The Big Bang Theory is a scientific model that explains the origins of the universe. Here are the key details:
Overview
- Event: The Big Bang refers to an explosion of energy and matter that occurred approximately 13.8 billion years ago, marking the beginning of time and expansion of the universe.
- Expansion: Following the initial explosion, the universe has been expanding ever since, as observed through the redshift of light from distant galaxies.
- Evidence:
- Cosmic Microwave Background (CMB) radiation, which is the thermal radiation left over from the time of recombination when the universe was about 380,000 years old.
- Abundance of light elements like hydrogen and helium, which matches predictions from Big Bang Nucleosynthesis.
- The observed large scale structure of the universe, which can be explained by the growth of tiny quantum fluctuations during the inflationary epoch.
History of the Theory
- 1927: Georges Lemaître, a Belgian priest and physicist, proposed the hypothesis of the primeval atom, which laid the groundwork for the Big Bang Theory.
- 1929: Edwin Hubble provided observational evidence of an expanding universe, known as Hubble's Law, which supports the idea of an initial explosive event.
- 1948: George Gamow, along with Ralph Alpher and Robert Herman, developed the idea further, predicting the existence of cosmic background radiation.
- 1964: Arno Penzias and Robert Wilson accidentally discovered the CMB while working on a satellite communication system, providing strong evidence for the Big Bang Theory.
Key Concepts
- Singularity: The theory posits that the universe began as an infinitely hot and dense point called a singularity.
- Inflation: A period of extremely rapid (exponential) expansion of the universe, thought to have occurred when the universe was around 10-36 seconds old, smoothing out any initial irregularities.
- Nucleosynthesis: The process through which the first light elements were formed in the early universe.
- Recombination: The era when electrons and protons combined to form neutral hydrogen atoms, allowing photons to travel freely through space, leading to the CMB.
Current Research
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