Editing Timeline of the universe

{{short description|none}}<!-- "none" is preferred when the title is sufficiently descriptive; see [[WP:SDNONE]] -->
{{for|more details|chronology of the universe}}
{{Use dmy dates|date=April 2022}}
{{More citations needed|date=October 2016}}
[[File:CMB Timeline300 no WMAP.jpg|thumb|upright=2.0|Diagram of Evolution of the universe from the Big Bang (left) to the present]]
The '''timeline of the universe''' begins with the [[Big Bang]], 13.799 ± 0.021 billion years ago, <ref name="esa">{{cite web |date=March 21, 2013 |title=Planck reveals an almost perfect universe |url=https://www.mpg.de/7044245/Planck_cmb_universe |access-date=2020-11-17 |publisher=Max-Planck-Gesellschaft}}</ref> and follows the formation and subsequent evolution of the [[Universe]] up to the present day.
Each ''[[era]]'' or ''[[Periodization#History|age]]'' of the universe begins with an "[[epoch]]", a time of significant change. Times on this list are relative to the moment of the Big Bang.

== First 20 minutes ==
{{Nature timeline}}

=== Planck epoch ===
* c. 0 seconds (13.799 ± 0.021 [[Bya (unit)|Gya]]): [[Planck epoch]] begins: [[Big Bang]] occurs in which ordinary space and time develop out of a primeval state described by a [[Quantum gravity|quantum theory of gravity]] or "[[Theory of everything]]". All matter and energy of the  universe is contained in a hot, dense point ([[gravitational singularity]])

=== Grand unification epoch ===
* c. 10<sup>−43</sup> seconds:  [[Gravity]] separates and begins operating on the universe—the remaining fundamental forces stabilize into the [[electronuclear force]], also known as the Grand Unified Force or [[Grand Unified Theory]] (GUT), mediated by (the hypothetical) [[X and Y bosons]] which allow early [[matter]] at this stage to fluctuate between [[baryon]] and [[lepton]] states.<ref>
{{cite book
 |author1=Cheng, Ta-Pei |author2=Li, Ling-Fong |year=1983
 |title=Gauge Theory of Elementary Particle Physics
 |url=https://archive.org/details/gaugetheoryeleme00chen_958 |url-access=limited |page=[https://archive.org/details/gaugetheoryeleme00chen_958/page/n443 437]
 |publisher=[[Oxford University Press]]
 |isbn=0-19-851961-3
}}</ref>

=== Inflation ===
* c. 10<sup>−35</sup> seconds: [[cosmic inflation|inflation]], expands the universe by a factor of the order of 10<sup>26</sup> over a time of the order of 10<sup>−33</sup> to 10<sup>−32</sup> seconds. The universe is [[supercooled]] from about 10<sup>27</sup> down to 10<sup>22</sup> kelvin.<ref>Guth, "Phase transitions in the very early universe", in: Hawking, Gibbon, Siklos (eds.), ''The Very Early Universe'' (1985).</ref> 
* c. 10<sup>−32</sup> seconds: Cosmic inflation ends.<ref name="Chow-2008">{{Cite book |last=Chow |first=Tai L. |url=https://www.worldcat.org/title/166358163 |title=Gravity, black holes, and the very early universe: an introduction to general relativity and cosmology |date=2008 |publisher=Springer |isbn=978-0-387-73629-7 |location=New York |oclc=166358163}}</ref>{{rp|193}} The familiar [[elementary particle]]s now form as a soup of hot ionized gas called [[quark–gluon plasma]];

=== Quark epoch ===
* c. 10<sup>−12</sup> seconds: [[Cosmological phase transition#Electroweak phase transition|Electroweak phase transition]]: The [[weak nuclear force]] is now a short-range force as it separates from [[electromagnetic force]], so matter particles can [[Higgs mechanism|acquire mass]] and interact with the [[Higgs Field]]. The [[quark–gluon plasma]] persists ([[Quark epoch]]). The universe cools to 10<sup>15</sup> kelvin.{{cn|date=January 2025}}

=== Quark-hadron transition ===
* c. 10<sup>−6</sup> seconds: As the universe cools to about 10<sup>10</sup> kelvin, a quark-hadron transition takes place in which quarks become [[color confinement|confined]] in more complex particles—[[hadrons]].<ref name=Peacock-1998>{{Cite book |last=Peacock |first=J. A. |url=https://www.cambridge.org/core/product/identifier/9780511804533/type/book |title=Cosmological Physics |date=1998-12-28 |publisher=Cambridge University Press |isbn=978-0-521-41072-4 |edition=1 |doi=10.1017/cbo9780511804533}}</ref>{{rp|305}}

