The Universe After the Big Bang

AfterAfter thethe BigBig BangBang

Prof.Prof. LynnLynn Cominsky,Cominsky, Dr.Dr. PhilPhil PlaitPlait andand SarahSarah SilvaSilva NASANASA E/POE/PO atat SSUSSU GoldenGolden AgeAge ofof CosmologyCosmology

 HowHow diddid thethe UniverseUniverse begin?begin?  StandardStandard BigBig BangBang theorytheory  InflationInflation  HubbleHubble ExpansionExpansion  WhatWhat isis thethe fatefate ofof thethe Universe?Universe?  ObservationsObservations ofof CMBRCMBR  DarkDark MatterMatter  DistancesDistances toto SupernovaeSupernovae  Today’sToday’s CosmologyCosmology  EinsteinEinstein andand thethe CosmologicalCosmological ConstantConstant  DarkDark EnergyEnergy andand thethe AcceleratingAccelerating UniverseUniverse

9/23/05 Prof. Lynn 2 Cominsky BigBig BangBang TimelineTimeline

We are here

9/23/05 Prof. Lynn 3 Cominsky BigBig Bang?Bang?

9/23/05 Prof. Lynn 4 Cominsky StandardStandard BigBig BangBang CosmologyCosmology  SometimeSometime inin thethe distantdistant pastpast therethere waswas nothingnothing –– spacespace andand timetime diddid notnot existexist  VacuumVacuum fluctuationsfluctuations createdcreated aa singularitysingularity thatthat waswas veryvery hothot andand densedense  TheThe UniverseUniverse expandedexpanded fromfrom thisthis singularitysingularity  AsAs itit expanded,expanded, itit cooledcooled  PhotonsPhotons becamebecame quarksquarks  QuarksQuarks becamebecame neutronsneutrons andand protonsprotons  NeutronsNeutrons andand protonsprotons mademade atomsatoms  AtomsAtoms clumpedclumped togethertogether toto makemake starsstars andand galaxiesgalaxies 9/23/05 Prof. Lynn 5 Cominsky StandardStandard BigBig BangBang CosmologyCosmology

 TopTop threethree reasonsreasons toto believebelieve bigbig bangbang cosmologycosmology 1. BigBig BangBang NucleosynthesisNucleosynthesis 2. HubbleHubble ExpansionExpansion 3. CosmicCosmic MicrowaveMicrowave BackgroundBackground (CMB)(CMB)

Big Bang by Physics Chanteuse Lynda Williams (SRJC)

9/23/05 Prof. Lynn 6 Cominsky BigBig BangBang NucleosynthesisNucleosynthesis  LightLight elementselements (namely(namely deuterium,deuterium, helium,helium, andand lithium)lithium) werewere producedproduced inin thethe firstfirst fewfew minutesminutes ofof thethe BigBig BangBang  ElementsElements heavierheavier thanthan 4HeHe areare producedproduced inin thethe starsstars andand throughthrough supernovaesupernovae  However,However, enoughenough heliumhelium andand deuteriumdeuterium cannotcannot bebe producedproduced inin starsstars toto matchmatch whatwhat isis observedobserved becausebecause starsstars destroydestroy deuteriumdeuterium inin theirtheir corescores  SoSo allall thethe deuteriumdeuterium wewe seesee mustmust havehave beenbeen mademade aroundaround threethree minutesminutes afterafter thethe bigbig bang,bang, whenwhen T~10T~109 KK  BBNBBN predictspredicts thatthat 25%25% ofof thethe mattermatter inin thethe UniverseUniverse shouldshould bebe helium,helium, andand aboutabout 0.001%0.001% shouldshould bebe deterium,deterium, whichwhich isis whatwhat wewe seesee

9/23/05 Prof. Lynn 7 Cominsky WhatWhat isis inflation?inflation?

