Big bang

Big Bang is a cosmological model that describes the observable universe's earliest known periods. The model postulates that the universe was in a high-temperature state and has been expanding since. The Big Bang theory is the prevailing cosmological model explaining the existence of the observable astronomical phenomena.

History

The term "Big Bang" was coined by Fred Hoyle, a critic of the theory, during a 1949 radio broadcast. It is popularly reported that Hoyle intended this to be pejorative, but Hoyle explicitly denied this and said it was just a striking image meant to highlight the difference between the two theories for the radio audience.

Theory

The Big Bang theory is a cosmological model of the observable universe from the earliest known periods through its subsequent large-scale evolution. The model describes how the universe expanded from an initial state of high density and temperature, and offers a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the cosmic microwave background (CMB) radiation, and the Hubble diagram.

Evidence

The three pillars of the Big Bang theory are the cosmic microwave background, the abundance of light elements, and Hubble's law. Observations of these phenomena continue to be consistent with the Big Bang theory.

Criticisms and alternatives

Despite its widespread acceptance, the Big Bang theory has been subject to various criticisms. Alternatives to the Big Bang theory have been proposed, including the steady state theory and the oscillating universe theory.

See also

• Cosmology
• Redshift
• Universe
• Cosmic microwave background
• Hubble's law