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1.AEuropeanspacecrafttookofftodaytospearheadthesearchforanother"Earth"amongthestars.
2.TheCorotspacetelescopeblastedoffaboardaRussianSoyuzrocketfromtheBaikonurcosmodromeinKazakhstanshortlyafter2.20pm.
3.Corot,shortforconvectionrotationandplanetarytransits,isthefirstinstrumentcapableoffindingsmallrockyplanetsbeyondthesolarsystem.Anysuchplanetsituatedintherightorbitstandsagoodchanceofhavingliquidwateronitssurface,andquitepossiblylife,althoughaleadingscientistinvolvedintheprojectsaiditwasunlikelytofind"anylittlegreenmen".
4.DevelopedbytheFrenchspaceagency,CNES,andpartneredbytheEuropeanSpaceAgency(ESA),Austria,Belgium,Germany,BrazilandSpain,Corotwillmonitoraround120,000starswithits27cmtelescopefromapolarorbit514milesabovetheEarth.Overtwoandahalfyears,itwillfocusonfivetosixdifferentareasofthesky,measuringthebrightnessofabout10,000starsevery512seconds.
5."Atthepresentmomentwearehopingtofindoutmoreaboutthenatureofplanetsaroundstarswhicharepotentialhabitats.Wearelookingathabitableplanets,notinhabitedplanets.Wearenotgoingtofindanylittlegreenmen,"ProfessorIanRoxburgh,anESAscientistwhohasbeeninvolvedwithCorotsinceitsinception,toldtheBBCRadio4Todayprogramme.
6.ProfRoxburghsaiditwashopedCorotwouldfind"rockyplanetsthatcoulddevelopanatmosphereand,iftheyaretherightdistancefromtheirparentstar,theycouldhavewater".
7.Tosearchforplanets,thetelescopewilllookforthedimmingofstarlightcausedwhenanobjectpassesinfrontofastar,knownasa"transit".Althoughitwilltakemoresophisticatedspacetelescopesplannedinthenext10yearstoconfirmthepresenceofanEarth-likeplanetwithoxygenandliquidwater,Corotwillletscientistsknowwheretopointtheirlenses.
8.MeasurementsofminutechangesinbrightnesswillenablescientiststodetectgiantJupiter-likegasplanetsaswellassmallrockyones.Itistherockyplanets-thatcouldbenobiggerthanabouttwicethesizeoftheEarth-whichwillcausethemostexcitement.Scientistsexpecttofindbetween10and40ofthesesmallerplanets.
9.Corotwillalsoprobeintostellarinteriorsbystudyingtheacousticwavesthatrippleacrossthesurfaceofstars,atechniquecalled"asteroseismology".
10.Thenatureoftheripplesallowsastronomerstocalculateastar’sprecisemass,ageandchemicalcomposition.
11."Aplanetpassinginfrontofastarcanbedetectedbythefallinlightfromthatstar.Smalloscillationsofthestaralsoproducechangesinthelightemitted,whichrevealwhatthestarismadeofandhowtheyarestructuredinternally.Thisdatawillprovideamajorboosttoourunderstandingofhowstarsformandevolve,"ProfRoxburghsaid.
12.Sincethediscoveryin1995ofthefirst"exoplanet"-aplanetorbitingastarotherthantheSun-morethan200othershavebeenfoundbyground-basedobservatories.
13.Untilnowtheusualmethodoffindingexoplanetshasbeentodetectthe"wobble"theirgravityimpartsonparentstars.ButonlygiantgaseousplanetsbiggerthanJupitercanbefoundthisway,andtheyareunlikelytoharbourlife.
14.Inthe2010s,ESAplanstolaunchDarwin,afleetoffourorfiveinterlinkedspacetelescopesthatwillnotonlyspotsmallrockyplanets,butanalysetheiratmospheresforsignsofbiologicalactivity.
15.Ataroundthesametime,theUSspaceagency,Nasa,willlaunchTerrestrialPlanetFinder,anotherspacetelescopedesignedtolocateEarth-likeplanets.
ChoosetheappropriateletterfromA-Dforquestion1.
1.Corotisaninstrumentwhich
(A)canhelptosearchforcertainplanets
(B)isusedtofindplanetsintheorbit
(C)canlocateplanetswithhumanbeings
(D)canspotanyplanetswithwater.
