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ever the pragmatist； rutherford was the first to see that there could be a valuable practicalapplication in this。 he noticed that in any sample of radioactive material； it always took the same amount of time for half the sample to decay—the celebrated half…life—and that thissteady； reliable rate of decay could be used as a kind of clock。 by calculating backwards fromhow much radiation a material had now and how swiftly it was decaying； you could work outits age。 he tested a piece of pitchblende； the principal ore of uranium； and found it to be 700million years old—very much older than the age most people were prepared to grant theearth。
in the spring of 1904； rutherford traveled to london to give a lecture at the royalinstitution—the august organization founded by count von rumford only 105 years before；though that powdery and periwigged age now seemed a distant eon pared with the roll…your…sleeves…up robustness of the late victorians。 rutherford was there to talk about his newdisintegration theory of radioactivity； as part of which he brought out his piece of pitchblende。
tactfully—for the aging kelvin was present； if not always fully awake—rutherford notedthat kelvin himself had suggested that the discovery of some other source of heat wouldthrow his calculations out。 rutherford had found that other source。 thanks to radioactivity theearth could be—and self…evidently was—much older than the twenty…four million yearskelvin’s calculations allowed。
kelvin beamed at rutherford’s respectful presentation； but was in fact unmoved。 he neveraccepted the revised figures and to his dying day believed his work on the age of the earth hismost astute and important contribution to science—far greater than his work onthermodynamics。
as with most scientific revolutions； rutherford’s new findings were not universallyaccepted。 john joly of dublin strenuously insisted well into the 1930s that the earth was nomore than eighty…nine million years old； and was stopped only then by his own death。 othersbegan to worry that rutherford had now given them too much time。 but even withradiometric dating； as decay measurements became known； it would be decades before we gotwithin a billion years or so of earth’s actual age。 science was on the right track； but still wayout。
kelvin died in 1907。 that year also saw the death of dmitri mendeleyev。 like kelvin； hisproductive work was far behind him； but his declining years were notably less serene。 as heaged； mendeleyev became increasingly eccentric—he refused to acknowledge the existenceof radiation or the electron or anything else much that was new—and difficult。 his finaldecades were spent mostly storming out of labs and lecture halls all across europe。 in 1955；element 101 was named mendelevium in his honor。 “appropriately；” notes paul strathern； “itis an unstable element。”
radiation； of course； went on and on； literally and in ways nobody expected。 in the early1900s pierre curie began to experience clear signs of radiation sickness—notably dull achesin his bones and chronic feelings of malaise—which doubtless would have progressedunpleasantly。 we shall never know for certain because in 1906 he was fatally run over by acarriage while crossing a paris street。
marie curie spent the rest of her life working with distinction in the field； helping to foundthe celebrated radium institute of the university of paris in 1914。 despite her two nobelprizes； she was never elected to the academy of sciences； in large part because after the deathof pierre she conducted an affair with a married physicist that was sufficiently indiscreet toscandalize even the french—or at least the old men who ran the academy； which is perhapsanother matter。
for a long time it was assumed that anything so miraculously energetic as radioactivitymust be beneficial。 for years； manufacturers of toothpaste and laxatives put radioactivethorium in their products； and at least until the late 1920s the glen springs hotel in the fingerlakes region of new york （and doubtless others as well） featured with pride the therapeuticeffects of its “radioactive mineral springs。” radioactivity wasn’t banned in consumerproducts until 1938。 by this time it was much too late for madame curie； who died ofleukemia in 1934。 radiation； in fact； is so pernicious and long lasting that even now herpapers from the 1890s—even her cookbooks—are too dangerous to handle。 her lab books arekept in lead…lined boxes； and those who wish to see them must don protective clothing。
thanks to the devoted and unwittingly high…risk work of the first atomic scientists； by theearly years of the twentieth century it was being clear that earth was unquestionablyvenerable； though another half century of science would have to be done before anyone couldconfidently say quite how venerable。 science； meanwhile； was about to get a new age of itsown—the atomic one。
part iii a new age dawnsa physicist is the atoms’ way of thinking about atoms。
…anonymous
。。
8EINSTEIN’S UNIVERSEAS
；小；说；〃；网
the nineteenth century drew to a close； scientists could reflect with satisfaction thatthey had pinned down most of the mysteries of the physical world： electricity； magnetism；gases； optics； acoustics； kinetics； and statistical mechanics； to name just a few； all had falleninto order before them。 they had discovered the x ray； the cathode ray； the electron； andradioactivity； invented the ohm； the watt； the kelvin； the joule； the amp； and the little erg。
if a thing could be oscillated； accelerated； perturbed； distilled； bined； weighed； or madegaseous they had done it； and in the process produced a body of universal laws so weightyand majestic that we still tend to write them out in capitals： the electromagnetic field theoryof light； richter’s law of reciprocal proportions； charles’s law of gases； the law ofbining volumes； the zeroth law； the valence concept； the laws of mass actions； andothers beyond counting。 the whole world clanged and chuffed with the machinery andinstruments that their ingenuity had produced。 many wise people believed that there wasnothing much left for science to do。
in 1875； when a young german in kiel named max planck was deciding whether to devotehis life to mathematics or to physics； he was urged most heartily not to choose physicsbecause the breakthroughs had all been made there。 the ing century； he was assured；would be one of consolidation and refinement； not revolution。 planck didn’t listen。 he studiedtheoretical physics and threw himself body and soul into work on entropy； a process at theheart of thermodynamics； which seemed to hold much promise for an ambitious young man。
1in 1891 he produced his results and learned to his dismay that the important work on entropyhad in fact been done already； in this instance by a retiring scholar at yale university namedj。 willard gibbs。
gibbs is perhaps the most brilliant person that most people have never heard of。 modest tothe point of near invisibility； he passed virtually the whole of his life； apart from three yearsspent studying in europe； within a three…block area bounded by his house and the yalecampus in new haven； connecticut。 for his first ten years at yale he didn’t even bother todraw a salary。 （he had independent means。） from 1871； when he joined the university as aprofessor； to his death in 1903； his courses attracted an average of slightly over one student asemester。 his written work was difficult to follow and employed a private form of notationthat many found inprehensible。 but buried among his arcane formulations were insightsof the loftiest brilliance。
in 1875–78； gibbs produced a series of papers； collectively titledon the equilibrium ofheterogeneous substances ； that dazzlingly elucidated the thermodynamic principles of； well；1specifically it is a measure of randomness or disorder in a system。 darrell ebbing； in the textbook generalchemistry； very usefully suggests thinking of a deck of cards。 a new pack fresh out of the box； arranged by suitand in sequence from ace to king； can be said to be in its ordered state。 shuffle the cards and you put them in adisordered state。 entropy is a way of measuring just how disordered that sta