John Mather Visit Nobel Prize in Physics 2006 for Cosmic Microwave Background measurements

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John Mather Visit Nobel Prize in Physics 006 for Cosmic Microwave Background measurements NEXT WEEK Wednesday :0-:00 BPS 00 BS session with astro students & faculty.

1 John Mather Visit Nobel Prize in Physics 006 for Cosmic Microwave Background measurements NEXT WEEK Wednesday :0-:00 BPS 00 BS session with astro students & faculty. Wednesday 8PM BPS 0 (refreshments at 7:0) Public Lecture The history of the Universe in a nutshell: from the Big Bang to life and the end of time Thursday :0 PM BPS 5 (refreshments at :0 in BPS 00) Physics & Astronomy Dept. Colloquium James Webb Space Telescope: Science Opportunities and Mission Progress The History of the Universe Size of Universe Primordial Nucleosynthesis Cosmic Microwave Background Planck time Inflation Hot Formation of H, He, Li Decoupling of CMB Time Galaxy Formation.7 Now Cool (0 K) (0 9 K) (000 K) ( K) High density Low density

2 Cosmology in 96 Big-Bang Nucleosynthesis Cooling of Universe (Alpher & Herman, 98) Radiation energy density urad R( hc hc because E phot ( ( or( Big-Bang Nucleosynthesis Alpher, Bethe & Gamow () paper --- all elements built in Big Bang? Later found: can t get much past He Steady State Model Bondi, Gold & Hoyle Perfect Cosmological Principle universe same at all points and at all times U has always been here. Nucleosynthesis in stars B FH Also tired light o means as observed at present time! A Prediction Cooling of Universe (Alpher & Herman, 98) Radiation energy density because u E rad phot R( hc hc ( ( R( o o means observed at present time! Hot universe filled with free electrons Electron opacity black body radiation field Cooling universe: at some point, e - + H + H 0 Universe becomes transparent. relic of black body radiation field should be observable today.

Redshifted radiation black body radiation field for a lower temperature u o, o,

3 Black-Body Radiation [CO Sect..] Black body for large : (Rayleigh-Jeans tail) also dilute black body Redshifted radiation black body radiation field for a lower temperature u o, o, T = present (observed) values u(r),, T(R) = values when R=R( = R o d = Rd o Both shape and energy density are predicted. Penzias & Wilson.

4 COBE satellite (99). How COBE Changed Things Nobel Prizes Penzias & Wilson, 978 Mather & Smoot, 006 Isotropy of the Cosmic Microwave Background Black body for large Dipole Anisotropy ~ part in 00. Blue = 0 o K Red = o K for v << c (9.6) Blue =.7 o K Red =.7 o K Dipole Anistropy motion of Sun through Universe. After removing dipole Red blue = o K

Isotropy of the Cosmic Microwave Background Black body for large

Dipole Anistropy ~ part in 00 600 km/sec motion of Local Group in

5 Isotropy of the Cosmic Microwave Background Black body for large Local Group Dipole Anisotropy ~ part in 00. Blue = 0 o K Red = o K.. for v << c (9.6) Blue =.7 o K Red =.7 o K Dipole Anistropy motion of Sun through Universe. Dipole Anistropy ~ part in km/sec motion of Local Group in grav. field of larger scale mass concentrations. After removing dipole Red blue = o K Opaque Universe The Cosmic Microwave Background Surface of Last Scattering (Decoupling) Transparent Universe.7 billion light years Earth Opaque Universe 5

6 When did decoupling occur? Saha equation: Collisional ionization rate = Recombination rate -E / kt (8.8) Solve for =, using = electron density R ~ 7.x0 - T ~ 800 K Taking composition and radiative transfer into account: T dec = 970K z dec = 089 R dec = 9x0 - t dec = 79,000 yrs. Decoupling also called recombination The Radiation Era T urad at c urad at rad c c R matter,0 matter R rad R matter See [CO pg. ] rad,0 Knowing R( as function of t Age of U ~ 00 yrs for 0 =, h = 0.7 6

7 During the Radiation Era: Log R( / Log t / RdR dt R t / instead of R t / in matter era. Terminology dr R dt 8 πgρr kc dr R dt CO call it relativistic = photons + neutrinos 8 πg ρ R kc matter crit rel urel rel c rel ( rel ( ( 7

Astronomy 113. Dr. Joseph E. Pesce, Ph.D Joseph E. Pesce, Ph.D.

Astronomy 113. Dr. Joseph E. Pesce, Ph.D Joseph E. Pesce, Ph.D. Astronomy 113 Dr. Joseph E. Pesce, Ph.D. The Big Bang & Matter 17-2 Cosmology ³ The study of the origins, structure, and evolution of the universe ³ Key moments: ² Einstein General Theory of Relativity