Timeline of the formation of the universe
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The timeline of the early universe outlines the formation and subsequent evolution of the
Universe The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. Acc ...
from the
Big Bang The Big Bang event is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models of the Big Bang explain the evolution of the observable universe from the ...
(13.799 ± 0.021 billion years ago) to the present day. An
epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...
is a moment in time from which nature or situations change to such a degree that it marks the beginning of a new ''
era An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. Compa ...
'' or ''
age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...
''. Times on this list are measured from the moment of the Big Bang.


The first 20 minutes


Planck epoch

* c. 0 seconds (13.799 ± 0.021
Gya A billion years or giga-annum (109 years) is a unit of time on the petasecond scale, more precisely equal to seconds (or simply 1,000,000,000 years). It is sometimes abbreviated Gy, Ga ("giga-annum"), Byr and variants. The abbreviations Gya or ...
): Planck epoch begins: earliest meaningful time. The Big Bang occurs in which ordinary space and time develop out of a primeval state (possibly a
virtual particle A virtual particle is a theoretical transient particle that exhibits some of the characteristics of an ordinary particle, while having its existence limited by the uncertainty principle. The concept of virtual particles arises in the perturbat ...
or false vacuum) described by a quantum theory of gravity or " Theory of Everything". All matter and energy of the entire visible universe is contained in a hot, dense point ( gravitational singularity), a billionth the size of a nuclear particle. This state has been described as a particle
desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
. Other than a few scant details, conjecture dominates discussion about the earliest moments of the universe's history since no effective means of testing this far back in space-time is presently available.
WIMPS Weakly interacting massive particles (WIMPs) are hypothetical particles that are one of the proposed candidates for dark matter. There exists no formal definition of a WIMP, but broadly, a WIMP is a new elementary particle which interacts via gra ...
(weakly interacting massive particles) or
dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab ...
and
dark energy In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovas, which showed that the univer ...
may have appeared and been the catalyst for the expansion of the singularity. The infant universe cools as it begins expanding outward. It is almost completely smooth, with quantum variations beginning to cause slight variations in density.


Grand unification epoch

* c. 10−43 seconds: Grand unification epoch begins: While still at an infinitesimal size, the universe cools down to 1032
kelvin The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and phys ...
.
Gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...
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 In particle physics, the X and Y bosons (sometimes collectively called "X bosons" ) are hypothetical elementary particles analogous to the W and Z bosons, but corresponding to a unified force predicted by the Georgi–Glashow model, a grand unifi ...
which allow early
matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...
at this stage to fluctuate between
baryon In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified ...
and
lepton In particle physics, a lepton is an elementary particle of half-integer spin ( spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...
states.


Electroweak epoch

*c. 10−36 seconds: Electroweak epoch begins: The Universe cools down to 1028 kelvin. As a result, the strong nuclear force becomes distinct from the
electroweak force In particle physics, the electroweak interaction or electroweak force is the unified description of two of the four known fundamental interactions of nature: electromagnetism and the weak interaction. Although these two forces appear very differe ...
perhaps fuelling the
inflation In economics, inflation is an increase in the general price level of goods and services in an economy. When the general price level rises, each unit of currency buys fewer goods and services; consequently, inflation corresponds to a reductio ...
of the universe. A wide array of exotic elementary particles result from decay of X and Y bosons which include
W and Z bosons In particle physics, the W and Z bosons are vector bosons that are together known as the weak bosons or more generally as the intermediate vector bosons. These elementary particles mediate the weak interaction; the respective symbols are , , and ...
and
Higgs bosons The Higgs boson, sometimes called the Higgs particle, is an elementary particle in the Standard Model of particle physics produced by the quantum excitation of the Higgs field, one of the fields in particle physics theory. In the Standa ...
. *c. 10−33 seconds:
Space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consider ...
is subjected to
inflation In economics, inflation is an increase in the general price level of goods and services in an economy. When the general price level rises, each unit of currency buys fewer goods and services; consequently, inflation corresponds to a reductio ...
, expanding by a factor of the order of 1026 over a time of the order of 10−33 to 10−32 seconds. The universe is
supercooled Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its melting point without it becoming a solid. It achieves this in the absence of a seed crystal or nucleus around which a crystal ...
from about 1027 down to 1022 kelvin. *c. 10−32 seconds: Cosmic inflation ends. The familiar
elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include electrons, the fundamental fermions ( quarks, leptons, an ...
s now form as a soup of hot ionized gas called quark–gluon plasma; hypothetical components of
cold dark matter In cosmology and physics, cold dark matter (CDM) is a hypothetical type of dark matter. According to the current standard model of cosmology, Lambda-CDM model, approximately 27% of the universe is dark matter and 68% is dark energy, with only a sm ...
(such as
axion An axion () is a hypothetical elementary particle postulated by the Peccei–Quinn theory in 1977 to resolve the strong CP problem in quantum chromodynamics (QCD). If axions exist and have low mass within a specific range, they are of interes ...
s) would also have formed at this
time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
.


Quark epoch

*c. 10−12 seconds: Electroweak phase transition: the four fundamental interactions familiar from the modern universe now operate as distinct forces. The
weak nuclear force In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, ...
is now a short-range force as it separates from electromagnetic force, so matter particles can acquire mass and interact with the
Higgs Field The Higgs boson, sometimes called the Higgs particle, is an elementary particle in the Standard Model of particle physics produced by the quantum excitation of the Higgs field, one of the fields in particle physics theory. In the Stand ...
. The temperature is still too high for quarks to coalesce into
hadron In particle physics, a hadron (; grc, ἁδρός, hadrós; "stout, thick") is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules that are held together by the ele ...
s, and the quark–gluon plasma persists (
Quark epoch In physical cosmology, the Quark epoch was the period in the evolution of the early universe when the fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction had taken their present forms, but th ...
). The universe cools to 1015 kelvin. *c. 10−11 seconds: Baryogenesis may have taken place with matter gaining the upper hand over anti-matter as
baryon In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified ...
to
antibaryon In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified ...
constituencies are established.


Hadron epoch

*c. 10−6 seconds:
Hadron epoch In physical cosmology, the hadron epoch started 20 microseconds after the Big Bang. The temperature of the universe had fallen sufficiently to allow the quarks from the preceding quark epoch to bind together into hadrons. Initially, the temperatur ...
begins: As the universe cools to about 1010 kelvin, a quark-hadron transition takes place in which quarks bind to form more complex particles— hadrons. This quark confinement includes the formation of
proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
s and
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
s ( nucleons), the building blocks of
atomic nuclei The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ...
.


