The cosmic microwave background Radiation's "surface of last scatter" is analogous to the light coming through the clouds to our eye on a cloudy day.
We can only see the surface of the cloud where light was last scattered..
cosmic microwave background (CMB), also called cosmic background radiation, electromagnetic radiation filling the universe that is a residual effect of the big bang 13.8 billion years ago.
Because the expanding universe has cooled since this primordial explosion, the background radiation is in the microwave region of the electromagnetic spectrum.
What does Cosmic Microwave Background Radiation tell us.
Hot and Cold Spots and the Composition of the Universe which is mostly Dark energy 68%, Dark Matter 27% and only 5% matter such as:
The cosmic microwave background (CMB) radiation tells us the age and composition of the universe and raises new questions that need to be answered.
See how the Cosmic Microwave Background works and can be detected here. (Image credit:
The top pair of figures show the temperature of the microwave sky in a scale in which blue is 0 Kelvin (absolute zero) and red is 4 Kelvin.
Note that the temperature appears completely uniform on this scale.
The actual temperature of the cosmic microwave background is 2.725 Kelvin.
The cosmic microwave background (CMB) is leftover radiation from the Big Bang or the time when the universe began.
As the theory goes, when the universe was born it underwent rapid inflation, expansion and cooling. (The universe is still expanding today, and the expansion rate appears different depending on where you look ).
