What is the Big Bang Theory?
The Big Bang Theory is a scientific explanation for the origin and evolution of the universe. According to this theory, the universe began as a singularity approximately 13.8 billion years ago. This singularity was an infinitely dense and hot point that expanded rapidly in an event known as the Big Bang.
As the universe expanded, it cooled, allowing subatomic particles to form. Within the first few minutes, these particles combined to create simple nuclei, primarily hydrogen and helium. After about 380,000 years, the universe had cooled sufficiently for electrons to combine with these nuclei, forming neutral atoms. This process is known as recombination.
The release of photons during recombination enabled the universe to become transparent, leading to the phenomenon known as cosmic microwave background radiation, which is a crucial piece of evidence for the Big Bang Theory. Over billions of years, gravitational forces caused matter to coalesce, forming stars, galaxies, and ultimately the large-scale structure of the universe we observe today.
The Big Bang Theory is supported by various astrophysical observations, including the redshift of distant galaxies and the uniform distribution of cosmic microwave background radiation. Despite its acceptance, some aspects of the theory are still under investigation, such as the exact mechanisms behind the expansion and the nature of dark matter and dark energy.