Cosmic Microwave Background (CMB)
Images
The Cosmic Microvave Background
A theoretical blackbody curve with 34 COBE data points equally
spaced along the curve: the data matches
the curve so closely that curve and data and not distinguishable.
The temperature is T=2.73 K.
COBE Full Sky
Map of the Variations in the
Cosmic Microwave Background This is the final 4-year
map of the CMB.
Blue are points of low temperature, high density.
Red are points of high temperature, low density.
The high density regions are "colder" because of a
gravitational redshift effect (Frak576).
The largest varitions are only about 1/10000.
Boomerang Map of the Variations in
the CMB Boomerang is a balloon mission in Antarctica
that studied detailed the CMB. It flew in 1998dec and the
first results published 2000apr27.
The image (25 X 10 degrees) is dominated by cold and hot spots
(which color is which?) of about 1 degree size on the sky.
The temperature variation is about 1/10000 of the T=2.73 K,
modern CMB blackbody temperature.
The bottom three panels show 3 model simulations for three
space-time geometries: hyperspherical, flat (Euclidean),
and hyperbolic.
These images suggest and detailed modeling show that the
data is consitent with a flat universe to a high degree.
The cosmic density in units of the critical density
for flatness is Omega_0 in range 0.88 to 1.12.
Simple inflation predicts Omega=1 to 1/10**4?????
The Omega_Lambda-Omega_Mass Plane
with SN Ia and Boomerang Data
Omega is the mass-energy density density of the universe
in units of the critical density: Omega < 1 and universe is
hyperbolic and open (infinite?) and Omega > 1 and the universe
is hyperspherical and closed (finite?): Omega=1 and the universe
is flat (Euclidean) and open (infinite?).
Two kinds of Omega have considered:
Omega_M is ordinary mass-energy which we understand well;
Omega_Lambda is cosmological constant energy which was introduced
by Einstein to create a cosmic repulsive force.
Omega_Lambda is poorly understood and may be just a fudge
factor subsuming a lot of unknown physics.
But the simplest cosmologies have the two Omegas as parameters
and these cosmologies guide our interpretation of observations.
This map shows 95 % confidence intervals for data from SN Ia
and Boomerang data.
If both are correct, then universe lies in the green region.
Thus Omega_M=~.35 (Omega_luminous=~.01) and Omega_Lambda=~.65.
The universe is close to being flat:
Omega_0 in range 0.88 to 1.12.
Simple inflation predicts Omega=1 to 1/10**4?????
Close to flat is not as exactly flat as inflation predicts, but
so far inflation looks good.
The age of the universe is in the range .85/H_0--1.05/H_0 or
about 14 Gyr for H_0=70.
The universal expansion is accelerating.
Note that the parameters of the universe discussed here only
have exact meaning within the modified Friedmann models of
the universe: if those models are wrong or approximations
(as there are in inflationary cosmology), then parameters
may not mean quite or anything like what it is thought they do.
