000035% of its mass undergoes fusion each second.
Another important point is that the gravitational binding energy requirement wasn't just exceeded by the Death Star; it was crushed. The Death Star blew the planet apart like a bomb, requiring about a million times more than the gravitational binding energy. You would need to cause fusion in a very large proportion of the planet to generate this much energy (Editor's note: far more than the proportion that is hydrogen).
You are essentially suggesting that the Death Star used inertial-confinement fusion in Alderaan (essentially the same process used to create fusion in deuterium-tritium pellets with laser beams). Did you know that inertial-confinement lasers require power levels of more than 2E14 watts (200 kJ in less than a nanosecond) to induce fusion in miniscule 1mm wide pellets of deuterium? And did you know that most of the mass in these pellets does not undergo fusion, in spite of this energy input? This is the big reason that inertial-confinement fusion reactors are still regarded as infeasible. Even if you somehow achieved 100% fusion in the pellet, you would only get a maximum of ~8MJ back. This means that, at best, assuming 100% reaction efficiency and a target body composed completely of very fusionable materials like deuterium-tritium mixtures, you would only decrease your energy requirement by a factor of 40. That's not enough to make a big difference in the DS's energy requirements, and that's a lot of really big if's- Alderaan was not a giant deuterium-tritium pellet, and it is impossible to achieve 100% fusion in an inertial-confinement reaction.
You correctly point out that we cannot release more than 9E16 joules from a single kilogram of matter. However, we don't know the mass of the Death Star (for all we know, the thing has a miniature black hole in it), and they may be using some other method to store matter/energy at high densities. The mass of the Death Star is not known; the comment that it must annihilate more than its entire mass is based on an assumption that its density is similar to modern ships, automobiles, etc.
You know as well as I do that I never claimed fusion bombs to be impossible. I am only trying to point out that the threshold energy is extremely high- this is why you need a fission bomb to act as the trigger for a fusion bomb. There is no such thing as a low-energy fusion trigger- you need lots of energy to initiate fusion, and the difference between the trigger energy and the fusion energy is not as stupendous as you claim. Again, I must remind you that in spite of 15 million K core temperatures and 250 million atmosphere core pressures, less than 0.000000000000000035% of (the Sun's) mass undergoes fusion each second. Do you really think it would be easy to make a significant percentage of the Earth's fusionable materials undergo fusion? I will remind you that a planet is not exactly a deuterium-tritium pellet, and fusion becomes progressively more difficult to induce with larger elements.
I am not using Trek-style technobabble. I am only pointing out that the mechanism of the Death Star's energy production is unknown, and we have no reason to claim that it is impossible, or to conclude that it could have accomplished what it did with a relatively miniscule amount of "trigger energy." The fact that it blew Alderaan apart at great velocity is canon, and indisputable.
I passed first-year physics quite easily.
I agree that producing fusion is not easy. Still we are dealing with a very powerful beam of energy that the DS has, I would not be surprised that just like an atom bomb in a bunch of hydrogen the laser would have been able to induce fusion, especially if like you claim it is supposed to deliver these huge amounts of energy. To turn this on its head, if we assume that the DS is able to deliver as much energy as you claim, is it not sufficient to produce fusion in a little part of the Earth? I use Occam's razor here, inducing fusion in the planet seems possible and it is a real process, as opposed to hypermatter which does not mean anything in particular, and could not provide energy densities higher than AM anyway. Fusion is certainly an easier process than tugging around a black hole inside the DS!
Fusion occurs, but only in systems which are (mostly) elementally homogeneous. Stellar cores, H-bombs, and fusion reactors qualify. A planet does not. The scientific realism of large-scale fusion in a planetary mass is no better than hypermatter. Sure, there must have been some fusion in Alderaan's mass somewhere. But it would cost more to induce than it would produce.
(Editor's note: His argument is based upon the notion that if we cannot explain the Death Star's power generation process, then we must assume that it could not possibly have generated that power. This is a blatantly unscientific mindset, to say the least. Suppose this clown had been around back before they discovered nuclear fusion? He would have looked at the measured power output of the Sun and concluded that it could not possibly be making that much power because GPE and chemical burning can't explain it. Luckily, real scientists were on the case, and since the power measurement was indisputable, they realized that they would simply have to be content with an unknown power source until they learned more. This is what we do with the Death Star; we can measure its energy output from ANH but we don't know how it works).
(2nd Editor's note: He mentions Occam's Razor but he obviously doesn't know what it is. Occam's Razor demands that when faced with two theories which both fit the facts, we must pick the simpler theory. It does not demand that we force unexplained phenomena to conform to known mechanisms even if the data is inconsistent. I refer once again to nuclear fusion in the Sun; using Stilgar's butchered version of Occam's Razor, early 20th century scientists would have had to accept either GPE or chemical burning to explain the sun's power output, rather than holding out for the mysterious unknown mechanism which eventually turned out to be nuclear fusion).
We do not know what was left behind from Alderan, that is my point. And if postulating that a core was left behind gives better answers than otherwise, the core was left behind. As to the "planet was totally blown away", this is not a very precise statement, and could mean a number of things, anything from the planet's surface was destroyed to the planet was vaporised, the statement covers it all and could be used equally to support all these. The novelisation is not the movie, especially since the early books were not (or were they?) intended as part of the canon. Whatever was left behind, fusion could have blown away what was not.
Your dogmatic approach to Alderaan's total destruction is problematic, to say the least. We can see right through the Millenium Falcon's cockpit window and there is nothing left. Even among the many anti-SW NG people, it is pretty rare to insist that Alderaan's core was left behind. If you are intending to make some sort of technical analysis of Death Star energy in a website, you will have trouble being taken seriously if you use an intact core as a premise.
Besides, you didn't bother to address my earlier issue with your "core left intact" theory. How could the mantle and crust be hurled out at 1E7 m/s without also blasting the core? IIRC, only 1/3 of Earth's mass is in the core, so the energy requirement for blasting the planet outwards at >1E7 m/s would still be in the 1E37-1E38 joule range even if the core is miraculously left behind. And you would have to explain why this massive energy release left the core alone.
(Editor's note: Notice how he goes from theory to observation rather than vice versa like a real scientist or engineer: "If postulating that a core was left behind gives better answers than otherwise, the core was left behind". It's ass-backwards. He is trying to force the observations to conform to his theory, rather than forcing his theory to conform to the observations. This is a perfect example of how not to rationalize an observation).
