CMB stands for Cosmic Microwave Background, which refers to a faint radiation that permeates the universe uniformly in all directions. It is often considered as a form of "afterglow" from the Big Bang, offering important insights into the early stages of the universe.
The Cosmic Microwave Background was first discovered in 1965 by Arno Penzias and Robert Wilson, who accidentally stumbled upon a persistent microwave signal that seemed to come from all directions of the sky. It was subsequently recognized as the radiation remnants of the hot and dense early universe, which has since expanded and cooled down over billions of years.
The CMB is characterized by a nearly perfect blackbody spectrum, meaning it corresponds to radiation emitted by an idealized object that absorbs all radiation incident upon it. It exhibits a uniform temperature of approximately 2.7 Kelvin (or -270.45 degrees Celsius), with tiny fluctuations in temperature that reflect the primordial density variations in the early universe.
Cosmologists study the CMB to gain insights into various aspects of the cosmos, such as the age, geometry, and composition of the universe. The analysis of these temperature fluctuations provides valuable information about the origin and evolution of large-scale structures like galaxies and galaxy clusters, as well as the presence of dark matter and dark energy.
In summary, the term CMB refers to the Cosmic Microwave Background, a faint, uniform radiation present throughout the universe that offers a glimpse into the early stages of the cosmos after the Big Bang.
