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  2. Big Bang - Wikipedia

    en.wikipedia.org/wiki/Big_Bang

    The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. [1] The notion of an expanding universe was first scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations. [2][3][4][5]

  3. Lambda-CDM model - Wikipedia

    en.wikipedia.org/wiki/Lambda-CDM_model

    Astronomy portal. v. t. e. The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components: a cosmological constant, denoted by lambda (Λ), associated with dark energy. the postulated cold dark matter, denoted by CDM. ordinary matter. It is referred to as the standard model of ...

  4. Baryon asymmetry - Wikipedia

    en.wikipedia.org/wiki/Baryon_asymmetry

    This refers to the small non-zero value of baryons over photons (≈ 5 −10) in the current Universe. In physical cosmology, the baryon asymmetry problem, also known as the matter asymmetry problem or the matter–antimatter asymmetry problem, [1][2] is the observed imbalance in baryonic matter (the type of matter experienced in everyday life ...

  5. Missing baryon problem - Wikipedia

    en.wikipedia.org/wiki/Missing_baryon_problem

    In cosmology, the missing baryon problem is an observed discrepancy between the amount of baryonic matter detected from shortly after the Big Bang and from more recent epochs. Observations of the cosmic microwave background and Big Bang nucleosynthesis studies have set constraints on the abundance of baryons in the early universe, finding that ...

  6. Chronology of the universe - Wikipedia

    en.wikipedia.org/wiki/Chronology_of_the_universe

    The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level. [1]

  7. History of the Big Bang theory - Wikipedia

    en.wikipedia.org/wiki/History_of_the_Big_Bang_theory

    The history of the Big Bang theory began with the Big Bang 's development from observations and theoretical considerations. Much of the theoretical work in cosmology now involves extensions and refinements to the basic Big Bang model. The theory itself was originally formalised by Father Georges Lemaître in 1927. [1]

  8. Big Bang nucleosynthesis - Wikipedia

    en.wikipedia.org/wiki/Big_Bang_nucleosynthesis

    v. t. e. In physical cosmology, Big Bang nucleosynthesis (also known as primordial nucleosynthesis, and abbreviated as BBN) [1] is the production of nuclei other than those of the lightest isotope of hydrogen (hydrogen-1, 1 H, having a single proton as a nucleus) during the early phases of the universe. This type of nucleosynthesis is thought ...

  9. Cosmological phase transition - Wikipedia

    en.wikipedia.org/wiki/Cosmological_phase_transition

    A cosmological phase transition is a physical process, whereby the overall state of matter changes together across the whole universe. The success of the Big Bang model led researchers to conjecture possible cosmological phase transitions taking place in the very early universe, at a time when it was much hotter and denser than today. [1][2]