Laser induced fusion is not the same as the fusion in the Sun, not the same as the fusion in a modern hydrogen bomb, and not the same as the fusion I would postulate would have been most likely caused by the DS. So, let's not compare apples and oranges beyond saying that they are both a type of fruit. Currently I think that the closest model of the fusion that the DS caused would be given by the hydrogen bomb - a great amount of energy delivered fast, by the super laser in this case (certainly the superlaser can deliver far more energy per unit time than a fission bomb), produces high pressures in a shockwave form which cause partial fusion in the surrounding material.
You claim that the dispersed hydrogen in a planetary mass might have undergone fusion, but there are two very serious problems with this claim:
Hydrogen-hydrogen fusion is useless. H-H fusion produces only 0.42MeV per reaction, so that it there is almost no net energy production (you need to put at least half that much energy into the nuclei to overcome the coulomb barrier and induce fusion in the first place, even under perfect conditions). Compare this to 5.49MeV for hydrogen-deuterium fusion and 17.59MeV for deuterium-tritium fusion. To compound the problem, the temperatures and pressures required for H-H fusion are actually higher than for H-D or D-T fusion! In fact, the only importance of H-H fusion in stellar cores is that it produces deuterium, which is the true fusion fuel of the stars. And guess what- almost no deuterium is naturally found in planets.
Alderaan is most definitely not analogous to a nuclear fusion bomb. A nuclear fusion bomb utilizes a fission trigger to create fusion in a tritium reactant mass. An elementally homogeneous reactant mass. If the fission trigger were surrounded by a random mixture of chemicals which just happen to contain some hydrogen, you would get nothing but the fission explosion. A planet is not an elementally pure sphere of tritium or deuterium; it has some hydrogen, but H-H fusion is useless and besides, almost no H-H collisions will ever occur because the hydrogen is widely dispersed rather than being concentrated into elementally pure regions. If a hydrogen nucleus does collilde with another nucleus, it probably won't be another hydrogen nucleus.
Any calculations based upon the assumption of fusion are completely invalid until that assumption can be justified with actual numbers. Fusion doesn't just happen by itself, for no reason. You have to provide a specific set of conditions, and at the very least, fulfill Lawson's criterion for reactant particle density and confinement time. A planet fails to satisfy this criterion. On what do you base your claim that "fusion occurs under a huge number of circumstances?" There is a very narrow set of circumstances under which fusion can occur, according to my texts and training.
BTW, you are mistaken when you state that laser-induced fusion is completely different from nuclear weapon fusion. laser-induced fusion is the same principle as fusion-bombs. Both are based on the principle of inertial confinement.
I am not sure what you mean by saying that fusion of hydrogen produces only 0.42 MeV of energy (i.e. 6.7E-14 Joules). I am not sure where you got that number from, or what it refers to (please, do tell me ;) ), but hydrogen fusion is a multi-step process. First you get two hydrogen atoms to combine to release a deuterium atom, a positron, and an electron neutrino. Next the deuterium atom combines with a hydrogen atom to form helium-3 and a gamma ray. Next two helium-3 atoms combine to form one helium-4 atom and two hydrogen atoms (this is the most likely path, the so called proton-proton I chain). And so on all over again. The overall effect is that of changing four hydrogen atoms into one helium-4 atom plus some assorted radiation, and so the energy released per helium atom formed is 4.3E-9 Joules (or 27 GeV), hardly the number you quote. I am guessing that you have only taken into account the initial step, and not all of it at that. Am I correct?
(Editor's note: The sneaky public-relations stuff begins. He slyly tries to make it look as if I've overlooked the subsequent stages in the H-H fusion cycle even though I actually listed some of those stages in my previous post. What he doesn't understand is that each stage is successively less likely).
Plus let me remind you that fusion is a function of both temperature and pressure, and this is why an atomic explosion is able to induce fusion in hydrogen. So, no, deuterium does not have to be found in the planet, it is produced along the initial step in the proton-proton I chain. Please, rather than give me facts I already know, point out how they contradict what I claim? I already know these things for Pete's sake, and in most cases they have no relation to my argument, they do not apply!!
Stilgar, you are not addressing the most important point in my post. There are no elementally pure regions of hydrogen anywhere in a planet. Hydrogen atoms are bound up into relatively huge molecules with heavier elements, and as a result, they are so far apart from one another that you will never be able to satisfy Lawson's criterion for inducement of a fusion reaction. This is the huge, and insurmountable problem with the idea that fusion was induced in Alderaan. And yes, this is directly applicable to your argument, even if you don't want to address it.
As for the full-cycle of fusion in the sun, you have (mostly) listed off the textbook reaction correctly. However, your energy yield is off by three orders of magnitude. The H-H reaction yields 0.42MeV per reaction (two reactions are required in the cycle), the successive H-D reaction yields 5.49MeV per reaction (two reactions are required in the cycle), and the He-He reaction yields 12.86MeV per reaction (one reaction occurs in the cycle). When you add all of that up, and throw in the effect of the two 511keV electron/positron annihilations, you end up with 26.7MeV, of which 0.5MeV is in the form of neutrinos. I don't know where you got that 27GeV per He4 atom figure, but it is obviously incorrect, and it is so large that it leads to a violation of Einstein's E=mc² equation. 6 H-1 atoms eventually combine into an He-4 atom and 2 H-1 atoms, and the mass of 6 H-1 atoms is roughly 9.96E-27 kg. If the reaction yields 4.3E-9 joules as you say, then we just got 4.3E17 J/kg from fusion! Einstein wouldn't like that conclusion very much at all.
Besides, you must recognize that each successive step (from H-H to H-D to He-He) is statistically more unlikely, because it depends on large numbers of the previous reaction occurring in close proximity. This is why I only account for the first stage- there is no reason to assume that any second-stage reactions will occur at all, because they are so statistically unlikely with the planet's hydrogen atoms so far apart from one another.
Remember that the product of an H-H reaction must encounter another H atom for the H-D reaction. Furthermore, two H-D reactions must occur in close proximity, and their products must head directly towards one another, for the He-He reaction to occur! In a star, this is no problem. There are huge numbers of H-H reactions producing huge numbers of deuterium atoms in close proximity to one another. But in a planet, H-H reactions will be few and far between because hydrogen atoms are so far apart, so the statistical probability of second and third stage reactions will drop to almost nil.
