The Big Bang is the scientific model that describes the origin of the Universe. He explains that the Universe was born there about 13.8 billion years from an extremely dense and warm state, then that it is expanding Since then. It's not a space explosion, it's a space explosion. expansion of space itself. The main evidence of the Big Bang is:

• Iexpansion of the Universe observed by the red offset of galaxies,
• on fossil radiation (cosmological diffuse background),
• the distribution of light elements (hydrogen, helium).

The idea of the Big Bang was first formulated in 1927 by Georges Lemaître, Belgian priest and astrophysicist. He proposed that the Universe come from a « primitive atom ». The term « Big Bang » later popularized in 1949 by astronomer Fred Hoyle (initially critically). Today, the Big Bang model is the framework of modern cosmology, even though the very first moments of the Universe remain partially unknown.