![]() These consisted only of the nuclei of the simplest chemical elements: mostly hydrogen and helium. Protons (hydrogen ions) and neutrons begin to combine into atomic nuclei in the process of nuclear fusion. Temperature: 4 x 10 8 kelvin ( Boesgaard & Steigman, 1985 p.322)ĭuring the photon epoch the temperature of the universe falls to the point where atomic nuclei can begin to form. Graphic from What are the odds? Part 2: Cosmic Inflation! by Ethan Siegelġ0 3 Particle energies drop below Coulomb barrier energies and nucleosynthesis ends. The abundances of the light elements due to Big-Bang nucleosynthesis. Nucleosynthesis: Between 3 minutes and 20 minutes after the Big Bang Temperature: 1 x 10 9 kelvin ( Boesgaard & Steigman, 1985 p.322) Wikipediaġ0 2 seconds Typical photon energies drop below the deuteron binding energy and nucleosynthesis begins. These photons are still interacting frequently with charged protons, electrons and (eventually) nuclei, and continue to do so for the next 380,000 years. Wikipediaġ x 10 0 Charged current weak interactions become too slow and the neutron to proton ratio freezes out Temperature: 1 x 10 10 kelvin ( Boesgaard & Steigman, 1985 p.322)ġ x 10 1 Electron positron annihilation Temperature: 5 x 10 9 kelvin ( Boesgaard & Steigman, 1985 p.322) Radiation Era (Photon epoch)īetween 10 seconds and 380,000 years after the Big BangĪfter most leptons and anti-leptons are annihilated at the end of the lepton epoch the energy of the universe is dominated by photons. Approximately 10 seconds after the Big Bang the temperature of the universe falls to the point at which new lepton/anti-lepton pairs are no longer created and most leptons and anti-leptons are eliminated in annihilation reactions, leaving a small residue of leptons. The majority of hadrons and anti-hadrons annihilate each other at the end of the hadron epoch, leaving leptons and anti-leptons dominating the mass of the universe. Lepton epoch: Between 1 second and 10 seconds after the Big Bang 353)ĥ x 10- 4 By this time the universe has a baryon-antibaryon asymmetry which results from post-inflationary B,C,CP violating processes Temperature: 4 x 10 11 kelvin ( Kolb & Turner 1990 pp.159, 281)ġ x 10- 1 Neutral current weak interactions become too slow and neutrinos decouple Temperature: 3 x 10 10 kelvin ( Boesgaard & Steigman, 1985 p.322) ![]() (See above regarding the quark-gluon plasma, under the String Theory epoch) - Wikipediaġ x 10- 5 Formation of hadrons from quarks Temperature: 2 x 10 12 ( Kolb & Turner 1990 p.72)ħ x 10- 5 Muon anti-muon annihilation Temperature: 1 x 10 12 kelvin ( Harrison, 1981, p. This cosmic neutrino background, while unlikely to ever be observed in detail, is analogous to the cosmic microwave background that was emitted much later. At approximately 1 second after the Big Bang neutrinos decouple and begin traveling freely through space. The quark-gluon plasma that composes the universe cools until hadrons, including baryons such as protons and neutrons, can form. Hadron epoch: Between 10 -6 seconds and 1 second after the Big Bang WikipediaĢ x 10- 7 Tauon anti-tauon annihilation Temperature: 2 x 10 13 kelvin ( Harrison, 1981, p. The fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction have now taken their present forms, but the temperature of the universe is still too high to allow quarks to bind together to form hadrons. In electroweak symmetry breaking, at the end of the electroweak epoch, all the fundamental particles are believed to acquire a mass via the Higgs mechanism in which the Higgs boson acquires a vacuum expectation value. Quark epoch: Between 10 -12 seconds and 10 -6 seconds after the Big Bang. Wikipediaġ x 10- 11 Electroweak unification spontaneous symmetry breaking Temperature: 3 x 10 15 ( Kolb & Turner 1990 p.72) Quark-Lepton Era The masses of particles and their superpartners would then no longer be equal, which could explain why no superpartners of known particles have ever been observed. If supersymmetry is a property of our universe, then it must be broken at an energy that is no lower than 1 TeV, the electroweak symmetry scale. From this point onwards the physics of the early universe is better understood, and less speculative. In the future more text and links could be added here, if someone wants to contribute MAK110726Īfter cosmic inflation ends, the universe is filled with a quark-gluon plasma. For another link, see Rob Knop's post on The History of the Universe at Galactic Interactions. ![]() I've also incorporated the Cosmology timeline from Niel Brandt's Timelines and Scales of Measurement Page (with original references). Graphic by NASA, copied from Red Orbit - Big BangĮditor's note: I'm just copying this from Wikipedia, as this is just a basic place holder page. The separation of forces and evolution of matter following the Big Bang.
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