Final answer:
The Big Bang Theory was confirmed by the discovery of cosmic background radiation, providing evidence for the beginning of the Earth.
Step-by-step explanation:
The discovery of cosmic background radiation confirmed the Big Bang Theory about the beginning of the Earth. According to this theory, the universe began with a primeval explosion of space, time, matter, and energy. The cosmic microwave background (CMB) radiation, which is the redshifted afterglow of the Big Bang, is a key piece of evidence supporting this theory.