Lepton epoch

*c. 1 second:
Lepton epoch In physical cosmology, the lepton epoch was the period in the evolution of the early universe in which the leptons dominated the mass of the Universe. It started roughly 1 second after the Big Bang, after the majority of hadrons and anti-hadrons a ...
begins: The universe cools to 109 kelvin. At this temperature, the hadrons and antihadrons annihilate each other, leaving behind
leptons In particle physics, a lepton is an elementary particle of half-integer spin (spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...
and antileptons – possible disappearance of antiquarks. Gravity governs the expansion of the universe: neutrinos
decouple __NOTOC__ Decoupling usually refers to the ending, removal or reverse of coupling. Decoupling may also refer to: Economics * Decoupling (advertising), the purchase of services directly from suppliers rather than via an advertising agency * Deco ...
from matter creating a
cosmic neutrino background The cosmic neutrino background (CNB or CB) is the universe's background particle radiation composed of neutrinos. They are sometimes known as relic neutrinos. The CB is a relic of the Big Bang; while the cosmic microwave background radiation (CMB ...
.


Photon epoch

* c. 10 seconds: Photon epoch begins: Most of the leptons and antileptons annihilate each other. As
electrons The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...
and
positrons The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. It has an electric charge of +1 '' e'', a spin of 1/2 (the same as the electron), and the same mass as an electron. When a positron collides w ...
annihilate, a small number of unmatched electrons are left over – disappearance of the positrons. * c. 10 seconds: Universe dominated by photons of radiation – ordinary matter particles are coupled to
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...
and radiation while dark matter particles start building non-linear structures as
dark matter halo According to modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure. It is a hypothetical region that has decoupled from cosmic expansion and contains gravitationally bound matter. A single dark matte ...
s. Because charged electrons and protons hinder the emission of light, the universe becomes a super-hot glowing fog. * c. 3 minutes: Primordial nucleosynthesis: nuclear fusion begins as
lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid el ...
and heavy hydrogen (
deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen (the other being Hydrogen atom, protium, or hydrogen-1). The atomic nucleus, nucleus of a deuterium ato ...
) and
helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
nuclei form from protons and neutrons. * c. 20 minutes: Nuclear fusion ceases: normal matter consists of 75% hydrogen nuclei and 25% helium nuclei – free electrons begin scattering light.


Matter era


Matter and radiation equivalence

*c. 47,000 years (z=3600):
Matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...
and radiation equivalence: at the beginning of this era, the expansion of the universe was decelerating at a faster rate. *c. 70,000 years: Matter domination in Universe: onset of gravitational collapse as the
Jeans length In stellar physics, the Jeans instability causes the collapse of interstellar gas clouds and subsequent star formation, named after James Jeans. It occurs when the internal gas pressure is not strong enough to prevent gravitational collapse of ...
at which the smallest structure can form begins to fall.


