万物简史英文版_比尔·布莱森-第31章

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ou　have　shuffled　off。　worse；　weare　still　introducing　huge　amounts　of　cfcs　into　the　atmosphere　every　year。　according　towayne　biddle；　60　million　pounds　of　the　stuff；　worth　1。5　billion；　still　finds　its　way　onto　themarket　every　year。　so　who　is　making　it？　we　are鈥攖hat　is　to　say；　many　of　our　largecorporations　are　still　making　it　at　their　plants　overseas。　it　will　not　be　banned　in　third　worldcountries　until　2010。

clair　patterson　died　in　1995。　he　didn鈥檛　win　a　nobel　prize　for　his　work。　geologists　neverdo。　nor；　more　puzzlingly；　did　he　gain　any　fame　or　even　much　attention　from　half　a　century　ofconsistent　and　increasingly　selfless　achievement。　a　good　case　could　be　made　that　he　was　themost　influential　geologist　of　the　twentieth　century。　yet　who　has　ever　heard　of　clair　patterson？

most　geology　textbooks　don鈥檛　mention　him。　two　recent　popular　books　on　the　history　of　thedating　of　earth　actually　manage　to　misspell　his　name。　in　early　2001；　a　reviewer　of　one　ofthese　books　in　the　journal　nature　made　the　additional；　rather　astounding　error　of　thinkingpatterson　was　a　woman。

at　all　events；　thanks　to　the　work　of　clair　patterson　by　1953　the　earth　at　last　had　an　ageeveryone　could　agree　on。　the　only　problem　now　was　it　was　older　than　the　universe　thatcontained　it。

w　w　w。x　iaoshu　otx　t。c　o　m



11　　　　MUSTER　MARK鈥橲　QUARKS

灏忥紝璇达紝t锛寈t锛屽ぉ锛屽爞
in　1911；　a　british　scientist　named　c。　t。　r。　wilson　was　studying　cloud　formations　bytramping　regularly　to　the　summit　of　ben　nevis；　a　famously　damp　scottish　mountain；　when　itoccurred　to　him　that　there　must　be　an　easier　way　to　study　clouds。　back　in　the　cavendish　labin　cambridge　he　built　an　artificial　cloud　chamber鈥攁　simple　device　in　which　he　could　cooland　moisten　the　air；　creating　a　reasonable　model　of　a　cloud　in　laboratory　conditions。

the　　device　　worked　　very　　well；　　but　　had　　an　additional；　unexpected　benefit。　when　heaccelerated　an　alpha　particle　through　the　chamber　to　seed　his　make…believe　clouds；　it　left　avisible　trail鈥攍ike　the　contrails　of　a　passing　airliner。　he　had　just　invented　the　particle　detector。

it　provided　convincing　evidence　that　subatomic　particles　did　indeed　exist。

eventually　two　other　cavendish　scientists　invented　a　more　powerful　proton…beam　device；while　in　california　ernest　lawrence　at　berkeley　produced　his　famous　and　impressivecyclotron；　or　atom　smasher；　as　such　devices　were　long　excitingly　known。　all　of　thesecontraptions　worked鈥攁nd　indeed　still　work鈥攐n　more　or　less　the　same　principle；　the　ideabeing　to　accelerate　a　proton　or　other　charged　particle　to　an　extremely　high　speed　along　a　track（sometimes　circular；　sometimes　linear）；　then　bang　it　into　another　particle　and　see　what　fliesoff。　that鈥檚　why　they　were　called　atom　smashers。　it　wasn鈥檛　science　at　its　subtlest；　but　it　wasgenerally　effective。

as　physicists　built　bigger　and　more　ambitious　machines；　they　began　to　find　or　postulateparticles　or　particle　families　seemingly　without　number：　muons；　pions；　hyperons；　mesons；　k…mesons；　higgs　bosons；　intermediate　vector　bosons；　baryons；　tachyons。　even　physicists　beganto　grow　a　little　unfortable。　鈥測oung　man；鈥潯�enrico　fermi　replied　when　a　student　asked　himthe　name　of　a　particular　particle；　鈥渋f　i　could　remember　the　names　of　these　particles；　i　wouldhave　been　a　botanist。鈥�

