More buzz words, etc. Structure evolution and types of WIMPS Bottom-up Cold Dark Matter (CDM) Top-Down Hot Dark Matter (HDM) “Cold” = “slow” = less then 1/10 speed of light “Hot” = “fast” = 0.99 or closer to speed of light Galaxies seen far away => formed early = bottom up = CDM

Key points to derivation of we live in flat universe From CBM: We assume we know how to calculate the size of the brick wall fluctuations! [Remember we assume ADIABATIC fluctuations] Apparent size depends ENTIRELY on the curvature of the of the universe => we think we’re flat “for sure” But only if adiabatic fluctuations apply!

Is there a way out? Yes! =“Isocurvature” fluctuations Dissociate the matter from the light “Brick wall” can be as smooth as you please Apparent size of the brick wall fluctuations Ambiguous => Assume a size that agrees with any geometry ( k = -1, 0, 0r 1

Summary: CMB associated with Big Bang BB plus GR says Universe was hot and is expanding CMB measurements with model fitting: Most likely universe is flat

Summary cont.: If universe is flat, there is lots (90%-95%) of something that is not ordinary (baryonic) matter. Therefore CMB + Clusters says need Dark Energy to make up the difference But clusters say only 30% of  can come from all forms of matter. Agrees with SNe Ia

SNe Ia CMB clusters

Summary Cont. So  m = 0.3,   = 0.7, k = 0 (flat) will expand forever in an accelerating manner Problem is “crazy” universe: Dark Energy, non-baryonic matter, invisible baryonic matter. Ways out: We’ve just screwed up big time Isocurvature can remove dark energy (from k = 0 and matter limits) from CMB measurements BUT still have SN Ia!

 rick Building or Pack of Cards? GR + CMB total +expanding universe  ig Bang General Smoothness of CMB Galaxies and Clusters exist Non-ordinary [but real] matter (non-baryonic), lots CMB “1st peak,” universe flat =  total = 1, k = 0 Supernovae says dark energy Galaxies formed early CDM Clusters say  m 0.3 “Final” Answer:  t =   +  m = 1; k = 0;  b = 0.05,  CDM = 0.25,   = 0.7

Onward ho! OK, where do supernovae fit in and how? First the concept: the standard candle If know how bright something is intrinsically, then if you can measure it’s apparent brightness, you can calculate the Distance (D) Apparent brightness = intrinsic brightness/4 p D 2 For Euclidian space D is “normal”