(C)
The2012LondonOlympicshadenoughproblemstoworryabout.Butonemorehasjustbeenadded-acommunicationsblackoutcausedbysolarstorms.
AfteraperiodofcalmwithintheSun,scientistshavedetectedthesignsofafleshcycleofsunspotsthatcouldpeakin2012,justintimeforthearrivaloftheOlympictorchinLondon.
NowscientistsbelievethatthispeakcouldresultinvastsolarexplosionsthatcouldthrowbillionsoftonsofchargedmattertowardstheEarth,causingstr ongsolarstormsthatcouldjamthetelecommunicationssatellitesandinteractlinkssendingfiveOlympicbroadcastfromLondon.
"TheSun'sactivityhasastr onginfluenceontheEarth.TheOlympicscouldbeinthemiddleofthenextsolarmaximumwhichcouldaffectthefunctionsofcommunicationssatellites,"saidProfessorRichardHarrison,headofspacephysicsattheRutherfordAppletonLaboratoryinOxfordshire.
Atthepeakofthecycle,violentoutburstscalledcoronalmassejections(日冕物质抛射)occurintheSun'satmosphere,throwingoutgreatquantitiesofelectr ically-chargedmatter."Acoronalmassejectioncancarryabilliontonsofsolarmaterialintospaceatoveramillionkilometr esperhour.Sucheventscanexposeastr onautstoadeadlyamount,candisablesatellites,causepowerfailuresonEarthanddisturbcommunications,"ProfessorHarrisonadded.Theriskisgreatestd uringasolarmaximumwhenthereisthegreatestnumberofsunspots.
NextweekinAmerica,NASAisscheduledtolaunchasatelliteformonitoringsolaractivitycalledtheSolarDynamicsObservatory(SDO),whichwilltakeimagesoftheSunthatare10timesclearerthanthemostadvancedtelevisionsavailable.
TheRutherfordAppletonLaboratoryhelpedtomakethehigh-techcamerasthatwillcaptureimagesofthesolarflares(太阳耀斑)andexplosionsastheyoccur.
ProfessorRichardHoldaway,thelab'sdirector,saidthattheSDOshouldbeabletoprovideearlywarningofasolarflareorexplosionbigenoughtoaffectsatellitecommunicationsonEarth"Ifwehaveadvancewarning,we'llbeabletoreducethedamage.Whatyoudon'twantisthingsswitchingoffforaweekwithnoideaofwhat'scausedtheproblem,"hesaid.
72.Thephrase"communicationsblackout"inparagraph1mostprobablyreferstoduringthe2012Olympics.
A.theextinguishingoftheOlympictorch
B.thecollapseofbroadcastingsystems
C.thetr ansportationbreakdowninLondon
D.thedestr uctionofweathersatellites
正确答案:B此题线索为第二三段的内容。



