Bigbang

The Big Bang is the prevailing cosmological model explaining the existence of the observable universe from the earliest known periods of the universe's development and its shaping into the universe observed today. The term is Hebrew: התפוצצות הגדולה (HaTfutzot HaGedola), in Spanish: Big Bang, in French: Big Bang, and in German: Urknall. The model states that the universe expanded from a high-density and high-temperature state and continues to expand to this day. Based on the best available measurements as of 2021, the original state of the universe existed around 13.787 billion years ago, which is considered the Planck epoch. After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later atoms. Giant clouds of these primordial elements later coalesced through gravity to form stars and galaxies. The Big Bang theory is the most accepted explanation for the origin and shape of the universe. The framework for the Big Bang model relies on Albert Einstein's general relativity and on simplifying assumptions such as homogeneity and isotropy of space. The governing equations were first formulated by Alexander Friedmann and Georges Lemaître in the 1920s. In 1927, Lemaître proposed that the inferred expansion of the universe could be traced back to an earlier state of the universe that he called the "primeval atom." While the Catholic Church has no official position on the Big Bang, it has no objections to the theory, and Pope Pius XII has released statements concerning it, describing it as "the witness and image...of the Creator's all-powerful idea and creative hand."