 InflationInflation refersrefers toto aa classclass ofof cosmologicalcosmological modelsmodels inin whichwhich thethe UniverseUniverse exponentiallyexponentially increasedincreased inin sizesize byby aboutabout 101043 betweenbetween aboutabout 1010-35-35 andand 1010-32-32 ss afterafter thethe BigBig BangBang (It(It hashas sincesince expandedexpanded byby anotheranother 101026))  InflationInflation isis aa modificationmodification ofof standardstandard BigBig BangBang cosmologycosmology  ItIt waswas originatedoriginated byby AlanAlan GuthGuth inin 19791979 andand sincesince modifiedmodified byby AndreasAndreas Albrecht,Albrecht, PaulPaul SteinhardtSteinhardt andand AndreAndre LindeLinde (among(among 9/23/05others)others) Prof. Lynn 8 Cominsky WhyWhy believebelieve inin inflation?inflation?

 InflationInflation isis aa predictionprediction ofof grandgrand unifiedunified theoriestheories inin particleparticle physicsphysics thatthat waswas appliedapplied toto cosmologycosmology –– itit waswas notnot justjust inventedinvented toto solvesolve problemsproblems inin cosmologycosmology  ItIt providesprovides thethe solutionsolution toto twotwo longlong standingstanding problemsproblems withwith standardstandard BigBig BangBang theorytheory  HorizonHorizon problemproblem  FlatnessFlatness problemproblemAlan Guth

9/23/05 Prof. Lynn 9 Cominsky HorizonHorizon ProblemProblem

 TheThe UniverseUniverse lookslooks thethe samesame everywhereeverywhere inin thethe skysky thatthat wewe look,look, yetyet therethere hashas notnot beenbeen enoughenough timetime sincesince thethe BigBig BangBang forfor lightlight toto traveltravel betweenbetween twotwo pointspoints onon oppositeopposite horizonshorizons  ThisThis remainsremains truetrue eveneven ifif wewe extrapolateextrapolate thethe traditionaltraditional bigbig bangbang expansionexpansion backback toto thethe veryvery beginningbeginning  So,So, howhow diddid thethe oppositeopposite horizonshorizons turnturn outout thethe samesame (e.g.,(e.g., thethe CMBRCMBR temperature)?temperature)? 9/23/05 Prof. Lynn 10 Cominsky NoNo inflationinflation  AtAt t=10t=10-35-35 s,s, thethe UniverseUniverse expandsexpands fromfrom aboutabout 11 cmcm toto whatwhat wewe seesee todaytoday  11 cmcm isis muchmuch largerlarger thanthan thethe horizon,horizon, whichwhich atat thatthat timetime waswas 33 xx 1010-25-25 cmcm

9/23/05 Prof. Lynn 11 Cominsky WithWith inflationinflation

 SpaceSpace expandsexpands fromfrom 33 xx 1010-25-25 cmcm toto muchmuch biggerbigger thanthan thethe UniverseUniverse wewe seesee todaytoday

9/23/05 Prof. Lynn 12 Cominsky FlatnessFlatness ProblemProblem

 WhyWhy doesdoes thethe UniverseUniverse todaytoday appearappear toto bebe nearnear thethe criticalcritical dividingdividing lineline betweenbetween anan openopen andand closedclosed Universe?Universe?  DensityDensity ofof earlyearly UniverseUniverse mustmust bebe correctcorrect toto 11 partpart inin 101060 inin orderorder toto achieveachieve thethe balancebalance thatthat wewe seesee

9/23/05 Prof. Lynn 13 Cominsky FlatnessFlatness ProblemProblem

 InflationInflation flattensflattens outout spacetimespacetime thethe samesame wayway thatthat blowingblowing upup aa balloonballoon flattensflattens thethe surfacesurface  SinceSince thethe UniverseUniverse isis farfar biggerbigger thanthan wewe cancan see,see, thethe partpart ofof itit thatthat wewe cancan seesee lookslooks flatflat

9/23/05 Prof. Lynn 14 Cominsky RedshiftRedshift andand DopplerDoppler ShiftShift

. Redshift z is determined by comparing laboratory wavelength λο to observed wavelength λ . If objects are moving away from observer, light will be redshifted . Velocity of object can be determined from z

∆λ λ − λο v z = λ = = ο λο c

9/23/05 Prof. Lynn 15 Cominsky DopplerDoppler ShiftShift

ComparisonComparison ofof laboratorylaboratory toto blue-shiftedblue-shifted objectobject

Comparison of laboratory to red-shifted object

9/23/05 Prof. Lynn 16 Cominsky CepheidCepheid variablesvariables andand NebulaeNebulae