today　accelerators　have　names　that　sound　like　something　flash　gordon　would　use　inbattle：　the　super　proton　synchrotron；　the　large　electron…positron　collider；　the　large　hadroncollider；　the　relativistic　heavy　ion　collider。　using　huge　amounts　of　energy　（some　operateonly　at　night　so　that　people　in　neighboring　towns　don鈥檛　have　to　witness　their　lights　fadingwhen　the　apparatus　is　fired　up）；　they　can　whip　particles　into　such　a　state　of　liveliness　that　asingle　electron　can　do　forty…seven　thousand　laps　around　a　four…mile　tunnel　in　a　second。　fearshave　been　raised　that　in　their　enthusiasm　scientists　might　inadvertently　create　a　black　hole　oreven　something　called　鈥渟trange　quarks；鈥潯�which　could；　theoretically；　interact　with　othersubatomic　particles　and　propagate　uncontrollably。　if　you　are　reading　this；　that　hasn鈥檛happened。

finding　particles　takes　a　certain　amount　of　concentration。　they　are　not　just　tiny　and　swiftbut　also　often　tantalizingly　evanescent。　particles　can　e　into　being　and　be　gone　again　in　aslittle　as　0。000000000000000000000001　second　（10…24）。　even　the　most　sluggish　of　unstableparticles　hang　around　for　no　more　than　0。0000001　second　（10…7）。

some　particles　are　almost　ludicrously　slippery。　every　second　the　earth　is　visited　by　10；000trillion　trillion　tiny；　all　but　massless　neutrinos　（mostly　shot　out　by　the　nuclear　broilings　of　thesun）；　and　virtually　all　of　them　pass　right　through　the　planet　and　everything　that　is　on　it；including　you　and　me；　as　if　it　weren鈥檛　there。　to　trap　just　a　few　of　them；　scientists　need　tanksholding　up　to　12。5　million　gallons　of　heavy　water　（that　is；　water　with　a　relative　abundance　ofdeuterium　in　it）　in　underground　chambers　（old　mines　usually）　where　they　can鈥檛　be　interferedwith　by　other　types　of　radiation。

very　occasionally；　a　passing　neutrino　will　bang　into　one　of　the　atomic　nuclei　in　the　waterand　produce　a　little　puff　of　energy。　scientists　count　the　puffs　and　by　such　means　take　us　veryslightly　closer　to　understanding　the　fundamental　properties　of　the　universe。　in　1998；　japaneseobservers　reported　that　neutrinos　do　have　mass；　but　not　a　great　deal鈥攁bout　one　ten…millionththat　of　an　electron。

what　it　really　takes　to　find　particles　these　days　is　money　and　lots　of　it。　there　is　a　curiousinverse　relationship　in　modern　physics　between　the　tininess　of　the　thing　being　sought　and　thescale　of　facilities　required　to　do　the　searching。　cern；　the　european　organization　for　nuclearresearch；　is　like　a　little　city。　straddling　the　border　of　france　and　switzerland；　it　employsthree　thousand　people　and　occupies　a　site　that　is　measured　in　square　miles。　cern　boasts　astring　of　magnets　that　weigh　more　than　the　eiffel　tower　and　an　underground　tunnel　oversixteen　miles　around。

breaking　up　atoms；　as　james　trefil　has　noted；　is　easy；　you　do　it　each　time　you　switch　on　afluorescent　light。　breaking　up　atomic　nuclei；　however；　requires　quite　a　lot　of　money　and　agenerous　supply　of　electricity。　getting　down　to　the　level　of　quarks鈥攖he　particles　that　make　upparticles鈥攔equires　still　more：　trillions　of　volts　of　electricity　and　the　budget　of　a　small　centralamerican　nation。　cern鈥檚　new　large　hadron　collider；　scheduled　to　begin　operations　in　2005；will　achieve　fourteen　trillion　volts　of　energy　and　cost　something　over　1。5　billion　toconstruct。

1but　these　numbers　are　as　nothing　pared　with　what　could　have　been　achieved　by；　andspent　upon；　the　vast　and　now　unfortunately　never…to…be　superconducting　supercollider；　whichbegan　being　constructed　near　waxahachie；　texas；　in　the　1980s；　before　experiencing　asupercollision　of　its　own　with　the　united　states　congress。　the　intention　of　the　collider　was　tolet　scientists　probe　鈥渢he　ultimate　nature　of　matter；鈥潯�as　it　is　always　put；　by　re…creating　as　nearlyas　possible　the　conditions　in　the　universe　during　its　first　ten　thousand　billionths　of　a　second。

the　plan　was　to　fling　particles　through　a　tunnel　fifty…two　miles　long；　achieving　a　trulystaggering　ninety…nine　trillion　volts　of　energy。　it　was　a　grand　scheme；　but　would　also　havecost　8　billion　to　build　（a　figure　that　eventually　rose　to　10　billion）　and　hundreds　of　millionsof　dollars　a　year　to　run。

in　perhaps　the　finest　example　in　history　of　pouring　money　into　a　hole　in　the　ground；congress　spent　2　billion　on　the　project；　then　canceled　it　in　1993　after　fourteen　miles　oftunnel　had　been　dug。　so　texas　now　boasts　the　most　expensive　hole　in　the　universe。　the　siteis；　i　am　told　by　my　friend　jeff　guinn　of　the　fort　worth　star…telegram；　鈥渆ssentially　a　vast；cleared　field　dotted　along　the　circumference　by　a　series　of　disappointed　small　towns。鈥�

