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AgeoftheuniverseH.Falcke Sixthousandversus14Billion:Howlargeandhowoldisthe universe? Version06/03/2017 HeinoFalcke DepartmentofAstronomy,RadboudUniversity,Nijmegen 1 Introduction...................................................................................................................................2 2 Sizeandageoftheuniverse....................................................................................................3 2.1 Sizeandtime.........................................................................................................................3 2.2 Measuringreliabledistancesintheuniverse.........................................................3 2.3 ParallaxeswithVLBI..........................................................................................................7 2.4 OtherGalaxies–Millionsandbillionsoflightyears..........................................10 3 Aretherewaysout?.................................................................................................................12 3.1 Thisisallfake!...................................................................................................................13 3.2 Maybethespeedoflightisnotconstant?.............................................................13 3.2.1 Thenatureoflight...................................................................................................14 3.2.2 Measuringthespeedoflightinthelaboratory..........................................16 3.2.3 Speedoflightatdifferentdistancesandagesoftheuniverse.............18 3.2.4 Summaryofthechangingspeedoflightidea.............................................19 3.3 DoestimegofasteroutsideEarth?..........................................................................19 3.3.1 Timedilation.............................................................................................................19 3.3.2 Observingtime-dependentprocessesintheuniverse............................19 3.4 Waituntilsciencecomestonewconclusions?...................................................20 4 DidGodmaketheuniverselookoldandlarge?..........................................................22 4.1 Defendingthequestion.................................................................................................22 4.2 ThereliabilityofGod......................................................................................................24 4.3 Miracles&mystery.........................................................................................................26 4.4 Howscienceandworldviewareintertwined.....................................................27 4.5 Responsibility,accountability,andtheoriginalsin..........................................28 4.6 Creationistscience..........................................................................................................30 5 Conclusions.................................................................................................................................32 1 AgeoftheuniverseH.Falcke 1 Introduction So,howbigandoldistheuniverseactually?Isitreallybillionsofyearsold?How canwebesosure? Occasionally,whenIgivepubliclecturesIgetthequestion,whethertheuniverse couldnotbemuchyounger.Howcanscientistsclaimtolookbackintime?Why wouldyoutrustthosescientists,whenthewordofGodintheBibleclaimsthat theuniversewiththestars,thesun,andtheearthisjust6,000yearsold? Manyofmycolleaguesfeelabituncomfortablediscussingthisquestioninpublic. However,alsothesepeoplepaytheirtaxes,someofwhichfinancesastronomy research,andsotheyhavetherighttoananswer.As“publicservants”wehave thedutytoprovidethem.So,Itry. Myanswerwillbetwo-fold:physicalandmetaphysical.Clearly,sciencehasalot tosayonthistopic,astheageandsizeoftheuniversehasbeenamatterof intenseresearchduringthepasthundredyears.However,alsometaphysical–in fact,theological–argumentscannotbeleftout:arehistoryandnatureactually reliable,oraretheyanillusion?Thequestionsoundsstrangetomanyscientists, butitdoesindeeddependonaparticularworldview–abelief–thateveryone implicitlyassumes. Letusstartwiththescience.Therearecountlessargumentsyoumaywantto make,butwhichonesaremoststraightforward?Youcannotexplainallof astrophysicsinafewminutesandthebestwayforwardisusuallytostartwith thebigview,beforegoingintodetails. Tomethemostcompellingandsufficientargumentforaveryolduniverse comesfromthesheersizeofitandthetimeittakesforlighttoreachus:from mostpartsoftheuniverseittakesmillionsorevenbillionsofyears,ratherthana fewthousandyears.Thisiswhateveryoneneedstounderstandandaddress first. Iwillfirstexplainhowtomeasurethesizeoftheuniverse.Thefocuswillnotbe onadetailedderivationofthetraditional“cosmicdistanceladder”,buton simplicity,robustness,andtransparencyoftheargument.Thereaderis challengedtofollowtheargumentwithaslittlepriorknowledgeaspossibleand todigdeeperwheredesired.Afterall,weonlyneedaveryroughorderof magnitudesizeestimatetodistinguishscientificallybetweenthetwoscenarios. Alreadywithsomebasicunderstandingoftrigonometryandcommonsense,itis straightforwardtoshowthattheuniverseisfarlargerthan6000lightyears–the distancelightcantravelin6000years. Asanextstep,Iwilladdressthequestionsofwhetherthespeedoflightcould changeorwhethertimecouldhavespedupintheevolutionoftheuniversein ordertomakealargeuniverseinamuchshortertime.Therequireddrastic evolutionofthespeedoflightandtime,however,areruledoutbycurrentultraprecisemeasurementsoflightaswellasprocessesweseeevolvinginfrontof oureyesinthedistantuniverse. Finally,Idiscusswhethertheuniversecouldhavebeencreatedafewthousand yearsago,justlookingold.Thisisperhapsamuchdeeperquestionandtouches ontheissueofthereliabilityofnatureandthenatureofGod.Whilegoingagainst 2 AgeoftheuniverseH.Falcke Occam’srazor–andhenceconsideredhighlyunlikelyinthescientific community,strictlyspeakingsucha“created-old”scenarioisscientificallynot falsifiable.Itwould,however,implyacreator,whoseverynatureisunreliable anduntrustworthy,settingupaworldthatgivesfalsewitnessofitsorigin.This castsintodoubtoneofthemostbasiccharacteristicsoftheGodportrayedinthe veryBibletheyoung-universeideaisderivedfrominthefirstplace. Section2givesabasicintroductiontothemeasurementsofthesizeofthe universeforageneralpublic.Section3discusseswhetheralternativescould makesuchalargeuniverseyoung,suchasachangingspeedoflight.Finally, section4isatheologicaldiscussiononwhyamodelinvokingtheBibletoexplain ayounguniverseisinconsistentwiththeBibleitself;thissectionrequiressome understandingofChristianthinking. 2 2.1 Sizeandageoftheuniverse Sizeandtime WhenIlivedintheUSinthe90’stherewasstillageneralnationalspeedlimiton highwaysof55milesperhour.So,everyonewasusedtodriveatamoreorless constantspeedof60mph(sincepolicewouldletyougetawaywithit):thespeed ofcarwasfixed!Hence,myfriendswouldgivedistancesintermsoftime.When youaskedhowfarawayacitywas,peoplewouldsimplysay“about2hours”, meaningitwasabout120milesaway. Thesameistrueinastrophysics:wetalkaboutlightyearsandmeanadistance.A lightyearis9.56trillionkilometers–simplythedistancelighttravelsinayear. Howfastlighttravelsisextremelywellestablishedthroughlaboratory experimentsandthespeedoflightisveryconstant(seeSec.3.2).Infact,itisso wellestablished,thattodaywedefinethemeterviathespeedoflight–simply becausewecanmeasurethelattermuchmorepreciselythanwecouldmakeany physicalrulerthatwoulddefinewhatameteris!i So,whilealightyearisameasureofdistance,itisalsoameasureofage.Light thatreachesusfromastarafewlightyearsawaytookafewyearstoreachus andweseehowthestarlookedlikeafewyearsago,whenthelightwassenton itsjourney. Hence,theskyislikeaphotoalbum,whereyouseepicturesfromdifferentparts ofyourlife.Lookingatobjectsatdifferentdistancesmeansyoualwayslookat differentphasesoftheuniverseii!So,yesyoucanlookbackintime.Infact,you doitallthetimewhenyoulookupintothesky. 2.2 Measuringreliabledistancesintheuniverse ThebasicscaleusedinastronomyistheAstronomicalUnit(AU)–whichisthe averagedistanceoftheearthtothesun:about150Millionkilometers.Dividing thisnumberbythespeedoflight,roughly300,000km/s,thismeansthatthesun isabout8.3lightminutesaway.Weareverysureaboutthisnow,sincewe directlyflyspacecraftthroughtheentiresolarsystem. Ifyouwanttofindoutyourself,youcoulddeterminethedistancetothesunin principlefromthegroundwithalittlebitoftravel,agoodfriend,andbywaiting foraVenusTransit.ThisishowtheAUwasfirstdeterminedreliably.Theonly 3 AgeoftheuniverseH.Falcke problemisthatwejustmissedthelastVenustransitinJune2012andthenext oneisonDecember11,2117.However,thereshouldstillbeenoughdataout thereontheInternetpostedbyenthusiasticamateurastronomerstoactually redothecalculationyourself. Figure1:VenusTransit.Thefirststepistomeasurethedistancetothesunfromdifferentpositions onEarth.Calculatingtheabsolutedistancethenmakesuseofthefactthattheratioofthevelocities ofEarthandVenusaregivenbyKepler’sthirdlawofplanetarymotion.(Exploratorium.edu) TheAUiscrucial,sincethenextstepinourdistancedeterminationis fundamentallybasedonthisdistance.Astheearthmovesaroundthesun,we willbe150Millionkmononesideofthesuninspringand150Millionkmonthe othersideofthesuninfall,meaningthatthecurrentlocationoftheearthis always300Millionkmremovedfromthelocationitwasjusthalfayearago. Nowimagineyouaresittingonamerry-go-roundandtakeapictureofthe crowdaroundyouwheneveryouhavemadehalfaturn.Thetwopictureswill notlookalike.Yourfriendsandfamily,standingclosetothemerrygoroundwill shiftfromonesidetothenextonsubsequentpictures,whiletreesandhousesat thehorizonwillonlyshiftatinybit,probablynotnoticeableatall.Thisisdueto achangeinperspective.Knowinghowlargethemerry-go-roundisand measuringhowmuchpeopleshiftonsubsequentimagesyoucanactually calculatewithalittlebitoftrigonometryhowfartheyareawayfromyou. Figure2:Thebasicsofparallaxmeasurements-usingsmallchangesofstarsontheskyastheEarth revolvesaroundthesun(fromATNF) 4 AgeoftheuniverseH.Falcke Thesameyoucandoforstars,usingthesolarsystemasagiantmerry-go-round (Figure2).Verynearbystarswillshiftatinybitontheskybetweenspringand fall,whiledistantoneswillhardlyshiftatall. Theshiftisactuallyexpressedasanangle.Tomeasuretheangulardistance betweentwopositionsonthesky,pointafingeratthemsubsequentlyand determinebyhowmanydegreesyouhavetomoveyourarm.Ofcourse,the parallaxangleitselfissosmallthatyouneedamuchmorepreciseinstrumentto measureitasdiscussedbelow. Themathtoturnthisangleintodistanceisprettymuchthesameaswhatisused bylandsurveyorswholookthroughtheirtheodolitesandmeasuretheangle betweentheirlineofsighttowardsthetopandbottomofaredandwhitestriped