听写必备上半年SSS文本全集听写必备.docx

听写必备上半年SSS文本全集听写必备.docx

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听写必备上半年SSS文本全集听写必备

SSS2009-01-01

ThisisScientificAmerican's 60-SecondScience.I'mSteveMirsky.Gotaminute?

HappyNewYear!

Anddon’tfeelbadabouttakingtodayoff.Afterall,you’vetraveledfar.AndI’mnottalkingaboutthetriphomefromthepartylastnight.AccordingtoNASA,justbybeingontheplanetEarthinthelastyear,you’vezippedabout584millionmilesaroundthesuntogetbackwhereyouwere.Atanaveragespeedofabout67,000milesperhour.Again,nottalkingaboutthedrivehomelastnight.

Ofcourse,thetripwasnotaperfectcircle.AsKeplershowed,theEarth’sorbitisanellipse,withthesunatoneofthetwofocalpoints.Healsofiguredouttheplanetgoesfasterwhenit’satperihelion,nearerthesun,thanwhenit’sataphelion,itsfarthestdistance—whichwouldexplainwhysummerseemstozipby,excepttheseasonsareafunctionofthetiltoftheEarth’saxis,notitsdifferentdistancesfromthesun.AndtheEarthrotated365andaquartertimesduringitssweeparoundthesun.Thetriptook8,766hours.Or31,557,600seconds.Or525,960minutesjustlikethisone.

ThanksfortheminuteforScientificAmerican's60-SecondScience.I'mSteveMirsky 

SSS2009-01-02

ThisisScientificAmerican's 60-SecondScience.I'mCynthiaGraber.Thiswilljusttakeaminute.

Mosquitoescarrynastydiseases—denguefever,westnile,malaria.Butthemicrobesthatcausethosediseasesdon’tattachthemselvestothemosquitoesandthenimmediatelylatchontotheirnextvictim.Theyneedtimetogrowandreplicateinthemosquitobeforemigratingtothebug’ssalivaryglands.Forexample,thedenguefevervirustakesabouttwoweekstoincubate.

SoresearchersfromtheUniversityofQueenslandinAustraliaandCentralChinaNormalUniversityarelookingatawaytoshortenthelivesofmosquitoes—andthuscurtailtheirdisease-transmittingability.

ResearchersworkedwithabacterialparasitecalledWolbachiathatinfectsnumerousinsectspecies.TheyspentthreeyearsadaptingittoinfecttheAedesaegypti mosquito,whichcarriesdenguefever.Itcutthelivesofthemosquitoesbymorethanhalf.ThoseresultswerereportedintheJanuary2ndissueofthejournalScience.ThescientistssaythatbecauseWolbachiashortensamosquito’slife,theinsectsarethatmuchlesslikelytopassonthediseasestheycarry.Soarelativelyinexpensiveandeffectivehumandiseasepreventionprogramcouldbetomass-infectmosquitoeswithWolbachia.Whichshouldmakethemedicalcommunitybuzz.

ThanksfortheminuteforScientificAmerican's60-SecondScience.I'mCynthiaGraber.

SSS2009-01-05

ThisisScientificAmerican's 60-SecondScience.I'mSteveMirsky .Gotaminute?

WeresidentsoftheMilkyWayshouldhavealittleextraskipinoursteptoday.Turnsoutourhomegalaxyismuchbiggerandmovingalotfasterthanwepreviouslythought.That’swhatresearchersfromtheHarvard–SmithsonianCenterforAstrophysicsreportedJanuary5thatthemeetingoftheAmericanAstronomicalSociety.

Olderstudiesofourgalaxy’sstructureandmotionusedindirectmeasurements.Butwecannowuseradiotelescopestodirectlyobservecertainfeaturesofthegalaxywhenwe’reinverydifferentplacesinourorbitaroundthesun.Andusingtraditionalsurveyingmethods,suchastriangulation,researcherscameupwiththenewfigures.

First,we’removingabout600,000milesperhourinourgalacticorbit,alotzippierthantheoldestimateof500,000.AndtheMilkyWay’stotalmassisabouthalfagainasmuchasweusedtothink.Whichmeanswe’reaboutasmassiveasthenearbyAndromedaGalaxy.TheMilkyWay’sbiggermassdoesmeanagreaterchanceofagravity-drivencollisionwithAndromeda.Butifthatclashoccurs,atleastnowwe’reinthesameweight-class.

ThanksfortheminuteforScientificAmerican's60-SecondScience.I'mSteveMirsky.

SSS2009-01-06

Tuneineveryweekdayforquickreportsandcommentariesontheworldofscience--it'lljusttakeaminute.

AstudypresentedatthemeetingoftheAmericanAstronomicalSocietyfindsthatthedebrissurroundingwhitedwarfstarsissimilartothecontentofrockyplanets--whichmeansthatrockyplanetscouldbecommontostarslikeoursun.CynthiaGraberreports.

SSS2009-01-06

ThisisScientificAmerican's 60-SecondScience.I'mCynthiaGraber.Thiswilljusttakeaminute.

Ifwewanttolearnmoreaboutourplanetandotherplanetsintheuniverse,wecangetsomehelpfromstarsthatarelongdeadandgone.That’swhatU.C.L.A.’sMichaelJurasaidattheAmericanAstronomicalSocietymeetingJanuary5th.HisteamusedobservationsfromNASA’sSpitzerSpaceTelescopetoinvestigatedeadwhitedwarfstars.

Dustanddebrisswirlaroundyoungstars.Thepiecesclumptogethertoformasteroidsandbiggerplanets.Whenastarlikeoursunfinallydies,itblowsitselfup,brightred.Thenitshrinksdownintoas