Answer:
temperature of about 2.72548 ± 0.00057 K.
Step-by-step explanation:
The cosmic background radiation is an electromagnetic radiation that remains from an early stage of the universe during the big bang. It was accidentally discovered in 1965 by two American radio astronomers Arno Penzias and Robert Wilson. The radiation was given off before the formation of stars and planets, when the universe was young, denser, hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma, which cooled down as the universe expanded. From calculations, it was deduced that the radiation had a temperature of 2.72548±0.00057 K, which is close to the temperature of the universe during its formation.