Contrary to misleading propaganda, the development of the equation E=mc² did NOT lead to the invention of the atom bomb. Nuclear weapons were developed as a result of progressive experiments in elementary-particle physics, which took off as a result of the discovery of radiation/X-ray and especially the subsequent discovery of radioactivity in 1896. At no time was the equation E=mc² a requirement in these experiments. This equation of mass-energy equivalence was devised as a result of research and experiments on electro- magnetism. Just as E=mc² wasn't (and still isn't) used in order to make conventional bombs, it isn't used in order to make thermonuclear devices either. The reason why the equation is brought up often (whenever the issue of atom bomb is raised) has little to do with science and everything to do with selling a massmarket product called Albert Einstein. This, despite the fact that Einstein didn't even invent the equation E=mc² anyway. This fact about the relationship between the equation and the bomb is something that honest scientists have no problem admitting: the Nobel prize winning physicist Steven Weinberg for example has written about this matter in his book Facing Up: "This is a good place to dispel the common misapprehension that nuclear weapons are somehow an outgrowth of Einstein's special theory of relativity. As originally derived in 1907, Einstein's famous equation E=mc² says that the liberation of an energy E by any system will cause it to lose a massm equal to E divided by c² the square of the speed of light. This is just as true of a burning tree as of a nuclear bomb (...) If one insists on saying that mass is converted to energy in nuclear reactions, then one must say the same of ordinary burning." Now, Seven Weinberg isn't some critic of Einstein's relativity theories, in fact he is one of their chief proponents. Someone else is also honest about this issue. Below is an excerpt of an article written by Raeto West:
Atom Bomb: Proof of the correctness of modern physics? Or merely empiricism?In the popular mind, there is a firm link between Einstein and the mushroom cloud, encouraged by mediocre education, media, and science writers. For example, I remember being assured by a biology experimenter that 'e=mc2' is "commonsense". Although there are a few opposing voices, for example, C P Snow's essay on Einstein, which explicitly stated there was no connection, most people think that what they're told is physics—vague speculation, impenetrable mathematics, paradox—led to the atom bomb. The thesis of this piece is that, in fact, the invention of the atomic bomb was almost entirely empirical. Fairly simple new concepts of the nucleus, electrons, neutrons, atomic weights etc. sufficed. Specifically, 'e=mc2', quantum ideas, uncertainty in measurement and the more elaborate mathematics had no effect on the discoveries leading to the invention; these discoveries each came as a complete surprise. The link with 'modern physics' is a myth. If Einstein had never lived, atomic weapons could have been developed exactly as they were. [Note on words: because scientific understanding has (so far) been incomplete, there's no firm line between empiricism, which is something like trial-and-error, and science. Empiricism means something that works, even if it's not understood. Consider metal smelting:—before the discovery of oxygen, oxides, and so on, metals were made by recipe: you mix reddish ore with charcoal and make the mixture hot, and out comes iron. Or consider electricity generation:—this looks much more scientific, far more than (say) a windmill, but arguably is just as purely empirical: Faraday found that a metal thing moved in a magnetic field gives an electric current—nobody knows why—and this is what a generator does. Technology may be scientific, or it may be trial-and-error, or a mixture: thus crystallography theory is mostly scientific, while flight is mostly experimental technology, and metallurgy and weather forecasting are a mixture. I haven't attempted here to define these terms precisely. The point is, important discoveries can be made by pure chance.] What follows is confined to fission, as in the atom bomb, not the 'hydrogen bomb'. Fusion came later, and in any case depended on the chance discovery of fission. The facts about fusion (if it exists) are largely censored, as is probably reasonable in view of the dangers. I've listed below, in approximate sequence, most of the key discoveries which led to the atom bomb. The sources are mainly popular—Ronald Clark's The Greatest Power on Earth (1980), George Gamow's little book The Atom and its Nucleus (1961), Thomas Powers' Heisenberg's War (1994), H T Pledge's Science since 16 00 (1939, 1966) and many others including Fermi's autobiographical writings. However, some evidence is Phil Holland's, drawn from his long experience of nuclear power. Discovery of the first particles, electrons, in 1895 by Thomson. Since these don't travel through air, vacuum technology of pumps and airtight vessels had to have been invented; so this discovery could not have happened before the end of th e 19th century. As with 'Becquerel rays' (a photographic plate or plates happened to be fogged) this was pure accident. The effect of a magnet on the rays was noticed, leading to the division between positive and negative (and, later, neutral) particles. But no theory accounted for these discoveries, although a link was made with electricity and charged ions. Discovery of radium by the Curies. In 1903 radium was found to give off 100 Calories per gramme per hour. 1g was estimated to give 1M Cals before decaying. This was completely unexpected, and incidentally allowed guesses as to the age of the earth to be extended enormously back in time. It was not called 'nuclear energy'—this was before the 'nucleus' had been found. Nor I think was there any link with e=mc squared, which was only popularised fifteen or so years later. Sommerfeld seems to have popularised the idea of a 'different order of magnitude' of energy being 'locked up' within 'the