Cosmology -- the Origin and Structure of the Universe Cosmological Principle – the Universe appears the same from all directions . There is no preferred location. (The physical laws apply to the whole Universe). Is there a preferred time ?

The Distance – Redshift Relation (Hubble Law) The Distribution of Matter – Large Scale Structure Implications of the finite velocity of light Consequences of star birth and death

Cosmological models -- “world views” How we perceive our Universe and our relation to it Historical models -- geocentric heliocentric galactocentric By mid 20th century -- 3 models or theories Big Bang -- Father LeMaitre, George Gamow Oscillating Universe Steady State -- Fred Hoyle Early 21st century – Big Bang cosmology firmly established

3 degree background radiation or cosmic microwave background radiation (CMB) Nobel Prize 1978

Subsequent work -- numerous measurements, balloon, satellites COBE WMAP

The Big Bang -- the standard model -- ~14 x 109 yrs

The Early Universe – the Hubble Deep Field (HDF) Deepest exposure with HST 10 consecutive days , 342 exposures, Reaching > 30th mag

Small irregular galaxies - among first objects Glow from first stars ?

Other considerations -- the critical density of matter, finite or infinite ? and the shape of space

Type Ia supernovae, the accelerating Universe and dark energy Nobel Prize 2011 Saul Perlmutter Brian Schmidt Adam Reiss

Recent development --- detection of gravity waves via polarization in the CMB BICEP2 experiment (2014) Inflation --- theory – proposed to explain the size and flatness of space, existence of inhomogeneities that led to star and galaxy formation The new results support/confirm inflation model

At the beginning of the 21st century: The Universe began in a superdense state; it is flat, expanding, the expansion is accelerating, it is dominated by dark energy, and will expand forever. What about the future ?