Dothefollowingstatementsagreewiththeinformationgiveninthereadingpassage?Forquestions2-5write
TRUEifthestatementagreeswiththeinformation
FALSEifthestatementcontraictstheinformation
NOTGIVENifthereisnoinformationonthisinthepassage
2.Scientistsaretryingtofindoutabouttheplanetsthatcanbeinhabited.
3.BBCRadio4recentlyfocusesonthebroadcastingofCorot.
4.Passingobjectsmightcauseafallinlight.
5.CorotcantellwhetherthereisanotherEarth-likeplanet.
Basedonyourreadingofthepassage,completethesentencesbelowwithwordstakenfromthepassage.UseNOMORETHANTHREEWORDSforeachanswer.
Withmeasurements,scientistswillbeabletosearchforsomegaseousandrockyplanets.Theywillbeextremelyexcitediftheycandiscoversomesmall6.__________,theexpectednumberofwhichcouldbeupto7.__________.
Corotwillenablescientiststostudythe8.__________ofstars.Inthisway,astar’smass,ageandchemicalcompositioncanbecalculated.
AccordingtoProfRoxburgh,changesinlightcanbecausedbypassingplanetsorstar9.__________.Therelatedstatisticscangainusabetter10.__________ofthestarformationandevolvement.
Observatorieshavefoundmanyexoplanets,whichare11.__________otherstarsthantheSun.Thecommonwayusedinfindingexoplanetscanonlydetecthugegasplanets,whichdonot12.___________.
WiththelaunchingofDarwin,astronomerswillbeabletoanalysewhetherthoserockyplanetshave13.__________forlife.
Don'twashthosefossils!
StandardmuseumpracticecanwashawayDNA.
1.Washing,brushingandvarnishingfossils—allstandardconservationtreatmentsusedbymanyfossilhuntersandmuseumcuratorsalike—vastlyreducesthechancesofrecoveringancientDNA.
2.Instead,excavatorsshouldbehandlingatleastsomeoftheirbountywithgloves,andfreezingsamplesastheyarefound,dirtandall,concludesapaperintheProceedingsoftheNationalAcademyofSciencestoday.
3.AlthoughmanypalaeontologistsknowanecdotallythatthisisthebestwaytouptheoddsofextractinggoodDNA,Eva-MariaGeigloftheJacquesMonodInstituteinParis,France,andhercolleagueshavenowshownjusthowimportantconservationpracticescanbe.Thisinformation,theysay,needstobehammeredhomeamongthepeoplewhoareactuallyoutinthefielddiggingupbones.
4.Geiglandhercolleagueslookedat3,200-year-oldfossilbonesbelongingtoasingleindividualofanextinctcattlespecies,calledanaurochs.ThefossilsweredugupatasiteinFranceattwodifferenttimes—eitherin1947,andstoredinamuseumcollection,orin2004,andconservedinsterileconditionsat-20oC.
5.Theteam'sattemptstoextractDNAfromthe1947bonesallfailed.Thenewlyexcavatedfossils,however,allyieldedDNA.
6.Becausetheboneshadbeenburiedforthesameamountoftime,andinthesameconditions,theconservationmethodhadtobetoblamesaysGeigl."AsmuchDNAwasdegradedinthese57yearsasinthe3,200yearsbefore,"shesays.
Washin,washout
7.Becausemanypalaeontologistsbasetheirworkontheshapeoffossilsalone,theirmethodsofconservationarenotdesignedtopreserveDNA,Geiglexplains.
8.Thebiggestproblemishowtheyarecleaned.Fossilsareoftenwashedtogetheron-siteinalargebath,whichcanallowwater—andcontaminantsintheformofcontemporaryDNA—topermeateintotheporousbones."NotonlyistheauthenticDNAgettingwashedout,butcontaminationisgettingwashedin,"saysGeigl.
9.MostancientDNAspecialistsknowthisalready,saysHendrikPoinar,anevolutionarygeneticistatMcMasterUniversityinOntario,Canada.Butthatdoesn'tmeanthatbestpracticehasbecomewidespreadamongthosewhoactuallyfindthefossils.
10.GettingholdoffossilsthathavebeenpreservedwiththeirDNAinmindreliesoncloserelationshipsbetweenlab-basedgeneticistsandtheexcavators,sayspalaeogeneticistSvantePbooftheMaxPlanckInstituteforEvolutionaryAnthropologyinLeipzig,Germany.Andthatonlyoccursinexceptionalcases,hesays.
