Eposode 97: Light of the Begninning

What does it mean?

Cosmic Microwave Background (CMB) – This is the radiation left over from the big bang. It was produced early in the age of the universe, when the average density and temperature were much higher than today. The expansion of the universe has cooled the radiation to its current temperature of about 2.7 kelvin (The SI unit of temperature is the kelvin, symbol K. The name is to honor the 19th Century Scottish physicist William Thomson, who is more commonly known as Lord Kelvin).