1there　are　practical　side　effects　to　all　this　costly　effort。　the　world　wide　web　is　a　cern　offshoot。　it　wasinvented　by　a　cern　scientist；　tim　berners…lee；　in　1989。

since　the　supercollider　debacle　particle　physicists　have　set　their　sights　a　little　lower；　buteven　paratively　modest　projects　can　be　quite　breathtakingly　costly　when　pared　with；well；　almost　anything。　a　proposed　neutrino　observatory　at　the　old　homestake　mine　in　lead；south　dakota；　would　cost　500　million　to　build鈥攖his　in　a　mine　that　is　already　dug鈥攂eforeyou　even　look　at　the　annual　running　costs。　there　would　also　be　281　million　of　鈥済eneralconversion　costs。鈥潯�a　particle　accelerator　at　fermilab　in　illinois；　meanwhile；　cost　260　millionmerely　to　refit。

particle　physics；　in　short；　is　a　hugely　expensive　enterprise鈥攂ut　it　is　a　productive　one。

today　the　particle　count　is　well　over　150；　with　a　further　100　or　so　suspected；　butunfortunately；　in　the　words　of　richard　feynman；　鈥渋t　is　very　difficult　to　understand　therelationships　of　all　these　particles；　and　what　nature　wants　them　for；　or　what　the　connectionsare　from　one　to　another。鈥潯�inevitably　each　time　we　manage　to　unlock　a　box；　we　find　that　thereis　another　locked　box　inside。　some　people　think　there　are　particles　called　tachyons；　which　cantravel　faster　than　the　speed　of　light。　others　long　to　find　gravitons鈥攖he　seat　of　gravity。　atwhat　point　we　reach　the　irreducible　bottom　is　not　easy　to　say。　carl　sagan　in　cosmos　raised　thepossibility　that　if　you　traveled　downward　into　an　electron；　you　might　find　that　it　contained　auniverse　of　its　own；　recalling　all　those　science　fiction　stories　of　the　fifties。　鈥渨ithin　it；organized　into　the　local　equivalent　of　galaxies　and　smaller　structures；　are　an　immense　numberof　other；　much　tinier　elementary　particles；　which　are　themselves　universes　at　the　next　leveland　so　on　forever鈥攁n　infinite　downward　regression；　universes　within　universes；　endlessly。

and　upward　as　well。鈥�

for　most　of　us　it　is　a　world　that　surpasses　understanding。　to　read　even　an　elementary　guideto　particle　physics　nowadays　you　must　now　find　your　way　through　lexical　thickets　such　asthis：　鈥渢he　charged　pion　and　antipion　decay　respectively　into　a　muon　plus　antineutrino　and　anantimuon　plus　neutrino　with　an　average　lifetime　of　2。603　x　10…8seconds；　the　neutral　piondecays　into　two　photons　with　an　average　lifetime　of　about　0。8　x　10…16seconds；　and　the　muonand　antimuon　decay　respectively　into　。　。　。鈥潯�and　so　it　runs　on鈥攁nd　this　from　a　book　for　thegeneral　reader　by　one　of　the　（normally）　most　lucid　of　interpreters；　steven　weinberg。

in　the　1960s；　in　an　attempt　to　bring　just　a　little　simplicity　to　matters；　the　caltech　physicistmurray　gell…mann　invented　a　new　class　of　particles；　essentially；　in　the　words　of　stevenweinberg；　鈥渢o　restore　some　economy　to　the　multitude　of　hadrons鈥濃�攁　collective　term　used　byphysicists　for　protons；　neutrons；　and　other　particles　governed　by　the　strong　nuclear　force。

gell…mann鈥檚　theory　was　that　all　hadrons　were　made　up　of　still　smaller；　even　morefundamental　particles。　his　colleague　richard　feynman　wanted　to　call　these　new　basicparticles　partons；　as　in　dolly；　but　was　overruled。　instead　they　became　known　as　quarks。

gell…mann　took　the　name　from　a　line　in　finnegans　wake：　鈥渢hree　quarks　for　mustermark！鈥潯。╠iscriminating　physicists　rhyme　the　word　with　storks；　not　larks；　even　though　thelatter　is　almost　certainly　the　pronunciation　joyce　had　in　mi