11.Pbo'steam,whichhasbeensequencingNeanderthalDNA,continuallyfacestheseproblems."WhenyouwanttostudyancienthumanandNeanderthalremains,there'sabigissueofcontaminationwithcontemporaryhumanDNA,"hesays.
12.Thisdoesn'tmeanthatallmuseumspecimensarefatallyflawed,notesPbo.TheNeanderthalfossilsthatwererecentlysequencedinhisownlab,forexample,hadbeenpartofamuseumcollectiontreatedinthetraditionalway.ButPboiskeentoseesamplesoffossilsfromeverymajorfindpreservedinlinewithGeigl'srecommendations—justincase.
Warmandwet
13.Geiglherselfbelievesthat,withcooperationbetweenbenchandfieldresearchers,preservingfossilsproperlycouldopenupavenuesofdiscoverythathavelongbeenassumedclosed.
14.Muchhumanculturaldevelopmenttookplaceintemperateregions.DNAdoesnotsurvivewellinwarmenvironmentsinthefirstplace,andcanvanishwhenfossilsarewashedandtreated.Forthisreason,Geiglsays,mostancientDNAstudieshavebeendoneonpermafrostsamples,suchasthewoollymammoth,oronremainsshelteredfromtheelementsincoldcaves—includingcavebearandNeanderthalfossils.
15.Betterconservationmethods,andafocusonfreshfossils,couldboostDNAextractionfrommoredelicatespecimens,saysGeigl.Andthatcouldshedmorelightonthestoryofhumanevolution.
(640wordsnature)
Glossary
Palaeontologists古生物学家
Aurochs欧洲野牛
Neanderthal(人类学)尼安德特人，旧石器时代的古人类。
Permafrost(地理)永冻层
Questions1-6
AnswerthefollowingquestionsbyusingNOMORETHANTHREEWORDSforeachanswer.
1.Howdidpeopletraditionallytreatfossils?
2.WhatsuggestionsdoGeiglandhercolleaguesgiveonwhatshouldbedonewhenfossilsarefound?
3.Whatproblemsmaybeposediffossilbonesarewashedon-site?NameONE.
4.WhatcharacteristicdofossilboneshavetomakethemsusceptibletobecontaminatedwithcontemporaryDNAwhentheyarewashed?
5.Whatcouldbebetterunderstoodwhenconservationtreatmentsareimproved?
6.Thepassagementionedseveralanimalspeciesstudiedbyresearchers.Howmanyofthemarementioned?
Questions7-11
Dothefollowingstatementsagreewiththeinformationgiveninthepassage?PleasewriteTRUEifthestatementagreeswiththewriterFALSEifthestatementdoesnotagreewiththewriterNOTGIVENifthereisnoinformationaboutthisinthepassage.
7.IntheirpaperpublishedintheProceedingsoftheNationalAcademyofSciences，GeiglandhercolleagueshaveshownwhatconservationpracticesshouldbefollowedtopreserveancientDNA.
8.ThefossilbonesthatGeiglandhercolleaguesstudiedareallfromthesameaurochs.
9.Geneticistsdon'thavetoworkonsite.
10.OnlynewlyexcavatedfossilbonesusingnewconservationmethodssuggestedbyGeiglandhercolleaguescontainancientDNA.
11.Paaboisstillworriedaboutthepotentialproblemscausedbytreatmentsoffossilsintraditionalway.
Questions12-13
CompletethefollowingthestatementsbychoosingletterA-Dforeachanswer.
12.“Thisinformation”inparagraph3indicates:
[A]ItiscriticaltofollowproperpracticesinpreservingancientDNA.
[B]ThebestwayofgettinggoodDNAistohandlefossilswithgloves.
[C]Fossilhuntersshouldwearhome-madehammerswhilediggingupbones.
[D]Manypalaeontologistsknowhowoneshoulddointreatingfossils.
13.ThestudyconductedbyGeiglandhercolleaguessuggests:
[A]thefactthatancientDNAcannotberecoveredfromfossilbonesexcavatedinthepast.
[B]thecorrelationbetweentheamountofburyingtimeandthatoftherecoveredDNA.
[C]thepaceatwhichDNAdegrades.
[D]thecorrelationbetweenconservationpracticesanddegradationofDNA.