 InIn 1923,1923, EdwinEdwin HubbleHubble usedused newnew Mt.Mt. WilsonWilson 100100 inchinch telescopetelescope toto observeobserve CepheidCepheid variablesvariables inin thethe nearbynearby “nebula”“nebula” Andromeda.Andromeda. 1.3  CepheidsCepheids varyvary periodicallyperiodically L =K P

. DistanceDistance toto CepheidsCepheids cancan bebe calculatedcalculated fromfrom theirtheir luminosityluminosity

9/23/05 Prof. Lynn 17 Cominsky StandardStandard CandlesCandles  IfIf youyou knowknow thethe absoluteabsolute brightnessbrightness ofof anan object,object, youyou cancan measuremeasure itsits apparentapparent brightnessbrightness andand thenthen calculatecalculate itsits distancedistance  CepheidsCepheids areare standardstandard candlescandles . SoSo areare somesome supernovaesupernovae π 2 Fobs = Labs/4 d 9/23/05 Prof. Lynn 18 Cominsky HubbleHubble ExpansionExpansion The Hubble constant

-1 -1 Ho = 558 km s Mpc is the slope of these graphs

Compared to modern measurements, Hubble’s results were off by a factor of ten! 9/23/05 Prof. Lynn 19 Cominsky HubbleHubble LawLaw

 vv == HHo dd == cczz wherewhere  vv == velocityvelocity fromfrom spectralspectral lineline measurementsmeasurements  dd == distancedistance toto objectobject  -1-1 -1-1 HHo == HubbleHubble constantconstant inin kmkm ss MpcMpc  zz isis thethe redshiftredshift Space between the galaxies expands while galaxies stay the same size

9/23/05 Prof. Lynn 20 Cominsky CosmicCosmic MicrowaveMicrowave BackgroundBackground  DiscoveredDiscovered inin 19651965 byby ArnoArno PenziasPenzias andand RobertRobert WilsonWilson whowho werewere workingworking atat BellBell LabsLabs  ClinchedClinched thethe hothot bigbig bangbang theorytheory

Excess noise in horned antennae was not due to pigeon dung!

9/23/05 Prof. Lynn 21 Cominsky CosmicCosmic BackgroundBackground ExplorerExplorer ((1989-1993)

. Differential Microwave Radiometer . PI George Smoot . Discovered fluctuations in the CMBR .These fluctuations are predicted by inflationary BB cosmology and are the seeds of the structure we now see

9/23/05 Prof. Lynn 22 Cominsky COBECOBE data/DMRdata/DMR

. These fluctuations have been called the “wrinkles on the face of God”

9/23/05 Prof. Lynn 23 Cominsky CMBCMB FluctuationsFluctuations

 COBECOBE measuresmeasures thethe angularangular fluctuationsfluctuations onon largelarge scales,scales, downdown toto aboutabout ll=16=16

9/23/05 Prof. Lynn 24 Cominsky FluctuationsFluctuations andand geometrygeometry

9/23/05 Prof. Lynn 25 Cominsky OldOld view:view: DensityDensity ofof thethe UniverseUniverse determinesdetermines itsits destinydestiny

Ω = Ω (total) M where Ω M = matter density (including regular and dark matter) Ω tot = density/critical density

Ω If tot = 1,Universe is flat, expansion coasts to a halt as Universe is critically balanced.

9/23/05 Prof. Lynn 26 Cominsky WilkinsonWilkinson MicrowaveMicrowave AnisotropyAnisotropy ProbeProbe (2001-present)(2001-present)

9/23/05 Prof. Lynn 27 Cominsky Universe’sUniverse’s BabyBaby PicturesPictures

Red is warmer

BlueBlue isis coolercooler

Credit: NASA/WMAP

9/23/05 Prof. Lynn 28 Cominsky CompareCompare toto COBECOBE

 TheThe WMAPWMAP imageimage bringsbrings thethe COBECOBE picturepicture intointo sharpsharp focus.focus.

movie

9/23/05 Prof. Lynn 29 Cominsky CMBCMB vs.vs. InflationInflation  InflationInflation alsoalso predictspredicts aa distinctdistinct spectrumspectrum ofof fluctuationsfluctuations forfor thethe CMBCMB whichwhich arisearise fromfrom thethe originaloriginal quantumquantum fluctuationsfluctuations inin thethe pre-inflationpre-inflation bubblebubble

Everything we see in the Universe started out as a quantum fluctuation!

