科技英语阅读答案Unit 2.docx

科技英语阅读答案Unit 2.docx

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科技英语阅读答案Unit2

AppendixIReferenceAnswers

Unit2Physics

PartIESTReading

Reading1

SectionAPre-readingTask

Warm-upQuestions:

Workinpairsanddiscussthefollowingquestions.

1.Whatisquantumphysics?

Quantumphysicsisthestudyofthebehaviorofmatterandenergyatthemolecular,atomic,nuclear,andevensmallermicroscopiclevels.Intheearly20thcentury,itwasdiscoveredthatthelawsthatgovernmacroscopicobjectsdonotfunctionthesameinsuchsmallrealms.

2.Doyouknowanythingaboutdarkmatter?

Darkmatterisahypothesizedformofmatterparticlethatdoesnotreflectoremitelectromagneticradiation.Theexistenceofdarkmatterisinferredfromgravitationaleffectsonvisiblematter,suchasstarsandgalaxies.

Asmallpercentageofthegravitationaleffectsobservedarefromvisiblematter（someestimatesareaslowas4%oftotalgravitationaleffects）.Theremaining96%ispresumedtoresultfromdarkmatterordarkenergy,thoughthesetermsaresomewhatindicativeofourignoranceoftheexactnatureoftheseunknownquantities,astheyhaveneverbeendirectlyobserved.

Onepossiblecandidatefordarkmatteraretheoreticalparticlesknownasweaklyinteractingmassiveparticles（WIMPs）,whicharebeingsearchedforbytheCryogenicDarkMatterSearch（CDMS）experiment.

3.Whatisdarkenergy?

Darkenergyisahypotheticalformofenergythatpermeatesspaceandexertsanegativepressure,whichwouldhavegravitationaleffectstoaccountforthedifferencesbetweenthetheoreticalandobservationalresultsofgravitationaleffectsonvisiblematter.Darkenergyisnotdirectlyobserved,butratherinferredfromobservationsofgravitationalinteractionsbetweenastronomicalobjects,alongwithdarkmatter.

Theterm"darkenergy"wascoinedbythetheoreticalcosmologistMichaelS.Turner.

4.Haveyoueverheardofthebigbangtheory?

Canyougiveanaccountofit?

TheBigBangisthedominant（andhighlysupported）theoryoftheoriginoftheuniverse.Inessence,thistheorystatesthattheuniversebeganfromaninitialpointorsingularitywhichhasexpandedoverbillionsofyearstoformtheuniverseaswenowknowit.

In1927,RomanCatholicpriestandphysicistGeorgesLemaitreindependentlycalculatedtheFriedmansolutionandagainsuggestedthattheuniversemustbeexpanding.ThistheorywassupportedbyHubblewhen,in1929,hefoundthattherewasacorrelationbetweenthedistanceofthegalaxiesandtheamountofredshiftinthatgalaxy'slight.Thedistantgalaxiesweremovingawayfaster,whichwasexactlywhatwaspredictedbyLemaitre'ssolutions.

In1931,Lemaitrewentfurtherwithhispredictions,extrapolatingbackwardsintimefindthatthematteroftheuniversewouldreachaninfinitedensityandtemperatureatafinitetimeinthepast.Thismeanstheuniversemusthavebeguninanincrediblysmall,densepointofmatter-a"primevalatom."

5.Howdoyouunderstandstringtheory?

Stringtheoryisamathematicaltheorythattriestoexplaincertainphenomenawhichisnotcurrentlyexplainableunderthestandardmodelofquantumphysics.

Stringtheorywasinitiallydevelopedinthe1970sinanattempttoexplainsomeinconsistencieswiththeenergybehaviorofhadronsandotherfundamentalparticlesofphysics.

Aswithmuchofquantumphysics,themathematicsthatappliestostringtheorycannotbeuniquelysolved.Physicistsmustapplyperturbationtheorytoobtainaseriesofapproximatedsolutions.Suchsolutions,ofcourse,includeassumptionswhichmayormaynotbetrue.

Thedrivinghopebehindthisworkisthatitwillresultina"theoryofeverything,"includingasolutiontotheproblemofquantumgravity,toreconcilequantumphysicswithgeneralrelativity,thusreconcilingthefundamentalforcesofphysics.

SectionCPost-readingTask

ReadingComprehension

1.Directions:

Workonyourownandfillintheblankswiththemainidea.

Part1（Paras.1-3）:

Briefintroductiontodarkenergy

Para.1:

Darkenergyisanunexplainedforcewhichtugsgalaxiesawayfromeachother.

Para.2:

Darkenergyissomewhatlikeanti-gravity.

Para.3:

Darkenergyisscientists’hypotheticformofenergytoexplaintheuniverse’sexpansion.

Part2（Paras.4-9）:

Thediscoveryofdarkenergy:

confoundingexpectations

Para.4:

Thediscoveryofdarkenergyisacaseofscienceconfoundingexpectations.

Para.5:

Expertsexpectedthatgravityhadsloweddowntheuniverse’srateofexpansion.

Para.6:

Theuniverse’srateofexpansionwasspeedingup.

Para.7:

Theresultwasbeyondexperts’expectationswhichcausedmuchnervouslaughter.

Para.8:

Themeasurementsofsupernovaeprovidedtheevidencethattheuniverse’srateofballooningwasspeedingup.