=== Lepton epoch ===
* c. 1 second: [[Lepton epoch]] begins: The universe cools to 10<sup>9</sup> kelvin. At this temperature, the hadrons and antihadrons annihilate each other, leaving behind [[leptons]] and [[antileptons]] – possible disappearance of [[antiquarks]]. Gravity governs the expansion of the universe: neutrinos [[Decoupling (cosmology)|decouple]] from matter creating a [[cosmic neutrino background]].{{cn|date=January 2025}}

=== Photon epoch ===
* c. 10 seconds: [[Photon epoch]] begins: Most leptons and antileptons annihilate each other. As [[electrons]] and [[positrons]] annihilate, a small number of unmatched electrons are left over – disappearance of the positrons.{{cn|date=January 2025}}
* c. 10 seconds: Universe dominated by photons of radiation – ordinary matter particles are coupled to [[light]] and radiation. 
* c. 3 minutes: Primordial [[nucleosynthesis]]: [[nuclear fusion]] begins as [[lithium]] and heavy hydrogen ([[deuterium]]) and [[helium nuclei]] form from protons and neutrons.
* c. 20 minutes: Primordial nucleosynthesis ceases

== Matter era ==

=== Matter and radiation equivalence ===
* c. 47,000 years (''z'' = 3600): [[Matter]] and radiation equivalence
* c. 70,000 years: As the temperature falls, [[Jeans length|gravity overcomes pressure]] allowing first aggregates of matter to form.

===Cosmic Dark Age===
[[File:WMAP 2012.png|thumb|All-sky map of the [[CMB]], created from nine years of [[WMAP]] data]]

* c. 370,000 years (''z'' = 1,100): The "[[Dark Ages (cosmology)|Dark Ages]]" is the period between [[decoupling (cosmology)|decoupling]], when the universe first becomes transparent, until the formation of the first [[star]]s. [[Recombination (cosmology)|Recombination]]: electrons combine with nuclei to form [[atoms]], mostly [[hydrogen]] and [[helium]]. Ordinary matter particles decouple from radiation. The photons present during the decoupling are the same photons seen in the [[cosmic microwave background]] (CMB) radiation.
* c. 10–17 million years: The "Dark Ages" span a period during which the temperature of [[cosmic microwave background radiation]] cooled from some {{cvt|4000|K|C F}} down to about {{cvt|60|K|C F}}.

=== Reionization ===
* c. 100 million years: Gravitational collapse: ordinary matter particles fall into the structures created by dark matter. [[Reionization]] begins: smaller ([[stars]]) and larger non-linear structures ([[quasars]]) begin to take shape – their [[ultraviolet]] light ionizes remaining neutral gas.
* 200–300 million years: First stars begin to shine: Because many are [[Population III stars]] (some [[Population II stars]] are accounted for at this time) they are much bigger and hotter and their life cycle is fairly short. Unlike later generations of stars, these stars are metal free. [[Reionization]] begins, with the absorption of certain wavelengths of light by neutral hydrogen creating [[Gunn–Peterson trough]]s. The resulting ionized gas (especially free electrons) in the [[Warm–hot intergalactic medium|intergalactic medium]] causes some [[Reionization#CMB anisotropy and polarization|scattering]] of light, but with much lower opacity than before recombination due the expansion of the universe and clumping of gas into galaxies.
* 200 million years: The [[List of oldest stars|oldest-known star]] (confirmed) – [[SMSS J031300.36−670839.3]], forms.
* 300 million years: First large-scale astronomical objects, [[protogalaxies]] and [[quasars]] may have begun forming. As Population III stars continue to burn, [[stellar nucleosynthesis]] operates – stars burn mainly by fusing hydrogen to produce more helium in what is referred to as the [[main sequence]]. Over time these stars are forced to fuse helium to produce [[carbon]], [[oxygen]], [[silicon]] and other heavy elements up to [[iron]] on the periodic table. These elements, when seeded into neighbouring gas clouds by [[supernova]], will lead to the formation of more [[Population II]] stars (metal poor) and [[gas giants]].
* 320 million years (''z'' = 13.3): [[HD1]], the oldest-known spectroscopically-confirmed [[galaxy]], forms.<ref>{{Cite web |last=Simion @Yonescat |first=Florin |title=Scientists have spotted the farthest galaxy ever |url=https://ras.ac.uk/news-and-press/news/scientists-have-spotted-farthest-galaxy-ever |access-date=2023-07-13 |website=The Royal Astronomical Society |date=6 April 2022 |language=en}}</ref>
* 380 million years: [[UDFj-39546284]] forms, current record holder for unconfirmed oldest-known [[quasar]].<ref name="Space-20121212">{{cite web |last=Wall |first=Mike |title=Ancient Galaxy May Be Most Distant Ever Seen|url=http://www.space.com/18879-hubble-most-distant-galaxy.html |date=12 December 2012|publisher=[[Space.com]] |access-date=12 December 2012 }}</ref>
* 600 million years: [[HE 1523-0901]], the oldest star found producing [[neutron capture]] elements forms, marking a new point in ability to detect stars with a telescope.<ref name="h152309">{{cite journal|url=https://authors.library.caltech.edu/16647/ |author=Collaborative |title=Discovery of HE 1523–0901 |journal=Astrophysical Journal Letters |volume=660 |pages=L117–L120 |publisher=CaltechAUTHORS |date=11 April 2007 |access-date=19 February 2019 }}</ref>
* 630 million years (''z'' = 8.2): [[GRB 090423]], the oldest [[gamma-ray burst]] recorded suggests that supernovas may have happened very early on in the evolution of the Universe<ref>{{cite web|title=GRB 090423 goes Supernova in a galaxy, far, far away|url=http://www.zimbio.com/member/paulano123/articles/6044508/GRB+090423+goes+Supernova+galaxy+far+far+away|archive-url=https://archive.today/20130105130128/http://www.zimbio.com/member/paulano123/articles/6044508/GRB+090423+goes+Supernova+galaxy+far+far+away|url-status=dead|archive-date=5 January 2013|work= Zimbio|access-date=23 February 2010}}</ref>

