LONDON—Scientistshavefoundanunusualwaytopreventourplanetfromoverheating:moveittoacoolerspot.Allyouhavetodoistosendafewcomets(彗星)inthedirectionofEarth,anditsorbit(轨道)willbechanged.Ourworldwillthenbesentmovingintoasaferolderpartofthesolarsystem. ThisideaforimprovingourclimatecomesfromagroupofUSNASA(美国航空航天局)engineersandAmericanastronomers.Theysaytheirplancouldaddanothersixbillionyearstotheusefullifetimeofourplanet—hopefullydoublingitsworkinglife. TheplanputforwardbyDr.Laughlin,andhiscolleaguesDonKorycanskyandFredAdams,needscarefullydirectingacometorasteroid(小行星)sothatitpassesclosebyourplanetandsendssomeofitsgravitationalenergy(重力势能)toEarth. “Earth’sorbitalspeedwouldincreaseasaresultandwewouldmovetoahigherorbitawayfromthesun,”Laughlinsaid. EngineerswouldthendirecttheircometsothatitpassedclosetoJupiter(木星)orSaturn(土星).Thecometwouldpickupenergyfromoneofthesegiantplanets.LateritsorbitwouldbringitbacktoEarth,andtheprocesswouldberepeated. Intheshortterm,theplanprovidesanidealwaytoworldwidewarming,althoughtheteamwasactuallyworriedaboutamuchgreaterdanger.Thesuniscertaintoheatupinaboutabillionyearsandso“seriouslycompromise”ourbiosphere(生物圈)—bycookingus. That’swhythegroupdecidedtotrytosaveEarth. Theplanhasoneortwoworryingsides,however.Forastart,spaceengineerswouldhavetobeverycarefulabouthowtheydirectedtheirasteroidorcomettowardsEarth.Thesmallestmiscalculation(误算)inorbitcouldfireitstraightatEarth—withdeadlyresults. Thereisalsothequestionofthemoon.AsthepresentissueofScientificAmericanmagazinepointsout,ifEarthwaspushedoutofitspresentlocation,itis“mostlikelythemoonwouldbestripped(剥离)awayfromEarth,”itstates.Thiswouldgreatlychangeourplanet’sclimate. 小题1:WhatmakesthescientistsplantomoveEarth? |
A.AfewcometsaremovingtothedirectionofEarth. |
B.Earth’sworkinglifeiscomingtoanendsoon. |
C.Earthwillbecometoohotformankindtokeepalive. |
D.ThemoonismovingfartherandfartherawayfromEar
李周回答:
小题1:C小题2:A小题3:A小题4:D
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