Cosmic Background Radiation, often referred to as the Cosmic Microwave Background (CMB), is a form of electromagnetic radiation that fills the universe and is a key piece of evidence supporting the Big Bang theory of the universe's origin. Here are the fundamental aspects of Cosmic Background Radiation:
Discovery: Cosmic Background Radiation was discovered accidentally in 1964 by Arno Penzias and Robert Wilson, two radio astronomers working at Bell Telephone Laboratories in New Jersey, USA. They were using a large radio antenna to conduct experiments but were puzzled by a persistent low-level noise that seemed to come from every direction in the sky.
Origin: The CMB is believed to have originated approximately 13.8 billion years ago, shortly after the Big Bang. At that time, the universe was extremely hot and dense. As the universe expanded and cooled, it left behind a remnant of radiation in the form of microwave photons.
Nature: The CMB consists of microwave photons with wavelengths in the microwave portion of the electromagnetic spectrum. These photons have cooled over billions of years due to the expansion of the universe and now have a temperature of approximately 2.7 Kelvin (about -454 degrees Fahrenheit or -270 degrees Celsius).
Uniformity: One of the most significant observations about the CMB is its remarkable uniformity. When astronomers measure the temperature of the CMB in different directions in the sky, they find that it is nearly the same in all directions, with only tiny fluctuations or variations at the level of about one part in 100,000. This uniformity strongly supports the idea that the universe was once much hotter and denser, as predicted by the Big Bang theory.