=== Galaxy epoch ===

* < 1 billion years, (13 [[Gya (unit)|Gya]]): first stars in the central bar portion of the Milky Way are born,<ref name=Helmi-2020>{{Cite journal |last=Helmi |first=Amina |date=2020-08-18 |title=Streams, Substructures, and the Early History of the Milky Way |url=https://www.annualreviews.org/doi/10.1146/annurev-astro-032620-021917 |journal=Annual Review of Astronomy and Astrophysics |language=en |volume=58 |issue=1 |pages=205–256 |doi=10.1146/annurev-astro-032620-021917 |arxiv=2002.04340 |bibcode=2020ARA&A..58..205H |issn=0066-4146}}</ref>
* 2.6 billion years (11 [[Gya (unit)|Gya]]): first stars in the thick disk region of the Milky Way are formed.<ref name=Helmi-2020/>
* 4 billion years (10 [[Gya (unit)|Gya]]): [[Gaia Enceladus]] merges into Milky Way.<ref name=Helmi-2020/> 
* 5 or 6 billion years, (8 or 9 [[Gya (unit)|Gya]]): first stars in the thin disk region of the Milky Way are formed.<ref name=Helmi-2020/>

=== Acceleration ===
* 8.8 billion years (5 Gya, ''z'' = 0.5): [[Accelerating expansion of the universe|Acceleration]]: [[dark-energy dominated era]] begins, following the [[matter-dominated era]] during which cosmic expansion was slowing down.<ref name="Frieman">{{Cite journal |last1=Frieman |first1=Joshua A. |last2=Turner |first2=Michael S. |last3=Huterer |first3=Dragan |year=2008 |title=Dark Energy and the Accelerating Universe |journal=Annual Review of Astronomy and Astrophysics |volume=46 |issue=1 |pages=385–432 |arxiv=0803.0982 |bibcode=2008ARA&A..46..385F |doi=10.1146/annurev.astro.46.060407.145243|s2cid=15117520 }}</ref>
[[File:Nature Timespiral.png|thumb|upright=2.0|Notable cosmological and other events of the natural history depicted in a spiral. In the center left the primal supernova can be seen and continuing the creation of the Sun, the Earth and the Moon (by [[Theia (planet)|Theia impact]]) can be seen]]

== Epochs of the formation of the Solar System ==
{{Main article|Formation and evolution of the Solar System}}

