The Big Bang (1927-1964)

The Big Bang theory is humanity's first scientific account of the universe's origin, supported by convergent evidence from four independent methods. Proposed by Georges Lemaître in 1927 and confirmed by Hubble's 1929 observations and the 1964 discovery of cosmic microwave background, it now narrows the universe's age to 13.8 billion years with a 0.1% margin. This outperforms the Periodic Table in age-of-the-universe precision, marking a 100-fold improvement in accuracy over prior estimates.