Cosmic Dark Age

* c. 370,000 years (z=1,100): The " Dark Ages" is the period between decoupling, when the universe first becomes transparent, until the formation of the first
star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
s. Recombination: electrons combine with nuclei to form
atoms Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, an ...
, mostly
hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
and
helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
. Distributions of hydrogen and helium at this time remains constant as the electron-baryon plasma thins. The temperature falls to 3000 kelvin. Ordinary matter particles decouple from radiation. The photons present at the time of decoupling are the same photons that we see in the
cosmic microwave background In Big Bang cosmology the cosmic microwave background (CMB, CMBR) is electromagnetic radiation that is a remnant from an early stage of the universe, also known as "relic radiation". The CMB is faint cosmic background radiation filling all spac ...
(CMB) radiation. * c. 400,000 years: Density waves begin imprinting characteristic
polarization (waves) Polarization (also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the ...
signals. * c. 10-17 million years: The "Dark Ages" span a period during which the temperature of
cosmic background radiation Cosmic background radiation is electromagnetic radiation from the Big Bang. The origin of this radiation depends on the region of the spectrum that is observed. One component is the cosmic microwave background. This component is redshifted pho ...
cooled from some 4000 K down to about 60 K. The background temperature was between 373 K and 273 K, allowing the possibility of
liquid water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a s ...
, during a period of about 7 million years, from about 10 to 17 million after the Big Bang (redshift 137–100). Loeb (2014) speculated that primitive life might in principle have appeared during this window, which he called "the Habitable Epoch of the Early Universe". * 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 Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
light ionizes remaining neutral gas. * 200–300 million years: First stars begin to shine: Because many are
Population III stars During 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926: Baade noticed th ...
(some
Population II stars During 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926: Baade noticed t ...
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 troughs. The resulting ionized gas (especially free electrons) in the intergalactic medium causes some
scattering Scattering is a term used in physics to describe a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including ...
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:
HD 140283 HD 140283 (also known as the Methuselah star) is a metal-poor subgiant star about 190 light years away from the Earth in the constellation Libra, near the boundary with Ophiuchus in the Milky Way Galaxy. Its apparent magnitude is ...
, the "Methuselah" Star, formed, the unconfirmed oldest star observed in the Universe. Because it is a
Population II star During 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926: Baade noticed th ...
, some suggestions have been raised that second generation star formation may have begun very early on. The 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 Stellar nucleosynthesis is the creation (nucleosynthesis) of chemical elements by nuclear fusion reactions within stars. Stellar nucleosynthesis has occurred since the original creation of hydrogen, helium and lithium during the Big Bang. As a ...
operates – stars burn mainly by fusing hydrogen to produce more helium in what is referred to as the
main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...
. Over time these stars are forced to fuse helium to produce
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
,
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
,
silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
and other heavy elements up to
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
on the periodic table. These elements, when seeded into neighbouring gas clouds by
supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...
, will lead to the formation of more Population II stars (metal poor) and
gas giants A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant ...
. * 380 million years:
UDFj-39546284 __NOTOC__ UDFj-39546284 is a high- redshift Lyman-break galaxy discovered by the Hubble Space Telescope in infrared Hubble Ultra-Deep Field (HUDF) observations in 2009. The object, located in the Fornax constellation, was identified by G. Illi ...
forms, current record holder for unconfirmed oldest-known
quasar A quasar is an extremely Luminosity, luminous active galactic nucleus (AGN). It is pronounced , and sometimes known as a quasi-stellar object, abbreviated QSO. This emission from a galaxy nucleus is powered by a supermassive black hole with a m ...
. * 400 million years (z=11):
GN-z11 GN-z11 is a high-redshift galaxy found in the constellation Ursa Major. It is one of the farthest known galaxies from Earth ever discovered. The 2015 discovery was published in a 2016 paper headed by Pascal Oesch and Gabriel Brammer (Cosmic Dawn ...
, the oldest-known
galaxy A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...
, forms. * 420 million years: The quasar
MACS0647-JD __NOTOC__ MACS0647-JD is a galaxy with a redshift of about ''z'' = 10.7, equivalent to a light travel distance of 13.26 billion light-years (4 billion parsecs). If the distance estimate is correct, it formed about 427 million years after the Big B ...
, the, or one of the, furthest known quasars, forms. * 600 million years
HE 1523-0901 HE 1523-0901 is the designation given to a red giant star in the Milky Way galaxy approximately 7500 light years from Earth. It is thought to be a second generation, Population II, or metal-poor, star ( e/Hnbsp;= −2.95). The star ...
, the oldest star found producing
neutron capture Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, ...
elements forms, marking a new point in ability to detect stars with a telescope. * 630 million years (z=8.2):
GRB 090423 GRB 090423 was a gamma-ray burst (GRB) detected by the Swift Gamma-Ray Burst Mission on April 23, 2009 at 07:55:19 UTC whose afterglow was detected in the infrared and enabled astronomers to determine that its redshift is ''z'' = 8.2, ...
, the oldest gamma ray burst recorded suggests that supernovas may have happened very early on in the evolution of the Universe * 670 million years: EGS-zs8-1, the most distant starburst or
Lyman-break galaxy Lyman-break galaxies are star-forming galaxies at high redshift that are selected using the differing appearance of the galaxy in several imaging filters due to the position of the Lyman limit. The technique has primarily been used to select gala ...
observed, forms. This suggests that galaxy interaction is taking place very early on in the history of the Universe as starburst galaxies are often associated with collisions and galaxy mergers. * 700 million years: Galaxies form. Smaller galaxies begin merging to form larger ones. Galaxy classes may have also begun forming at this time including
Blazars A blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet composed of ionized matter traveling at nearly the speed of light) directed very nearly towards an observer. Relativistic beaming of electromagnetic radiation from the ...
, Seyfert galaxies, radio galaxies, and dwarf galaxies as well as regular types (
elliptical Elliptical may mean: * having the shape of an ellipse, or more broadly, any oval shape ** in botany, having an elliptic leaf shape ** of aircraft wings, having an elliptical planform * characterised by ellipsis (the omission of words), or by conc ...
, barred spiral, and
spiral galaxies Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''UDFy-38135539 UDFy-38135539 (also known as "HUDF.YD3") is the Hubble Ultra Deep Field (UDF) identifier for a galaxy which was calculated to have a light travel time of 13.1 billion years with a present proper distance of around 30 billion light-years. It ...
, the first distant quasar to be observed from the reionization phase, forms. Dwarf galaxy z8 GND 5296 forms. Galaxy or possible proto-galaxy
A1689-zD1 A1689-zD1 is a galaxy in the Virgo constellation. It was a candidate for the most distant and therefore earliest-observed galaxy discovered , based on a photometric redshift. If the redshift, z~7.6, is correct, it would explain why the galaxy' ...
forms. * 720 million years: Possible formation of
globular clusters A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of member ...
in Milky Way's Galactic halo. Formation of globular cluster, NGC 6723, in the Milky Way's galactic halo * 740 million years:
47 Tucanae 47 Tucanae, or 47 Tuc (also designated NGC 104) is a globular cluster located in the constellation Tucana. It is about away from Earth, and 120 light years in diameter. 47 Tuc can be seen with the naked eye, with an apparent magnitude of 4.1. It ...
, second-brightest globular cluster in the Milky Way, forms * 750 million years: Galaxy
IOK-1 IOK-1 is a distant galaxy in the constellation Coma Berenices. When discovered in 2006, it was the oldest and most distant galaxy ever found, at redshift 6.96. It was discovered in April 2006 by Masanori Iye at National Astronomical Observatory ...
a Lyman alpha emitter galaxy, forms.
GN-108036 GN-108036 is a distant galaxy discovered and confirmed by the Subaru Telescope and the Keck Observatory located in Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from th ...
forms—galaxy is 5 times larger and 100 times more massive than the present day Milky Way illustrating the size attained by some galaxies very early on. * 770 million years: Quasar ULAS J1120+0641, one of the most distant, forms. One of the earliest galaxies to feature a supermassive black hole suggesting that such large objects existed quite soon after the Big Bang. The large fraction of neutral hydrogen in its spectrum suggests it may also have just formed or is in the process of star formation. * 800 million years: Farthest extent of
Hubble Ultra-Deep Field The Hubble Ultra-Deep Field (HUDF) is a deep-field image of a small region of space in the constellation Fornax, containing an estimated 10,000 galaxies. The original data for the image was collected by the Hubble Space Telescope from Septembe ...
. Formation of SDSS J102915+172927: unusual population II star that is extremely metal poor consisting of mainly hydrogen and helium. HE0107-5240, one of the oldest Population II stars, forms as part of a binary star system. LAE J095950.99+021219.1, one of the most remote
Lyman alpha emitter A Lyman-alpha emitter (LAE) is a type of distant galaxy that emits Lyman-alpha radiation from neutral hydrogen. Most known LAEs are extremely distant, and because of the finite travel time of light they provide glimpses into the history of the un ...
galaxies, forms. Lyman alpha emitters are considered to be the progenitors of spiral galaxies like the Milky Way.
Messier 2 Messier 2 or M2 (also designated NGC 7089) is a globular cluster in the constellation Aquarius, five degrees north of the star Beta Aquarii. It was discovered by Jean-Dominique Maraldi in 1746, and is one of the largest known globular clusters. ...
, globular cluster, forms. * 870 million years:
Messier 30 Messier 30 (also known as M30 or NGC 7099) is a globular cluster of stars in the southeast of the southern constellation of Capricornus, at about the declination of the sun when the latter is at December solstice. It was discovered by the French ...
forms in the Milky Way. Having experienced a
Core collapse (cluster) A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of member ...
, the cluster has one of the highest densities among globular clusters. * 890 million years: Galaxy SXDF-NB1006-2 forms * 900 million years: Galaxy
BDF-3299 BDF-3299 is a remote galaxy with a redshift of z = 7.109 corresponds to a distance traveled by light to come down to Earth of 12.9 billion light-years. See also * List of most distant galaxies *List of the most distant astronomical objects This ...
forms. * 910 million years: Galaxy BDF-521 forms


