MoveEarth—it’snosciencefictionLONDON-Scientistshavefoundanunusualwaytopreventourplanetfromoverheating:moveittoacoolerspot.Allyouhavetodoissendafewcomets（彗星）inthedirectionofEarthandits

　　MoveEarth—it’snosciencefiction

　　LONDON-Scientistshavefoundanunusualwaytopreventourplanetfromoverheating:moveittoacoolerspot.Allyouhavetodoissendafewcomets（彗星）inthedirectionofEarthanditsorbitwillbechanged.Ourworldwillthenbesentspinningintoasafercolderpartofthesolarsystem.

　　ThisideaforimprovingourclimatecomesfromagroupofUSNationalAeronauticsandSpaceAdministration（NASA）engineersandAmericanastronomers.Theysaytheirplancouldaddanothersixbillionyearstotheusefullifetimeofourplanet—effectivelydoublingitsworkinglife.

　　TheplanputforwardbyDrLaughlinandhiscolleaguesDonKorycanskyandFredAdams

　　needscarefullydirectingacometorasteroidsothatitpassesclosebyourplanetandsendssomeofitsgravitationalenergytoEarth.

　　“Earth’sorbitalspeedwouldincreaseasaresultandwewouldmovetoahigherorbitawayfromtheSun”Laughlinsaid.

　　EngineerswouldthendirecttheircometsothatitpassedclosetoJupiterorSaturn.Thecometwouldpickupenergyfromoneofthesegiantplanets.LateritsorbitwouldbringitbacktoEarthandtheprocesswouldberepeated.

　　Intheshorttermtheplanprovidesanidealwaytoglobalwarmingalthoughtheteamwasactuallyconcernedwithamuchgreaterdanger.Thesuniscertaintoheatupinaboutabillionyearsandso“seriouslycompromise”ourbiosphere（生物圈）—bycookingus.

　　That’swhythegroupdecidedtotrytosaveEarth.

　　Theplanhasoneortwoworryingaspectshowever.ForastartspaceengineerswouldhavetobeverycarefulabouthowtheydirectedtheirasteroidorcomettowardsEarth.Thesmallestmiscalculation（误算）inorbitcouldfireitstraightatEarth—withdeadlyconsequences.

　　ThereisalsothequestionoftheMoon.AsthecurrentissueofScientificAmericanmagazinepointsoutifEarthwaspushedoutofitscurrentpositionitis“mostlikelytheMoonwouldbestrippedawayfromEarth”itstates.Thiswouldgreatlychangeourplanet’sclimate.

　　1.WhatmakesthescientistsplantomoveEarth?

　　A.AfewcometsaremovingtothedirectionofEarth.

　　B.Earth’sworkinglifeiscomingtoanendsoon.

　　C.Earthwillbecometoohotformankindtokeepalive.