rodofadefinedlength.Thefurtherawaytherod,thesmalleritappears,andthe smallertheangleyoumeasure. Itturnsoutthatthisisnotaneasymeasurementtodoyourself–simplybecause starsareveryfaraway.ThecloseststarisProximaCentauri,whichis4.2 lightyears,i.e.40trillionkm.Thisstarwillmoveontheskyonlyby1.5seconds ofarc(orarcsecondsinshort)betweenfallandspring! Howmuchisthis?Weknowwhatarightangleis.Therightanglecanbe subdividedinto90degrees.Eachdegreehas60arcminutesandeacharcminute isdividedinto60arcseconds.Trackingahalfcirclethroughthezenithonthe sky,willextendover180degrees,whilethefullmoonwillcoverhalfadegree only. Figure3:Coordinatesofsourcesontheskyandtheirextentaregivenindegreesofafullcircle projectedaroundtheearth(burro.case.edu) Asapracticalexampleofsmallangles,pictureadartboardatthenominal distanceof2.37m.Tohitthebullseyeyoumusthavetothrowyourdartwitha deviationofmaximally9arcminutesrelativetotheperfectlineconnectingyour handwiththeverycenteroftheboard.Ifwewouldprojecttheannualreflex motionofProximaCentauriof1.5arcsecondsontothedartboard,theprojected starwouldonlyshiftby17µmfromthecenteroftheboard–lessthanthewidth 5 AgeoftheuniverseH.Falcke ofahumanhair!Youwouldnotbeabletonoticethisshiftwithyourbareeye(let alonehitabullseyethatsmall). Suchameasurementisverydifficulttodoandnowonderittookuntilthe19th centurytoactuallydetectaparallaxshiftreliably.Infact,itstillishardtoday,but apparentlysomededicatedamateurastronomerscandoitwithcommercially availabletelescopeequipment–atleastinafewcases.So,probablyyoucandoit aswell,ifyoureallywanttoknowyourselfandarewillingtoworkhard. Ofcourse,todayparallaxmeasurementsaremuchbetterdonefromspace,where telescopesliketheHubbleSpaceTelescopeorESA’sGaiamissionhavemeasured distanceswithexquisiteprecisiondowntothousandsoflightyearsiii.Hereone hastorelyonthefactthatthisdiversegroupofastronomersandengineersdoes theirjobwell.InthelatestGAIAdatareleasethereare2millionstarsforwhicha reliabledistancebasedonparallaxmeasurementshasbeendetermined–a methodthatstillonlyinvolvesmeasuringangles. Thisisanexcellentfoundationtostandonfordeterminingdistancestoeven morestars.Thisisnotimportantformymainargument–wedonotneedmore starstogetthebasicscaleoftheuniverse,butitmaybeusefultounderstand thatalsotherestofthestarsnicelycorroboratethestorytoldhere. Thereasonisthatthebrightness,temperature,andcolorivofstarsdepend mainlyonhowmassivetheyare.Thereisarelativelytightcorrelationbetween alltheseparameters,whichisreflectedindiagramssuchasthefamous Hertzsprung-Russelldiagram(Figure4),whereonesortsstarsbycolorand luminosityandwhere“normal”vstarsallfallononenarrowline. Theheavierstarsare,thehigherthepressureinitscenter,thehigherthecentral temperature,andthebluerisalsotheemittedlightatthesurface.Inthatsense starsareremarkablysimpleandcanbedescribedbyafewbasicequations. Notallparameterscanbemeasuredforallstars,butthereisenoughofa representativesampletocovertheentirerangeofstarsweseeonthesky.The massofstarscan,e.g.,bemeasuredfromtheirrotationspeedandorbits,ifthey areinabinarysystem,wheretwostarsorbiteachother.Thesurface temperaturecanbedeterminedfromtheobservedcolor,basedontheformula forblackbodyradiation.Thisformulaistheonethatmakesmeltingsteelglow moreyellow-whitethehotteritis. So,knowingtheexactdistanceforafewstarsofacertaintype,i.e.,acertain color,onecangetreliabledistancesforallotherstarsofthesametypeandcolor, justbymeasuringhowbrighttheyappearinthesky.Thefurtherawayitis,the fainteritwillbe. 6 AgeoftheuniverseH.Falcke Figure4:AHertzsprung-Russelldiagram,whichshowsthatmoststarsfallontheso-called”main sequence“(diagonallineofstarsinthecenter)duringthelargestpartoftheiractivelives.Thereisa tightrelationbetweenthecolor,surfacetemperature,intrinsicluminosity,massandsizeofastar. Knowingtheemittedcolorweknowtheintrinsicluminosityofastarandwecanestimatethe distancetoitfromitsobservedbrightnessonthesky(“spectroscopicparallax”).Whitedwarfsand giantstarsarestellarphasesattheendofthelifetimeofastarandcanbewelldistinguishedfrom normal(main-sequencestars)fromtheiremittedlight(e.g.,theirspectra). 2.3 ParallaxeswithVLBI However,thereisonetechniquethatIampersonallymoreinvolvedwithand whichdeliversevenmoreimpressiveresults:verylongbaselineradio interferometry,orVLBI.Hereradiotelescopesdistributedovertheentireworld arecombinedintoonegiantnetworkoftelescopesthatcandeliver measurementsthatareaspreciseasatelescopethesizeoftheearth.Whatthey essentiallydoisGPSinreverse.Thatallowsthemtodoparallaxmeasurements, whichareaspreciseasseveraltensofmicroarcsecondsvi. VLBIdoesexactlythesameasdiscussedbefore–measuretherelativepositions ofradio-emittingstarsontheskyhalfayearapart,butnowwithamuchhigher precisionpossiblethanwithanyopticaltelescopetoday(Figure5). 7 AgeoftheuniverseH.Falcke Figure5:ParallaxmeasurementsusingVLBI AnexampleofsuchameasurementisshowninFigure6.Youseethatthe positionofthissourceontheskyshiftsby0.18milliarcsecondswithinhalfayear andback.Thisisindeedthereflexmotionseenontheskyduetotheearth orbitingaroundthesun.DividingoneAstronomicalUnitbyhalftheangle,0.09 milliarcsecond(=4.4×10-10radians)wegetadistanceof36.000lightyearsor 340quadrillionkm(=3.41017km). Figure6:RelativeshiftofthestarformingregionW49Nonthesky(“parallax”)separatedbyhalfa year,asmeasurementswithVLBI(fromZhangetal.2013). 8 AgeoftheuniverseH.Falcke Note,that36,000lightyearsmeansthatthelightwasemitted36,000yearsago. Lighthadtotravelthatlongtogethereinthefirstplace.Bynowthisdistant sourceismucholder,butthelightfromitspresentstatehasnotreachedusyet. Isthisjustafreaksourceorameasurementerror?No,thesamecolleaguesof mineattheHarvard-SmithsonianCenterforAstrophysicsandoftheMax-PlanckInstitutfürRadioastronomieinBonnhavedonemoreofthisfundamentalwork andmappedoutthestructureofourMilkyWay.Therearenotsomanyuseful radio-emittingstars,butenoughtocoveronequadrantofourgalaxyandtogeta reliablesenseofthesizeofourMilkyWay(Figure7).Thestarsspan14 kiloparsecs,acrossourowngalaxy,whichis45,000lightyearsfromoneendto theother.Thesedistancesaredirectlymeasuredviatheirparallax,i.e.themost directandreliablewaytomeasuredistances. Figure7:Artist'simpressionofourMilkyWayoverlaidwithactualmeasurementsofthelocationof radioemittingstars(greendots),determinedfromparallaxmeasurementswithradiotelescopes. Theaxesareinkiloparcsec,where1kpcis3260lightyears.Thereddotmarksthelocationofour solarsystemandtheredstaristhecenterofourMilkyWay.(Reidetal.2014) Ofcourse,weknowthattheMilkyWayhasmorethanonequadrantandhence onecansafelyassumethattheMilkyWayextendsattheveryleast90,000 lightyears. So,thenexttimeyoulookuponthenightskyinadarkregionandyoumarvelat theMilkyWay(Figure8),rememberthatitstretchesalmost100,000lightyears fromoneendtotheother! 9 AgeoftheuniverseH.Falcke Figure8:TheMilkyWayarchingatahighinclinationacrossthenightsky(fish-eyemosaicshotat Paranal,Chile).ThebrightobjectisJupiterintheconstellationSagittarius.Galacticnorthis downwards(ESO). 2.4 OtherGalaxies–Millionsandbillionsoflightyears Sofarwehavediscussedonlyonegalaxy,namelyourown.Whataboutthe others?Well,thereistheAndromedagalaxy(alsocalledM31,Figure9).Itisa marvelousmasterpiecetolookat;infact,youcouldseeitsbrightfluffy innermostpartswithyournakedeyeunderverygoodconditions(ifyouknow howtofindit).Usingbinocularsgivesabetterview. Figure9:PictureoftheAndromedagalaxystretchingabout3degrees,i.e.,sixmoondiameters, acrossthesky(AdamEvans) WhatisinterestingaboutAndromedaisthatitresemblesverymuchourMilky Wayinitsproperties.Wouldyousitintheouterpartsofthisgalaxy–aswedoin ourown,youwouldseeaglowingbandverymuchlikeourMilkyWayatthe nightsky.Thisneighborgalaxyisroughly3degreesacrossonthesky.Three degreescorrespondtoroughlysixtimesthemoon(seehere,foraphotomontage 10 AgeoftheuniverseH.Falcke toillustratethis).Holdyourthumpupagainsttheskyandyoucancoverthe moonortheinnermostpartofAndromeda. Now,rememberthatourownMilkyWayextendsalmostovertheentiresky,say 300degrees,andthatthecenteroftheMilkyWayis27,000lightyearsaway.You havetoextendyourarmsfromlefttorighttoembracetheentireskyandstill coveronlyalittlemorethanhalfoftheMilkyWay.Howfarwouldyouhaveto moveaway,sothattheentireMilkyWaywouldshrinktothesizeofthe Andromedagalaxy?Well,togetfroma300to3degreesize,youneedtobea factor100furtheraway.Hence,Andromedashouldbeabout2.7Million lightyearsaway. Infact,ourownteamhadlookedatacompaniongalaxyofAndromeda,M33,and usedVLBItogetageometricdistancetoit(Brunthaleretal.2005).Themethod isverysimilartotheparallaxmethod,exceptthatweactuallysawthegalaxy rotateontheskyoverthecourseofyearsandknewhowfastitwasrotatingfrom measuringtheDopplereffect.Thediskofthegalaxyisrotatingwith106km/sec, yetthetwospotsinthedisk,wewereobserving,movedonlyby30 microarcsecondperyearonthesky. Acarthatwoulddriveontheroadinfrontofyourhousewiththatspeedwould movefromlefttoright,i.e.overroughly180°,inasmallfractionofasecond(and recklesslyendangereveryonelivingthere,ofcourse).Thesamecarmovingwith thatspeedonahighwaythatisafewkilometersaway,wouldseemtotakea littlelongerbeforeitdisappearsfromyourview,butprobablywouldbestilltoo fasttotrackitwithyourfingers. Howfarawaydoyouhavetogotocatchitappearingasslowaswedid?Youcan calculateviithatyouhavetomovestarsthatrotatearoundagalaxywith106 km/secondoutto2.4Millionlightyearsinordertohavethemmoveonlysucha tinyfractionoftheskywithinayear.Thesetwosimpleconsiderationsgive basicallythesameanswer:Andromedaanditsneighborsmustbeabout2anda halfMillionlightyearsaway. Asimilartechniquetogetadirectgeometricdistancehasbeenreported,e.g.by Herrnsteinetal.(1999)andHumphreysetal.(2013,andreferencestherein),for thegalaxyNGC4258(usingadiskofwatervaporrotatingacentralblackhole). Thegalaxyisatadistanceof25Millionlightyearswitha3%error. Ofcourse,thisisstillnottheendoftheuniverse.Thereareothermethodstogo further:stepbystep.Thatcosmicdistanceladdercanbecomplicatedand confusingattimes,soweonlymakeaverysimplesanitycheckhere. HavealookattheHubbleDeepField(Figure10):thisisadeepimageofthesky takenbytheHubbleSpaceTelescope.Itmeasures2.6arcminutesacross,roughly thesizeoftheeyeofaneedlethatyoulookthroughwhileyouholditupagainst thesky.Iusuallyshowthistoimpressontopeoplehowmanygalaxiesandstars thereareintheuniverse(theimagecoversonly1/28,000,000ofthetotalareaof thesky,hencetherearehundredsofbillionsofgalaxiesintheentireuniverse). 