9/23/05 Prof. Lynn 30 Cominsky WMAPWMAP angularangular powerpower spectrumspectrum

9/23/05 Prof. Lynn 31 Cominsky ΩΩ CosmologicalCosmological ParametersParameters -- TOTTOT

 TheThe strongstrong firstfirst peakpeak atat ll =200=200 confirmsconfirms inflationaryinflationary expansionexpansion  RecallRecall thatthat inflationinflation explainsexplains thethe apparentapparent flatnessflatness ofof thethe UniverseUniverse  ΩΩ FlatnessFlatness meansmeans thatthat TOT == 1.01.0  So,So, inin thethe oldold view,view, wewe livelive inin aa criticallycritically balancedbalanced UniverseUniverse  However,However, toto quotequote RockyRocky Kolb:Kolb:

9/23/05 Prof. Lynn 32 Cominsky DarkDark MatterMatter

 InIn 1930,1930, FritzFritz ZwickyZwicky discovereddiscovered thatthat thethe galaxiesgalaxies inin thethe ComaComa clustercluster werewere movingmoving tootoo fastfast toto remainremain boundbound inin thethe clustercluster

. SomethingSomething elseelse thatthat cannotcannot bebe seenseen mustmust bebe holdingholding thethe galaxiesgalaxies inin thethe cluster!cluster!

9/23/05 Prof. Lynn 33 Cominsky GalaxyGalaxy RotationRotation CurvesCurves

. In 1970, Vera Rubin discovered that the gas and stars in the outer parts of galaxies were moving too fast . This implies that most of the mass in the galaxy is outside the region where we see the stars . Since we do not see light from this matter, it is called Dark Matter NGC 3198 9/23/05 Prof. Lynn 34 Cominsky HotHot gasgas inin GalaxyGalaxy ClustersClusters . Measure the mass of light emitting matter in galaxies in the cluster (stars) . Measure mass of hot gas - it is 3-5 times greater than the mass in stars . Calculate the mass the cluster needs to hold in the hot gas - it is 5 - 10 times more than the mass of the gas plus the mass of the stars!

9/23/05 Prof. Lynn 35 Cominsky DarkDark MatterMatter HaloHalo

 TheThe rotatingrotating disksdisks ofof thethe spiralspiral galaxiesgalaxies thatthat wewe seesee areare notnot stablestable  DarkDark mattermatter haloshalos provideprovide enoughenough gravitationalgravitational forceforce toto holdhold thethe galaxiesgalaxies togethertogether  TheThe haloshalos alsoalso maintainmaintain thethe rapidrapid velocitiesvelocities ofof thethe 9/23/05outermostoutermost starsstars Prof. inin Lynn thethe 36 galaxiesgalaxies Cominsky HubbleHubble ExpansionExpansion revisitedrevisited

 WeWe havehave alreadyalready seenseen howhow thethe galaxiesgalaxies movemove awayaway fasterfaster atat furtherfurther distancesdistances  WeWe measuredmeasured thethe slopeslope ofof thethe velocityvelocity ofof thethe galaxiesgalaxies vs.vs. theirtheir distancesdistances  HubbleHubble constantconstant  ButBut isis thethe HubbleHubble constantconstant reallyreally constant?constant?  InIn otherother words,words, hashas thethe expansionexpansion occurredoccurred atat thethe samesame raterate inin thethe pastpast asas itit isis rightright now,now, andand willwill thethe futurefuture expansionexpansion alsoalso bebe atat thisthis samesame rate?rate? 9/23/05 Prof. Lynn 37 Cominsky MeasuringMeasuring thethe HubbleHubble ExpansionExpansion

 IfIf thethe expansionexpansion raterate isis constant,constant, distancedistance betweenbetween 22 galaxiesgalaxies followsfollows yellowyellow dotteddotted lineline backback inin timetime  If rate is speeding up, then the Universe is older than we think Real Big Bang Derived from constant rate 9/23/05 Prof. Lynn 38 Cominsky DistancesDistances toto SupernovaeSupernovae

