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26 September 2010

My Essay Part (X) - Cosmic Microwave Background

The Cosmic Microwave Background as detected by WMAP satellite: The red region is where matter is dense and the blue region is the voids.

But not for another 380000 years does much to our soup of atomic nuclei because the universe is still hot enough for the electrons to stay away from the nucleus flying freely with the photons. Until the temperature of the universe dropped to about 3000 degrees Kelvin, the electrons start to combine with the nucleus forming the first stable atoms and this process will release visible light photons that bath our universe. As the space-time continue to expand, the photons slowly lose its energy and changes its frequency from visible light towards infrared and now microwaves.

When astrophysicist now look into every part of the night time sky with microwave detectors, they find an unmistakable fingerprint of 2.73 degree Kelvin microwave photons whose patterns in the sky retains the memory of the distribution of matter just after atoms were formed.

1 comment:

Anonymous said...

more important than the cool down is the fact that the intensity of the microwave background precisely matches that of a perfect absorber and emitter attests to the fact that matter and radiation in the early universe were in equilibrium, i.e., both had identical temperatures thus the Big Bang was a smooth and uniform event. Had deviations from the blackbody spectrum been detected, these would have indicated energetic processes in the early universe and a clumpier distribution of primordial matter. but no such deviations were detected, such is the beauty of immense dimensions.