11 AgeoftheuniverseH.Falcke Figure10:TheHubbleDeepField-adeepimageofarandompieceofskyshowingthousandsof remotegalaxies.Itcoversabout2.6arcminutesoftheskyoneitherside. However,herewewanttogetasimplefeelingonhowfarawaythesesgalaxies are.Takearulerandmeasurethesizeofanaverage(spiral)galaxyintheimage. Thenmeasurethetotalwidthoftheimageanddividethetwonumbers,to expressthegalaxywidthasfractionofthetotalimagesizeandmultiplyby2.6 arcminutes,thesizeoftheimage.Youwillfindthattheseaveragegalaxiesare about0.07arcminutesor4arcsecondswide.Comparethistotheangularsizeof Andromedaof3×60arcminutes,whichappearsafactor2,500biggeronthesky. NowwecanplaythesamegameaswedidbeforewithAndromedaandtheMilky Way.Ifthesegalaxiesareanywherenearthesizeoftypicalgalaxiesthatwe knowhereinourlocaluniverse,theyhavetobeafewthousandtimesfurther awaythanAndromeda.Thismeansinorderforthosegalaxiestofitinatiny speckwithintheeyeofaneedle,wearenolongertalkingaboutafewmillion lightyears,butrathertensofbillions(1010)oflightyears!Theconclusion:the lightfromthesegalaxiestooksometenbillionyearstoreachusandweseethat partoftheuniverseasitwasabouttenbillionyearsago. Infact,thereareotherindependentmethods,whichgivemoreprecisesizeand ageestimates,liketheHubblelaw,butitallboilsdowntothesamehuge numbersforthesizeandageoftheuniverse! 3 Aretherewaysout? Ifyoudonotlikeanolduniverse,whatareyouroptionsaroundthis?Itis intellectuallyinterestingtothinkaboutchallengesandIwilltrytodiscussthem brieflyhere: 12 AgeoftheuniverseH.Falcke 3.1 Thisisallfake! Honestly,Ihavenotheardanyoneactuallymakethisclaimanditseemstome thatitisveryhardtodenythetruthfulnessoftheevidenceforthelargesizeof theuniverse.However,insocietiesofalltimestruthseemstobewhatever convenientlysuitsonesownpoliticalpurposerightnowandnobodyistobe trusted.AlreadyPontiusPilaterevealedthiscynicattitude,whenJesustestified infrontofhimandPilatesimplyasked“Whatistruth?”(John18,38).Obviously, hewaswellawareofhowtruthcanbetwisted. So,maybeallIsaidaboveisjustfakeandaconspiracy?Well,ifyouhavesucha deepmistrustofscience,thereisprobablylittleIcoulddo.Afterall,Iama scientistmyselfandpartofthesameclub.However,attheveryleastIamtrying torelate,thattheseobservationsarenot“justatheory”.Theyarebasedonvery solidandreproducibleempiricalevidence.Hence,Ihavetriedtoprovidesome simplestepsyoucanfollowyourselfinordertomakeupyourownmind. Parallaxmeasurementstonearbystarsyoucouldinprincipledoonyourown. ComparingthesizeoftheMilkyWayandAndromedayoucandowithyourown binocularandyournakedeyesviii.TherawdatausedtoproducetheHubbleDeep Fieldandtodotheastrometricradiomeasurementsmentionedaboveareall openlyavailableforeveryoneintheentireworldviatheInternetthroughthe archivesoftheSpaceTelescopeScienceinstituteandtheNationalRadio AstronomyObservatory.Theoriginalarticlesarealsoavailableforeveryonevia theAstrophysicsDataSystem.Theidentificationnumbersofobservationsare typicallytabulatedinthepublishedpapers,whichallowyoutolocatethedata setsinthearchives.Thereductionmethodsaredescribedinthearticlesandthe datareductionsoftwareispublicallyavailableforfree. Whenwediscussaboutopensciencetoday,youwillfindthatastronomyhas beenexercisingthistoalargeextentalreadyfordecades. Yes,youneedskillstore-reducethedatayourselfandalotoftime,butin principleyoucoulddoityourself.Inanycase,trainedscientistsalloverthe worldcanre-checkit,withrelativelylittlefunding.Oneneedstounderstand thatscientistsarenotahomogenousblock–theyareinfiercecompetitionwith eachother.Thereisalotofrewardforthosewhoareabletooverturnanold dogmaandestablishanewone.Ifayoungresearchercanshowthatamajor resultisfundamentallywrong,bynothavingtoinvestmuchmorethanhisorher owntime,thereisalottogain–ifheorshecanprovethepoint. Still,thebasicdistancescalesIhavediscussedherehavestoodthetestoftime overmanydecades.Thisisagoodsigninitselfthatwithsomuchdatabeing openlyavailablethebasicpictureisessentiallycorrectix. 3.2 Maybethespeedoflightisnotconstant? ThisisinfactthequestionIgetthemostfromthegeneralpublic.Indeed,my entireargumentisbasedonaconstantvalueforthespeedoflight:about 300,000km/s.Thereisaverysolidcaseforlargedistances,buttheageofthe universeonlyentersviathefactthatlightfromthosedistantplacesneedssome (finite)timetoreachus.So,couldnotthespeedoflightchange?Onecouldspend anentirebookonitsowntoaddressthis,butIwilltrytokeepitbasic. 13 AgeoftheuniverseH.Falcke 3.2.1 Thenatureoflight Firstofall,beverycarefulwhatyouwishfor.Thespeedoflightisperhapsthe mostfundamentalphysicalconstantwehaveandessentiallyallofphysicsand modernhigh-techrestsonit.WithoutitthefamousequationsofMaxwell, describingradiation,wouldnotworkandhotbodiescouldnotcoolviaradiation, ironwouldnotglowredwhenheatedup,andneitherwouldthesunshineand providewarmth. Lightissomethingreallyamazing.Itcanbedescribedaseitherelectromagnetic waves,i.e.,waveswhereelectricandmagneticfieldlineswigglethroughempty space,orasphotons,i.e.masslessparticleswhichcarryacertainenergy.This wave-particledualityisitselffascinating,butforsimplicityweherepicturelight onlyaswaves. Youcaninprinciplegeneratelightbymovingelectricchargesupanddown. Pictureacowboywithawhipmovinghisarmupanddown.Thewhipwill transportenergyfromthearmtotheendofthewhip,whereitcancreatealotof damagewiththatenergy.However,ittakesawhilebeforetheenergyfromthe musclesreachestheendofthewhip:awavecanbeseentravelingalongthe rope,whenthecowboyflapshisarms–thefasterthearmmovesupanddown themorewavecyclescanbeseen.Thenumberofcyclespersecondisthe frequencyofthewaveandtheseparationbetweenwavecrestsisthe wavelength.Theseparationbetweentwocrestspurelydependsonthe frequencywithwhichthecowboyflapsthearmsandthespeedwithwhichthe wavepropagatesalongthewhip.Thefasteritpropagatesthelongerthe wavelength.Bycomparingwavelengthandfrequency,youcantherefore measurethespeedofthewavepropagation. Itturnsoutthatwecandescribeallelectromagneticradiationthatway.Radio wavesareelectromagneticwaveswithalowfrequency(well,thisstillmeans MillionsorBillionsofcyclespersecond!)andalongwavelength–from hundredsofmeterstocentimeters,whileopticallighthasamuchhigher frequency(~500trillioncyclespersecondandawavelengthhundredtimes smallerthanhumanhair(seeFigure11). NowpictureadaringpersonthatcatchestheendoftheCowboy’swhip:Despite thiscatch,thecowboycanstillmovehisarmandinjectmoreenergyintothe whip!Theenergyfromthearmstillpropagatesfreelyoutwardsuntiltheother personabsorbsit.Hence,theenergyisactuallystoredinthewhipforacertain while.Evenifthearmhadstoppedafteraveryshortwhiplash,theenergyisstill propagatinguntilitreachestheend–thelonger,ofcourse,thelongerthewhip is. Hadthecowboyusedastickinstead,hisopponentcouldhavecaughttheendof thestickandalmostarrestedthecowboy’sarm.Thecouplingbetweenthetwo wouldbeinstantaneous,nowaveswouldexist,noenergywouldbetransferred, norworkbedone,justaforceexchanged. 14 AgeoftheuniverseH.Falcke Figure11:„Light“isoneparticularformofelectromagneticradiationdescribedbyitsfrequencyand wavelength.Radiowaveshavelowfrequenciesandlargewavelengths,whileopticallightorX-ray radiationhaveveryhighfrequenciesandtinywavelengths.Theproductofwavelengthand frequencyisthesameforalltheseformsofradiationandequalsthespeedoflight.(Lawrence BerkeleyLab) Thatiswhatwouldhappenifyouhadaninfinitespeedoflight.Lightcouldnot carryenergyaway–infact,lightwouldnotexist.Forexample,thehotand wigglingelectronsinanold-fashionedlightbulbcouldnotdumptheirenergy freelyintoradiation.Thesamewouldbetrueforthehotgasatthesurfaceofthe sun.Radiationisamajorsourceofcooling.Withoutcoolingthesunwouldblow upduetoitsheatsurplus.Ontheotherhand,solarradiationiswhatheatsthe Earthsurface.Withoutradiation,therewouldbehardlyanyheatandnolifeas weknowit. Thisaspect,thatlightequalsenergyisdeeplyengrainedinmanyareasof physics.Infact,oneofthefundamentalsofthermodynamicsstatesthatindeed allintransparentbodiesradiatetheirheatawayvialight(seeblackbody radiation).Thehottertheyarethebrightertheyradiate.Hence,peoplewhoget excitedandheatedupbyfallinginloveliterallyglowmore–albeitmainlyin near-infraredradiation. Thetheoreticalderivationofthefrequencyspectrumofthatheatradiation,the Planckspectrum,actuallyledtothedevelopmentofthequantumtheory,which weoweoursmartphonesandcomputersto. Ofcourse,youcouldstillhaveachangingspeedoflight,couldyounot?Inthe beginningofthe20thcenturyscientiststhoughtthatlightwastransported throughaninvisible“ether”thatwassupposedtofilltheentireuniverse. Consequently,theymeasuredthespeedoflightinthedirectionofthemotionof Earthandperpendiculartoit.Surely,thespeedoflightwouldneedtobe differentityouweretomovetowardsoragainsttheether?Surprisingly,the famousMichelson-Morley-Experimentshowedthatthespeedoflightwasalways thesame,irrespectiveinwhichdirectiontheearthwasmoving.Theetherdid notexistandlightwouldpropagateinvacuum,wherethereisnoreference medium. 15 AgeoftheuniverseH.Falcke Howcanyouthenmeasurespeed?Afterall,ifthereisonlyvacuuminthe universe,youhavenofixpointtomeasureanyspeedandyoucanonlymeasure yourspeedrelativetoanotherbody.Forcarsthatrelativebodyistheroad,but youdonotknowhowfasttheroaditselfismovinginanabsolutesenserelative to“theuniverse”.Theroadmovesatdifferentspeedsrelativetothesun,relative tothecenteroftheMilkyWay,orrelativetothenextclusterofgalaxies. Similarly,youcanonlymeasurethespeedoflightrelativetoanobserver. So,doesthespeedoflightanobservermeasuresdependonwherethelightcame from?Thenweshouldmeasureaslightlydifferentspeedoflightforeverylight rayweobserve.Also,thespeedoflightonJupiterwouldbedifferentthanon Earthanddependinwhichdirectionyoumove.TheMichelson-Morley experimentshowsthisnottobetrue.Thespeedoflightseemstobeconstant whereveryoumeasureitandwhateverlightraysyouusetomeasureitfromx. Einsteinthendrewthedaringbutlogicalconclusion:Ifthespeedoflightis constant,whereverImeasureit,maybesomethingelseischanging,namelytime andspace.Whatyouactuallysee,whenyoumovefasterandfastertowardsa lightbeam,isthatlightwaveslookcompressedor,equivalently,thatthelight wavesseemstobeoscillatingfaster.Thissimplymeansthatyouhaveashorter wavelengthorahigherfrequency,i.e.thelightwillchangecolor.Italsocanbe understoodaschangingtimeandspace,dependingonhowfasttwoobservers travelrelativetoeachother.Howeverirrespectiveofhowfastyougo,thelight beamwillstillmovewiththespeedoflightrelativetoyou!Thisbecamethebasis forEinstein’stheoryorrelativity,whichhaspassedallexperimentaltestsofvery differentnature–literallywithflyingcolors. Consequently,implementingachangingspeedoflightwouldaffectallphysical models:thermodynamics,electromagnetismandlightpropagation,quantum physicsandthetheoryofrelativity.Thecombinationofthesetheoriesiswhat ourmoderntechnologicalworldisbasedon.Youcannotsimplywaveyourarms andspeculateaboutthespeedoflightchanging,youwouldfundamentally changeallofphysicsandtechnologytoday. 