Final answer:
Penzias and Wilson inadvertently discovered the Cosmic Microwave Background while trying to reduce noise in radio communications, leading to major support for the Big Bang theory and earning them the Nobel Prize in Physics in 1978.
Step-by-step explanation:
The discovery of the Cosmic Microwave Background (CMB) by Arno Penzias and Robert Wilson is a landmark event in the field of astronomy and cosmology. Initially, Penzias and Wilson set out to eliminate persistent background noise in their radio communications experiments at Bell Laboratories. While attempting to identify and filter out the source of this noise, they stumbled upon a consistent microwave signal that seemed to come from every direction in the sky. After consulting with scientists at Princeton University, they were informed that their findings coincided with theoretical predictions of the CMB, the residual thermal radiation from the Big Bang. In essence, they had discovered the faint afterglow of the universe's creation, present throughout the cosmos. Their serendipitous discovery provided major empirical support for the Big Bang theory, solidifying it as the prevailing cosmological model for the origin and evolution of the universe. This milestone earned Penzias and Wilson the Nobel Prize in Physics in 1978.