NOBOUNDARIES 　　Imaginethis:youaretwenty-yearsoldandapromisinggraduatestudentatoneofthetopunviersitiesintheworld.Oneday,yourdoctortellsyouthatyouhaveanincurablediseaseandmaynothavemorethantwelvemonthstolive.Howwouldyoufeel?WhatwouldyoudoMostofuswouldprobablyfeelverysadgiveupourdreamsandhopesforthefuture.HereiswhatStephenHawkingthought: 　　(Theredidnotseem)muchpointinworkingonmyPhD---Ididnotexpecttosurvivethatlong.YettwoyearshadgonebyandIwasnotthatmuchworse.Infact,thingsweregoingratherwellformeandIhadgotengagedtoaverynicegirl,JaneWilde.Butinordertogetmarried,Ineededajob,andinordertoget.IneededaPhD. 　　Insteadofgivingup,Hawkingwentonwithhisresearch,gothisPhDandmarriedIane.Nordidheletthediseasestophimfromlivingthekindoflifehehadalwaysdreamtof.Hecontinuedhisexplorationoftheuniverseandtravelledaroundtheworldtogivelectures.In2002,HawkingvisitedChinaandspoketouniversitystudentsinHangzhouandBeijing.Ashisdiseasedhasdisabledhim,Hawkinghastositinhisnow-famouswheelchairandspeakthoughacomputer.Hetoldthestudentsabouthistheoriesandthoughtsonsomeofthegreatestquestions:Whatistime,howdidtheuniversebegin,andwhatexactlyareblackholes? 　　Hawkingbecamefamousintheearly1970s,whenheandAmericanRogerPenrosemadenewdiscoveriesabouttheBigBangandblackholes.Sincethen,Hawkinghascontinuedtoseekanswerstoquestionsaboutthenatureoftheuniverse.In1988,hewroteABrifehistotyofTime,whichquicklybecameabest-seller.Readerswerepleasedandsurprisedtofindthatascientistcouldwriteabouthisworkinawaythatordinarypeoplecouldunderstand. 　　Inthebook,Hawkingexplainsbothwhatitmeanstobeascientistandhowscienceworks.Hetellsreadershowdiscoveriesaremadeandhowtheychangetheworld.Science,accordingtoHawking,isoftenmisundertood:peopleoftenthinkthatscienceisabout"ture"factsthatneverchange.Scientists,onthehand,Hawkingwrites,knowthattheirjobisneverfinishedandthateventhebestthorycanouttobewrong. 　　Ascientifictheoryistheresultofthescientificmethod.scientistslookattheworldandtrytodescribeandexplainwhattheysee.First,theycarefullyobservewhattheyareinterestedin.Toexplainwhattheyhaveseen,theybuildatheotyaboutthewayinwhichthingshappenandthecausesandeffects.Finally,thescientiststestthetheorytoseeifitmatcheswhattheyhaveseenandifitcanpredictfutureevents.Ifwhattheyareobservingcanbetestedinapracticalway,scientistswilluseexperiments.Butif,likeHawking,theyarestudyingsomethingthatistoolargeortoodifficulttoobservedirectly,theywilluseamodeltotestthetheory. 　　PeoplewholistentoHawkong'slecturessometimesfinditdiffculttounderstandhim,becausehisthoughtsandideasoftenseemaslargeastheuniverseheistryingtodescribe.Thespeechcomputerisnottheproblem.Infact,peoplewhohearitoftensayitsoundsjustlikeahumanvoice.Hawkingishappywithit,too."Theonlytrouble,"saysHawking,whoisBritish,"isthatitgivesmeanAmericanaccent." 　　-关于斯帝芬`霍金的