Briefreviewofcosmology

Universeisexpanding

Δλ/λ∝d

Hubble'slaw(1929): v=Hd

thefirstobservaEonalevidenceofBigBangtheory

EdwinPowellHubble(1889-1953)

BigBang

•  1927

GeorgesLemaître(1894–1966)

•  EinsteingeneralrelaEvity•  homogeneousandisotropicuniverse

•  (cosmologicalprinciple)

•  Friedmann'sequaEons

-descripEonoftheuniversefromtheBigBangonwards

•  FredHoyle–1949

AlexanderFriedman(1888–1925)

SirFredHoyle(1915-2001)

universeisisotropicandhomogeneousinspaceandEme

•  1964–ArnoPenziasandRobertWilson–discoveryofCosmicMicrowaveBackgroundradiaEon–CMB–withT=2.725K

•  distribuEonandevoluEonofgalaxies

BigBangnucleosynthesis

•  Alpher-Bethe-Gamow•  predictsquanEtyof4He,3He,2Hin7Liwithrespectto1H

•  dependanceonη=nB/nγ←CMB⇒mass%•  75%H•  25%4He,(~)•  ~10−42H,(OK)•  ~10−43He•  ~10−107Li,7Be(2x)

1.beginningtoinfla?on–Planckepoch:

0-10-43s,T~1034K-gravitaEondecouples

GUT

10-38s–stronginteracEondecouples→hugeamountofenergyreleased→

InflaEon:growsinsizebyafactorof1035

2.electroweakepoch:10-38to10-10s

phasetransiEon,soupofelementaryparEcles:photons,gluons,quarks

weakandEMinteracEondecouple

3.par?cleepoch:10-10to1squarksandanEquarksannihilatesymmetrybreaking→residualquarks→mafer

Hadronepoch:from10-6to10-5s,T~1015K:quarks→hadronsunstabledecay,pandnremainLeptonepoch:mostleptonsandanEleptons→annihilaEon→residualleptons

4.from1to100sn↔p+e-+�νen+e+↔p+�νe nn/np=e-(m_n-m_p)/kTn+νe�↔p+e-

atT~10GKstops:nn/np=0.223

neutrons:βdecaywithτ=617s

5.3-20minwhenTdecreasesto~1GKdeuteronsareproduced:p+n↔21H+γraEop:nattheend:np:nn=7:1→nHe:nH=1:12or.mHe:m=0.25

n+p→21H+γ.

21H+n→3H+γin21H+p→3He+γ.

Finally,4Heisproduced:21H+21H→4He+γ,3He+n→4He+γand3H+p→4He+γ.

atomicnuclei:mostnboundinHe,verylifleinLithium,Beryllium,Deuteriumnuclei

•  noelements>Be•  becausenostablenucleiwithA=5or8(seetriplealphaprocess)•  UniverseconEnuesexpanding

•  comparissonwithobservaEons:•  WMAP

•  10.000years: endofradiaEonera,beginningofmaferdominatedera

•  380.000years:T~3000K–atomsform,maferandradiaEondcouple–universebecomestransparent→CMB

•  >400Myr:

formaEonofstars,

galaxies,planets...