Regarding fusion bombs, you are repeating a common misconception when you state that they are hydrogen-based. They cannot induce useful fusion in hydrogen, because the confinement time is too low for the second and third stage reactions to occur. See Lawson's criterion. This is why nuclear weapons must use deuterium and tritium rather than hydrogen (in spite of the common, and completely incorrect term "hydrogen bomb"). By taking a short-cut to higher-energy reactions, they can create a large yield. If the fission trigger were surrounded with hydrogen instead of tritium, you would get some fusion but not enough yield to make it worthwhile, compared to the fission bomb alone.
(Editor's note: you may notice this trend throughout the rest of the post: I keep trying to remind him of real-world examples that disprove his theories, while he keeps trying to evade those examples in favour of pure theory. Technobabble types love theory over observation because it's hard to lie about observation but it's easy to befuddle and obfuscate with theory and terminology, particularly when they're on small discussion boards where they hope not to run into guys like me, who actually know what the terms mean).
For the sake of both our sanities, let's agree to some less rigorous rules of proof than actually designing and building a prottype DS! Shall we? First of all, let's apply the same rules to both sides of the argument. Namely you will have to show that hypermatter is a fuel denser in energy than AM, and try to explain why it it is needed? Next, show that ALL the energy needed to totally explode Alderan (let's leave for now the question of whether a core was left behind - the figures can be adjusted later) would have come from the DS. OTOH, I will try to find out how much energy the DS would heave to supply and how quickly to have a chance of starting fusion reaction say in an ocean (it is a simpler mixture, hydrogen and oxygen, both of which can fuse either with themselves or the other), taking into account the energy required to overcome the moderator like properties of impurities that can not undergo fusion, i.e. are either iron and heavier, or the conditions involved are insufficient to induce fusion in them. I think I have a harder job, as for example I have little idea where to look up the collisonal crossection figures for a hydrogen oxygen plasma at millions degrees and substantial pressures.
(Editor's note: He seems to realize that his nuclear fusion idea won't hold water, so he backtracks a bit and tries to make it look as if I must show how hypermatter works or I'm not applying "the same rules to both sides of the argument". Again, I can't help but think of analogies to astrophysics before we understood nuclear fusion: using his logic, no one would be permitted to discount GPE or chemical reactions as an explanation for its energy output until they can explain an alternate theory. That is brain-damaged methodology; as Sherlock Holmes once said, once we eliminate the impossible, whatever remains must be the truth. The act of eliminating stupid or imposslble theories is quite useful, and hardly unfair).
As for the 0.42MeV figure that you are ridiculing, my textbook lists it as the experimentally verified energy yield for the first-stage H-H fusion reaction. Second and third-stage reactions won't happen because the statistical probabilities are so low when you start with such widely dispersed hydrogen atoms. Even first-stage reactions are highly unlikely.
Look up Lawson's criterion for nuclear fusion, and then demonstrate that you can satisfy Lawson's criterion for nuclear fusion with water. You will not be able to do this. Are you familiar with Lawson's criterion?
In short, hypermatter (a completely undefined term) is a far more reasonable explanation for the DS than fusion, because we know fusion to be impossible in water thanks to Lawson's criterion, unless you apply so much heat and pressure that the gravitational binding energy of a planet will seem insignificant in comparison. The pressure and temperature at the centre of the Sun wouldn't be anywhere near what you would need.
Inducing fusion in a planet does not blatantly defy "what we know about the universe", it is merely very hard, but still possible in theory. The main difficulty comes from two points, or maybe facets of the same problem. The DS has to supply enough energy to induce fusion in substantial parts of the planet, given that sufficient energy is supplied, fusion WOULD occur. The energy has to be supplied in such a way, and fast enough, that pressures and temperatures at least in parts of the planet were sufficient for fusion. Another major problem (the one Mike so strongly insists on) is that a planet conatins a mixture of elements, some of which will not fuse. The elements that will not fuse will act in a way like moderator rods in a fission reactor, they will reduce the amount of any fusion happening. The only way I can think of overcoming the moderating effect of the non-fusing "impurities" would be to further increase the temperatures and pressure created by the DS superlaser, provided you did that, the effect of the impurities would be overcome. So, you see, provided that the DS super laser is advanced enough to heat at least some parts of an Earth type planet in a such a way that very high temperatures and pressures are created, fusion would occur.
OTOH, the problem with hypermatter (as I understood it) is that it seems to claim that it is a source of energy even denser than AM, which to my understanding is nonsense because AM already converts 100% of mass into energy - this is the limit, you can not do better. Furthermore, hypermatter as explained on the sites, seems to imply to deliver more energy than is conatined in the mass of the DS itself, which is a TOTAL impossibility (though I am glad to see Mike admit this, and say that hypermatter can not do it). Another major problem arises is that if the DS releases these huge amounts of energy, where does it get them? Right now, according to Mike's claims, the DS seems to be more powerful than stars, something like the power of between at least a million suns to around 50 billion suns. At a power of 50 billion suns the DS would be almost as powerful as all the stars in our own galaxy put together! Perhaps, it does not release that much energy?
"given that sufficient energy is supplied, fusion WOULD occur." This is a commonly held misconception. You need more than just high temperature and pressure to induce fusion. In addition to high temperatures and pressures, you must satisfy Lawson's criterion for confinement time and reactant particle density.
"Another major problem (the one Mike so strongly insists on) is that a planet conatins a mixture of elements, some of which will not fuse." The other elements will prevent fusion, but not because they are not fusionable! It is because they literally get in-between the hydrogen atoms, so that almost all collisions are likely to be between hydrogen atoms and some bigger atom, rather than hydrogen with hydrogen.
You know perfectly well that fusion occurs at a low rate inside a star- you've mentioned this fact before. Didn't you ever ask yourself why? The sun is based on H-H fusion, which is basically useless. This is why all fusion reactors and weapons are based on D-D, D-T , or T-T fusion (skipping by the H-H stage), and this is why there is no reason to believe your theory of massive H-H fusion in Alderaan (simultaneous fusion of a measurable fraction of a percent is massive for H-H fusion).
