Big Bang Theory
The Big Bang Theory is a cosmological model that describes the universe's expansion from a very high-density and high-temperature state. It is a theory within the field of physical cosmology, which is itself a branch of astrophysics and astronomy, all of which fall under the broader category of science. The Big Bang Theory posits that the universe began as an infinitely dense and hot point nearly 13.8 billion years ago, and has been expanding and cooling ever since. This model is supported by a wide range of observational evidence, including the redshift of distant galaxies and the cosmic microwave background radiation. The Big Bang Theory provides a framework for understanding the history and evolution of the universe, making it a fundamental component of our current understanding of the cosmos.