large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_02_asimov_64kb_53
large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_02_asimov_64kb
English
12904
The amount of energy liberated by a gram of uranium in 1 second of radioactivity was an insignificant fraction of the energy released by a burning candle. THE AMOUNT OF ENERGY LIBERATED BY A GRAM OF URANIUM IN ONE SECOND OF RADIOACTIVITY WAS AN INSIGNIFICANT FRACTION OF THE ENERGY RELEASED BY A BURNING CANDLE
nergy was wrong (which seemed unlikely), or the painfully collected evidence of geologists and biologists was wrong (which seemed unlikely),—or there was some source of energy greater than any known in the 19th century, whose existence had somehow escaped mankind (which also seemed unlikely). Yet one of those unlikely alternatives would have to be true. And then in 1896 came the discovery of radioactivity. The Energy of Radioactivity It eventually became clear that radioactivity involved the giving off of energy. Uranium emitted gamma rays that we now know to be a hundred thousand times as energetic as ordinary light rays. What’s more, alpha particles were being emitted at velocities of perhaps 30,000 kilometers per second, while the lighter beta particles were being shot off at velocities of up to 250,000 kilometers per second (about 0.8 times the velocity of light). At first, the total energy given off by radioactive substances seemed so small that there was no use worrying about it. E PAINFULLY COLLECTED EVIDENCE OF GEOLOGISTS AND BIOLOGISTS WAS WRONG WHICH SEEMED UNLIKELY OR THERE WAS SOME SOURCE OF ENERGY GREATER THAN ANY KNOWN IN THE NINETEENTH CENTURY WHOSE EXISTENCE HAD SOMEHOW ESCAPED MANKIND WHICH ALSO SEEMED UNLIKELY YET ONE OF THOSE UNLIKELY ALTERNATIVES WOULD HAVE TO BE TRUE THEN IN EIGHTEEN NINETY SIX CAME THE DISCOVERY OF RADIOA ACTIVITY THE ENERGY OF RADIOACTIVITY IT EVENTUALLY BECAME CLEAR THAT RADIOA ACTIVITY INVOLVED THE GIVING OFF OF ENERGY URANIUM EMITTED GAMMARRAYS THAT WE NOW KNOW TO BE A HUNDRED THOUSAND TIMES AS ENERGETIC AS ORDINARY LIGHT RAYS WHAT'S MORE ALPHA PARTICLES WERE BEING EMITTED AT VELOCITIES OF PERHAPS THIRTY THOUSAND KILOMETERS PER SECOND WHILE THE LIGHTER BATEER PARTICLES WERE BEING SHOT OFF AT VELOCITIES OF UP TO TWO HUNDRED FIFTY THOUSAND KILOMETERS PER SECOND ABOUT ZERO POINT EIGHT TIMES THE VELOCITY OF LIGHT AT FIRST THE TOTAL ENERGY GIVEN OFF BY RADIOACTIVE SUBSTANCES SEEMED SO SMALL THAT THERE WAS NO USE WORRYING ABOUT IT
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