Take a good look at the sun. In its core, we will find more than 1E29 kg of hydrogen, pressurized to more than a hundred billion atmospheres and maintained at more than 10 million K. From this enormous volume of hydrogen, at this enormous pressure and temperature, we get 3.8E26 joules per second. The Earth contains less than 1E20 kg of hydrogen, widely dispersed across its upper layers. Your theory claims that the DS used an inertial-confinement fusion reaction (precisely analogous to laser-induced fusion, so all the same equations apply) to generate more than 1E32 joules of energy in one second.
In other words, you are saying that with less than a billionth of the Sun's core mass of hydrogen, we will get more than a million times more power output using the same type of fusion reaction.
Sure, as I've said before, you will get some fusion in a planetary mass if you apply that much energy to it- it's statistically improbable but it will happen in tiny quantities. But you won't get enough fusion to make any difference whatsoever to the DS's energy requirement. And as for achieving many trillions of times the sun's rate of fusion, as you suggest ...
Do the math, and you will see that the fusion ignition energy would be much higher than the gravitational binding energy. It takes a 200 kJ laser to initiate fusion in a pellet of almost pure D-T. The gravitational binding energy of that pellet is less than 1E-20 joules. For any given body of matter, its gravitational binding energy will be absolutely dwarfed by the amount of energy required to initiate fusion even if it is composed purely of fusionable materials!
(Editor's note: Actually, I should have said "any given body of matter of reasonable mass", thus precluding ultra-massive celestial objects, and I should have said "fusion at the rates you're talking about" rather than simply saying "fusion", but that's the problem when you're typing in newsgroup posts; you sometimes don't take the time to properly qualify your statements).
In other words, if the DS induced a significant amount of fusion in Alderaan, it is even more staggeringly powerful than I thought.
Mike, you say that increasing temperature and pressure in themselves is insufficinet in themselves to induce fusion because it does not satisfy Lawson's (?) criteria for confinment. What exactly do you think happens when you deliver a lot of energy quickly? You create very hot and dense conditions, and as the expanding material impacts against its surroundings, it can create "very confined" areas. Add more energy and/or add it faster and you will get bigger "confinment". That's one point.
Why use "hypermatter", it is confusing especially since I remember distinctly reading some claims that it delivers more power than AM technology, just say unspecified reactor technology deliverering so and so energy.
Well, elements that are non-fusionable will prevent fusion, and they will do so because the non-fusionable elements will act like a screen for the fusionable elements, i.e. they will "literally get in between". Clearly both ways are saying exactly the same thing... I thought it was clear :)
Let me repeat, the hydrogen hydrogen combination into deuterium is merely the first step of Sun's fusion. The Sun does not get most of its energy from this first step but from the following ones. I think what you are trying to say is that the first step maybe the most hard to achieve and thus is the limiting reaction (I do not know whether this is so, I would have to look it up) Either way, since the first step is the hardest, once it occurs, the others follow :)
I am not talking about laser confined fusion, at least I do not think I am. What I am talking about is fusion at shock fronts, i.e. heat up a bunch of material with the superlaser and let it collide at extermely high speed with stationary or slower moving material, creating very high pressures, temperatures, and densities along the shock front. Just to give you a clue to what would have been happening inside Alderan, take into account that the whole planet exploded in a few seconds, and any material had only that much time to move through the planet, this would indicate enormous shocks, almost relativistic ones!
As to my figures, I only used the mass of hydrogen in Earth's oceans to arrive at them. If I wanted to do this fully, I would add hydrogen bound in freshwater, atmosphere water vapour, locked up in a variety of minerals, as well as the water locked up in rocks through out the planet. And this is only the hydrogen. Other elements can fuse as well, and a pair of fusing nuclei does not have to be the same, for example you can fuse hydrogen with sillicon, and so on in any combination.
As to the calculations. FIRST LET ME POINT OUT WHAT I HAVE BEE REPEATING: FUSION IN THE SUN IS VERY INEFFICIENT AND PROVIDES ENERGY AT DENsiTIES EVEN LOWER THAN CHEMICAL REACTIONS! THE KIND OF FUSION I AM TALKING ABOUT OCCURS UNDER DIFFERENT CIRCUMSTANCES - THE TWO CAN NOT BE FULLY COMPARED.
Now. The proton-proton I chain, i.e. fusion of hydrogen into helium-4 turns 0.7% of hydrogen's mass into energy. Surface water on Earth has mass of 1.4*10^21 kilograms. One water molecule contains 2/18ths of hydrogen by mass, i.e. Earth's surface water contains 2/18*1.4*10^21 kg = 1.6*10^20 kg of hydrogen. So, if all of the hydrogen fused into helium-4, it would would give energy equivalent to 0.7% of its mass, i.e. 0.007*1.6*10^20 kg = 1.1*10^18 kg. This mass would give 1.1*10^18 kg * (2.998 m/s)^2 = 9.8*10^34 Joules of enrergy. Since Earth's gravitational binding energy is 2.4*10^32 Joules, it means that only something like one quarter of one percent of the hydrogen in Earth's surface water needs to undergo fusion in order to provide enough energy to overcome Earth's gravitational binding energy. Then add the energy that might have been derived from fusion of some other elements.
I hope this clears up what I am quite sure would have happened.
Stilgar, you seem to feel that Lawson's criterion is merely a matter of pressure and temperature. That is untrue- do you know what Lawson's criterion is?
You are correct in concluding that I've been saying that the first step is the hardest. It has the highest initiation energy of the bunch. One might therefore conclude that once you get past this barrier, the rest is easy. However, this is not true; each stage is statistically more unlikely than the previous one due to obvious geometrical concerns; I have stated this point many times now, without acknowledgement from your end. I have repeatedly explained why no one in their right minds even thinks about using H-H fusion in reactors or weapons, again without acknowledgement.
Also, you are talking about laser-induced fusion. The principle of laser-induced fusion is inertial confinement (another statement I have made several times without acknowledgement) which is precisely what you claim happened at Alderaan. Any scientific principles applying to laser-induced fusion apply to Alderaan completely. The huge ratio of fusion initiation energy to gravitational binding energy also applies in spades, which is why this is an absolute dead end. As I said many posts ago, the notion of planetary fusion creates more problems than it solves.
