全新主题大学英语读写译教程4-3

1UnitThreeSpaceAgeSectionAPre-readingQuestions:1.WhatdoyouknowaboutMars?CouldyougiveadescriptionofMarsindetail?2.CouldMarsbecomehumanbeing’ssecondhometowninfuture?Whyorwhynot?3.HaveyouheardofanyMarsexplorationrovers?Ifso,namesomeofthem.Doyouwonderiftherearelivesonotherplanets?Agroupofscientistsarenotjustwondering,butatthesametimetheyarelookingforevidence—wateronMars.Mars:AWaterWorld?EvidenceMounts,butScientistsRemainTight-lipped1EvidencethatsuggestsMarswasonceawater-richworldismountingasscientistsscrutinizedatafromtheMarsExplorationrover,Opportunity,busilyatworkinasmallcrateratMeridianiPlanum.Thatinformationmaywellbeleadingtoabiologicalbombshellofafindingthattheredplanethasbeen,andcouldwellbenow,anextraterrestrialhomeforlife.2ThereisapalpablebuzzhereattheJetPropulsionLaboratory(JPL)inPasadena,CaliforniathatsomethingwonderfulisabouttohappenintheexplorationofMars.3ThereisnodoubtthattheOpportunityMarsroverisrelayingamotherlodeofgeologicaldata.Usinganarrayoftoolscarriedbythegolfcart-sizedrobot—fromspectrometers,arockgrinder,camerasandpowerfulmicroscopicimager—scientistsarecarefullypiecingtogetheracompellinghistoricalportraitofawetandwildworld.24WhereOpportunitynowroves,somescientistsheresuggest,couldhavebeenunderneathahugeoceanorlake.ButwhathastrulybeenuncoveredbytherobotatMeridianiPlanumisunderjudiciousandtight-lippedreview.5Thosefindingsandtheirimplicationsareheadedforamajorpressconference,rumoredtooccurearlynextweek—butgivenunanimityamongroverscientistsandagreementonhowandwhoshouldunveilthedramaticfindings.Turnsout,evenonMars,apoliticalandegooutcrophangsoverscience.6Scientificbull’s-eye7ItisclearthatOpportunity’sEarth-to-Marsholeinone—bouncingintoasmallcratercompletewithrockoutcrop—hasalsoproventobeascientificbull’s-eye.Therobotiswheelingaboutthecraterthatissome70feet(22meters)acrossand10feet(3meters)deep.8ItisalsoapparentthatthereisabacklogofscientificmeasurementsthatMarsroverscientistsworkingOpportunityhavepocketedandkeptclosetotheirlabcoats.9Forone,theroverfoundthesiteladenwithhematite—amineralthattypically,butnotalways—formsinthepresenceofwater.Thentherearethepuzzlingspherulesfoundinthesoilandembeddedinrock.Theytoomightbewater-related,butalsocouldbeproducedbytheactionsofameteorimpactoraspewingvolcano.10Afewsphereshavebeenslicedinhalfandtheirinsidesimaged.Patchesofthesespherules,or“berries”assomecallthem,haveundergonespectrometerexamtodiscerntheirmineralandchemistrymakeup.Close-upphotosofsoilandrockhavealsoshownthread-likefeaturesandevenanoddlyshapedobjectthatlookslikeRotinipasta.311Brewofdissolvedsalts12ThereisspeculationthatthesoilunderneaththewheelsofbothSpiritandOpportunityroverscontainssmallamountsofwatermixedwithsaltinabrine.Thatbrewofdissolvedsaltskeepsthemixturewellbelowthefreezingpointofpurewater,permittingittoexistinliquidform.13Opportunityhasrevisitedselectspotsintheoutcrop,drawnthere,inpart,tolookforcross-beds—sedimentarydepositsthatareformedinbeach,riverandsand-duneenvironments.UsingitsRockAbrasionTool(RAT),theroverhascarriedoutseveralcleaningandgrindingsessionsonexposedrockoutcrop.14Cross-bedsarepatternsofcurvinglinesortracesfoundwithinthestrataofsandstoneandothersedimentaryrocks.Cross-beddingindicatesthegeneraldirectionandforceofthewindorwaterthatoriginallylaiddownthesediments.15Rightaroundthecorner16Opportunity’sresearchisa“workinprogress”,saidRayArvidson,deputyprincipalinvestigatorfortheMarsExplorationRover(MER)projectfromWashingtonUniversityinSt.Louis.Dataisbeinggatheredtopresent“acoherentstory”,hesaidduringapressbriefing.17“Thatstoryisrightaroundthecorner,”ArvidsontoldSPACE.com.“Butweneedtofinishthisworkinprogress,finishthesetofexperiments,getthedatadownfromthespacecraft,processedandanalyzed.ThenIthinkthatthestorywillbeknown,”hesaid.18Arvidsonsaidmultipleworkinghypothesesarestillatplay.Waterisinvolved,butonlyonsomeofthehypotheses.Untilcoordinated4experimentsontheoutcroparecompleted,whattherighthypothesisisremainsunknown,headded.19Severingtheumbilicalcord20Marsexplorationusingtherovershasallowedon-the-spot“discoverydrivenscience”,saidMERDeputyProjectScientistAlbertHaldeman.HelikenedtheMarsrobotworknowunderwaytodeepoceanresearchusingremotelyoperatedsubmersibles.21“ItturnsoutthatthebestwaytoexplorerocksonMarsisgolookatcraters.Mobilitybuysustheabilitytodothat.Itwastherightfitforlookingatrocks,”HaldemantoldSPACE.com.“ThediscoveryfromtheMicroscopicImagerandseeingthosespherulesandfindingalargerpopulationofspherulesandseeingthemintherocksandtheoutcrop—thatprogressionofdiscoveryinfluencesourthinking.”22HaldemansaidthenextstepwillbeseveringtheumbilicalcordbetweenOpportunityandthecraterit’sexploring.TherobotwouldwheelitselfoutofthatsiteandontotheexpansiveterrainofMeridianiPlanum.23“Thatumbilicalcord’shardtobreak.It’smorethanevenjustatensionwithinthescienceteam,”Haldemansaid.24Tantalizinghints25ScientistsarecarefullyanalyzingtherockdatagleanedbytheOpportunityrover.“Wereallywanttounderstandthatwe’vegotthosefiguredoutright,”Haldemansaid.Uptonowtheyhaveofferedsome“tantalizinghints”,hesaid,thatspeaktoa