atom'. Rutherford's suggestion, about 1910, that the atom must have a nucleus, concentrated in a tiny proportion of space, was made when it was found that only one positively charged particle out of very many was deflected when passing through gold foil. (This was followed by years of puzzlement as philosophers tried to grasp the idea of matter which was mostly space). Rutherford also discovered the splitting of nitrogen nucleus with alpha particles. He was '.. completely astonished..' In 1913 and 1914, H G J Moseley is credited with establishing that the number of positive charges in the nucleus is the 'atomic number', which gave a firm foundation for arranging elements in the periodic table. He seems to have used X-ray crystallography, which has a theoretical basis (Bessel numbers), based on straightforward wave theory, for which Bragg became well-known. Nothing in Moseley's work, so far as I can tell, had any content based on 'modern physics.' He was killed in 1915. Discovery of isotopes (the word means 'the same place'—meaning the same place in the periodic table, insofar as this existed at the time) by the mass spectroscope, mainly the work of Aston, who for example used chlorine. The technique works by separating fast-moving molecules of the sample into a sort of spectrum, the heavier ones being more difficultto deflect. All this was completely empirical. Discussion well into the 1930s was of the nucleus being made of hydrogen nuclei and helium nuclei (as neutrons were not yet discovered). Joliot, with Marie Curie's daughter, used polonium with beryllium, presumably, again, in a purely empirical way, and found the combination gave what came to be called neutrons. Chadwick in 1932 formally announced his discovery of the neutron. This was important, because, being neutral, these particles could penetrate the nucleus more easily. Possibly Chadwick expected this discovery, since the fact that isotopes exist makes things like neutrons an obvious possibility—since they allow the nucleus to be made heavier without changing its charge. Proton bombardment in 1930-2 was supposedly encouraged by Gamow's calculations re waves [Clark]—which made the nucleus appe The discovery of fission in uranium was purely by accident. Fermi, working through elements methodically to see what happened when they were 'bombarded' with neutrons, expected to make new isotopes, but in 1934 was puzzled by his results with uranium, and probably dismissed what he found as a contaminant. Only in 1939 did Hahn & Strassmann identify barium (and krypton?). Then Lise Meitner and Frisch provided the 'liquid drop' model of fission of nucleus into two parts. [Powers] Szilard noticed fission fragments must emit neutrons if they split; H G Wells's chain reaction idea, based on the ideas of Frederick Soddy (The Interpretation of Radium, 1907, revised later as The Interpretation of the Atom), in The World Set Free (1914), became a possibility [Clark]. Again, this was empirical—it was found that elements with high atomic numbers have proportionally more neutrons than low ones. Nobody had any idea why. But, clearly, if a heavy element split, there would be surplus neutrons. Uranium-235 isotope fission was proved to happen by experiment; it was guessed, and proved, that U235 was the portion of uranium which was m ost liable to fission. Nobody knew (or knows now) why it differed from U238, except perhaps in the sense that an odd number was expected to behave differently from an even number. 1939: Bohr and Wheeler at Princeton realised fast free neutrons were produced during fission. In 1939 Joliot, and Fermi, showed 'two or more' free neutrons came out with each fission of U 235. This encouraged speculation about a possible chain reaction. But, again, this was a purely experimental result. Plutonium, a new element of mass 239, was discovered in a cyclotron; again, purely by chance. In 1940 it was suggested it might be fissionable. Fermi discovered entirely by chance that neutrons could be controlled: the difference between a marble bench and a wooden bench suggested that 'light atoms, comparable in size to the neutron' [sic; Gamow] were best to slow down neutrons. Hence the use of graphite. [PH. There was a similar incident in which Fermi decided for no particular reason to try a block of paraffin wax.] The critical mass (the amount varies with shape and surroundings) had to be determined. Nobody had much idea what it was. In 1940 Frisch and Peierls calculated (wrongly) the critical mass. Various other wrong values were obtained. The actual values found were found empirically by many experiments over many years, 'some of which led to unexpected criticality incidents. I know of one incident at Windscale.. some incidents in USA did a lot more radiation damage.' [PH]. When in 1941 plutonium 239 was found to be even more fissionable, another project was started to separate this in the US [about this time was the well-known event of Slotin ensuring his own death when he separated masses with his hands.] Another incident (p. 167 in Clark) describes a man simply leaning over U235 pieces, causing them to approach danger point. Fermi worked on the atomic 'pile' with graphite to slow neutrons down—so they didn't just mov e fast out of the equipment—and cadmium a moderator [found empirically to absorb neutrons! Nobody knew why; possibly because there are many of isotopes of cadmium]. In Chicago in December 1942, the pile was found to get hot. This was 'the boiler', not yet 'the bomb'. The separation of U235, again, was an empirical engineering problem. Uranium hexafluoride, for use in gas separation, is corrosive and the problems were considerable. Even th en, the theory of gases was wrong and separation occurred the other way round from what was expected with some isotopes. [PH] Before the first bomb test, in 1945, there were doubts about 'igniting' the atmosphere, or the hydrogen in water, suggesting, what is per haps obvious enough, that there was considerable doubt as to the processes at work. Even some calculations as to explosive yield were wildly wrong.