As for trying to suggest that silicon and other light elements might have also undergone fusion, this is even worse than claiming that Alderaan might have undergone H-H fusion at trillions of times the rate of a star's core. Hydrogen is the easiest element to induce fusion in, but the energy required to induce fusion in a significant portion of the Earth's hydrogen will absolutely dwarf the energy required to overcome gravitational binding energy. This is yet anotherstatement that I have made repeatedly without acknowledgement from your end. It doesn't matter whether some fusion is possible; what matters is your claim that the Death Star might have blown up Alderaan without using at least 2.1E32 joules in doing so- it would require far more than that to induce fusion, so there is no possibility of reducing the Death Star's power requirements with this line of thinking. Bringing up silicates and other less fusionable elements is a pointless endeavour. We would need to stick Alderaan in the middle of a supernova to achieve such reactions at a reasonable rate.
Yes, you are correct that we can exceed power density of the sun's fusion with chemical reactions and many other technologies. But again, you never ask yourself why. I know why, but you are not acknowledging the reasons that I keep pointing out. The sun uses a great deal of pressure, and it uses a great deal of temperature. Why then, is its fusion reaction so poor if, as you say, all you need is hydrogen, temperature and pressure? It is because everything I have been saying is correct, as verified by the example of the sun: the nuclear fusion reaction is a matter of statistical probabilities, and those probabilities control the maximum rate of nuclear fusion. The only way to raise this rate is to set up a very special set of artificial conditions. For example, in a nuclear weapon we use elementally pure tritium, a substance which is ridiculously rare in nature.
Again, your entire argument rests on your assumption that fusion might have occurred in as much as 0.1% of the Earth's hydrogen in less than 1 second. You seem to assume that 0.1% is a small number because it "feels" small, but when we're talking about H-H fusion, it is a huge number. Instead of trying to prove that fusion could occur at such a large rate with real numbers and calculations and scientific principles, you simply repeat the numbers regarding how much energy you would get if it happened anyway.
Please try to be open-minded rather than simply arguing because you don't want to lose a debate. Even under ideal fusion conditions, you will never get so many of the atoms in a body of pure hydrogen to undergo fusion in such a short time, never mind the dispersed hydrogen atoms scattered throughout a planetary surface. You keep claiming that I can't use the sun as an example of nuclear fusion because it is a very low-efficiency power generator, but you refuse to acknowledge that there is a very good reason that it is such a low-intensity generator.
You could add up all of the hydrogen in the entire planet, multiply it by one million, put it all in one place, raise it all to the temperature and pressure of the sun's core, and you would still have only a miniscule fraction of the fusion power you would need to blow up Alderaan.
This is becoming dogma, Stilgar. If you don't even know what Lawson's criterion for fusion is, how can you honestly tell me that you are "sure" that fusion occured at Alderaan, in enough quantity to actually help the Death Star?
No, I have not come across a Lawson's criteria, sounds like engineering to me. Physically speaking fusion is a function of pressure, temperature, and the likelihood of collisions between particles that will react. So, let me guess your Lawson's criteria is an empirical engineering equation involving pressure, temperature, a constant for the material fusing, plus a geometric constant... density being expressed as a combination of the other values :) How am I doing?
Mike, I do not have time to continue this. It has become clear to me that we will not agree on this and I can put my time to better use elsewhere. Another topic then?
P.S. I will look up Lawson's criteria (if I can find it, I guess some plasma text?), if you promise to look what shocks are about :) Also, think what would happen if you fired at lower relativistic speeds hydrogen and oxygen at a mixture of the two. You see my idea is more like the idea behind a particle accelerator than laser induced fusion. We can at least agree that there are many ways to blow up a planet :) I am simply trying to hypothesise something other than the brute force approach requiring the DS to rise to the power output of half of our galaxy. Till later.
P.S. Do you think hydrogen - sillicon fusion, or oxygen - hydrogen fusion is possible? ;)
Stilgar, I agree that we will never see eye-to-eye on this. You insist that fusion will occur, but you refuse to acknowledge that for your theory to work, it must occur at unheard-of rates, in an unheard-of medium (water).
(Editor's note: of course, it isn't impossible to make nuclear fusion occur at measurable rates in water. However, it requires conditions many times more extreme than those in the core of the Sun. If the entire planet, which is mostly iron, has to be placed under those conditions, then Stilgar's argument runs into the same problem I've mentioned many times: the ignition cost exceeds the yield)
BTW, I'm afraid you guessed wrong on Lawson's criterion. It is not an engineering concern. It is a nuclear physics concept. The product of reactant particle density (the number of atoms of hydrogen per cubic metre) multiplied by the confinement time must be greater than a certain number. Confinement time is extremely low for inertial confinement, because the outer layers are free to move outwards (unlike a nuclear bomb where there is a sheath, or a star where there is gravitational pressure from above).
(Editor's note: you may have guessed by now that I'm holding back just a little bit of information about Lawson's Criterion, because I was interested in testing his knowledge level. He claims to be knowledgeable about nuclear physics so I've given him a ridiculously easy task: look up a confinement criterion for which I've already supplied the name and most of the concept. This is not one of those "trick questions" people use to make others look bad; I've made it as easy as possible).
If you want to end this discussion, I'm perfectly happy to. This will be my final word then: it is possible to achieve sufficient fusion to unleash 1E32 joules of energy from 4E19 kg of water. The only problem is that you will need to pump more than 1E40 joules into the planet to make it happen. This is why I say it's infeasible- what's the point of generating 1E32 joules if you have to create an artificial supernova to make it happen?
As for fusion between different elements, it's possible. But the coulomb barrier is very high, so the reaction rates will be very low (even lower than they are for H-H fusion). The best reaction rates are for elements with a high atomic mass relative to atomic number (eg. tritium which has an atomic mass of 3 but an atomic number of 1).
I looked up books like "Quantum Physics Of Atoms, Molecules, Solids, Nuclei, And Particles", or "Advanced Stellar Astrophysics", and others... None of them even mentios the Lawson's crterion. HMMM... Perhaps you should give me some references for recent texts. Either way, in the "Advanced Stellar Astrophysics" text I found what looks like a way for calculating the likelihood of fusion and its rates from basic principles. However, it is about a dozen pages of very advanced equations, served staright up with in most cases no derivation, and involving things like Schrodinger equations, Jacobians, Fourier transforms, nuclear energy levels calculations, and other goodies like this :) I can follow this if I pay attention, but I do not claim to understand them anywhere close to fully (at least not yet). I think that even if I managed to code all the equations and claculations in HTML, anyone here would be able to follow it, or find any mistakes in my calculations if I made them :) I will see what I can do... but you will not get your answer any time soon.