Galaxy epoch

* 1 billion years (12.8
Gya A billion years or giga-annum (109 years) is a unit of time on the petasecond scale, more precisely equal to seconds (or simply 1,000,000,000 years). It is sometimes abbreviated Gy, Ga ("giga-annum"), Byr and variants. The abbreviations Gya or ...
, z=6.56): Galaxy
HCM-6A HCM-6A is an LAE galaxy that was found in 2002 by Esther Hu and Lennox Cowie from the University of Hawaii and Richard McMahon from the University of Cambridge, using the Keck II Telescope in Hawaii. HCM-6A is located behind the Abell 370 g ...
, the most distant normal galaxy observed, forms. Formation of hyper-luminous quasar SDSS J0100+2802, which harbors a black hole with mass of 12 billion solar masses, one of the most massive black holes discovered so early in the universe. HE1327-2326, a population II star, is speculated to have formed from remnants of earlier Population III stars. Visual limit of the
Hubble Deep Field The Hubble Deep Field (HDF) is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope. It covers an area about 2.6 arcminutes on a side, about one 24-millionth of the w ...
. Reionization is complete, with intergalactic space no longer showing any absorption lines from neutral hydrogen in the form of Gunn–Peterson troughs. Photon scattering by free electrons continues to decrease as the universe expands and gas falls into galaxies, and intergalactic space is now highly transparent, though remaining clouds of neutral hydrogen cause Lyman-alpha forests. Galaxy evolution continues as more modern looking galaxies form and develop, although barred spiral and elliptical galaxies are more rare than today. Because the Universe is still small in size, galaxy interactions become common place with larger and larger galaxies forming out of the galaxy merger process. Galaxies may have begun clustering creating the largest structures in the Universe so far – the first
galaxy clusters A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-la ...
and galaxy superclusters appear. * 1.1 billion years (12.7 Gya): Age of the
quasar A quasar is an extremely Luminosity, luminous active galactic nucleus (AGN). It is pronounced , and sometimes known as a quasi-stellar object, abbreviated QSO. This emission from a galaxy nucleus is powered by a supermassive black hole with a m ...
CFHQS 1641+3755. Messier 4 Globular Cluster, first to have its individual stars resolved, forms in the halo of the Milky Way Galaxy. Among the clusters' many stars,
PSR B1620-26 b PSR may refer to: Organizations * Pacific School of Religion, Berkeley, California, US * Palestinian Center for Policy and Survey Research * Physicians for Social Responsibility, US ;Political parties: * Revolutionary Socialist Party (Portugal) ( ...
forms. It is a gas giant known as the "Genesis Planet" or "Methusaleh." The oldest observed
exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...
in the Universe, it orbits a
pulsar A pulsar (from ''pulsating radio source'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Ea ...
and a
white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...
. * 1.13 billion years (12.67 Gya):
Messier 12 Messier 12 or M 12 (also designated NGC 6218) is a globular cluster in the constellation of Ophiuchus. It was discovered by the French astronomer Charles Messier on May 30, 1764, who described it as a "nebula without stars". In dark conditions th ...
, globular cluster, forms * 1.3 billion years (12.5 Gya):
WISE J224607.57-052635.0 WISE may refer to: Arts, entertainment, and media *WISE (AM), a radio station licensed to Asheville, North Carolina *WISE-FM, a radio station licensed to Wise, Virginia *WISE-TV, a television station licensed to Fort Wayne, Indiana Education *Web ...
, a luminous infrared galaxy, forms. PSR J1719-1438 b, known as the Diamond Planet, forms around a pulsar. * 1.31 billion years (12.49 Gya): Globular Cluster Messier 53 forms 60,000 light-years from the galactic centre of the Milky Way * 1.39 billion years (12.41 Gya):
S5 0014+81 S5 0014+81 is a distant, compact, hyperluminous, broad-absorption-line quasar, or blazar, located near the high declination region of the constellation Cepheus, near the North Equatorial Pole. Characteristics The object is an OVV (opticall ...
, a hyper-luminous quasar, forms * 1.4 billion years (12.4 Gya): Age of Cayrel's Star, BPS C531082-0001, a
neutron capture Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, ...
star, among the oldest Population II stars in Milky Way. Quasar RD1, first object observed to exceed
redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...
5, forms. * 1.44 billion years (12.36 Gya):
Messier 80 Messier 80 (also known as M80 or NGC 6093) is a globular cluster in the constellation Scorpius. It was discovered by Charles Messier in 1781, being one of his first discoveries. This star cluster is, as to its angle from the solar system, midwa ...
globular cluster forms in Milky Way – known for large number of "
blue stragglers A blue straggler is a main-sequence star in an open or globular cluster that is more luminous and bluer than stars at the main sequence turnoff point for the cluster. Blue stragglers were first discovered by Allan Sandage in 1953 while performin ...
" * 1.5 billion years (12.3 Gya):
Messier 55 Messier 55 (also known as M55 or NGC 6809) is a globular cluster in the south of the constellation Sagittarius. It was discovered by Nicolas Louis de Lacaille in 1752 while observing from what today is South Africa. Starting in 1754, Charles M ...
, globular cluster, forms * 1.8 billion years (12 Gya): Most energetic gamma ray burst lasting 23 minutes,
GRB 080916C GRB 080916C is a gamma-ray burst (GRB) that was recorded on September 16, 2008, in the Carina constellation and detected by NASA's Fermi Gamma-ray Space Telescope. It is the most powerful gamma-ray burst ever recorded. The explosion had the energy ...
, recorded.
Baby Boom Galaxy The Baby Boom Galaxy is a starburst galaxy located 12.477 billion light years away (co-moving distance is 25.08 billion light years). Discovered by NASA's Spitzer Science Center at the California Institute of Technology, the galaxy is the reco ...
forms.
Terzan 5 Terzan 5 is a heavily obscured globular cluster belonging to the bulge (the central star concentration) of the Milky Way galaxy. It was one of six globulars discovered by French astronomer Agop Terzan in 1968 and was initially labeled ''Terzan 11' ...
forms as a small dwarf galaxy on collision course with the Milky Way. Dwarf galaxy carrying the Methusaleh Star consumed by Milky Way – oldest-known star in the Universe becomes one of many population II stars of the Milky Way * 2.0 billion years (11.8 Gya): SN 1000+0216, the oldest observed supernova occurs – possible
pulsar A pulsar (from ''pulsating radio source'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Ea ...
formed. Globular Cluster Messier 15, known to have an intermediate black hole and the only globular cluster observed to include a planetary nebula,
Pease 1 Pease 1 is a planetary nebula located within the globular cluster M15 33,600 light years away in the constellation Pegasus. It was the first planetary nebula known to exist within a globular cluster when it was discovered in 1928 (for Francis G. Pe ...
, forms * 2.02 billion years (11.78 Gya): Messier 62 forms – contains high number of variable stars (89) many of which are
RR Lyrae RR Lyrae is a variable star in the Lyra constellation, figuring in its west near to Cygnus. As the brightest star in its class, it became the eponym for the RR Lyrae variable class of stars and it has been extensively studied by astro ...
stars. * 2.2 billion years (11.6 Gya): Globular Cluster
NGC 6752 NGC 6752 (also known as Caldwell 93 and nicknamed the Great Peacock Globular) is a globular cluster in the constellation Pavo. It is the fourth-brightest globular cluster in the sky, after Omega Centauri, 47 Tucanae and Messier 22, respectively. ...
, third-brightest, forms in Milky Way * 2.4 billion years (11.4 Gya): Quasar
PKS 2000-330 PKS 2000-330 (also known as QSO B2000-330) is a quasar located in the constellation Sagittarius. When identified in 1982, it was the most distant and most luminous object known. Distance measurements The "distance" of a far away galaxy depen ...
forms. * 2.41 billion years (11.39 Gya):
Messier 10 Messier 10 or M10 (also designated NGC 6254) is a globular cluster of stars in the celestial equator, equatorial constellation of Ophiuchus. The object was discovered by the French astronomer Charles Messier on May 29, 1764, who cataloged it as n ...
globular cluster forms.
Messier 3 Messier 3 (M3; also NGC 5272) is a globular cluster of stars in the northern constellation of Canes Venatici. Discovery It was discovered on May 3, 1764, and was the first Messier object to be discovered by Charles Messier himself. Messier or ...
forms: prototype for the
Oosterhoff type I A globular cluster is a spheroidal conglomeration of stars. wikt:globular, Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many mil ...
cluster, which is considered "metal-rich". That is, for a globular cluster, Messier 3 has a relatively high abundance of heavier elements. * 2.5 billion years (11.3 Gya): Omega Centauri, largest globular cluster in the Milky Way forms * 2.6 billion years (11.2 Gya):
HD 130322 HD 130322 is an 8th-magnitude star in the constellation of Virgo. It is an orange dwarf, a type of star somewhat dimmer and cooler than the Sun. Spectral type of the star is K0V. It can only be seen with binoculars or telescope. Being almo ...
planetary system, known as the first observed
exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...