Conclusions:■ How was it known that fission was likely to give off enormous amounts of energy? Without being fairly certain on this detail, the entire, expensive project—'No other nation had the mental and physical resources.. $2 bn.. entire towns built' [Clark] —would not have been started. The answer seems to be the line from the Curies to Fermi. It's true that e=mc2 seems to be used as a buttressing argument, but the defining evidence was empirical. Moreover, there is some doubt as to the correctness of nuclear reactions and their thermodynamics; thus the 'weights' of neutrons and protons etc. are given with seeming confidence, and yet of course there are long processes of inference, possibly wrong, going into these calculations. The complete failure of fusion power adds weight to this suggestion. I would suggest that e=mc2 was adopted simply because it gave a big number, rather than through any cogency in argument. It's possible that nuclear reactions involve large amounts of energy because the nucleus is harder to alter than the outer parts of atoms: so that, if all the products of an atom bomb were collected together, perhaps they would add up to exactly the original contents—though this would be a difficult experiment to try. ■ So it seems that the atomic bomb was certainly helped by some aspects of 20th century physics—the fairly simple sort listed above. The supposedly theoretical stuff, from relativity and quantum theory to Schrödinger's waves and uncertainty principle as popularly misunderstood, probably had not the slightest effect. The following remarks are political rather than scientific: ■ The situation in atomic physics—except that lucky discoveries seem to have petered out—is the same combination of accident and observation. Advances are largely delusory. Look for example at nuclear power; people promoting the excitement of new technology, stress the wonders of such power stations. And yet, the absurd fact is that they use steam turbines! This is a technology Faraday would have recognised, and moreover not a very good one, since more than three quarters of the energy is wasted in transmission and other losses. Presumably, if the physics were genuinely understood, electricity could be manufactured or controlled directly. ■ Another highly dubious idea seems to be the supposed predominance of Jews in developing the atom bomb. In fact, few if any of the key ideas seem to have been Jewish, although it's true that almost all the technical spadework of Los Alamos was carried out by Jews. Apart from this, it's possible that their main role was after the war, in spreading atomic technology to Stalin's Russia—many of the atom spies were Jews—and the Middle East. This of course is a field abounding in mythology. Thus, in Powers' large book on Heisenberg, the 'Jewish physics' idea in Germany is attributed to [Philipp Eduard Anton von] Lenart [Lenard] whose 'crude' leaflet was handed out at a lecture; Powers gives only one passage from it, that Einstein's ideas were unsubstantiated speculations, puffed by Jewish newspapers—something which seems largely accurate—but no other evidence. ■ Viewed in the light of a huge engineering project, the whole conventional justification for the atomic bomb looks doubtful. Bertrand Russell's idea (elsewhere, this site) that it was to be used to keep Asia down may prove to be more accurate. ■ Perhaps this story also helps answer a question posed by one of the Mrs Bertrand Russell, namely, that if these people were so transcendentally brilliant, how come they could find no better political solution than a balance of terror? The sad fact would appear to be that they were simple technical types, blundering along. This piece (above) provoked a reply by a man who spent much of his life working on atomic power and weapons, and who says e=mc2 was important in developing nuclear weapons. Phil Holland comments: "I enjoyed this correspondence — it is the usual support for e=mc2 ('don't try to prove it but suggest it must be true' and 'don't quote experimental results but hint that some experiment must have proved it'."
So then, this issue demonstrates that there is a big gap between science as it is conducted by scientists, and science as it is propagated to the wider public. Basically what's happening here that scientists are systematically behaving like astrologers of the past who habitually were selling falsehood but supplemented that with factual (astronomical) information. For example they were capable of timing the regular movements of stars and used this knowledge as a cloak of credibility and performed the quack of devination/fortune-telling.
Likewise our modern day astrologers and alchemists (the non-applied-physics outfit) are piggybacking on the prestige of applied science/technology in order to be reputable and so get away with flogging (by 'means of persuasion' and propaganda tactics) their unproven, false theories as if they are things that are genuinely proven matters.That which has been is that which will be, And that which has been done is that which will be done. So there is nothing new under the sun.
|
No comments:
Post a Comment