How do cosmic background rays help determine the age the universe was formed?

Hint: Big bang theory explains the beginning or the origin and the evolution of the observable universe. So, using this theory we will continue the explanation of how cosmic rays background helped to determine the age the universe was formed

Complete answer:
The universe found its origin or existence through an explosion or a big bang. About 13.8 billion years ago, a tiny point (the initial state of high density and temperature) got concentrated. This tiny point began to expand and finally exploded and the fragments of the explosion started moving away in the form of galaxies. Thus, 13.8 billion years ago is considered the age of the universe.
Big bang theory not only explains the evolution of the universe, but also, it describes the CMB radiation, that is, the cosmic microwave background radiation.
The measurements of the temperature fluctuations in the cosmic microwave background are used to define the age of the universe. The cosmic inflation got caused at approximately \[{{10}^{-37}}\] seconds into the expansion of the universe.
\[\therefore \]The radiation emitted by the explosion during the formation of the universe is used to determine the age the universe was formed.

Additional information:
The radiation because of the formation of the atoms by the combination of the electrons and nuclei after about 379,000 years of cooling of the universe is known as the cosmic microwave background.

Note:
Hubble-Lemaitre law explains about the galaxies, that is, their movement (the farther away from the galaxies, the faster they are moving away from earth). The cosmic background explorer (COBE) defines the usage of the cosmic rays to determine the age the universe was formed.