Para.9:

Thescientistsobservedmanysupernovaeatdifferentdistancestodeterminehowfasttheyarespeedingawayfromus.

Part3（Paras.10-13）:

Therateoftheexpansionoftheuniverse:

shockingresults

Para.10:

Therateoftheuniverse’sexpansionisaccelerating.

Para.11:

Moreresearchesdonebyotherexpertsalsoshowthesameresults.

Para.12:

Einstein’scosmologicalconstanthasbeenrevivedtoexplainthepuzzlingfindings.

Para.13:

Thecosmologicalconstantisoneoftheleadingtheoriestoexplaintheexpansionoftheuniverse.

Part4（Paras.14-17）:

Thedifferencebetweendarkenergyanddarkmatter

Para.14:

Theconfusionofdarkenergyanddarkmatter.

Para.15:

Darkmatterisaninvisiblehypothesizedformofmatter.

Para.16:

Darkmatteranddarkenergyseemtomakeupmostofthemassoftheuniverse.

Para.17:

Thediscoveryofdarkenergystirredupalotofotherissues,suchasmakingsomepeoplebelievethatthereareseveraluniverses.

2.Directions:

Workinpairsanddiscussthefollowingquestions.

1）What’sdarkenergybeforeandafteryoustudiedthetext?

Before,Iknownothingaboutdarkenergy.Now,Iknowthatdarkenergyisahypotheticalformofenergythatpermeatesspaceandexertsanegativepressure,whichwouldhavegravitationaleffectstoaccountforthedifferencesbetweenthetheoreticalandobservationalresultsofgravitationaleffectsonvisiblematter.Darkenergyisnotdirectlyobserved,butratherinferredfromobservationsofgravitationalinteractionsbetweenastronomicalobjects,alongwithdarkmatter.

2）Inyoureyes,what’sgravityandanti-gravity?

Referto:

3）Didgravityslowdowntherateoftheexpansionoftheuniverse?

Whyorwhynot?

No.Gravitywasspeedinguptherateoftheexpansionoftheuniverse.Theevidencewasbasedonmeasurementsofsupernovaethatastronomerswereusingaslamppoststotrackdistance.

4）CanyouexplainDopplerEffectindetail?

TheDopplereffect（orDopplershift）,namedafterAustrianphysicistChristianDopplerwhoproposeditin1842inPrague,isthechangeinfrequencyofawaveforanobservermovingrelativetothesourceofthewave.Itiscommonlyheardwhenavehiclesoundingasirenorhornapproaches,passes,andrecedesfromanobserver.Thereceivedfrequencyishigher（comparedtotheemittedfrequency）duringtheapproach,itisidenticalattheinstantofpassingby,anditislowerduringtherecession.

http:

//en.wikipedia.org/wiki/Doppler_effect

5）DoyouknowanystoryofEinstein’scosmologicalconstant?

Inphysicalcosmology,thecosmologicalconstant（usuallydenotedbytheGreekcapitalletterlambda:

Λ）wasproposedbyAlbertEinsteinasamodificationofhisoriginaltheoryofgeneralrelativitytoachieveastationaryuniverse.EinsteinabandonedtheconceptaftertheobservationoftheHubbleredshiftindicatedthattheuniversemightnotbestationary,ashehadbasedhistheoryontheideathattheuniverseisunchanging.However,thediscoveryofcosmicaccelerationinthe1990shasrenewedinterestinacosmologicalconstant.

http:

//en.wikipedia.org/wiki/Cosmological_constant

6）Whatisdarkmatter?

What’sthedifferencebetweendarkenergyanddarkmatter?

Darkmatterismatterthatisundetectablebyitsemittedradiation,butwhosepresencecanbeinferredfromgravitationaleffects.Darkmatterisinvisible.

http:

//en.wikipedia.org/wiki/Dark_Matter_（disambiguation）

7）Isittrueorfalsethattheuniverseisformedmainlyofdarkenergyanddarkmatter?

Canyougivesomeevidence?

Yes.Itistrue.Somestudiesshowthatdarkenergyisthoughttoaccountfor74percentoftheuniverse,whiledarkmatteraddsabout22percent.

8）Areyouoneofthebelieversinmultipleuniverses?

Why?

（Open）

3.Directions:

Readthefollowingpassagecarefullyandfillintheblankswiththewordsyou’velearnedinthetext.

Darkenergy—themysteriousstuffthatisstretchingspaceandspeedingtheexpansionoftheuniverse—issaidtohavebeenaroundatleast9billionyears.Itisahypotheticalformofenergy,whichissomewhatlikeanti-gravitythatdrawsgalaxiesawayfromeachother.Inthemid-1990s,whenastronomerswentaboutmeasuringtherateoftheexpansionoftheuniverse,theysurprisinglyfoundthattheuniverse’sballooningwasspeedingup,whichwasbeyondmanyastrophysicists’expectations.Someotherresearchersalsofoundthattheuniverseisblowingupfastertodaythanatanytimeinthepast.AllthesepuzzlesopenupanopportunityforsomescientiststoreviveEinstein’sdiscardedidea—cosmologicalconstant.Thoughdarkenergyanddarkmatter（invisible）areseparateentities,peoplearealwaysconfusedaboutthem.Itseemsthatdarkenergyaccountsfor74percentoftheuniverse,whiledarkmatteraddsabout22percent.Thedisco