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in which the science was at least as important as the characters, a story which could not happen without the scientific content. It would conform to the definition he had used in 1951 in an article for The Writer and had repeated in his frequently reprinted essay, "Social Science Fiction," in Reginald Bretnor's 1953 collection, Modern Science Fiction: "Science fiction is that branch of literature which is concerned with the impact of scientific advance upon human beings." In the Modern Science Fiction essay, he inserted the word "Social" before "science fiction.'' |
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In spite of the definition, scientific advance was not always at the heart of Asimov's science fiction. Occasionally, a hard scientific datum or development would inspire a short story. But Asimov's novels were more inspired by history than science; they were more speculative than extrapolative. |
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The Gods Themselves was to be different. The idea had sprung from a scientific anomaly the impossibility of plutonium-186 and it was to develop into a story whose science was as hard as any conceived by Harry Stubbs, whose carefully extrapolated alien environments had begun to be published in Astounding in June 1942 (only three years after Asimov's first publication), under the pseudonym Hal Clement. The impossibility of plutonium-186 was basic to the story. For readers to understand this, Asimov had to educate them in the complexities of nuclear physics. |
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One important fact was the structure of the atomic nucleus, which is composed of neutrons and protons, identical in weight but differing in charge. Both are massive as atomic particles go many times more massive than electrons, for instance, which orbit in "shells" around the nucleus, give the element its chemical properties, and balance, with their negative charge, the positive charge of the nucleus. Ordinarily, like charges repel each other. The protons clustered together in the nucleus ought to push each other away, but they are held together by what is known as the strong nuclear interaction, the strongest known force in the universe. This interaction seems to be exerted by the neutrons because a number of protons in the nucleus need a larger number of neutrons to hold them together. |
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Elements are placed in the periodic table of elements according to their charge, that is, the number of electrons they possess as well as the corresponding number of protons in the nucleus. Their atomic weights, however, are the total of protons and neutrons in the nucleus; sometimes this is not a simple number when an element has isotopes (different forms of the same element with one neutron more or less in the nucleus), whose natural atomic weights average out as a fraction. |
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