oct 23, 1968 - In 1965, Radio astronomers Arno Penzias and Robert Wilson discovered Cosmic Microwave Background radiation at the temperature of -454.765 degree Fahrenheit, or 2.725 degree Kelvin. This provided evidence that the big bang caused extreme heat that is still mesurable.
Added to timeline:
Date:
oct 23, 1968
Now
~ 56 years ago