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1、二七教育网www.wei027.com10天突破阅读训练-3深度阅读ScientistssaytheyhavediscoveredhintsofalienlifeontheSaturn’smoon.ThediscoveryofasortoflifewasannouncedafterresearchersattheUSspaceagency,NASA,analyzeddatafromspacecraftCassini,whichpointedto,theexistenceofmethane-basedform
2、oflifeonSaturn’sbiggestmoon.Scientistshavereportedlydiscoveredcluesshowingprimitivealienbeingsare"breathing"inTitan’sdenseatmospherefilledwithhydrogen.TheyarguethathydrogengetsabsorbedbeforehittingTitan’splanet-likesurfacecoveredwithmethanelakesandrivers.T
3、his,theysay,pointstotheexistenceofsome"bugs"consumingthehydrogenatthesurfaceofthemoonlessthanhalfthesizeoftheEarth."Wesuggestedhydrogenconsumptionbecauseit’stheobviousgasforlifetoconsumeonTitan,similartothewayweconsumeoxygenonEarth,"saysNASAscientistChrisM
4、cKay."Ifthesesignsdoturnouttobeasignoflife,itwouldbedoublyexcitingbecauseitwouldrepresentasecondformoflifeindependentfromwater-basedlifeonEarth."Todate,scientistshavenotyetdetectedthisformoflifeanywhere,thoughthereareliquid-water-basedmicroorganismsonEarth
5、thatgrowwellonmethaneorproduceitasawasteproduct.OnTitan,wheretemperaturesarearound90Kelvin(minus290degreesFarenheit),amethanebasedorganismwouldhavetouseasubstancethatisliquidasitsmediumforlivingprocesses,butnotwateritself.WaterisfrozensolidonTitan’ssurface
6、andmuchtoocoldtosupportlifeasweknowit.ScientistshadexpectedtheSun’sinteractionswithchemicalsintheatmospheretoproduceacoatingofacetyleneonTitan’ssurface.ButCassinidetectednoacetyleneonthesurface.TheabsenceofdetectableacetyleneontheTitan’ssurfacecanverywellh
7、aveanon-biologicalexplanation,saidMarkAllen,aprincipalinvestigatoroftheNASATitanteam."Scientificconservatismsuggeststhatabiologicalexplanationshouldbethelastchoiceafterallnon-biologicalexplanationsareaddressed,"Allensaid."Wehavealotofworktodotoruleoutpossi
8、blenon-biologicalexplanations.Itismorelikelythatachemicalprocess,withoutbiology,canexplaintheseresults."1.WhathavescientistsfoundaboutSaturn?ATheyhavefoundanewmoonorbitingSaturn.BTheyhavefoundmethane-basedlif