(Editor's note: Notice how he tries to make it seem as if I'm asking for the impossible. Yes, it's ridiculously difficult to figure out fusion initiation conditions from first principles, but that's not how we figure them out. We use formulae derived from empirical observations. If he was half as knowledgeable as he claimed to be, he would know this already).
The parameters you describe for your Lawson's criterion, I think, could be calculated from the properties I suggested :) Anyway, give me some RECENT references for this stuff.
(Editor's note: Notice how he seems to be claiming that unless a text is recent, it isn't any good. That is totally untrue and it's a very common mindset among scientific illiterates. Information in textbooks becomes obsolete if and only if it is later found to be incorrect. It does not have a built-in expiry date. Some of the items in science textbooks can be hundreds of years old).
I have to add that I have a MUCH HARDER job than you. All you do is claim unknown technology, while demand from me to almost design the DS in principle ;) Generally I do not have a problem with claiming in sci-fi some unknown technology on the principle "that we see it work", I think it is a valid approach, and preferable to invoking technobabble. However, in your case for the DS power output I have A BIG problem with you claiming for it a peak power output in the range of tens of billions times the power output of the Sun. And this is why I am searching for some other explanation. I do not think you can simply claim the brute force approach in every explanation you propose if it gives you some literally astronomical figures. I feel that the least you have to do is to clearly justify that it is reasonable for the DS to have a peak power output in the ranges of millions to billions times the power output of the Sun.
P.S. Once again, think particle accelerators and shocks... sorry, I could not resist ;) BTW, confinment seems to be a problem with the physical vessel housing the fusion reactions and not with creating it.
Stilgar, I'm not at all surprised to hear that you couldn't find references to Lawson's criterion in an astrophysics book or quantum mechanics book. For fusion power generation and weaponry (or your Alderaan fusion idea), we need to achieve reaction energies and reaction rates far superior to what we see in stars (you already know the sun has an extremely low reaction rate- why should this surprise you?)
"I looked up books like "Quantum Physics Of Atoms, Molecules, Solids, Nuclei, And Particles", or "Advanced Stellar Astrophysics", and others... None of them even mentios the Lawson's crterion. HMMM..." Try reading books on nuclear fusion rather than astrophysics. Your interest in astronomy is not applicable to the problem of inertial-confinement nuclear fusion. I don't understand why you insist on attempting to apply stellar fusion to your inertial-confinement theory, when you know that stellar fusion would be totally inadequate!
Try reading a real nuclear fusion-related book like "Fusion Energy" by R.A. Gross, published by John Wiley and Sons. It discussed Lawson's criterion in detail, along with many other fascinating aspects of fusion reactors, including alternate designs such as stellarators, heliotrons, torsatrons, reversed-field pinch reactors, and of course, tokomaks and inertial-confinement laser-induced fusion.
"However, in your case for the DS power output I have A BIG problem with you claiming for it a peak power output in the range of tens of billions times the power output of the Sun." Millions, not billions. That is the amount of energy required to make Alderaan explode the way it did. If you've got a theory that actually works (as opposed to nuclear fusion which would require even more energy to induce), then by all means, propose it, along with actual numbers to show that it would work, rather than simply assuming that it would work.
(Editor's note: I find it ironic that he mocks my conclusion that the Death Star makes millions of times more power than the Sun, even though that conclusion is based on direct measurement of the kinetic energy added to Alderaan. It's ironic because his theory describes the water in Alderaan's oceans undergoing nuclear fusion at trillions of times the reaction rate in the Sun!)
"I feel that the least you have to do is to clearly justify that it is reasonable for the DS to have a peak power output in the ranges of millions to billions times the power output of the Sun." I already have. It is physically impossible to raise the energy state of Alderaan's mass by 1E38 joules without adding at least 1E38 joules. That's Conservation of Energy. Your entire argument stems from your gut-level revulsion at the idea that the DS is so incredibly powerful, but you need to provide something more substantive than "I think that's way too high!" or a fusion theory which won't work.
As for complaining that you have a much harder task than I do, this is not true at all. You only need to do one thing: determine the energy requirement (actual numbers, none of this "reasonably high temp and pressure" qualitative nonsense) for inducing fusion in water.
"BTW, confinment seems to be a problem with the physical vessel housing the fusion reactions and not with creating it." Sorry, but that's completely untrue. Without confinement, you will never achieve fusion. That's what Lawson's criterion is all about. Every method of fusion requires confinement, from tokomak reactors (which use magnetic fields to pressurize the plasma and also to protect the walls) to stars (which use gravitational forces to pressurize the plasma) to nuclear weapons (which use a sheath around the D-T mixture to pressurize the plasma by preventing free outward expansion long enough for the fission bomb's outward pressure to induce fusion). See the trend? Notice that the protection of reactor walls is not an issue with stars and fusion bombs.
Mike as I mention in my other post the quantum mechanics and astrophysics texts apply because they show how to derive fusion initiation energies, reaction rates, and energies produced from first principles, i.e. overcoming the coulomb barrier, stability of nuclei, and collisional crossections. So, while I agree 100% that the fusion processes we are hypothesising about are occuring differently (I have said so myself), up to this point they are the same.
Mike, the book you mention about Lawson's criterion, is it a pop-science book or a text? How old is it? Is it the only book that has what you are talking about?
I see, you demand that I construct the DS to prove my point ;) Well... as I said, not just yet. LOL And I want to say that any theory based on real and checkable principles is superior than claiming unspecified processes. How would you explain the energy needed to explode Alderan? As to the energy itself all I am preapared to conceed is in the range of gravitational binding energy, i.e. 2.4*10^32 Joules (according to your calculations - I have not checked them).
Of course it is impossible to raise the energy of Alderan by whatever without this energy being added. This is not the point. The point is where this energy comes from. You are saying it comes from the DS, I am saying it is more likely to be released from the planet itself.
