What led to the conceptualization of the Big Bang?
Cosmic Microwave Background (CMB) radiation.
The discovery of Cosmic Microwave Background (CMB) radiation.by 1978-Nobels Arno A. Penzias and Robert W. Wilson confirmed the explosive nature to the origin of our universe.
CMB is called the echo of the Big Bang (BB) event.
2006-Nobels John Mather and George Smoot analyzed NASA's satellite data and their findings supported the estimate of the age of our universe.