system, forms * 3.0 billion years (10.8 billion Gya): Formation of the Gliese 581 planetary system:
Gliese 581c Gliese 581c (Gl 581c or GJ 581c) is a planet orbiting within the Gliese 581 system. It is the second planet discovered in the system and the third in order from the star. With a mass at least 5.5 times that of the Earth, it is classified as a s ...
, the first observed ocean planet and
Gliese 581d Gliese 581d (often shortened to Gl 581d or GJ 581d) is a proposed extrasolar planet orbiting within the Gliese 581 system, approximately 20.4 light-years away in the Libra constellation. It is the third planet claimed in the system and (assumi ...
, a super-earth planet, possibly the first observed
habitable planets Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from a ...
, form. Gliese 581d has more potential for forming life since it is the first exoplanet of terrestrial mass proposed that orbits within the habitable zone of its parent star. * 3.3 billion years (10.5 Gya):
BX442 BX442 (Q2343-BX442) is a grand design spiral galaxy of type Sc. It has a companion dwarf galaxy. It is the most distant known grand design spiral galaxy in the universe, with a redshift of z=2.1765 ± 0.0001. Although commonly referred to as the ...
, oldest grand design spiral galaxy observed, forms * 3.5 billion years (10.3 Gya): Supernova SN UDS10Wil recorded * 3.8 billion years (10 Gya): NGC 2808 globular cluster forms: 3 generations of stars form within the first 200 million years. * 4.0 billion years (9.8 Gya): Quasar 3C 9 forms. The Andromeda Galaxy forms from a galactic merger – begins a collision course with the Milky Way.
Barnard's Star Barnard's Star is a red dwarf about six light-years from Earth in the constellation of Ophiuchus. It is the fourth-nearest-known individual star to the Sun after the three components of the Alpha Centauri system, and the closest star in the ...
, red dwarf star, may have formed. Beethoven Burst
GRB 991216 GRB 991216, nicknamed the Beethoven Burst by Dr. Brad Schaefer of Yale University, was a gamma-ray burst observed on December 16, 1999, coinciding with the 229th anniversary of Ludwig van Beethoven's birth. A gamma-ray burst is a highly luminous f ...
recorded. Gliese 677 C c, a planet in the habitable zone of its parent star, Gliese 667, forms * 4.5 billion years (9.3 Gya): Fierce star formation in Andromeda making it into a luminous
infra-red Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
galaxy * 5.0 billion years (8.8 Gya): Earliest Population I, or Sunlike stars: with heavy element saturation so high, planetary nebula appear in which rocky substances are solidified – these nurseries lead to the formation of rocky
terrestrial planets A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Ven ...
, moons,
asteroids An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...
, and icy
comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s * 5.1 billion years (8.7 Gya): Galaxy collision: spiral arms of the Milky Way form leading to major period of star formation. * 5.3 billion years (8.5 Gya):
55 Cancri 55 Cancri is a binary star system located 41 light-years away from the Sun in the zodiac constellation of Cancer. It has the Bayer designation Rho1 Cancri (ρ1 Cancri); ''55 Cancri'' is the Flamsteed designation (abbrevia ...
B, a "
hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital periods (). The close proximity to their stars and high surface-atmosphere temp ...
", first planet to be observed orbiting as part of a star system, forms.
Kepler 11 Kepler-11, also designated as 2MASS J19482762+4154328, is a Solar analog, Sun-like star slightly larger than the Sun in the constellation Cygnus (constellation), Cygnus, located some 2,150 light years from Earth. It is located within the ...
planetary system, the flattest and most compact system yet discovered, forms – Kepler 11 c considered to be a giant ocean planet with hydrogen-helium atmosphere. * 5.8 billion years (8 Gya):
51 Pegasi b 51 Pegasi b, officially named Dimidium , and formerly unofficially dubbed Bellerophon , is an extrasolar planet approximately away in the constellation of Pegasus. It was the first exoplanet to be discovered orbiting a main-sequence star, the S ...
also known as Bellerophon, forms – first planet discovered orbiting a main sequence star * 5.9 billion years (7.9 Gya):
HD 176051 Extrasolar PlanetsEncyclopaedia HD 176051 is a spectroscopic binary star system approximately 49 light years away from Earth in the constellation Lyra. The pair orbit with a period of 22,423 days (61.4 years) and an eccentricity of 0.25 ...
planetary system, known as the first observed through
astrometrics Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, th ...
, forms * 6.0 billion years (7.8 Gya): Many galaxies like
NGC 4565 NGC 4565 (also known as the Needle Galaxy or Caldwell 38) is an edge-on spiral galaxy about 30 to 50 million light-years away in the constellation Coma Berenices. It lies close to the North Galactic Pole and has a visual magnitude of approximatel ...
become relatively stable – ellipticals result from collisions of spirals with some like IC 1101 being extremely massive. * 6.0 billion years (7.8 Gya): The Universe continues to organize into larger wider structures. The great walls, sheets and filaments consisting of galaxy clusters and superclusters and voids crystallize. How this crystallization takes place is still conjecture. Certainly, it is possible the formation of super-structures like the
Hercules–Corona Borealis Great Wall The Hercules–Corona Borealis Great Wall or simply the Great Wall is the largest known structure in the observable universe, measuring approximately 10 billion light-years in length (the observable universe is about 93 billion light-years in di ...
may have happened much earlier, perhaps around the same time galaxies first started appearing. Either way the
observable universe The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time, because the electromagnetic radiation from these obj ...
becomes more modern looking. * 6.2 billion years (7.7 Gya):
16 Cygni Bb 16 Cygni Bb or HD 186427 b is an extrasolar planet approximately away in the constellation of Cygnus. The planet was discovered orbiting the Sun-like star 16 Cygni B, one of two solar-mass () components of the triple star system 16 Cygni in 1 ...
, the first gas giant observed in a single star orbit in a
trinary star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a ''star cluster'' or ''galaxy'', although, broadly speaking, ...
, forms – orbiting moons considered to have habitable properties or at the least capable of supporting water * 6.3 billion years (7.5 Gya, z=0.94):
GRB 080319B __NOTOC__ GRB 080319B was a gamma-ray burst (GRB) detected by the Swift satellite at 06:12 UTC on March 19, 2008. The burst set a new record for the farthest object that was observable with the naked eye: it had a peak visual apparent magnitude ...
, farthest gamma ray burst seen with the naked eye, recorded.
Terzan 7 Terzan 7 is a sparse and young globular cluster that is believed to have originated in the Sagittarius Dwarf Spheroidal Galaxy (Sag DEG) and is physically associated with it. It is relatively metal rich with Fe/Hydrogen.html"_;"title="Iro ...
, metal-rich globular cluster, forms in the
Sagittarius Dwarf Elliptical Galaxy The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an elliptical loop-shaped satellite galaxy of the Milky Way. It contains four globular clusters in ...
* 6.5 billion years (7.3 Gya): HD 10180 planetary system forms (larger than both 55 Cancri and Kepler 11 systems) * 6.9 billion years (6.9 Gya): Orange Giant, Arcturus, forms * 7.64 billion years (6.16 Gya): Mu Arae
planetary system A planetary system is a set of gravitationally In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interacti ...
forms: of four planets orbiting a yellow star,
Mu Arae c Mu Arae c, also known as HD 160691 c, formally named Dulcinea (pronounced or ), is an extrasolar planet orbiting the star Mu Arae of the constellation Ara. It was the first 'hot Neptune' or 'mega-Earth' to be discovered. None of the four planets ...
is among the first terrestrial planets to be observed from Earth * 7.8 billion years (6.0 Gya): Formation of Earth's near twin, Kepler 452b orbiting its parent star
Kepler 452 Extrasolar PlanetsEncyclopaedia Kepler-452 is a G-type main-sequence star located about 1,800 light-years away from Earth in the Cygnus constellation. Although similar in temperature to the Sun, it is 20% brighter, 3.7% more massive ...
* 7.98 billion years (5.82 Gya): Formation of Mira or Omicron ceti, binary star system. Formation of
Alpha Centauri Alpha Centauri ( Latinized from α Centauri and often abbreviated Alpha Cen or α Cen) is a triple star system in the constellation of Centaurus. It consists of 3 stars: Alpha Centauri A (officially Rigil Kentaurus), Alpha Centaur ...
Star System, closest star to the Sun. GJ 1214 b, or Gliese 1214 b, potential earth-like planet, forms * 8.2 billion years (5.6 Gya): Tau Ceti, nearby yellow star forms: five planets eventually evolve from its planetary nebula, orbiting the star –
Tau Ceti e Tau Ceti e, also called 52 Ceti e, is an exoplanet orbiting Tau Ceti that was detected by statistical analyses of the data of the star's variations in radial velocity that were obtained using HIRES, AAPS and HARPS. Its possible properties wer ...
considered planet to have potential life since it orbits the hot inner edge of the star's habitable zone * 8.5 billion years (5.3 Gya): GRB 101225A, the "Christmas Burst", considered the longest at 28 minutes, recorded