"As for complaining that you have a much harder task than I do, this is not true at all. You only need to do one thing: determine the energy requirement (actual numbers, none of this "reasonably high temp and pressure" qualitative nonsense) for inducing fusion in water. Excuse me! There is nothing "only" or simple about calculating conditions during fusion and predicting the results. It is far from a simple task as has been shown by the decades of research into fusion with limited success. It is clearly more challenging than invoking hypermatter :)
(Editor's note: Again, he is either lying or ignorant. The criteria for nuclear fusion initiation have been tabulated for decades. That's how we've been able to build thermonuclear weapons and experimental nuclear fusion reactors. The problems we're encountering with nuclear fusion reactors relate mostly to materials science, not to an ignorance of ignition conditions. He keeps trying to make it seem as if we must derive those criteria from first principles, but that's nonsense. The world of science and engineering is full of things which are figured out from empirical tabulated data rather than first principles, and in fact, most practical applications of science don't start from first principles). Again, if his knowledge were a fraction of what he claimed it to be, he would know this.
Actually the quantum text specifies that the problem with fusion is not with achieveing ignition but with the container surviving those conditions. The point the text makes is that if you had a strong enough container, you could create fusion in it by increasing pressure, temeparture, and densities as required for fusion. Let me quote:
There are ways of achieving such a temperature, if ways can be found to produce a container that would not be destroyed by the temperature. The Sun is so massive that gravitational fields provide a container automatically. On Earth, it might be done by using magnetic fields acting on charged nuclei to contain them. Attempts have been made to build such a container, fill it with hydrogen, and then heat the contents by, for instance, firing in a laser beam (cf sounds familiar? ;) ). There have been some indications of success, but only for very short times before the conatiner fails. p 608 "Quantum Physics Of Atoms, Molecules, Solids, Nuclei, And Particles", by Robert Eisenberg and Robert Resnick, John Wiley and Sons, second edition. The book is a standard advanced physics text at unis.
(Editor's note: he quotes from the text but he doesn't understand it. The container is only important because it is necessary to maintain confinement, and confinement is a criterion of ignition. In inertial confinement fusion, there is no container so the pellet must be blown apart at such incredible speed that inertial resistance to acceleration creates a sufficient confinement effect to induce fusion).
Finally I want to check one thing. You do realise that the initiation energy for fusion is released back 100% once fusion occurs, and is not absorbed or in some way taken up?
(Editor's note: Again, he's hopelessly butchered the concept. The initiation energy for a nucleon pair is not wasted if it reacts, but most of the initiation energy goes to nucleons that don't react. Nuclear fusion is all about miniscule probabilities).
Stilgar, I noticed you began your last post with an interesting comment: "So, while I agree 100% that the fusion processes we are hypothesising about are occuring differently (I have said so myself), up to this point they are the same." This is the basic problem with your argument- they aren't the same. You are postulating that a stellar H-H fusion reaction can produce D-T fusion bomb reaction rates. You can't mix and match reaction types and rates like that.
"Mike, the book you mention about Lawson's criterion, is it a pop-science book or a text? How old is it? Is it the only book that has what you are talking about?" A pop-science book? "Fusion Energy" is hardly a pop-science book. It contains full equations for determining reaction rates, among other things. Every single text I've ever seen on nuclear fusion technology contains a reference to Lawson's criterion, from "Fusion Energy" to reference materials at Ontario Hydro, to my old first-year physics textbook from university. I find it hard to believe you haven't been able to find a single reference to Lawson's criterion if you are as familiar with fusion as you claim.
(Editor's note: More evasion tactics. He can't find it so he tries to claim that it must not be a "real" concept, or perhaps it's obsolete. The sad thing is that you can find it in any decent first-year university physics text).
"As to the energy itself all I am preapared to conceed is in the range of gravitational binding energy, i.e. 2.4*10^32 Joules (according to your calculations - I have not checked them)." All you are prepared to accept? I wasn't aware that you had the ability to refute canon. At mere escape velocity it would have taken hours for the Alderaan explosion to unfold, but the Millenium Falcon dropped into orbit 1 planetary diameter from where Alderaan's surface should be, less than 5 minutes later, and there was nothing left but a meteor shower. The explosion was clearly in the range of 1E38 joules. You won't accept that because you don't like it, but that's too bad. It's in the film. There is no reason any rational human being can watch ANH and conclude that the planet took hours to explode, unless there's some sort of vision impairment involved. This is one of the reasons that the fusion theory is so laughable- even if 100% of the planet's hydrogen underwent fusion it would contribute less than 0.1% of the energy necessary to blast Alderaan apart.
"Excuse me! There is nothing "only" or simple about calculating conditions during fusion and predicting the results." No one is asking for precise figures on the reaction- just determine how much heat and pressure are required to induce fusion. I'll do some quickie calcs based on deuterium (just to be generous to your cause).
Based on the experimentally determined reactivity of D-D fusion, it is entirely possible to induce fusion in as much as 0.25% of a body of deuterium in as little as 50 microseconds (microseconds are considered extremely large units of time in fusion tech) by heating it to 10 keV (yes, keV are often used as a unit of temperature in fusion texts), and pressurizing it to 100 GPa.
No problem, right? Well, there is a teeny weeny problem. The DS beam hits the core and both pressurizes and heats the planet from the inside out, so 2E30 joules of heat energy will have to conduct from the centre of the planet to its surface (and into its water) in less than 0.05 seconds. Two big stumbling blocks: temperature and time.
The physics of heat conduction are fairly simple: it is physically impossible for heat to flow from the mantle upwards to the crust unless the mantle is hotter than the crust. Therefore, in order to heat the oceans to 100 million K we must heat the entire crust to 100 million K, the mantle to more than 100 million K, and the core even hotter. To do this, we need to add at least 1E36 joules of thermal energy to the planet. Whoops! We just exceeded the gravitational PE requirement!
But hey, it gets worse! If you want all of this heat energy to travel from the core to the surface in 0.05 seconds, it must shoot through the planet at 1.2E8 m/s (relativistic heat conduction!). That would be quite a neat trick, especially if the conducting medium is gaseous, which it would be.
We also have the huge rocky debris chunks. They prove that most of the planet was still in solid form at the time it exploded; how could the oceans have been heated to 100 million K if they were sitting on a planet that was still cold enough to be solid or liquid?
And finally, we have the rather obvious criticism that if the entire planet blew apart like a bomb (complete with massive surface acceleration and superheating to plasma like a fission bomb) in order to ignite the fusion reaction, then in what way have you decreased the energy requirement for the Death Star?