 TypeType IaIa supernovaesupernovae areare “standard“standard candles”candles”  OccurOccur inin aa binarybinary systemsystem inin whichwhich aa whitewhite

dwarfdwarf starstar accretesaccretes beyondbeyond thethe 1.41.4 MMo ChandrasekharChandrasekhar limitlimit andand collapsescollapses andand explodesexplodes  DecayDecay timetime ofof lightlight curvecurve isis correlatedcorrelated toto absoluteabsolute luminosityluminosity  LuminosityLuminosity comescomes fromfrom thethe radioactiveradioactive decaydecay ofof CobaltCobalt andand NickelNickel intointo IronIron  SomeSome TypeType IaIa supernovaesupernovae areare inin galaxiesgalaxies withwith CepheidCepheid variablesvariables  GoodGood toto 20%20% asas aa distancedistance measuremeasure 9/23/05 Prof. Lynn 39 Cominsky SupernovaeSupernovae asas StandardStandard CandlesCandles  HereHere isis aa typicaltypical supernovasupernova lightcurvelightcurve andand itsits spectrumspectrum Measure Measure shape of redshift  curve and peak distance distance

 CompareCompare twotwo distancesdistances toto seesee ifif expansionexpansion raterate hashas changedchanged 9/23/05 Prof. Lynn 40 Cominsky SupernovaeSupernovae andand CosmologyCosmology

 AnalyzeAnalyze lightcurveslightcurves vs.vs. redshiftsredshifts forfor manymany TypeType 1a1a supernovaesupernovae atat redshiftsredshifts zz <2<2  ObservationsObservations ofof overover 100100 SNSN (over(over 77 years)years) byby PerlmutterPerlmutter etet al.al. andand SchmidtSchmidt etet al.al. havehave showedshowed thatthat theythey areare dimmerdimmer thanthan wouldwould bebe expectedexpected ifif thethe UniverseUniverse waswas expandingexpanding atat aa constantconstant raterate oror slowingslowing downdown (as(as waswas previouslypreviously thought)thought)  ThisThis meansmeans thatthat somesome unknownunknown “dark“dark 9/23/05energy”energy” isis causingcausing Prof. Lynn thethe UniverseUniverse 41toto flyfly apartapart atat ever-increasingever-increasingCominsky speeds.speeds. EinsteinEinstein andand thethe CosmologicalCosmological ConstantConstant  WhenWhen EinsteinEinstein firstfirst formulatedformulated hishis equationsequations ofof GeneralGeneral Relativity,Relativity, hehe believedbelieved inin aa staticstatic UniverseUniverse (or(or steadysteady statestate Universe)Universe)  SinceSince thethe equationsequations seemedseemed toto predictpredict anan unstableunstable universeuniverse thatthat wouldwould eithereither expandexpand oror contract,contract, hehe “fixed”“fixed” hishis equationsequations byby insertinginserting aa “Cosmological“Cosmological Constant”Constant” calledcalled ΛΛ  WhenWhen HubbleHubble laterlater foundfound thatthat thethe UniverseUniverse waswas expanding,expanding, EinsteinEinstein calledcalled thethe creationcreation ofof thethe CosmologicalCosmological ConstantConstant hishis “greatest“greatest blunder”blunder” 9/23/05 Prof. Lynn 42 Cominsky EinsteinEinstein andand DarkDark EnergyEnergy  However,However, nownow wewe seesee thatthat therethere isis indeedindeed aa cosmologicalcosmological constantconstant termterm –– butbut itit actsacts inin thethe oppositeopposite sensesense toto Einstein’sEinstein’s originaloriginal ideaidea  TheThe DarkDark EnergyEnergy impliedimplied byby thethe non-zeronon-zero valuevalue ofof ΛΛ pushespushes thethe UniverseUniverse apartapart eveneven faster,faster, ratherrather thanthan addingadding stabilitystability toto anan unstableunstable Universe,Universe, asas EinsteinEinstein originallyoriginally intended.intended.  TheThe darkdark energyenergy density/criticaldensity/critical densitydensity == ΩΩΛ  ΩΩ ΩΩ ΩΩ CurrentCurrent measurements:measurements: ΤΟΤ –– Μ == Λ ~~ 0.70.7 9/23/05ThereThere areare manymany Prof. theoriestheories Lynn forfor DarkDark43 Energy:Energy: vacuumvacuumCominsky fluctuations,fluctuations, extraextra dimensions,dimensions, etc.etc. NewNew view:view: DensityDensity ofof thethe UniverseUniverse