3.2.2 Measuringthespeedoflightinthelaboratory Still,evenifweweretosucceedtoderiveatheorythatallowsmajorchangesof thespeedoflight,whatdotheexperimentstellus?Thespeedoflightitselfis huge,roughly300,000km/second,butyoucangetaroughmeasurementofthis speedbydoingasimpleexperimentathomeusingamicrowaveandeggs. Remember,thatthespeedoflightisthesameforallformsofelectromagnetic radiation,beitradiowaves,lightrays,orgammarays. Itisalsoimportanttorememberthatthespeedoflightrelatesthefrequencyof lighttothewavelengthoflightwavesxi-essentiallyhowfastthewavetravelsin oneoscillationperiod.Wouldthespeedoflightchangewithtime,also frequencies(i.e.colors)andwavelengthsoflightwouldkeepchangingwithtime. Forexamplelasersareproducedinresonancecavities,wherelightgoesback andforth,withasizetunedtomultiplesofthedesiredwavelength.Witha changingspeedoflightyouwouldconstantlyhavetoretuneyourlasers,usedin somanydevicesthesedays.Youwouldhavealsohavetoretuneyourclocks constantly,asweusefrequenciestomeasuretime.Infact,theveryInternetyou 16 AgeoftheuniverseH.Falcke areusingtoreadorobtainthispiecewouldloosesynchronization,sinceitrelies onperfectlysynchronizedlightbeamsinglassfibers.Also,yourGPSinyourcar wouldleadyouastraywhenchangingthenspeedoflightjustalittlebit,asit comparesthearrivaltimesofradiowavesemittedfromdifferentsatellites. Measuringthespeedoflightissoaccuratethesedays,thatonedefinesitasa fixedGoldStandardfromwhichonecanderivemanyotherunits,likethelength ofameter(Evenson&Petersen1976). So,todayformallylabsdonotevenmeasurethespeedoflightanymore.They wouldmeasuretime,wavelength,orfrequency.However,giventhatwavelength, frequencyandspeedoflightaredirectlyrelatedtoeachother,onecanusethese experimentstoseeifanythingischangingwithtimeatall. Speciallabscanmeasurefrequenciesaccuratelyto16digitstoday(Kolachevsky etal.2009)!Figure12showsmeasurementsmadeinthegroupofNobellaureate TheodorHänschofthefrequencyemittedbythesimplestatomthereis: hydrogen.Thatfrequencyismeasuredusinglaserstunedtoacertainwavelength anditstaysconstanttothe14thdigitoveracoupleofyears(0.000000000001%). Notethatyouwouldneedtochangethespeedoflightby0.25%everyyearin ordertoslowitdownbyfactorof2.3Millionover6000yearstoexplainasizeof 14billionlightyears.Wouldthespeedoflightchangetoday,itwouldhavebeen easilyseeninsuchprecisionexperiments. Figure12:Laser-basedfrequencymeasurementsofthe1S–2STransitioninAtomicHydrogenasa functionoftimearefoundtobestabletoroughlythe14thdigit(Kolachevskyetal.2009) So,toinvokeachangeofthespeedoflighttosavetheideaofayounguniverse, youwouldhavetoposethatitwaschangingalmostsuddenlyinthepast,butnot atalltodaywithinextremelysmalllimits.Theproblemwiththatideais, however,thatwecanstillseebackintimelookingatauniverseinayounger stateandmeasurephysicalprocessesthere.AsIexplaininthefollowing,what 17 AgeoftheuniverseH.Falcke wefindisthatalsobackthenthespeedoflightwasnotmuchdifferentfrom whatitistoday. 3.2.3 Speedoflightatdifferentdistancesandagesoftheuniverse Figure13showsimagesoftheremarkablenovaoutburstofthestarV838Mon. Thestarisatadistanceof20,000lightyearsandin2002suddenlycreateda brightburstoflight.Thelighttravelledradiallyoutwardswiththespeedoflight duringthatepochoftheuniverse.Itilluminatedsurroundingdust,whichlitup andbecamevisibletoo.Thisiswhatyouseeinthepicturesanditiscalledalight echo.TheimagesoftheHubbleSpaceTelescopeactuallyshowhowthelight fromthecentralstartravelsoutwards.Havinganindependentestimateofthe distancetothisstar,wecannowmeasurethegrowthofthe“lightbubble”and hencedirectlydeterminethespeedoflightbackthenxii.Theconclusionisthatfor something20,000lightyearsaway,thespeedoflightcannothavechangedmuch morethan25%–byfarnotenoughtoreconcilethatsourcewithanageof6000 years.Similarlightechoeswereclaimedforsupernova1987AintheLarge MagellanicCloud,some160,000lightyearsaway(Sugermanetal.2005). Figure13:LightreflectedfromdustsurroundingthevariablestarV838Mon.Astimegoesby,the lightfromabrightnovaoutburstincenterreacheslargerandlargerradiiilluminatingmoreand moreofthesurroundingdustshells.Theconclusionisthatpropagationoftthelighthasnotchanged enormouslyoverthepast20,000years.(Sparksetal.2008) However,wecangoevenfurtherandlookforexampleatthespectraofvery distantgalaxiesbillionsoflightyearsawayanddosimilarkindsofmeasurements asinthelaboratorymeasurementsmentionedabove.Scientistsdothese observationssincetheyactuallywanttotestwhetherfundamentalconstantsare indeedconstantasafunctionoftime.Itturnsoutthatevenatthesedistancesthe frequenciesandwavelengthemittedbyatomsareexactlythesameaswhatwe observetoday,whentakingtheexpandinguniverseintoaccount(Uzan2002, Kolachevskyetal.2009).Theseexperimentsaredesignedtomeasurethefinestructureconstant,buttheyalsodependcruciallyonthevalueofthespeedof light(aswellastheelementarychargeandthePlanckconstant). 18 AgeoftheuniverseH.Falcke 3.2.4 Summaryofthechangingspeedoflightidea Insummary,thereisnoevidencetodaythatthespeedoflightischangingorwas changing.Evencreationistsdonotseemtoinvokethisexplanationanymore(see here,olderclaimswerejuststatisticalflukes).Ofcourse,physicsisneverentirely finished,soitispossiblethatatsomepointonedoesfindtinychangesinthe speedoflightandinfactvaryingspeedoflighttheoriesdoexistoutsidethe standardmodelofphysics.Findingsuchavariationwouldbeanawesome discovery,worthyofaNobelPrize,but,giventhelimitswehavetoday,theeffect couldneverbesolargetomaketheuniversesignificantlyyoungerthanit appearstoday. Remembertomakethistheorywork,youwouldhavetoclaimthatthespeedof lightwasconstantduringthepastcenturies,butatleast2.3Milliontimesfaster intheprevious6000years!Thisislikehavingasnailsuddenlyrunataspeedof 25.000km/hr–evenfasterthanthefastestunmannedrocketeverfired(see hereforadiscussionofthespeedofsnails!).Thisisnottheuniverseweseeout there. 3.3 3.3.1 DoestimegofasteroutsideEarth? Timedilation WhileroamingtheInternetIcameacrossanothersuggestion,raisedina creationistwebsitetoexplainthe“distantstarlightproblem”(asitisproperly acknowledged).Maybetimeintherestoftheuniversegoesmuchfaster,thanon EarthandhencewhattookaweekhereonEarthtookbillionsofyearsoutthere? Theargumentinvolvessomeformofgravitationalredshift,centeredonEarth. Andindeed,clocksonEarthgo37microsecondsperdayslowerthaninspace whereGPSsatellitesorbittheEarth.Thistimedilationisactuallypredictedin Einstein’stheoryofrelativityandaccountedforintheGPSnavigationsystemwe alluse.However,tomakegravitationaltimedilationsoextremethattimewould gomillionsoftimesfasteroutsideofEarth,wouldrequireextremecurvaturesof space.Onlyintheveryvicinityofblackholesorneutronstars–extremelydense concentrationsofmatter–wouldoneexpectsuchanenormousslow-downof time.However,thoseobjectalsocomewithanextremegravitationalattraction thatwouldcrushanylifeonEarthintoextremelythinpancakes. 3.3.2 Observingtime-dependentprocessesintheuniverse Thesearetheoreticalarguments.Ifindoubt,wecouldstillmeasurehowfast “clocks”ranintheearlyuniverse,bylookingbackintime,i.e.atlargedistances. Thatprincipleoflookingbackintimestillappliesevenforayounguniverse. Interestingly,weactuallydoseephysicalprocessesevolveatlargedistancesin theuniverseonhumantimescales,whichwecanuseasroughclocks.For example,explosionslikesupernovae(Figure14)orGammaRayBurstshappen withinseconds,buttheirexplosionshellsdevelopoverdays,weeksandmonths andwecanseethemdirectlyorindirectlyexpand.Thereisnoevidencethattime speedsuporslowsdownwithdistance.Wedonotseethattheseexplosions suddenlyrunamilliontimesfaster,whenlookingattheearlyuniverse. 19 AgeoftheuniverseH.Falcke Figure14:RadioimagesofasupernovaexplosionseeninthestarforminggalaxyM82atadistance of12Millionlightyears.Asupernovaisashockwavegeneratedbymatterejectedfromanexploding star(notalightechoasinFigure13).Thetwoinletsatthebottomrightshowhowtheexplosion rapidlyexpandedwithinayear.Theexpansionspeedof12,000km/secisnotuntypicalfor explosionsofthiskind.(fromhere,seeBrunthaleretal2010,Kimanietal.2016). Thereis,however,aneffectpredictedbyEinstein’stheoryofrelativitythatlight isstretchedandtimeissloweddownastheuniverseexpands.Thismakes processesatlargedistancesappearslowerthannearbybyafactorofafewfor sourcesthatareafewbillionsoflightyearsaway.Thisisnormallycorrectedfor instandardcosmologyandnotdiscussedmuch,asitisessentiallytakenfor grantedinthiskindofresearch. However,someastronomershaveexplicitlylookedattheevolutionoflight comingfromtheseexplosions–essentiallytryingtoseeifstellarexplosionslast longerwhenbeingfurtheraway(Blondinetal.2008forsupernovaeoftypeIaor Zhangetal.2013forGRBs).Whilethestatisticalevidencemaybeweak(e.g., Littlejohns&Butler2014)tosupportseeingtheexpectedtimedilationfactor(of orderofafew)inthisdata,thisclearlyrulesoutanymodelwheretimewould suddenlyspeedupbyfactorsofmillions! Hence,thedistantandolduniverseweseeevolveinfrontofoureyesisshowing processesevolveatanormalpace.Itisnotspeedingupbyanysignificantfactor thatcouldmaketheuniverseevolveinafewthousandyears. 3.4 Waituntilsciencecomestonewconclusions? Maybethewiseapproachistojustwaituntilsciencecomestoadifferent conclusion?Havenotscientificfindingschangedwithtime?Scienceinhundred yearswillforsurelookverydifferent.Thescienceofnutritionadvicesalso changeseveryyear:awhileagomorethanoneeggperdaywasconsidered almostdeadly(atleastinmyrecollection)andnowsuddenlytheyaresaveto eat.Werenotourgrandparentssmarterthansomeofthesescientists?Whycan onenotassumethatthequestionoftheageoftheuniversewillbeanswered quitedifferentlyinacoupleofyears? 