(Editor's note: He ignores this point but it's the final nail in his coffin. In order to induce significant inertial-confinement fusion of the type that you see in laser-initiated fusion or thermonuclear bombs, you must make the target explode like a bomb. But he's created a catch-22; he must make the planet explode like a bomb in order to generate the energy that will supposedly be used to make the planet explode like a bomb!).
I know you won't accept any of this; I suspect you will invent a theory for how the DS superlaser might have made the planet expand from the inside out without having to go to the bother (and energy expense) of superheating it, and also how a portion of the beam would have avoided drilling down to the core so that it could streak across the surface, looking for water. The Death Star gets more magical all the time.
Stilgar, I found this quote to be emblematic of the problem with your argument: "Actually the quantum text specifies that the problem with fusion is not with achieveing ignition but with the container surviving those conditions. The point the text makes is that if you had a strong enough container, you could create fusion in it by increasing pressure, temeparture, and densities as required for fusion."
You are completely misinterpreting the text. The only reason we care about the container is that without it, there is no outside force to maintain the pressure we need for ignition! You seem to think that ignition is easy; this is frankly ludicrous. Ignition is the huge problem, and this is why we need fancy containment/confinement technologies.
Yep, never in my career, in no textbook have I come across anything called the Lawson's criterion. This is why I am puzzled. As to the quote I gave, I can not retype the whole book, but the point was clear: the problem is with containment and not ignition, provided you have the container, the ignition is easy. There is no point in arguing about it with me, that's what the text said, and the guys writing it seem to have quite impressive credentials... I am inclined to believe them. (Editor's note: Notice the textbook example of an appeal to authority: he can't justify his simple-minded interpretation of the text so he resorts to red-faced mutterings about the authors' credentials)
I calculated the numbers Mike, if all of Earth's hydrogen underwent fusion, it would release 400 times more energy than is necessary to overcome the gravitational binding energy, I do not understand why you insist on stopping fusion at its first, most inefficient point, hydrogen fusion means all the way to helium. And you will forgive me if I do not take your assumptions and calculations at face value ;) On one hand you say the fusion processes are different, on the other you bring in all these assumptions for what processes I know not. Anyway, till later, in the end the truth will become apparent.
(Editor's note: I didn't have to respond at this point. Others on the board were wise to Stilgar's incredibly repetitive argument, and they all saw how he was ignoring all of the rebuttals. Another poster nicknamed Cyborg Stan was able to find what Stilgar couldn't, in spite of Stilgar's claims of scientific expertise, and a poster named Shadowhawk easily pointed out how Stilgar was ignoring all of the rebuttals to his argument).
Cyborg Stan responds:
"In 1957, J.D. Lawson showed that the product
of ion density n and confinement time t must satisfy,
at a minimum, approximately
nt > (approx) 3 x 10^20 s/m³.
This Lawson criterion must be reached to produce ignition, by which we mean a self-sustaining thermonuclear 'burn' that continues after all external heating is turned off. To reach break-even, the point at which the energy output due to fusion is equal to the energy input to heat the plasma, requires an nt about an order of magnitude less."
Giancoli, Douglas C. Physics : Princibles with Applications (Fourth Edition). Prentice Hall, 1995 (on page 895)
Shadowhawk also responds:
Stilgar, the whole problem with 'causing all of Earth's hydrogen to undergo fusion' is that all of Earth's hydrogen is, get ready for this, dispersed across a near-sphere (.0034% elliptical) 12,756km in diameter! And in between each hydrogen atom is lots of rock or an oxygen molecule (hydrogen in the atmosphere is even worse)! It ain't all contained in the core or in a pocket in the mantle! No, the vast majority of the hydrogen on the planet is bound up in water, which covers about 75% of the surface of this planet. Even if you could induce fusion in a portion of the hydrogen, the fusion reaction sure isn't going to get very far. As Mike has said (MANY TIMES), the amount of energy to induce fusion in all of Earth's oceans would be on the order of the energy required to blow the planet into small chunks of rock. You just seem to ignore what doesn't work with your theory, and accept what works.
Yea, yippie, fusing all of Earth's hydrogen would cause enough energy to overcome gravitational binding. But, you seem to totally ignore the problem of density! Totally ignoring the problem of pressure and containment (a fusion reaction will *STOP* without containment) (H-H would be virtually the ONLY reaction to occur on the planet. The deuterium density would be stunningly low, far too low for the next stage to occur regularly, and the chances almost nil that higher energy reactions would occur). Totally ignoring (and conviently not doing the calculations yourself) that to cause wide-spread fusion in a planet would require about as much energy needed to blow the thing to bits.
This conversation has obviously stopped being about Hypermatter/low-density M/AM reactors (hello? Hypermatter could be neutronium/anti-neutronium! Tons of reactant per cubic centimeter!), and only about causing fusion in planets. Stilgar, until you start posting concrete equations, you are NOT going to convince anyone that most of the energy for Alderaan's destruction came from Alderaan itself (which is the basis of your entire argument, remember?).
In case you were left feeling lost by all this, I'll paraphrase Stilgar's basic argument:
If 1% of Alderaan's hydrogen underwent nuclear fusion, it could have provided all of the energy necessary to overcome the gravitational binding energy of the planet. Since fusion is a simple matter of heat and pressure, it was bound to happen. Therefore, the Death Star didn't have to hit Alderaan with 2.4E32 joules (I'm ignoring the 1E38 figures because they're just based on film observations).
There are a huge number of problems with the argument, but let's list off the biggest:
The energy cost of raising the entire planet to the temperatures and pressures of the Sun's core would vastly outstrip the energy yielded from any nuclear fusion in the tiny amount of hydrogen on its surface.
Even if you were to duplicate the conditions in the Sun, you would only duplicate the rate of fusion in the Sun. You actually need trillions of times the Sun's rate of fusion to accomplish what Stilgar describes as an inevitability.
If you go with the "compression wave in the ocean" idea, you must make the planet explode like a bomb in order to create the necessary pressure. If you must make the planet explode like a bomb in order to generate the energy that will make the planet explode like a bomb, you're putting the cart before the horse.
The violence of the Alderaan explosion vastly outstripped 2.4E32 joules. He can't simply ignore the 1E38 J range of figures derived from the kinetic energy of Alderaan's rapid expansion, because if he ignores film observations, he's arguing scientific matters but he's using dialogue instead of observation as the base evidence. That's a pseudoscientific mentality.
Continue to Stilgar Episode V: The Blowhard Strikes Back
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