Acceleration

* 8.8 billion years (5 Gya, z=0.5):
Acceleration In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the ...
: dark-energy dominated era begins, following the
matter-dominated era The relative expansion of the universe is parametrized by a dimensionless scale factor a . Also known as the cosmic scale factor or sometimes the Robertson Walker scale factor, this is a key parameter of the Friedmann equations. In the early st ...
during which cosmic expansion was slowing down. * 8.8 billion years (5 Gya):
Messier 67 Messier 67 (also known as M67 or NGC 2682) and sometimes called the King Cobra cluster or the Golden Eye cluster is an open cluster in the southern, equatorial half of Cancer. It was discovered by Johann Gottfried Koehler in 1779. Estimates of it ...
open star cluster forms: Three exoplanets confirmed orbiting stars in the cluster including a twin of our Sun * 9.0 billion years (4.8 Gya):
Lalande 21185 Lalande 21185 (also known as BD+36 2147, Gliese 411, and HD 95735) is a star in the south of Ursa Major. It is the apparent brightest red dwarf in the northern hemisphere.Only AX Microscopii and Lacaille 9352, in the southern hemisphere ...
, red dwarf in
Ursa Major Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...
, forms * 9.13 billion years (4.67 Gya):
Proxima Centauri Proxima Centauri is a small, low-mass star located away from the Sun in the southern constellation of Centaurus. Its Latin name means the 'nearest tarof Centaurus'. It was discovered in 1915 by Robert Innes and is the nearest-kno ...
forms completing the Alpha Centauri trinary system


