Cosmology

• Characteristics of the Universe

• static/evolving

• finite/infinite

• open/closed

• Density parameter

• critical density

• matter density

• luminous matter (1%)

• dark matter (30%)

• energy density (~70%)

Key Observations

• Universe is evolving

• Hubble diagram, v = Hd

• Matter curves space

• deflection of starlight by sun

• Big Bang

• 3K Cosmic Background Radiation

• ratio of H to He abundance

Anthropic Principle:

our presence (intelligence) constrains universe’s properties

Supporting Concepts

• Doppler effect

• blue shift: source approaching

• red shift: source receding

• Heavy element synthesis

• H, He created in BB

• other elements in stellar fusion

• Hydrodynamic equilibrium

• gravity vs. pressure

• negative feedback

Star's Life Cycle

• Protostar

• Main Sequence

• Burns H --> He

• From 50 Msun --> 0.1 Msun

• Red Giant/Red Supergiant

• Large envelope

• Eject C, N

• White Dwarf/Supernova

• Radiate away energy

• Eject all other elements