Presentation on theme: "Dark Matter, Dark Energy, and the Current State of Cosmology Nick Kaiser Institute for Astronomy University of Hawaii."— Presentation transcript:
Dark Matter, Dark Energy, and the Current State of Cosmology Nick Kaiser Institute for Astronomy University of Hawaii
The Coma Cluster
Zwicky & the Missing Mass Measured galaxy speeds in Coma Virial theorem: M/L ~ 500 M_sun/L_sun The missing mass An outstanding problem in cosmology –90-98% of the universe is in a mysterious form –detectable only by its gravitational attraction
The Dark Matter Puzzle Where is it? How much is there? What is it?
Cosmology in a nutshell: The old cosmology –Friedmann; Einstein; de Sitter …. The New Cosmology –Inflation - scalar fields The Hot Big Bang Structure Formation
The Friedmann Model Scale factor R(t) mass density and curvature of space problems –horizon –flatness
Inflationary Cosmology In the beginning there was the field…. Vector, tensor and scalar fields Weinberg-Salaam: –unified theory - the Higgs field The inflaton –central to inflation –solves the old problems –predicts a flat universe =1 –quantum fluctuations structure formation
The Hot Big Bang The cosmic kitchen –big bang nucleosynthesis Abundance of baryons – baryons ~ 0.02 Relics –cosmic background –neutrinos
Structure Formation Quantum fluctuations gravitational instability dark matter the cosmic web
The Cosmic Web
The history of the Universe
Inventory of Dark Matter Galaxies –luminous parts M/L ~ 1-5 –flat rotation curves M/L ~ 30 Pairs … Groups … Clusters –M/L ~ Super-Cluster Dynamics – = 1?
Gravitational Lensing Gravity bends light rays –probe of dark matter –highly versatile microlensing - machos galaxy lensing lensing by cluster lensing by superclusters
Theory of gravitational lensing
Lensing by galaxies
Lensing by clusters
Cosmic Microwave Background Relic from the big bang Probe of t ~ 100,000 yr COBE –large angle BOOMERANG –small angles –flat Universe
The COBE Sky
From COBE to BOOMERANG
The Universe is flat!
What is the Matter? Neutrinos? –No longer popular Axions or other fields? WIMPs? Etc etc etc…. Plenty of theory - scarce observations
Dark Energy Consensus model: ~ 0.3 CMB = 1 resolution: the accelerating Universe –expansion history from supernovae –fainter than expected –universe is being accelerated - dark energy –late time inflation - yet another field?
The Nearest Galaxies LMC SMC February 22, 1987
Expansion History from SN 9
The Current Status of Cosmology A working model for creation of the Universe and the structure therein Impressive concordance with current observations Embarrassing number of ingredients –luminous baryons; dark baryons; neutrinos; dark matter; dark energy…. Epicycles?