时文拓展阅读7 好奇号记录火星最大甲烷含量.docx
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1、时文拓展阅读I“好奇号”记录火星最大甲烷含量自20世纪初期开始,人们凭着望远镜中看到的火星影像和头脑中的想象,认为火星上可能存在生命,乃至火星人。正是这种对神秘星球的无限遐想,促使人类一次一次地进行探索,一次一次地将遥远星际之外的秘密带回地球。最近好奇号又给人类历史上增添了怎样的光彩呢?一起来看看吧。阅读短文并回答问题NASA,sCuriosityvehic1erecent1yrecordedthe1argest1eve1ofmethane(甲烷)evermeasuredduringitsseven-yearMarsmission.Thediscoveryisexcitingbecauseth
2、eexistenceofmethanegascou1dsupportthecasefor1ifeonMars.Methanehasnoco1ororsme11.Aspecia1instrumentonCuriosity,sMarsScience1aboratoryrecordedtheincreasedgas1eve1.Thedevice,ca11eda1aserspectrometer,measures1eve1sofchemica1e1ementsandgasesintheMartianatmosphere.Inadditiontomethane,theinstrumentcanrecor
3、d1eve1sofwaterandCO2.Near1ya11themethanegasfoundinEarth,satmosphereisproducedbybio1ogica1activity.Itusua11ycomesfromanima1andp1ant1ife.Butitcana1sobeformedbygeo1ogica1(地质的)processes,suchasinteractionsbetweenrocksandwater.NASAsaidtheincreasedmethanewasmeasuredtobeabout21partsperbi11ionbyvo1ume(ppbv).
4、Oneppbvmeansthatifyoutakeavo1umeofaironMars,onebi11ionthofthevo1umeofairismethane.ItwasnotthefirsttimeCuriosityhasfoundmethanegasintheMartianatmosphere.Aboutayearago,NASAannouncedthatCuriosityhaddiscoveredsharpseasona1increasesinthegas.Thistime,NASAsaidthemeasuredmethanegas1eve1wasc1ear1y1argerthana
5、nyothersobservedinthepast.NASAofficia1seventemporari1ystoppedCuriosity,sotheractivitiestoinvestigatefurther.Itsexcitingbecausemicrobia1(微生物的)1ifeisanimportantsourceofmethaneonEarthJNASAsaidinastatementannouncingthediscovery.However,Curiosity,steamcarriedoutafo11ow-upmethaneexperimentthatshowedasharp
6、dropin1eve1softhegas.Thesecondexaminationfoundthe1eve1was1essthanonepartperbi11ionbyvo1ume.Thatnumberwasc1osetothebackground1eve1sCuriosityseesa11thetime.Theriseandfa11ofthemethanegas1eve1s1eftNASAscientistswithmorequestionsthananswers.Thescientistsarecontinuingtostudypossib1ecausesforthesuddenincre
7、ase.Themethanemysterycontinues.Curiositydoesnothaveinstrumentsthatcanexact1yidentifywhetherthesourceofthemethaneisbio1ogica1orgeo1ogica1.One1eadingtheoryisthatmethaneisbeingre1easedfromundergroundareascreatedbypossib1e1ifeformsthatdisappeared1ongago.EventhoughMarshasnoactivevo1canoes,scientistsbe1ie
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