20 AgeoftheuniverseH.Falcke Infact,Iwasonceaskedatayoung-vs-olduniverseconference,whatthechance wouldbeforthistohappen.Iansweredthatthechanceforsciencetoevershow thattheuniverseisonly6000yearsold,isstrictlyzero(andnotjustasmall number).Bymypersonalstandardsthiswas,infact,aratherunusuallybold statement,butIdidnotwanttonotraiseanyfalsehopes.Naturallyhalfthe audiencelaughedatme.HowcanIsaythis,ifIhaveactuallysaidinaprevious articlemyselfthatscienceiswrongmostofthetime? Firstofall,thereisacertaindifferencebetweenthescienceofnutritionadvices (whereIadmittosometimeshavemyownseriousdoubtsonhowcrediblethey are)andthatofphysicsandastrophysics.Starsintheuniversedonottalkback, theydonotchangetheirmind,theydonotletthemselvesbeinfluencedby media,fashion,orresearchersandthereisnobigindustrymakingmoneywith themoutsidescienceitselfxiii. Secondly,sciencetendstobecommonlywrongwhenresearchisconductedat theforefrontofourknowledge.Itisacontinuousplayofclaimsand counterclaims,tests,aswellascollisionsofegosandsometimeshypes.However, inthewakeofthesediscussionsabodyofresearchbuildsupthatrarely collapsesentirely–atleastnotinphysics! Yes,itistrue,physicalknowledgetendstogetexpanded,modified,butitisnot reversed.Newtonianphysicsfromcenturiesago,thatweallstilllearninschool, isstillperfectlycorrectundernormalconditionsanddescribesmostofourdaily liveswell,despitethefactthatEinsteinchangedourviewofspaceandtime fundamentally. Thereasonisquitesimple:Modelsinphysicsarenotanopinionthatcanchange, butrathertheyareatheoreticaldescriptionofreality.Assuch,amodelmaybe anapproximationandasimplification,butithastodescriberealityadequately withintheerrors.Asalongasrealityisreliablealsothosemodelswillcontinueto dotheirjobwellforthesituationstheywerecreated.Sometimesrealitybecomes morecomplicated,butthenthemodelsneedtotakeextrafactorsintoaccount andanewmodelneedstobecreated. Hence,ifyouwanttowaitforsciencetochangeyouhavetothinkcarefullywhat youareexpectingtochangeintheargumentsgivenabove?Mostfundamentalto allofthisisthesizeofthesolarsystem.Doesanyoneseriouslybelievethatthis sizewillchange,despitethefactthatwearetravellingwithspacecraftthrough it?WoulditbesmarttothinkColumbusandothersxivwerewrongandscience willeventuallydiscoverthattheworldisflatafterall?Wouldanyoneexpectthat sciencewillchangeandwediscoverthatthedistancebetweenEuropeand Americashrinkstoasizeofafewhundredmetersonly? Doesthelatterquestionsoundbizarre?Itshouldsoundbizarre,becauseaneven moreextremeshrinkingofoursolarsystemwouldbeneededinordertomake theparallaxdistanceschangesuchthattheuniversecanfitwithin6000light years.Whatisthechanceforthistohappen? Therestofthedistancemeasurementismeasuringanglesandconvertingthis intodistances.ThemathforthishasnotchangedsincethetimesofPythagoras andtheparallaxangleshavebeenmeasuredoverandoveragainbydifferent 21 AgeoftheuniverseH.Falcke groupsfordifferentsources.Thesemeasurementswillnotchange.These distanceswillnotchangesignificantlyeitherxv. Thesamereasoningisvalidforthespeedoflightandtheevolutionoftime.Iam veryhopefulwewilleventuallyfindsomethinginterestingthateventuallytakes usbeyondthetheoryofEinstein.Maybewewillevenfindsometinychangeof thespeedoflightoranextraeffectthatmakestimegoslightlynon-linear. However,themagnitudeofthiseffectcannotbethatenormoustochangetheage ortheuniversefrom14billionto6000years.Ifso,wewouldhaveseenit alreadyeasily. Thisallisnotsurprising.Afterall,anynewtheorywillhavetostilldescribe realityweliveinasNewtonandEinsteindescribeitrightnow.Abetter understandingofaerodynamicswillneverchangethefactthatairplanescanfly rightnow.Similarly,abettermodelofspaceandtimewillnotchangethefactthe GPSworksrightnow–asystemwhichweexperiencetoworkinourdailylives andwhichcruciallydependsonmainstreamphysicstogetdistances,thespeed oflightandtimemeasuredhereonEarthandinspaceveryprecisely. Thehopethatsciencemaychangeandreverseinthisparticularmatteris completelyunfounded.Ifyouarestrandedonasmallislandinabigocean,you shouldnothopethatEarthwillshrinkeventuallyandyoucanswimhome,but ratheraccepttherealityandlearntobuildasolidship. 4 DidGodmaketheuniverselookoldandlarge? ThefinalquestionIdogetonceinawhileiswhyGodcouldnothavemadethe universeinaninstanceaslargeasitis6000yearsago?Thisquestionsounds utterlycrazytosomeofmycolleagues,butisofgraveconcerntothosewhoask it. Inthemiddleagesthisquestionoccasionallyaroseinthequestionofwhether Adam,asafirsthumanbeing,couldbedepictedashavinganavel,leadinginthe 19thcenturytosomethingliketheinfamousOmphalos(greek:navel)hypothesis, whichclaimedthattheuniversewascreatedyoung,butpurposelymadelookold tomisleadus–infact,ifyouextendthatidea,theuniversecouldhaveformeda weekago. Letmefirstdefendthequestionbriefly,beforeItrytoanswerit.Infact,Iamnot surethisquestionitselfismoreexoticthansomeotherhypothesesthatarebeing discussedtodayinscience.Afterall,thereareserousarticlesinthescientific literature(e.g.,Beaneetal.2002),whichdiscussthepossibilitywhetherour universeisnotreal,butisnothingbutabigcomputersimulationcreatedbya muchmoreadvancedaliencivilization.Theseideasonegetswhenmovies replacetraditionalcreationstoriesxvi,butthisisstillnotareasontonotdiscuss them.Notsurprisingly,inaworldwherevirtualrealitiesmoreandmorereplace actualrealties,themereconceptofrealityisbeingquestioned. 4.1 Defendingthequestion Hence,theunderlyingquestionis,whetherrealityandhistoryareanillusionand perhapsmisleading.Thisisindeedquiteanimportantissueandscientificallywe simplycannotanswerit.Ifwewerecreatedasplitsecondagowithallthe 22 AgeoftheuniverseH.Falcke memoriesimplementedinourmindsandhistoryfrozenintothisworld,then howcouldwetellyesterdayexisted? “Yesterday”isaveryabstractconcept.Itonlyexistsasthememoryandthecause ofwhatisrightnow.Theonlyreasonwhywebelieveyesterdayexistedis, becauseourexperienceshowstimeasalinearprogressionofthingsthatseemto causeeachother.However,whatifthe“experience”couldnotbetrustedeither? Moreover,humanexperiencesuggeststhatsometimesthings“happenoutofthe blue”.Inthepastthiswasattributedtothewillofthegods.Todaysomemay argue,thisissimplybecausewedonotalwayshavealltheinformationreadily availabletotelluswhatactuallycausedit.Theclaimisthatwecouldknowthe futureinprinciple,ifwewouldknowallparametersexactlynow. However,thatisscientificallynottenablefortworeasons.Firstly,onecanshow that–asamatterofprinciple–wecanneverknowtheentirestateoftheentire universe,sincethenalsothedevicemeasuringthesestateswouldneedtoknow itsownstateaccuratelyandwouldneedtobelargerthantheuniverseitself. Secondly,chanceandchaosispartoftoday’sphysics.Inprocesseslike radioactivedecayofindividualnuclei,quantumstatetransitionsofsingle systems,orevenanentirebigbang“justhappen”–insometheories–“simply becausethereisacertainstatisticalprobability.Foranyparticularinstance, however,itisimpossibletoidentifyaconcretecause,whytheeventhappened rightnowandrighthere.Inthesecases,wemerelyhavereplaced“thegods”with “chance”and“probability”–theonlydifferencebeing,thatsomesenseof “purpose”and“reason”wasattributedtotheformer,whilenoneofthatis thoughttoexistforthelatter.Claiminganyabsenceofpurposeisaworldview andanassumption. Ofcourse,inaworldgovernedbychanceandprobability,itmayperhapssound absurdtoconsideramaturelycreateduniverseareasonableoptiontoconsider. Afterall,whatisthechancethatamatureandself-consistentuniversesuddenly springsintoexistenceatsomepoint?Theprobabilityisinsanelylow.However,is itmuchlowerthanauniversethatevolvedtoitspresentstateoutofasinglebig bangwiththehelpofafewlawsofnatureandasetofabout26naturalconstants convenientlysettotherightvalues? Thisquestionisrelatedtothefamous“fine-tuning”debatethathasledmanyof mycolleaguestoembracetheideathataplethoraofparallel(andmainlyfailed) universesexist–theso-calledmultiverseidea.Iamaverybadstatistician,but mygutfeelingisthatitmaynotbepossibletogiveascientificallysoundanswer, whetheranyoneofthesescenariosisreallymorelikelythananyother.We simplydonotknowallpriorassumptionsonehastomakeaboutphysics,space, andtimebefore,after,andaroundthisuniverseinordertoaddressthisquestion quantitativelyandscientificallyaccurate(e.g.,seearticlebymyRadboud colleagueandmathematicianK.Landsmanwhoclaimsthatasingleuniverseis statisticallynotlesslikelythanamultiverse).Hence,believinganimmeasurable multiverseistheanswertoallquestionsmaybeasgoodorbadscienceas believinginthecreationofamatureuniversebyanintelligentdesigneror believinginasingleuniversethat“magically”evolvedoutofnothing. 23 AgeoftheuniverseH.Falcke Consequently,Ithinkthatthequestionwhethertheuniversewascreated recently,butonlylooksmatureisinprincipleavalidquestiontoaskandinfact touchesonveryfundamentalissues.However,answeringthequestionisnot possiblewithouttakingintoaccountthebeliefsystemofthosewhoareaskingit. Scientistssimplyassumethattheuniverseis“reasonable”anddevelops accordingtocauseandconsequences.Thisisthebasicaxiomofscienceandin myexperiencethisisaverygoodassumptionfortheuniverseasawhole. Admittedly,theexistenceofcauseandconsequencesisanassumptionandit evenbreaksdownwhenlookingatindividualquantumsystemsasdiscussed above.Similarly,thisprinciplemayalsobreakdownwhenponderingthefateof anindividual. Dootherassumptionsleadtodifferentconclusions?Doesreligionchangethis argument?Inthefollowing,IwilldiscussthisfromadistinctlyChristian perspective.Afterall,Christianityisnotonlystillthelargestreligioninthe world,butitisalsotheone,whichdominatedthecultureswithinwhichmodern scienceemergedand,ofcourse,theoneIpersonallyidentifywithandtrustin. 4.2 ThereliabilityofGod So,couldGodnothavecreatedtheworld6000yearsagoandjustmadeitlook likeitwasveryold?Personally,Ibelievehecouldhave,hadhewantedto,but doesthatideafitthetraditionalChristianviewofthecharacterofGod? Inessence,myviewisthatproclaimingaGodwhocreatesauniversethatlooks old,butthatisactuallyyoung,wouldbethinkingofGodasamagicianwhotries tofoolus.Thiswouldmaketheworldanditshistoryappearlikeatheaterplay, whichisnotreal,butonlyshow.Evenworse,forobjectsliketheexplodingstar inFigure14,wewouldhavetosaythathehadtoimprinttheexplosionintothe lightthatwasalreadyunderwayandthestaractuallyneverexploded.Afterall, 6000yearsago,whentheyounguniversewassupposedlycreated,thelightwe nowseefromthisexplosionwasalreadyMillionsoflightyearsawayfromits homegalaxy.Yetthelightshowsanobjectevolve.ThatwouldbetrulyaMaster deceptionandindeednotbemuchdifferentfromacomputersimulationthatis suddenlyswitchedonwithanalreadyfullyevolveduniverse,thatiscompletely notreal. Foranybelieverthisshouldposeaseriousmoralproblem.Isnottruthan overarchingthemeofbiblicalrevelation?Whatrevelationcanyoustillbelievein, ifGodissopurposelytryingtodeceiveourperceptionoftherealworld?What aspectofrealitycouldstillbetrusted?SuchaGodwouldbeinstarkcontrast withtheGodthathumanshaveexperiencedinthepast,whomtheyreadaboutin theBible,andwhomtheybelievetorevealHimselfreliablythroughhistory. Thathistory,isnotonlyhumanhistory,butisintimatelylinkedtothehistoryof theentireuniverse.InthebiblicalbookofGenesis,thecreationofhumansis clearlypartofthatglobalhistoryoftheemergenceofourworld.Itseemsvery difficulttoclaimareliablerevelationofGodthroughhumanhistory,butatthe sametimedoubtingtherevelationoftheage-oldcreationoftheuniverse throughtheverysamehistoryoftheworld. 24 AgeoftheuniverseH.Falcke Formillennia,theknowledgeavailabletohumankindwaslimited.Thequestion oftheageoftheworldwasaveryabstractandanacademicone–initiallyonly debatableamongtheologians,forlackofanyotherevidence.Inthepastone coulddiscussforageswhetherornotAdamhadanavel–therewasnowayto saywhowasrightxvii.Thesetimeshavechanged:atleastnowwecanreliably investigate,whethertheEarthhadanavelornot. FundamentaltotheJewish-ChristianbelieveisthebeliefinonealmightyGod, whoisthesinglecreatorandoriginofeverything.Aparticularimportantaspect stressedoverandoveragainisthatHetranscendstime,isreliable,truthful, faithfulandunchanging.ThisisnicelyexpressedinthePsalms,songsoftheOld Testament,whereitsays:“Beforethemountainswerebornoryoubroughtforth thewholeworld,fromeverlastingtoeverlastingyouareGod.”