Epochs of the formation of the Solar System

* 9.2 billion years (4.6–4.57 Gya): Primal supernova, possibly triggers the formation of the
Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
. * 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 The giant planets constitute a diverse type of planet much larger than Earth. They are usually primarily composed of low-boiling-point materials (volatiles), rather than rock or other solid matter, but massive solid planets can also exist. Ther ...
(
Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...
,
Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...
,
Uranus Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather ...
,
Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...
) evolve around the sun. * 9.257 billion years (4.543–4.5 Gya): Solar System of Eight planets, four terrestrial (
Mercury (planet) Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman god ' ( Mercury), god of commerce, messenger ...
,
Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
,
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
,
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
) evolve around the sun. Because of accretion many smaller planets form orbits around the proto-Sun some with conflicting orbits – Early Heavy Bombardment begins.
Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...
Supereon and
Hadean The Hadean ( ) is a Eon (geology), geologic eon of History of Earth, Earth history preceding the Archean. On Earth, the Hadean began with the Formation of the Earth, planet's formation about 4.54 billion years ago (although the start of the H ...
eon begin on the Earth. Pre-Noachian Era begins on Mars.
Pre-Tolstojan Pre-Tolstojan, also Pretolstojan Period, refers to the oldest period of the history of Mercury, 4500–3900 MYA. It is the "first period of the Eomercurian Era and of the Mercurian Eon, as well as being the first period in Mercury's geologic h ...
Period begins on Mercury – 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. Many of the
Galilean moons The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in December 1609 or January 1610, and recognized by him as satellites of Jupiter ...
may have formed at this time including
Europa Europa may refer to: Places * Europe * Europa (Roman province), a province within the Diocese of Thrace * Europa (Seville Metro), Seville, Spain; a station on the Seville Metro * Europa City, Paris, France; a planned development * Europa Cliff ...
and
Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...
which may presently be hospitable to some form of living organism. * 9.266 billion years (4.533 Gya): Formation of Earth-
Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
system following
giant impact The giant-impact hypothesis, sometimes called the Big Splash, or the Theia (planet), Theia Impact, suggests that the Moon formed from the ejecta of a collision between the proto-Earth and a Mars-sized planet, approximately 4.5 billion years ago ...
by hypothetical planetoid Theia (planet). Moon's gravitational pull helps stabilize Earth's fluctuating
axis of rotation Rotation around a fixed axis is a special case of rotational motion. The fixed-axis hypothesis excludes the possibility of an axis changing its orientation and cannot describe such phenomena as wobbling or precession. According to Euler's rota ...
. Pre-Nectarian Period begins on Moon * 9.271 billion years (4.529 Gya): Major collision with a pluto-sized planetoid establishes the
Martian dichotomy The most conspicuous feature of Mars is a sharp contrast, known as the Martian dichotomy, between the Southern and the Northern hemispheres. The two hemispheres' geography differ in elevation by 1 to 3 km. The average thickness of the Marti ...
on Mars – formation of North Polar Basin of Mars * 9.3 billion years (4.5 Gya): Sun becomes a main sequence yellow star: formation of the Oort Cloud and
Kuiper Belt The Kuiper belt () is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...
from which a stream of
comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s like Halley's Comet and Hale-Bopp begins passing through the Solar System, sometimes colliding with planets and the Sun * 9.396 billion years (4.404 Gya): Liquid water may have existed on the surface of the Earth, probably due to the greenhouse warming of high levels of methane and carbon dioxide present in the atmosphere. * 9.4 billion years (4.4 Gya): Formation of
Kepler 438 b Kepler-438b (also known by its Kepler Object of Interest designation ''KOI-3284.01'') is a confirmed near-Earth-sized exoplanet. It is likely Terrestrial planet, rocky. It orbits on the inner edge of the habitable zone of a red dwarf, Kepler-438, ...
, one of the most Earth-like planets, from a protoplanetary nebula surrounding its parent star * 9.5 billion years (4.3 Gya): Massive meteorite impact creates South Pole
Aitken Basin Aitken may refer to: * Aitken (crater), a crater on the Moon, named after Robert Grant Aitken (1864–1951), an American astronomer * South Pole–Aitken basin, an immense impact crater on the far side of the Moon. At roughly in diameter and dee ...
on the Moon – a huge chain of mountains located on the lunar southern limb, sometimes called "Leibnitz mountains", form * 9.6 billion years (4.2 Gya):
Tharsis Bulge Tharsis () is a vast volcanic plateau centered near the equator in the western hemisphere of Mars. The region is home to the largest volcanoes in the Solar System, including the three enormous shield volcanoes Arsia Mons, Pavonis Mons, and As ...
widespread area of vulcanism, becomes active on Mars – based on the intensity of volcanic activity on Earth, Tharsis magmas may have produced a 1.5-bar atmosphere and a global layer of water 120 m deep increasing greenhouse gas effect in climate and adding to Martian water table. Age of the oldest samples from the Lunar Maria * 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. Herschel Crater formed on Mimas (moon), a moon of Saturn. Meteorite impact creates the Hellas Planitia on Mars, the largest unambiguous structure on the planet.
Anseris Mons Anseris Mons is an isolated massif (mountain) in the southern highlands of Mars, located at the northeastern edge of Hellas Planitia at longitude 86.65°E and latitude 29.81°S. The mountain is in diameter and rises to an elevation of approximat ...
an isolated massif (
mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited Summit (topography), summit area, and ...
) in the southern highlands of Mars, located at the northeastern edge of Hellas Planitia is uplifted in the wake of the meteorite impact * 9.8 billion years (4 Gya): HD 209458 b, first planet detected through its transit, forms.
Messier 85 Messier 85 (also known as M85 or NGC 4382 or PGC 40515 or ISD 0135852) is a lenticular galaxy, or elliptical galaxy for other authors, in the Coma Berenices constellation. It is 60 million light-years away, and it is estimated to be 125,000 light ...
, lenticular galaxy, disrupted by galaxy interaction: complex outer structure of shells and ripples results. Andromeda and Triangulum galaxies experience close encounter – high levels of star formation in Andromeda while Triangulum's outer disc is distorted * 9.861 billion years (3.938 Gya): Major period of impacts on the Moon:
Mare Imbrium Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the colli ...
forms * 9.88 billion years (3.92 Gya):
Nectaris Basin Mare Nectaris (Latin ''nectaris'', the "Sea of Nectar") is a small lunar mare or sea (a volcanic lava plain noticeably darker than the rest of the Moon's surface) located south of Mare Tranquillitatis southwest of Mare Fecunditatis, on the near ...
forms from large impact event: ejecta from Nectaris forms upper part of densely cratered Lunar Highlands –
Nectarian The Nectarian Period of the lunar geologic timescale runs from 3920 million years ago to 3850 million years ago. It is the period during which the Nectaris Basin and other major basins were formed by large impact events. Ejecta from Nectaris for ...
Era begins on the Moon. * 9.9 billion years (3.9 Gya):
Tolstoj (crater) Tolstoj is a large, ancient impact crater on Mercury. It was named after Leo Tolstoy. The albedo feature Solitudo Maiae appears to be associated with this crater.Davies, M. E., Dwornik, S. E., Gault, D. E., and Strom, R. G., 1978, Atlas of Me ...
forms on Mercury. Caloris Basin forms on Mercury leading to creation of "Weird Terraine" – seismic activity triggers volcanic activity globally on Mercury.
Rembrandt (crater) Rembrandt is a large impact crater on Mercury. With a diameter of 716 km it is the second-largest impact basin on the planet, after Caloris, and is one of the larger craters in the Solar System. It was discovered by ''MESSENGER'' during i ...
formed on Mercury. Caloris Period begins on Mercury.
Argyre Planitia Argyre Planitia is a plain located within the impact basin Argyre in the southern highlands of Mars. Its name comes from a map produced by Giovanni Schiaparelli in 1877; it refers to Argyre, a mythical island of silver in Greek mythology. Arg ...
forms from asteroid impact on Mars: surrounded by rugged massifs which form concentric and radial patterns around basin – several mountain ranges including Charitum and
