Cosmic Microwave Background Radiation
Ever notice that when we tune the analog Television between
the two channel we see white snow noise on the screen.it is coming from the
radiation/EM Wave (1%) left over from the BIG BANG. Today, we call it Cosmic Microwave
Background Radiation.
The discovery of the cosmic microwave background
(CMB) in the early 1960's was powerful confirmation of the Big Bang theory.
When
the CMB was initially emitted (about 300,000 years after THE BIG BANG) it was
not in the form of microwaves at all, but mostly visible and ultraviolet light.
Over the past few billion years, the expansion of the universe has redshifted
this radiation toward longer and longer wavelengths, until today it appears in
the microwave band.
Today wherever we see in all direction the temperature is extremely uniform all over the sky.The CMB is remarkable in that no matter which direction in the sky
you look, it appears to be almost the same temperature.i.e. 2.7 Kelvin. This is called isotropy.
pixel in the map above corresponds to the pixel temperature. It
seems to be a perfectly uniform temperature distribution in the radiation
field. However, the fact that we see galaxies and stars in the sky today tells
us that there must have been some "clumpiness" in the matter
distribution in very early times. This uneven matter distribution should have
left an imprint on the radiation distribution of the time. Thus, we should see
tiny irregularities in the CMB today which represent these ancient matter
inhomogeneities.
Another set of instruments on the COBE satellite were designed to
look for these irregularities in the CMB; they were called the Differential
Microwave Radiometers. If there were to be irregularities in the CMB, they
could be seen as tiny hot and cold variations on the sky. In 1992, the COBE
research team announced that it had evidence that these hot and cold spots did
exist, and they released the map below.
However, tiny temperature variations or fluctuations (at the part per million
level) can offer great insight into the origin, evolution, and content of the universe.
The temperature variations in the CMB are very, very small, and the CMB is
uniform up to about 1 part in 100,000. So the variances in temperature have a
range of 2.7K ± 0.00003. If you were to just look at the CMB, it would look
entirely uniform, but scientists have enhanced these small perturbations in the
CMB so that you can see them in the map
Comparision of COBE,WMAP,PLANCK Sensitivity
This CMB image is a picture of the last scattering epoch, i.e. it is an image of the moment when matter and photons decoupled, literally an image of the recombination wall. This is the last barrier to our observations about the early Universe, where the early epochs behind this barrier are not visible to us.
Below is the Latest Release From Planck Satellite by European Space Agency.
The clumpness of the CMB image is due to fluctuations in
temperature of the CMB photons. Changes in temperature are due to changes in
density of the gas at the moment of recombination (higher densities equal
higher temperatures). Since these photons are coming to us from the last
scattering epoch, they represent fluctuations in density at that time.
The origin of these fluctuations are primordial quantum
fluctuations from the very earliest moments that are echo'ed in the CMB at
recombination. Currently, we believe that these quantum fluctuations grew to
greater than galaxy-size during the inflation epoch, and are the source of
structure in the Universe.
also visit below site:-
http://www.bigbangregistry.com/panojs3/exploreMap.php#navbar
also visit below site:-
http://www.bigbangregistry.com/panojs3/exploreMap.php#navbar
