Prospects in Theoretical Physics

1
COSMOLOGY
Prospects in Theoretical Physics Institute for
Advance Study July, 2002
2

• What every string theorist should know about
  the Universe
• Inflationary Cosmology
• Cyclic Universe

3
Salient Features of the Universe
Homogeneity and isotropy
Universe expanding uniformly
thermal background of radiation with T3K
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
4
1 Mpc 3.3 x1019 km 3.26x106 l-yr
5
(No Transcript)
6
6000 Mpc
7
Salient Features of the Universe
Homogeneity and isotropy for 6000 Mpc gt x gt
100 Mpc
Universe expanding uniformly
thermal background of radiation with T3K
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
8
H 72 3 (stat) 7 (sys) km/s/Mpc
Hubble Key Project
9
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
10
Salient Features of the Universe
Homogeneity and isotropy for 6000 Mpc gt x gt
100 Mpc
Universe expanding uniformly
thermal background of radiation with T3K
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
11
evidence Universe was once hotter than .1 eV
12
evidence that the Universe was once hotter than 1
MeV
evidence of baryon asymmetry
13
Salient Features of the Universe
Homogeneity and isotropy for 6000 Mpc gt x gt
100 Mpc
Universe expanding uniformly
thermal background of radiation with T3K
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
14
compare temperature at two points angle q apart
15
?? p/l
16
temperature fluctuation
temperature fluctuation
17
temperature fluctuation
temperature fluctuation
18
?? p/l