Nereidum Montes The Nereidum Montes is a mountain range on Mars. It stretches 1,143 km, northeast of Argyre Planitia. It is in the Argyre quadrangle. The mountains are named after a Classical albedo feature. Nereidum Montes has gullies in some areas. A ...
are uplifted in its wake * 9.95 billion years (3.85 Gya): Beginning of
Late Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...
Imbrium Period on Moon. Earliest appearance of Procellarum KREEP Mg suite materials * 9.96 billion years (3.84 Gya): Formation of
Orientale Basin Mare Orientale (Latin ''orientāle'', the "eastern sea") is a lunar mare. It is located on the western border of the near side and far side of the Moon, and is difficult to see from an Earthbound perspective. Images from spacecraft have reveale ...
from asteroid impact on Lunar surface – collision causes ripples in crust, resulting in three concentric circular features known as
Montes Rook Montes Rook is a ring-shaped mountain range that lies along the western limb of the Moon, crossing over to the far side. It completely encircles the Mare Orientale, and forms part of a massive impact basin feature. This range in turn is encircled ...
and
Montes Cordillera Montes Cordillera is a mountain range on the Moon. This feature forms the outer wall of peaks that surround the Mare Orientale impact basin, the inner ring being formed by the Montes Rook. The center of the range is located at selenographic coord ...
* 10 billion years (3.8 Gya): In the wake of Late Heavy Bombardment impacts on the Moon, large molten
mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than four ...
depressions dominate lunar surface – major period of Lunar vulcanism begins (to 3 Gyr).
Archean The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic. The Earth Earth ...
eon begins on the Earth. * 10.2 billion years (3.6 Gya):
Alba Mons Alba Mons (formerly and still occasionally known as Alba Patera, a term that has since been restricted to the volcano's summit caldera; also initially known as the Arcadia ring) is a volcano located in the northern Tharsis region of the planet Ma ...
forms on Mars, largest volcano in terms of area * 10.4 billion years (3.5 Gya): Earliest fossil traces of life on Earth ( stromatolites) * 10.6 billion years (3.2 Gya):
Amazonian Period The geological history of Mars follows the physical evolution of Mars as substantiated by observations, indirect and direct measurements, and various inference techniques. Methods dating back to 17th century techniques developed by Nicholas Steno, ...
begins on Mars: 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
Eratosthenian The Eratosthenian period in the lunar geologic timescale runs from 3,200 million years ago to 1,100 million years ago. It is named after the crater Eratosthenes, which displays characteristics typical of craters of this age, including a surface ...
period begins on the Moon: main geologic force on the Moon becomes impact cratering * 10.8 billion years (3 Gya):
Beethoven Basin Beethoven is a crater at latitude 20°S, longitude 124°W on Mercury. It is 630 km in diameter and was named after Ludwig van Beethoven. It is the eleventh largest named impact crater in the Solar System and the third largest on Mercury ...
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 * 11.2 billion years (2.5 Gya):
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...
begins * 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): Star formation in Andromeda Galaxy slows. Formation of
Hoag's Object Hoag's Object is an unusual ring galaxy in the constellation of Serpens Caput. It is named after Arthur Hoag, who discovered it in 1950 and identified it as either a planetary nebula or a peculiar galaxy. The galaxy has approximately eight bill ...
from a galaxy collision.
Olympus Mons Olympus Mons (; Latin for Mount Olympus) is a large shield volcano on Mars. The volcano has a height of over 21.9 km (13.6 mi or 72,000 ft) as measured by the Mars Orbiter Laser Altimeter (MOLA). Olympus Mons is about two and a h ...
, the largest volcano in the Solar System, is formed * 12.1 billion years (1.7 Gya):
Sagittarius Dwarf Elliptical Galaxy The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an elliptical loop-shaped satellite galaxy of the Milky Way. It contains four globular clusters in ...
captured into an orbit around Milky Way Galaxy * 12.7 billion years (1.1 Gya): Copernican Period begins on Moon: defined by impact craters that possess bright optically immature ray systems * 12.8 billion years (1 Gya): The Kuiperian Era (1 Gyr – present) begins on Mercury: modern Mercury, a desolate cold planet that is influenced by space erosion and solar wind extremes. 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 Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...
begins evolving the recognisable surface features that include rivers, lakes, and deltas * 13 billion years (800
Mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * Burmese ...
): 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 Hyades may refer to: * Hyades (band) *Hyades (mythology) *Hyades (star cluster) The Hyades (; Greek Ὑάδες, also known as Caldwell 41, Collinder 50, or Melotte 25) is the nearest open cluster and one of the best-studied star clusters. Loca ...
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 * 13.15-21 billion years (590–650 Mya): Capella star system forms * 13.2 billion years (600 Mya): Collision of spiral galaxies leads to the creation of
Antenna Galaxies The Antennae Galaxies (also known as NGC 4038/NGC 4039 or Caldwell 60/Caldwell 61) are a pair of interacting galaxy, interacting galaxies in the constellation Corvus (constellation), Corvus. They are currently going through a Starburst Galaxies, ...
. Whirlpool Galaxy collides with
NGC 5195 NGC 5195 (also known as Messier 51b or M51b) is a dwarf galaxy that is interacting with the Whirlpool Galaxy (also known as M51a or NGC 5194). Both galaxies are located approximately 25 million light-years away in the constellation Canes Venatic ...
forming a present connected galaxy system.
HD 189733 b HD 189733 b is an exoplanet approximately away from the Solar System in the constellation of Vulpecula. Astronomers in France discovered the planet orbiting the star HD 189733 on October 5, 2005, by observing its transit across the star's face. ...
forms around parent star
HD 189733 HD 189733, also catalogued as V452 Vulpeculae, is a binary star system approximately 64.5 light-years away in the constellation of Vulpecula (the Fox). The primary star is suspected to be an orange dwarf star, while the secondary star i ...
: the first planet to reveal the climate, organic constituencies, even colour (blue) of its atmosphere * 13.345 billion years (455 Mya):
Vega Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, an ...
, the fifth-brightest star in our galactic neighbourhood, forms. * 13.6–13.5 billion years (300-200 Mya):
Sirius Sirius is the list of brightest stars, brightest star in the night sky. Its name is derived from the Ancient Greek language, Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinisation ...
, the brightest star in the Earth's sky, forms. * 13.7 billion years (100 Mya): Formation of
Pleiades The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of ...
Star Cluster * 13.73 billion years (70 Mya): North Star,
Polaris Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris ( Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude that ...
, one of the significant navigable stars, forms * 13.780 billion years (20 Mya): Possible formation of
Orion Nebula The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the nig ...
* 13.788 billion years (12 Mya): Antares forms. * 13.792 billion years (7.6 Mya):
Betelgeuse Betelgeuse is a red supergiant of spectral type M1-2 and one of the largest stars visible to the naked eye. It is usually the tenth-brightest star in the night sky and, after Rigel, the second-brightest in the constellation of Orion ...
forms. * 13.8 billion years (Without uncertainties): Present day.


See also

*
Timeline of natural history This timeline of natural history summarizes significant geological and biological events from the formation of the Earth to the arrival of modern humans. Times are listed in millions of years, or megaanni ( Ma). Dating of the geologic record ...
(formation of the Earth to evolution of modern humans) *
Detailed logarithmic timeline This timeline shows the whole history of the universe, the Earth, and mankind in one table. Each row is defined in ''years ago'', that is, years before the present calendar date, date, with the earliest times at the top of the chart. In each tabl ...
* Timeline of the far future *
Timelines of world history The following is a list of timeline articles: Prehistory *For events dating from the formation of the universe see: Timeline of the early universe and Timeline of the universe *For events dating from the formation of the planet to the rise of m ...


References

{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System, History, Science Formation of the Universe Formation of the Universe cosmology epochs