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"Big Bang theory" redirects here. For the American TV sitcom, see The Big Bang Theory. For other uses, see Big Bang (disambiguation).
According to the Big Bang model, theUniverse expanded from an extremely dense and hot state and continues to expand today. A common analogy explains that space itself is expanding, carrying galaxies with it, like spots on an inflating balloon. The graphic scheme above is an artist 's concept illustrating the expansion of a portion of a flat universe.
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Social impact[show] Astronomy portal Category: Physical cosmology v t e The Big Bang theory is the prevailing cosmological model for the early development of the Universe.[1] According to the theory, the Big Bang occurred approximately 13.798 ± 0.037 billion years ago,[2][3][4][5][6] which is thus considered the age of the universe.[7][8][9][10] At this time, the Universe was in an extremely hot and dense state and began expanding rapidly. After the initial expansion, the Universe cooled sufficiently to allow energy to beconverted into various subatomic particles, including protons, neutrons, and electrons. Though simple atomic nuclei formed within the first three minutes after the Big Bang, thousands of years passed before the first electrically neutral atoms formed. The majority of atoms that were produced by the Big Bang are hydrogen, along with helium and traces of lithium. Giant clouds of these primordial elements later coalesced through gravity to form stars and galaxies, and the heavier elements were synthesized either within stars or during supernovae.
The Big Bang is the scientific theory that is most consistent with observations of
References: XDF (2012) view - each light speck is a galaxy - some of these are as old as 13.2 billion years[26] - the universe is estimated to contain 200 billion galaxies.