(Psalm90:2),orin anotherpassage:“Theywillperish,butyouremain;theywillallwearoutlikea garment.Likeclothingyouwillchangethemandtheywillbediscarded.Butyou remainthesame,andyouryearswillneverend.”(Psalm102:26-27). ThisreliabilityexpressedintheBibleisnotonlyaquestionofthespiritual reliabilityofGod,butiswitnessedandexperiencedinareliabilityofnatureitself. Asdiscussedlater(Sec.4.5),thisphysicalreliabilityisalsoaprerequisitefor humanstobeabletofunctionasindependentandspirituallyaccountablebeings. QuestioningitwouldbeaslipperypathforanyChristiantheology. Ontheotherhand,theconceptofabsoluteand100%reliabilityisratherforeign tohumans.Weareusedtolies,tricks,andalternativetruths.Emperorsandrules areknowntochangethetruthandtheirlawstowhateversuitstheirneeds. However,theGodoftheBibleisnot! Evendivinemercyisnotarbitrary,butcomeswithconsequences.Christianityis forcedtolookatthedyingandresurrectedJesusinordertounderstandand experiencereconciliationwiththecreator.Simplychangingtherulesof engagementtosuitourshortcomingsisnotapartoftheequationoftheGodof theBible.Thereisapricetobepaidforsinandevil–evenifGodistheonewho paysintheend.Causeandconsequencesarestrictlyupheldalsointhisspiritual domainofChristianbelief. WhenJesustalksabouttheunchangingdivinelaws,statingthat“Tillheavenand earthpass,onejotoronetittleshallinnowisepassfromthelaw,tillallbefulfilled” (Matthew5:17-20),isthatonlymeantforspirituallaws?Doesthatnotalsoapply totheentireorderthiscreationissubjectedto?Whatwortharethesespiritual lawsifGodchangesthelawsoftheworldwithinwhichhumanshavetooperate atwillandorderdoesnotreallyexist?IfHewillnotchangespirituallawsthat humansshalladhereto,whyshouldHefiddlewiththenaturallawsthatrocks needtoadhere?Afterall,thelawsofnaturearethefoundationuponwhichour dailylifeoperates. Consequently,thefirstChristianthinkersliketheapostlePaul,wereconvinced thatthepropertiesofGodarealsoreflectedinHiscreation.Inhislettertothe RomansPaulwrites“ForsincethecreationoftheworldGod’sinvisiblequalities— hiseternalpoweranddivinenature—havebeenclearlyseen,beingunderstood fromwhathasbeenmade,sothatpeoplearewithoutexcuse.”(Romans1:20) 25 AgeoftheuniverseH.Falcke Paulthinksthat“God’squalities…havebeenseenfromwhathasbeenmade”.The latterreferstothingsthatGodmade,i.e.Hiscreation.So,wecanunderstand naturewithourmindandtherebywewilllearnsomethingaboutGod.IfGod’s divinenatureincludesbeingreliable,faithfulandtruthful,Hiscreationshall reflectthataswell–andviceversa. Statingthattheuniversedisguisesitselfassomethingthatitisnot,i.e.is unreliableanddeceiving,thenalsoimpliesthatGodhimselfisnottobetrusted. Afterall,theonlyobviouspurposeofalargeuniverseofbillionsoflightyearsin size,whichwascreatedassuchyoung,wouldthenbetopurposelymisleadus. Rightnowwedonot“need”thelargeuniverseoutsideoursolarsystemanymore forourexistence.Godcouldhavecreatedamuchsmalleruniverse–justafew thousandslightyearsinsizetobeconsistentwithayounguniverse,butHechose otherwiseandwefindauniverseclearlyexhibitingoldages. ItisforthatreasonthatIwouldconsideracreationmodelthatinvolvesa universethatbearsfalsewitnessofitsoriginisinherentlyincompatiblewith basicChristianprinciplesxviii,whichspeakofareliablecreator. 4.3 Miracles&mystery However,istheBiblenotfullofmiraclesandmysteries?Whymakesuchafuss aboutanorderlyuniverse?MaybeGodisabsolutelytrustworthyinmattersof salvation,butdoesnotcareverymuchaboutthereliabilityofourscientific projects? Indeed,mysteryisafactoflife.Itisabsolutelymysterious,whytheopponents scorethedecisivegoalinthelastminuteofovertimeinafootballmatchandnot yourownteam.Itismysteriouswhyyouhavemetthatspecialoneyouloveat therighttimeintherightspace,orwhynot.PassagesintheBibleremain mysterious.Evenourcomputerssometimesseemtobehaveinmysteriousways. Humanknowledgeislimited,sometimesfundamentally. Asdiscussedbefore,itisalsoprudenttoremainskepticalabouteveryindividual newscientificresult,buttoquestionfundamentallytheentirebodyofscientific evidencewouldalsoquestionourabilitytomakeanyobservationsatall. Scientificinstrumentsareonlyextensionsofournormalabilitiestoassessthe worldwithoursensesandourminds.Questioningscienceingeneralwould questionourabilitytoassessrealityingeneralanditwouldalsoquestionour abilitytomakesenseofanyspiritualrevelation.Eventhemostdramaticspiritual experiencesintheBiblehappeninandthroughthephysicalworld.Itappearsto meverydifficulttomaintainananti-realisticstanceasaChristian,butstill believeinaGod,whorevealsHimselfintherealworldthroughhistory.Insucha picturelifewouldbemorelikeadream–orperhapsacomputersimulation,for thatmatter. Miraclesareanotherissue.Icoulddiscussthematlengthhere.Ilovemiracles, butIwilllimitmyselftothequestion,whytheyarenotrelevanttothediscussion oftheageoftheuniverse.Miraclesareeventswheresuddenlythefateofpeople changed–usuallyforthebetter–inacompletelyunexpectedmanner.No explanationisgivenintheBibleastohowexactlythingshappenedotherthanit 26 AgeoftheuniverseH.Falcke wascompletelymiraculoustothosewhowitnessedit.Thestoriesarewrittenas sucheyewitnessaccountsandnotaslogbooksoflaboratoryexperiments. Todaywehavenowaytoscientificallyinvestigatehowthewinegotintothe amphoraeattheweddinginCana,whenJesussenttheservantsouttofillthem withwater(John2:1-10).WedonotknowwhatexactlyJesuswaswalkingon, whenhisdisciplessawhimontheseaofGalileelateatnight(Matthew14:22– 34),andwehavenoideahowexactlytheservantofaRomancenturionwas healed(Matthew8:5-13).TheBibledescribessoberandconciselywhatwas observed,butdoesnotexplainhowthingshappenedindetail.Amiracleis primarilyalifechangingexperienceanditdoesnotevenhavetobesupernatural tobeperceivedasamiracle.Itmay,itmaynot.Itisimportantthattheright thingshappenattherighttime.Innowayisthereawaywecanprove–oneway ortheother–thataparticularnaturallawwasviolatedornotthroughthese stories.Miraclesaresignsofhopeinsituationswhereallhopeislostandnot elementsofanyscientifictheory. Incontrasttogeneralperceptionsalsointhebiblicalmiraclesarestillthevery rareexceptionratherthantherule.EvenJesuswaswalkingonaplainandsimple roadmostofthetimeandnotonwater.Hence,youcannotturnthisaroundand suddenlypostulatesupernaturalmiraclesatwillandmakethemtherulerather thantheexceptionforthehistoryofouruniverse.Togeneratethevisible universein6000years,Godwouldhavetobreak,suspendormodifyalmost everynaturallawthereisinamannerthatiscompletelyunpredictableand untraceable.Thiswouldnotbea“miracle”asanexception,butrather arbitrarinessasthedefaultmodeofoperation.Preachingsuchacreation “history”doesnotproclaimtheorderlyGodproclaimedintheBible. 4.4 Howscienceandworldviewareintertwined Thepointabout,theequivalencebetweenthereliabilityofGodandnaturecan evenbemadestronger.Iwouldgosofartohypothesize,thattheproclamationof areliableGod,whichinturnimpliesareliablecreation,wasevenanecessary pre-requisiteforsciencetofunctioninthefirstplaceandtomakeitassuccessful asitistoday. Humanrulerscanchangerulesastheylike,childrenliketochangeruleswhile theyplay(andthengetintotroublewitheachother),butGoddoesnotand hencenaturedoesnot.Ifthelawsofnaturewouldchangeonsuchaday-to-day basis,physicallawswouldbecomemeaninglessandnoreliablemachinecouldbe built.Ifwecannottrustthatthelawsofaerodynamicsarevalidtodayinthe samewaytheyworkedyesterday,wewouldsolelyhavetorelyonmiracles–or actuallyluck–forairplanestofly.Ipredict,eventhemostfaithfulamongus wouldneverstepintosuchanairplaneunlesstheyhadnootherchoice. Thissoundsalmosttrivial,butthestabilityofnatureisaveryfundamentalpoint. Wetakethisstabilityforgranted.However,thismaybeaculturalselection effect.Probably,thebiggestintellectualrevolutiontheJewishfaithhadbrought aboutwastoreplacealltheindividualgodswithasingle,almightycreator,i.e.,a singleunchangingcauseandmaintainerofthisuniverse, Hadsomeonegrownupinananimisticreligion,filledwithghostsandspirits, thathaveawilloftheirown,searchingforlawsofnaturewouldnotmakemuch 27 AgeoftheuniverseH.Falcke sense.Forexample,Chineseastronomywasformanycenturieswayaheadof astronomyintheWest,butacomparablepictureofasingleGodastheoriginof everythingdidnotexist;neitherwastheretheexpectationofnaturallaws.The universeitselfwasacomplexevolvingthingfilledwithgodsandspirits:“Chinese spiritsandgodsneednotbeseenasall-powerful,transcendent,orcreatorsofthe world.Theyareintimatelyinvolvedintheaffairsoftheworld…Asthespirits associatedwithobjectslikestars,mountains,andstreams,theyexerciseadirect influenceonthingsinthisworld,makingphenomenaappearandcausingthingsto extendthemselves”(“TheSpiritsofChineseReligion,”byStephenF.Teiser, quotedhere). Similarly,didBabylonianandGreekastrologyassembleanimpressivebodyof dataonplanetarymotionandmethodstochartandpredictthem,butthisdata wasagainmainlyusedtopredictthewillofthegods. Askingwhatthelawsofnaturearewouldhavebeenratherpointlessinsucha culturalenvironment.Unsurprisinglyitdidnothappentheretotheextentit wouldhavebeennecessarytoderivethelawsofNewtonandKepler. Hence,Idonotbelieveforamomentthatthedevelopmentofmodernscience canbeseenwithoutthecultural,philosophicalandtheologicalbackgroundin whichitdeveloped.Ofcourse,thereareprobablymultiplefactorsneededto explaintheemergenceofscience–afterall,alsotheGreeks,Romans,andArabs laidimportantfoundations,butintheendsciencebrokethroughinaheavily Christianenvironment. Thebeliefinareliableandaccountablereality,whichconnectspastandfuture viathepresent,isafundamentalcornerstoneofscienceandoftheChristian faith–causeandconsequencesinanorderlycreation.Starsdonothaveawillof theirowninGenesis.Itisthereforealsoneitheramiraclenorcoincidencethat sciencedidflourishanddevelopintheChristianculture.Scienceandfaithare moreintertwinedthanwethink.Wecannotentirelyseparatethemfromeach otherorcompletelyignoreeitherofthem,whenwewanttomakesenseofthe worldaroundus. TousetheBibletodaytomarginalizeobviousscientificevidencewould thereforemeantoignorethousandyearsofChristianhistoryandrepeatthe errorsmadebyadefaultingChurchinthelateMiddleAges,desperatelyclinging foritspower. 