Transcript COSMOLOGY Prospects in Theoretical Physics Institute for Advance Study July, 2002

COSMOLOGY
Prospects in Theoretical Physics
Institute for Advance Study
July, 2002
• What every string theorist should
know about the Universe
• Inflationary Cosmology
• Cyclic Universe
Salient Features of the Universe
• Homogeneity and isotropy
• Universe expanding uniformly
• thermal background of radiation with T~3K
• chemical composition is roughly 75% H, 25% He, + trace
• ordinary matter is more abundant than ordinary antimatter
• nearly scale invariant, adiabatic CMB fluctuations
• universe is spatially flat
• hierarchy of lumpy structure from 1 kpc to 100 Mpc scales
• ordinary matter is a minority (1/6x) of all matter
• matter is a minority (1/4x) of all energy
• expansion rate is accelerating
1 Mpc =3.3 x1019 km = 3.26x106 l-yr
Salient Features of the Universe
• Homogeneity and isotropy for 6000 Mpc > x > 100 Mpc
• Universe expanding uniformly
• thermal background of radiation with T~3K
• chemical composition is roughly 75% H, 25% He, + trace
• ordinary matter is more abundant than ordinary antimatter
• nearly scale invariant, adiabatic CMB fluctuations
• universe is spatially flat
• hierarchy of lumpy structure from 1 kpc to 100 Mpc scales
• ordinary matter is a minority (1/6x) of all matter
• matter is a minority (1/4x) of all energy
• expansion rate is accelerating
H = 72 ±3 (stat) ±7 (sys) km/s/Mpc
Hubble Key Project
Consequences
• Universe has a finite age
age ~ 1/H ~ 14 Gyrs
• Universe has a horizon
Finite age + finite speed of light
• Can look back in time
red shift (z)  time
Salient Features of the Universe
• Homogeneity and isotropy for 6000 Mpc > x > 100 Mpc
• Universe expanding uniformly
• thermal background of radiation with T~3K
• chemical composition is roughly 75% H, 25% He, + trace
• ordinary matter is more abundant than ordinary antimatter
• nearly scale invariant, adiabatic CMB fluctuations
• universe is spatially flat
• hierarchy of lumpy structure from 1 kpc to 100 Mpc scales
• ordinary matter is a minority (1/6x) of all matter
• matter is a minority (1/4x) of all energy
• expansion rate is accelerating
evidence Universe
was once hotter
than .1 eV
evidence
that the
Universe
was once
hotter
than
1 MeV
evidence
of
baryon
asymmetry
Salient Features of the Universe
• Homogeneity and isotropy for 6000 Mpc > x > 100 Mpc
• Universe expanding uniformly
• thermal background of radiation with T~3K
• chemical composition is roughly 75% H, 25% He, + trace
• ordinary matter is more abundant than ordinary antimatter
• nearly scale invariant, adiabatic CMB fluctuations
• universe is spatially flat
• hierarchy of lumpy structure from 1 kpc to 100 Mpc scales
• ordinary matter is a minority (1/6x) of all matter
• matter is a minority (1/4x) of all energy
• expansion rate is accelerating
compare temperature at two points angle q apart
q~ p/l
temperature fluctuation
temperature fluctuation
Large angular scales
outside the horizon at last scattering
temperature fluctuation
temperature fluctuation
q~ p/l