SN data

U R Ω = Ω + ΩΛ (total) M here where Ω M = matter density (including regular and dark matter) Ω Λ = cosmological constant or dark energy density Ω tot = density/critical density Perlmutter et al. 40 supernovae 9/23/05 Prof. Lynn 44 Cominsky Today’sToday’s CosmologyCosmology

 ΩΩΤΟΤ == 1.01.0 fromfrom CMBCMB measurements.measurements. WeWe livelive inin aa flatflat Universe.Universe.

 ΩΩΜ <0.3<0.3 fromfrom extensiveextensive observationsobservations atat variousvarious wavelengths.wavelengths. IncludesIncludes darkdark mattermatter asas wellwell asas normalnormal mattermatter andand light.light.

 ΩΩΛ ~~ 0.70.7 fromfrom TypeType 1a1a SNSN observations.observations. ManyMany differentdifferent theoriestheories forfor “dark“dark energy.”energy.” UniverseUniverse acceleratesaccelerates eveneven thoughthough itit isis flat.flat.  HubbleHubble constantconstant == 7070 km/sec/Mpckm/sec/Mpc fromfrom HSTHST observations.observations. AgeAge ofof UniverseUniverse isis 9/23/05aroundaround 13.713.7 billionbillion Prof. Lynn years.years. 45 Cominsky 9/23/05 Prof. Lynn 46 Cominsky ResourcesResources

. Inflationary Universe by Alan Guth (Perseus) . A Short History of the Universe by Joseph Silk (Scientific American Library) . Before the Beginning by Martin Rees (Perseus) . Inflation for Beginners (John Gribbin) http://www.biols.susx.ac.uk/Home/John_Gribbin/cosmo.htm . Ned Wright’s Cosmology Tutorial http://www.astro.ucla.edu/~wright/cosmolog.htm . James Schombert Lectures http://zebu.uoregon.edu/~js/21st_century_science/lectures/lec24.html 9/23/05 Prof. Lynn 47 Cominsky ResourcesResources

.Bell Labs Cosmology Archives http://www.bell-labs.com/project/feature/archives/cosmology/ .Big Bang Cosmology Primer http://cosmology.berkeley.edu/Education/IUP/Big_Bang_Primer.html .Martin White’s Cosmology Pages http://astron.berkeley.edu/~mwhite/darkmatter/bbn.html . CosmicCosmic BackgroundBackground ExplorerExplorer http://space.gsfc.nasa.gov/astro/cobe/cobe_home.http://space.gsfc.nasa.gov/astro/cobe/cobe_home. htmlhtml . Hyperspace by Michio Kaku (Anchor Books)

9/23/05 Prof. Lynn 48 Cominsky WebWeb ResourcesResources

. Ned Wright’s CMBR pages http://www.astro.ucla.edu/~wright/CMB-DT.html .Ned Wright’s Cosmology Tutorial http://www.astro.ucla.edu/~wright/cosmolog.htm

. MAP mission http://map.gsfc.nasa.gov .SNAP mission http://snap.lbl.gov/

9/23/05 Prof. Lynn 49 Cominsky WebWeb ResourcesResources

 BrianBrian Schmidt’sSchmidt’s SupernovaSupernova PagesPages http://msowww.anu.edu.au/~brian/PUBLIC/public.htmlhttp://msowww.anu.edu.au/~brian/PUBLIC/public.html  HubbleHubble SpaceSpace TelescopeTelescope seessees DistantDistant SupernovaSupernova http://oposite.stsci.edu/pubinfo/pr/2001/09/pr.htmlhttp://oposite.stsci.edu/pubinfo/pr/2001/09/pr.html  MAPMAP Teacher’sTeacher’s GuideGuide byby LindsayLindsay ClarkClark http://www.astro.princeton.edu/~clark/teachersguide.http://www.astro.princeton.edu/~clark/teachersguide. htmlhtml . George Smoot’s group pages http://aether.lbl.gov/

9/23/05 Prof. Lynn 50 Cominsky