How does weak background radiation coming from every direction in the sky support the Big Bang theory
The weak background radiation coming from every direction in the sky, known as the Cosmic Microwave Background (CMB), is one of the strongest pieces of evidence supporting the Big Bang theory. Here's how it supports the theory:
1. Predicted by the Big Bang theory: The idea of a background radiation was first proposed by George Gamow, Ralph Alpher, and Robert Herman in the 1940s, as they theorized that the universe began with a hot and dense state of matter. They predicted that as the universe expanded, this initial radiation would cool down and be present everywhere as a remnant of the Big Bang.
2. Discovery of the CMB: In 1965, Arno Penzias and Robert Wilson accidentally stumbled upon the CMB when they noticed a persistent background radio noise coming from all directions in the sky. They initially thought it was due to technical difficulties or pigeon droppings on their antenna, but after rigorous analysis, they realized they had discovered the CMB.
3. Uniform distribution: The CMB is extremely uniform in temperature across the entire sky, with only very small variations in temperature at the level of one part in 100,000. This uniformity supports the idea that the universe was once in a hot and dense state, as predicted by the Big Bang theory.
4. Blackbody spectrum: The CMB has a distinct blackbody spectrum, which means it follows the pattern of radiation emitted by a perfect thermal radiator. This spectrum matches the predictions made by the Big Bang theory, providing further evidence for its validity.
5. Cosmic redshift: When the CMB was initially emitted, it consisted of high-energy photons. However, as the universe expanded, these photons stretched out and cooled down, resulting in the observed microwave radiation. This redshift of the CMB spectrum is consistent with the expansion of the universe as predicted by the Big Bang theory.
6. Hemispherical asymmetry: Despite its overall uniformity, the CMB also exhibits a slight asymmetry in temperature between different parts of the sky. This asymmetry supports the idea that small fluctuations in the early universe eventually led to the formation of galaxies and other structures we observe today, in line with the predictions of the Big Bang theory.
In summary, the discovery and characteristics of the CMB provide strong observational support for the Big Bang theory, lending credibility to the idea that the universe began in a highly energetic and dense state around 13.8 billion years ago.