4.5 Responsibility,accountability,andtheoriginalsin Interestingly,theissueofreliabilityaswellascauseandconsequencesrunseven deeperandhaseventheologicalimplications.Oneofthemostimportantbiblical storiesinthisrespectisthatofAdamofEve(Genesis2:4-3:24),whichintroduces theconceptofthe“originalsin”–thethoughtthathumanshavelosttheir intimateconnectiontotheircreatorfromtheirverybeginningandeversinceare doomedtomakewrongchoices. Interestingly,orthodoxChristianssometimesinvokethisAdamasaprincipal witnessagainstanolduniverse.Theargumentessentiallyis:ifGenesisisnot historical,thenAdamisnothistorical,thentherewasnooriginalsin,andthere wouldbenoneedforsalvationxix.Thiskindofthinkingmaybecompletely 28 AgeoftheuniverseH.Falcke foreignforanon-believer,forwhomsalvationisanabstractterm.However,the needforandtherealityofsalvationisconsideredself-evidentbythosewhohave experienceditpersonally.Forthem,theissuerunsverydeepandspiritual salvationofhumansisasrealasphysicalhealingisforthosewhohadonce brokenalegorrecoveredfromavirusinfection.Thathealingmusthavehada physicalcause,mustitnot?Hence,thosewhowerehealedandsavedmaytend towardsaversionofhistorythattakestheirparticularexperienceintoaccount. Asaresult,insomecommunitiesthereissuddenlyaconnectionbetweena scientificquestion,namely,theageandnatureoftheuniverseandaspiritual truth,namelypersonalsalvation.Inthiscase,scientificresultscansuddenly causeseriousdogmaticandpersonalpains–andviceversa. Itisthusworthtodiggingalittledeeperintothisissue.Iwouldadmitthatthere isindeedanintriguingbutsubtlelinkbetweenthespiritualandthenatural worldworthexploring.However,thatlinkisseriouslycompromised,when upholdingacreationaccount,whichbetraystheprincipleofcauseand consequences.Theimpliedworldviewwouldunderminetheveryprinciples expressedinthestoryofAdam&Eve. Afterall,areliablecreationandareliableGod,arealsothecornerstoneof humanaccountabilityandresponsibility.Itseemsobviousthatwithoutrules, thereisnowrongdoing,withoutorder,noconsequencescanbeforeseen,and withoutknowledgethereisnounderstandingofgoodorevil.Order,causeand consequences,andtheabilitytoknowandunderstandtheworldarecrucialfor science.Theyarealsocrucialforeveryhumantobeabletomakedecisionsand takeresponsibility.Questioningtheseveryprinciplesscienceisbuildon, however,alsoimplicitlyquestionssomefundamentalsofChristianbelief. ThekeymomentinGenesis2isthefamousscenewhereAdameatsthe forbiddenfruitfromthe“treeofknowledgeofgoodandevil”(Genesis2:9).Itis interestinginitselfthatthistreeisconnectedto“knowledge”.Theserpentthen goesontosay“ForGodknowsthatwhenyoueatfromityoureyeswillbeopened, andyouwillbelikeGod,knowinggoodandevil.”(Genesis3:5). Whatmakeshumansspecial,accordingtoGenesis,isthatwecanknow!Asa consequence,weareabletodistinguishgoodfrombadandtherebymirror propertiesofGod(ofcourse,withtheproblemthathumans–beinghumanand notgodly–areultimatelynotabletohandlethisknowledgeproperly).However, rarelydowerememberthatunderstandinggoodandevil–andbeing responsibleforit–onlyworksifyouhavethecapacitytoforeseeand understandtheconsequencesofyouractions. Letmegivetwoextremeexamples:Everydaysomewhereintheuniverseastar explodesinasupernova,likelydestroyinganentireplanetarysystem.Evenif someformoflifewerepresentinthissystem,nobodywouldblamethestar:it cannothelpitanditdoesnotknowwhatitisdoing.Unlikehumansthestarhas noknowledge. Similarly,ifwewouldpictureaworldwithoutorderlylawsofnatureyoucould dropsomeonefromahightowerandnotfeelguilty:afterall,maybethelawsof gravity,pullingthepoorfellowtothegroundandkillinghim,mightnothave 29 AgeoftheuniverseH.Falcke existedjustafewmomentsagoxx.Evenwithyourabilitytoacquireknowledge youwouldbeunabletoforeseeandunderstandtheoutcomeofyouractions. Inaworldwherecauseandconsequencesarearbitrary,noevilcanbe committedandinaworldwithoutknowledgenoevilcanbeunderstood.A universethatpretendstohavebeenevolvingandtohavecontinuallygrownin size,butinsteadwasmadeindiscreteunrelatedsteps,wouldbesuchaworld wherecauseandconsequencearenottobetrustedanymore.Suchauniverseis likeathiefwhowantstocoveruphisdeedsandfabricatesfalsecluestomislead thepolice. Animportantaspectofsuchareliableworldisthenotionthattheworldand circumstancescanchange,butthatthebasicrulesstaythesame.TheChristian conceptofsinandsalvationwouldberadicallydifferent,perhapsimpossible,if neitherGodnorHiscreationwouldbereliablythesameyesterdayandtodayand forever.(Hebr13:8).Indeed,theunchangingnatureofGodisadeep-rooted convictionexpressedintheBible. Hence,also–orperhapsespecially–inaworldview,wheretheneedfor salvationisderivedfromAdam&Eve,anorderlyhistoryisneeded.TheGarden ofEden–theworldthefirsthumansweredescribedtolivein–alreadyhadto havebeenbeareliableworldinorderforthosehumanstomakeinformed choices,basedontheirnewlyacquiredknowledge.Causeandconsequence neededtoexistalreadyatthispoint.Theywerenaturallybuiltintotheentire creationxxi. Ontheotherhand,ifcauseandconsequencedidnotplayaroleinthehistoryof creation,whyshouldthenatureofAdamhaveanyconsequenceatall?Afterall, thestoryofAdamisjustaplayinthetheaterofcreationwherethedecóris changedunpredictably?Howcanoneclaimthateventsinthepastrequire forgivenessandsalvation,ifoneessentiallyclaimsthatthepastcannotbe trusted? Postulatingthatrulesofnaturearemisleading,unreliable,arbitrary,orchanging, impliesthathistoryitselfisunreliable.Hence,whilea6000yearolduniverseis occasionallyadvocatedbysomeinordertosavethehistoricityoftheBibleand toreinforcedoctrineslikethe“originalsin”,theyactuallydestroythevery foundationofit.Clearlysaid:usingthehistoricitydescribedintheBible,asan argumenttoquestionthehistoricityofnaturedoesnotmakemuchsense, becauseitquestionsallhistoricity,includingthatoftheBible. 4.6 Creationistscience Havingsaidthat,Idonotquestiontheintegrityofthosewhostilldefendayoung Earthcreation.Manyofthemhavegoodintentionsandcaredeeplyabouttheir faith. Someofthemsimplydonotcareasmuchaboutscience,asIdo.Somemaynot havetheknowledgeortheinclinationtounderstandandreadthesignsof nature.SomearesimplycontentwithknowingthatGodcreatedtheuniverse– whetherthiswas6000yearsagoor14billionyearsmaynotmakeany differenceintheirdailylife.Iwilldisagreewiththem,Iwilltrytoinformthen, butIwillnotimposemyviewonthem–aslongasthereisnoattempttoenforce 30 AgeoftheuniverseH.Falcke ayounguniversemodelontothechurchorontosociety.Everyonehastheright tohisorherownviews. However,whenroamingtheInternetonecanalsofindagroupof“creationist scientists”,whoclaimtodoscienceandwhowanttoseetheirsciencebe acceptedbyeveryone.Theytoostartwiththeassumptionthattheword“yom”in Genesis1impliesa24hourdayandthatthereforetheearthwascreatedin144 hours(i.e.,6daysof24hourseach).Mostscholarswilllikelynotagreewiththat interpretationofyom,sincetheyfeelitmakesthestoryofGenesisinherently inconsistentxxii.Nonetheless,the144hourcreationxxiiiisthecentraldogmaofthe creationistbeliefsystemandscienceismainlyatoolforthemtoreaffirmthat view. Consequently,creationistsciencerequiresany“physicalreality”tobeconsistent withthatparticularinterpretationofGenesis.144hr-creationsimisoftenledby relativelysmartandwell-educatedmenxxivwithasolidscientificbackground. Theyhavetheirownorganizations,theirownpublications,theirowntextbooks andtheirownscienceconferences.Theyalsohaveastrongoutreachprogram towardsChristianbelieverswithpopularsciencemagazines,websites,books andaudio-visualmedia. Interestingly,Creationismpurposelylinkscreationistfaithtoanewtypeof science,therebymakingtheirfaithsubjecttoscientifictests. Thecreationistmantraisthatmainstreamscienceiswronginitsbigconclusions (afterallthelargeandolduniversecollideswiththeirowninterpretationofthe Bible).Thisisaboldstatement,sinceourentiremoderntechnologicalworld fromsmartphonesandcomputerstomedicalapparatuses,airplanes,carsand spacecraftsarebased,explained,anddevelopedonthebasisofthescientific progressthatwasdevelopedthroughoutthecenturiesbyscientists,manyof whichwhowereactuallyalsodevoutChristians. Ofcourse,inthisdayandageithasbecomeverypopulartodoubteverything thatsmellslike“mainstream”.Aretherenotscandalsanderrorsaboundin mainstreamscience?Hence,theclaimisquicklymadethatnon-mainstream ideasaresimplybeingsuppressed. Indeed,scienceisahumanaffairanditincludesallhumanemotionsand corruptions.Atitsforefrontscienceworksasacompetition.Asaconsequence scientistsneedtofightfortheirownrecognitionandformoneytodotheir research.However,intheend,whateverispresentedneedstowork.Ideas,being mainstreamofnot,arenowopenlyavailabletoeveryone,theyhavetobe defendedinpublic,theyneedtobetestedbyexperiments,andthesetestsneed tobereproducible. Inthatrespectscienceisnotverydifferentfromfootballoranyothersports. Beforeamatch,newspapersarefullofspeculationfromplayers,coaches,experts andfansthatknowbestwhoshouldinprinciplewin.Attheendofthedayone teamwinsthecompetitionandnoneofthatchitchatplaysanyroleanymore.The finalresultcountsxxv. So,ifcreationistsclaimtheirscienceisbetterthanthatof“mainstreamscience“ theyhavetodemonstratethatandneedtowinthatcompetition,ratherthan startingtheirowncompetition.TheInternetisfulloflittlearticlesandpower 31 AgeoftheuniverseH.Falcke pointpresentations,wherecreationiststrytoarguewhyacertaindatingmethod isflawedorwheretheypresentsome“creationmodel”thatexplainscreationin 144hours.Mostofthemareonapopularlevelthough,hardlyanyofthemhave madeanactualimpactbeyondtheirownpeergroup,andevenwithinthispeer groupthesemodelsdiffervastlyfromeachother. Whatever144hourcreationmodelisoutthere,ithastochangephysicsina drasticwayinordertobeconvincing.Sofar,thishasnothappened.Thereisnot asingledeviceorasingletechnologicalbreakthroughwecanattributeto creationistscience. Ofcourse,whenlookingatthesecreationists’powerpointsandlecturesasa layperson,onemaygetconfused:arethesedatingmethodsperhapsallflawed? Iscreationistsciencethebetterscience,butjustignored? WhatItrytoteachmystudentsistolookatthebigpicturefirst,whentheytryto developanewtheory.Askyourselffirst:canitworkatall?Dotheorderof magnitudenumbersmakeanysense?Onlythenstartworryingaboutthedetails! Ihavetriedthesamehere:thesizeandappearanceoftheuniverseistherenow foreveryonetosee.Inordertoexplainauniverseofabillionlightyearsthatwas createdin6000years,youhavetomakeenormous,absolutelyradicalchangesto thefundamentalsofmodernphysics.Thereisnowayyoucandothiswithany physicsweknowandusetoday.Itisnotenoughtocomplainaboutsomeobscure “datingmethods”toproveayounguniverse,youactuallyhavetoshakeand revolutionizephysicsatallfrontsinawaynobrilliantthinkerinthehistoryof mankindhaseverdonebefore.Noneofthescienceideasfloatedsofarby creationistscomesanywherenearacoherenttheorythatcanstandupagainst thescrutinyofcurrentexperimentsandobservations.Theyfailnotbyalittlebit; theyfailbyahugemargin.Creationistsciencesimplydoesnotholduptothe standardoftruththatwerequireinscience.Thechurchshouldnotbecontent withanylesserstandards. 