* 9.2 billion years (4.6–4.57 Gya): Primal supernova, possibly triggers the [[formation of The Solar System]].
* 9.2318 billion years (4.5682 Gya): [[Sun]] forms – Planetary nebula begins accretion of planets.
* 9.23283 billion years (4.56717–4.55717 Gya): Four [[Jovian planets]] ([[Jupiter]], [[Saturn]], [[Uranus]], [[Neptune]]<!--(and may be [[Planet Nine]] a.k.a Phattie -->) evolve around the Sun.
* 9.257 billion years (4.543–4.5 Gya): Solar System of Eight planets, four terrestrial ([[Mercury (planet)|Mercury]], [[Venus]], [[Earth]], [[Mars]]<!--(and maybe [[Fifth planet (hypothetical)|Fifth hypothtical planets]] a.k.a [[Planet V]] and [[Phaeton (hypothetical planet)|Phaeton]])-->) evolve around the Sun. Because of accretion many smaller planets form orbits around the proto-Sun some with conflicting orbits – [[early heavy bombardment]] begins. A large planetoid strikes Mercury, stripping it of outer envelope of original crust and mantle, leaving the planet's core exposed – Mercury's iron content is notably high.
* 9.266 billion years (4.533 Gya): Formation of Earth-[[Moon]] system following [[giant impact]] by hypothetical planetoid [[Theia (planet)]]. Moon's gravitational pull helps stabilize Earth's fluctuating [[axis of rotation]].
* 9.271 billion years (4.529 Gya): Major collision with a pluto-sized planetoid establishes the [[Martian dichotomy]] on Mars
* 9.3 billion years (4.5 Gya): Sun becomes a main sequence yellow star: formation of the [[Oort cloud]] and [[Kuiper belt]] 
* 9.396 billion years (4.404 Gya): [[Liquid water]] may have existed on the surface of the [[Earth]]
* 9.7 billion years (4.1 Gya): Resonance in Jupiter and Saturn's orbits moves Neptune out into the Kuiper belt causing a disruption among asteroids and comets there. As a result, [[Late Heavy Bombardment]] batters the inner Solar System. Meteorite impact creates the [[Hellas Planitia]] on Mars, the largest unambiguous structure on the planet.
* 10.4 billion years (3.5 Gya): Earliest fossil traces of life on Earth ([[stromatolite]]s)
* 10.6 billion years (3.2 Gya): Martian climate thins to its present density: groundwater stored in upper crust (megaregolith) begins to freeze, forming thick cryosphere overlying deeper zone of liquid water – dry ices composed of frozen carbon dioxide form 
* 10.8 billion years (3 Gya): [[Beethoven Basin]] forms on Mercury – unlike many basins of similar size on the Moon, Beethoven is not multi ringed and ejecta buries crater rim and is barely visible
* 11.6 billion years (2.2 Gya): Last great tectonic period in Martian geologic history: [[Valles Marineris]], largest canyon complex in the Solar System, forms – although some suggestions of thermokarst activity or even water erosion, it is suggested Valles Marineris is rift fault.

== Recent history ==
* 11.8 billion years (2 Gya):  [[Olympus Mons]], the largest volcano in the Solar System, is formed
* 12.1 billion years (1.7 Gya): [[Sagittarius Dwarf Spheroidal Galaxy]] captured into an orbit around Milky Way Galaxy
* 12.7 billion years (1.1 Gya): [[Copernican period|Copernican Period]] begins on Moon: defined by impact craters that possess bright optically immature ray systems
* 12.8 billion years (1 Gya):  Interactions between Andromeda and its companion galaxies Messier 32 and Messier 110. Galaxy collision with Messier 82 forms its patterned spiral disc: galaxy interactions between NGC 3077 and Messier 81; Saturn's moon [[Titan (moon)|Titan]] begins evolving the recognisable surface features that include rivers, lakes, and deltas
* 13 billion years (800 [[mya (unit)|Mya]]): [[Copernicus (lunar crater)]] forms from the impact on the Lunar surface in the area of Oceanus Procellarum – has terrace inner wall and 30 km wide, sloping rampart that descends nearly a kilometre to the surrounding mare
* 13.175 billion years (625 Mya): formation of [[Hyades (star cluster)|Hyades]] star cluster: consists of a roughly spherical group of hundreds of stars sharing the same age, place of origin, chemical content and motion through space
* 13.2 billion years (600 Mya): Whirlpool Galaxy collides with [[NGC 5195]] forming a present connected galaxy system. [[HD 189733 b]] forms around parent star [[HD 189733]]: the first planet to reveal the climate, organic constituencies, even colour (blue) of its atmosphere 
* 13.6–13.5 billion years (300-200 Mya): [[Sirius]], the brightest star in the Earth's sky, forms. 
* 13.7 billion years (100 Mya): Formation of [[Pleiades]] Star Cluster
* 13.780 billion years (20 Mya): Possible formation of [[Orion Nebula]]
* 13.792 billion years (7.6 Mya): [[Betelgeuse]] forms.
* 13.8 billion years (Without uncertainties): Present day.<ref name="spacepd">{{cite web|url=https://www.space.com/24054-how-old-is-the-universe.html |author=Nola Taylor Redd |title=How Old is the Universe? |publisher=Space |date=8 June 2017 |access-date=19 February 2019 |archive-url =https://web.archive.org/web/20190217200401/https://www.space.com/24054-how-old-is-the-universe.html |archive-date =17 February 2019 |url-status=live}}</ref>

== See also ==
* [[Chronology of the universe]]
* [[Formation and evolution of the Solar System]]
* [[Timeline of natural history]] (formation of the Earth to evolution of modern humans)
* [[Timeline of the far future]]
* [[Timelines of world history]]

== References ==
{{reflist}}
{{Portal bar|Astronomy|Stars|Outer space|Solar System|History|Science}}

[[Category:Ancient timelines|Formation of the Universe]]
[[Category:Astronomy timelines|Formation of the Universe]]
[[Category:Timelines of world history|cosmology epochs]]