5 Conclusions FromaChristianperspectivestudyingthenatureofcreationrevealssomething aboutthenatureoftheCreator.Studyingcreationiswhatscientistslikemedo foralivingandtheyhavetodoittruthfullyandhumbly.Theuniverseas presentedtousismillionsandbillionsoflightyearsinsize,asonecanseewith verybasicmeasurements.Neithertimenorspeedoflightcanbemadetochange insuchadrasticwaytomaketheuniverseyoung.Thus,theuniverseitselftells usthatitisnot6000yearsoldandthatittookmorethan144hourstoform. Todefenda144hrcreationonehastoquestionthewitnessofnatureitselfand saythattheuniverseonlyappearsold,butinrealityitisnot.Scientifically,this cannotbechallenged,afteralltheuniversecouldinprinciplejustbeagiant deceptionoracomputersimulation,setupwithallmemoriesimplantedto deceiveus.However,suchapositionisfundamentallyincompatiblewithbasic biblicalviews.Ascreationreflectsitscreator,thisactuallyimpliesaGodwhois misleadingandunreliable.Godwouldhavehadtobuildintothisuniversemany intricatefeaturesonlytomisleadanddeceiveus. 32 AgeoftheuniverseH.Falcke Alsomiraclesarenotawayout.IntheBibletheyarepresentedasveryspecific andexceptionlifechangingexperiencesofpeopleratherthanthelawoftheland. Thereforetheycannotbeinvokedasadefaultmodeofoperationtoexplainhow theworldevolved.Moreover,questioningthehistoricityofnaturealtogether alsoquestionsthehistoricityoftheBible–afterallChristiansbelievethatGodis revealedinthephysicalworldthroughhistory.Therefore,theBiblecannotbe usedasanargumentagainstanoldandlargeuniverse.Todosotodaywould requireonetostatethatwecannottrustrealityatall.NeitherwouldtheBiblebe trustableinsuchananti-realisticworldview. Natureitselfspeaksofanalmostimmeasurablesizeandofanalmost incomprehensibleageoftheuniverse.FromaChristianperspectivethisvastness innumbersreflectsacreatorwhoisevenlargerandolderthanwecanimagine. Infact,thisfeelingofanimmeasurableandawe-inspiringsizeofcreation radiatesalreadythroughthewordsofbiblicalwritersandprophets.Job(36:26) shoutsout“HowgreatisGod—beyondourunderstanding!Thenumberofhisyears ispastfindingout.”Jeremiamarvelsabouttheincomprehensiblenumberofthe heavenlyhosts:“…ascountlessasthestarsintheskyandasmeasurelessasthe sandontheseashore.”(Jeremiah33:22). TheprophetsoftheBibledonotpreachasmalluniverse,asmallcreation,or– forthatmatter–asmallcreator.Neithershouldwe. ByinsistingonayoungEarthinthefaceofoverwhelmingevidence,creationists makeGodnotonlyappearsmall,theyalsodestroytheverycredibilityof scripturetheyseektouphold.Thisbuildsunnecessary,sometimes insurmountable,hurdlestobelieveandtrustthebiblicalmessageforthosewho havenotbeenfedbiblicalstoriesfromearlychildhoodon. ThewarningofchurchfatherAugustinestillstandsaftermorethan1600years “Usually,evenanon-Christianknowssomethingabouttheearth,theheavens,and theotherelementsofthisworld…Now,itisadisgracefulanddangerousthingfor aninfideltohearaChristian,presumablygivingthemeaningofHolyScripture, talkingnonsenseonthesetopics…,howaretheygoingtobelievethosebooksin mattersconcerningtheresurrectionofthedead,thehopeofeternallife,andthe kingdomofheaven,whentheythinktheirpagesarefulloffalsehoodsonfacts whichtheythemselveshavelearntfromexperienceandthelightofreason?”(from “TheliteralmeaningofGenesis”,AD401,Book1,chap19,39). Hence,inthelightofwidelyandpublicallyaccessibleknowledgeandexperience aboutthesizeoftheuniverse,a6000yearolduniversecanbefirmlyandsafely rejectedonscientificandontheologicalgrounds. Acknowledgement:Iamthankfultoanumberofcolleagueswhohavecritically andconstructivelycommentedonvariousaspectsofthispaper:StefanPaas, GijsbertvandenBrink,CeesDekker,BramAchterberg,DanFabrycky. iThismeansthatintoday’sphysicalunitsthespeedoflightisaconstantby definition!However,donotgetconfused.Thisismainlydoneforpractical mattersanddoesnotmean,wecannotchecktheconstancyoflightby experiments.Infact,wecanalwayschangethedefinitionforanygiven 33 AgeoftheuniverseH.Falcke experiment,defineastandardlengthscaleinsteadandcheckifthespeedoflight changesafterall. iiAlittletwisttothisstorycomesfromthefactthatwearelookingintodifferent partsoftheuniverseineachdirection.So,weseeahistoryalongdifferentlines ofsightwithrespecttoEarth.However,dothosedifferentpartsoftheuniverse alsoshareacommonhistory,oraretheydisjoint?Itiswellestablishedthatthe universeisisotropic–onaverageitlooksverymuchthesameinalldirections fromus.However,wouldthatbealsotrueforanyotherpointintheuniverse? Wouldotherearthsinothergalaxiesseethesamehistoryaswedo?Inthatcase theuniversewouldalsobe“homogenous”.Itwouldhaveonlyonecommon history.Thisisanassumption,buteventhatcanbetestedtosomedegreeof precisionandtheanswerseemstobeareassuringyes(e.g.,Goodman1995, PhRvD,52,1821,„GeocentrismReexamined“). iiiGAIAdatarelease1seemstohaveaminimumparallaxerrorof0.2 milliarcsecond.Forameasurementwithasignificanceof5σ(i.e1 milliarcsecond),thiscorrespondstoparallaxdistanceof3000lightyears. ivAswellastheirspectralfingerprint. v„Normal“(or„main-sequencestars“)impliesmiddle-agedstarsthatarenot recentlybornorhavecometotheendoftheirlifetime,wheretheyundergo spectacularchangesinstructure. viThisisquitesomething!ForaGPSsystem,whichmeasuresourposition relativetosatellitesat20.000kmheight,thiswouldmeanmeasuringrelative positionstoabout1mm.Thisisjustbarelypossiblewiththemostadvanced techniques.However,VLBIcandothisfeatformeasuringtherelativepositions ofcosmicsources,sincetheirantennasaremuchbigger,theyusehigher frequencies,andtheycanaffordtohavebigatomicclocksateachradio telescope. viiD=106km/sec×oneyear/30microarcseconds viiiYouwillbeoffbyafactorofafew,sinceyouwillmissthefaintouterpartsof Andromeda.Itwillstillgiveyouahugedistance. ixThisdoesnottakeawaythefactthatindividualdistanceestimatescanbeoffby afactorofafewinextremecases,butalmostneverbyanorderofmagnitude. xNote,thatthespeedoflightcanbeslower,iflightispassingthroughamedium. Thisisbecausepartsofthelightareabsorbedandemitted,interferingwiththe originalray.Thisslowsthewholelightraydowncomparedtoitsspeedin vacuum. xiThewavelengthofalightwave,λ,isgivenbythespeedoflight,c,dividedby thefrequencyν:,λ=c/ν. xiiNote,thatnormallyoneactuallyassumesthatthespeedoflightisgivenand thendeterminesthedistancetothisobjectfromthelightecho.Thefactthat herebothdistancesagreewithintheerrors,canthenbeturnedaroundtostate thatthespeedoflightdidnotchangebymorethan~25%. 34 AgeoftheuniverseH.Falcke xiiiWithastrologybeingperhapstheexception,butastrologydoesnotfund scientificstudiesasfarasIknow.Ofcourse,alsotheeducationalstructurein somecountriescouldbeconsideredpowerful“industries”.Fortunately,thereare stillhundredsofexcellentresearchinstitutionsthatgloballycompeteagainst eachotherforfundingandreputationinmanyverydifferentfields.Hence,there isnotsomethinglikeanorganizedastronomycarteloutthere,thatcould manipulateresultsonsuchascale. xivNeitherColumbusnorhiscontemporariesbelievedthattheworldwasflat. Thatisacommonmyth,butuntruenevertheless(e.g.,M.Rossano2011).They miscalculatedtheperimeteroftheearthandthelocationofIndia,butno informedmedievalpersonthoughttheworldwasflat.Actually,Columbus expectedtofindIndiaapproximatelywhereheactuallyfoundtheCaribbean islands.Hissailorswerenotafraidtofallofftheearth,butthatIndiawouldbe muchfartherawaythanColumbusthoughtitwas(seealsoHannam,“The GenesisofScience”). xvAsasidenote:infact,thedistancebetweenEuropeandAmericadoeschange! Americamovesawayfromusby17mmperyearduetocontinentaldriftand platetectonics.Thisismeasured–yearin,yearout–bygeodeticVLBI,i.e.,with thesameradiotelescopesandthesametechniqueusedtomeasurethestructure oftheMilkyWay.TheresultisindependentlyconfirmedbyGPSmeasurements, i.e.verydifferentinstruments.However,thisdiscoverydoesnotchangethebasic scaleofourearth,ratheritconfirmsplatetectonicsandverifiesthatVLBIis reliable. xviTheseideaswereapparentlynotanAprilfool’sjoke,butwerestimulatedby theHollywoodmovie“Matrix”.Thereasonthatthisideawasconsidered scientificallytestableisthatacomputersimulationwouldhaveacertain “granularity”andwouldalsoexhibit“glitches”,whichonecouldtrytodetect.The comparisontoancientcreationstoriesgoesevenfurther:alsoasimulation wouldhaveacreatoranditsolvesthefine-tuningargumentofteninvokedby creationistsandapologetics. xviiTheancientnaveldiscussioncanstillbefoundinsomemodernInternetblogs (e.g.,here,whichalsoprovidessomehistoricalcontextandtheadmissionthat thisdiscussionwasbizarreattimes).Interestingly,heremoderncreationists argueagainstAdamhavinganavel,withexactlythesameargumentIused above.AlMaxeyexclaims:„ItismyfirmconvictionthattosuggestGodcreated AdamandEvewithnavelsistosuggestHeisthecreatorofagranddeception,and IsimplyamunwillingtomakesuchanassertionaboutmyGod”.Well,isnotthe imprintedlightofanevolvingsupernovainayoungUniversemodelaneven greaterdeception?Afterall,thiswecanseeevennow,whileAdam’snavelwe cannot. xviiiIwasonceaskedbyasmartandtriumphantstudenthowIcouldbesosure thatGodwouldnotcreateamatureuniverse?AfterallJesusdidturnwaterinto goodwine,whichobviouslymustbeold!Itmaysufficetosaythatthereisno waywecanscientificallytestthisinterestinghypothesis.Thewineislonggone whiletheuniverse–luckily–isstillaround. 35 AgeoftheuniverseH.Falcke xixOfcourse,inthevastuniverseofChristiantheologythethinkingabout salvationismuchmorecomplexthansketchedhere. xxObviously,Jesusrecognizedthisphysicallawwhenrefusingthetemptationto throwhimselffromtheheight,notpresumingonGodandangelstointervene andthusputHimtothetest(Matthew4:5-7). xxiSometimescreationistsrefertoGenesis8:22inordertoarguethattheBible wantstosaythatonlyfromthatmomentonwards(i.e.eversincetheFlood)God hadpromisedtobereliableinhisdealingswithnature.However,thatpassageis onlyabouttheassuredsurvivalofthehumanrace(whichwasnotatallassured intheearlyofhumanhistory).Theuniverseassuchcouldhaveeasilygoneon withouthumanbeings. xxiiIfyomwere24hours,Godwouldhaverestedonly24hoursattheend. However,giventhattheseventhdayinGenesishasnonight,indicatesthatthe writerwantstoexpressthatwearestilllivinginthat“day”.Also,itmakesno sensetohaveearthdaysbeforethelightswerecreatedthatseparatedayfrom night.Aliteralandunbiasedreadingimmediatelymakesclearthattheword‚day’ isusedinvariousandrathercomplicatedwayshere(S.Paas,VUAmsterdam, personalcommunication). xxiiiIusetheterm“144hourcreation”heretoindicatethatsomeoneconsiders thedaysinGenesistobeof24hourlength.TherearemanyotherChristians thinkersthroughouthistory,whodidbelieveina„6daycreation“,but consideredthose„days“tobeofvariablelength. xxivItismypersonalimpressionthatthegenderbalanceamongcreationist scientistsisevenmoreskewedtowardsmenthaninmainstreamphysics,butI havenosolidstatisticstobackitupapartfromsomepersonalencountersand fromhavingquicklyscannedovertheresearchstafflistedonvariousrelevant websites. xxvIwastoldthatinAmericancollegefootballtherankingofteamsisalsobased ontheopinionofjournalistsandnotjustresultsonly.Ifthatistrue,itmight explainwhyintheUSevidence-basedthinkingsometimeshasahardtime...but, Icouldbeverywronghere! 36