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Timeline of natural history

File:Geological time spiral.png
Visual representation of the history of life on Earth as a spiral

This timeline of natural history summarizes significant cosmological, geological and biological events from the formation of the Universe to the rise of modern humans. Times are listed in millions of years, or megaanni (Ma).

Formation of the Universe - The first second

13,798 ± 0,037 Ma ago: estimated age of the universe according to the Big Bang theory.

  • 13.79 Ma (ca. 0 seconds): Before the Big Bang: cosmologists do not know how the universe began, but suggestions include an abrupt bang, a quantum emergence, budding off from a multiverse or even the latest stage in a cycle of expansion, collapse and renewed expansion.

Planck Epoch

  • 13,790 Ma (ca. 0 seconds): 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 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 an unimaginably hot, dense point (Gravitational singularity), a billionth the size of a nuclear particle. This state has been described as a particle desert. 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.
  • 13,790 Ma (ca. 0 seconds): Infant Universe experiences cooling as it begins expanding outward - almost completely smooth, quantum variations begin causing slight variations in density

Grand Unification Epoch

  • 13,790 Ma (ca. 10–43 seconds): Grand unification epoch begins: While still at an infinitesimal size, Universe cools down to 1032 kelvins.
  • 13,790 Ma (ca.10–43 seconds): Gravity separates and begins operating on the Universe - remaining fundamental forces stabilize into electronuclear force, also known as the Grand Unified Force or Grand Unified Theory (GUT). Hypothetical X and Y bosons[1] appear however physical characteristics such as mass, charge, flavour and colour charge are meaningless.

Electroweak epoch

  • 13,790 Ma (ca. 10–36 seconds): Electroweak epoch begins: The Universe cools down to 1028 kelvins. As a result the Strong Nuclear Force becomes distinct from the Electroweak Force perhaps fuelling the inflation (cosmology) of the universe. A wide array of exotic elementary particles result from decay of X and Y bosons which include W and Z bosons and Higgs bosons.
  • 13,790 Ma (ca. 10–33 seconds): Space is subjected to a superfast inflation, influenced by a replusive energy field, expanding from the size of an atom to that of a grapefruit in a tiny fraction of a second. The inflation also generates two types of waves (gravitational and density) along which the previous quantum fluctuations inflate becoming structures that will influence future galaxy clustering
  • 13,790 Ma (ca. 10–32 seconds): Cosmic inflation ends. Particles of matter (quarks, gluons, electrons) form as a soup of hot ionized gas called quark-gluon plasma - photons of light (radiation are scattered by travelling through this plasma. It is also possible that one potential type of dark matter (axions) is synthesized.

Quark Epoch

  • 13,790 Ma (ca. 10–12 seconds): Quark epoch begins. Electroweak phase transition: supersymmetry breaking as the Electromagnetic and Weak Nuclear forces become distinct. Cooling makes the Weak Nuclear Force actually weak, so matter particles can acquire mass - the Higgs Field turns on!
  • 13,790 Ma (ca. 10–12 seconds): As fundamental interactions begin acting on the Universe, it remains too hot for quarks to bind together into larger forms of matter - domination of radiation over matter with quarks and gluons experiencing degrees of freedom. The universe cools to 1015 kelvins.
  • ca. 13,790 Ma (ca. 10–11 seconds): Baryogenesis may have taken place with matter gaining the upper hand over anti-matter as baryon to antibaryon constituencies are established. A second potential type of dark matter (neutrinos) may have been synthesized.

Hadron Epoch

  • ca. 13,790 Ma (ca. 10–6 seconds): Hadron epoch begins: As the universe cools to about 1010 kelvins, a quark-hadron transition takes place in which quarks bind to form more complex particles - hadrons. This quark confinement includes the formation of protons and neutrons (nucleons), the building blocks of atomic nuclei.
  • ca. 13,790 Ma (ca. 1 second): Lepton epoch begins: The universe cools to 109 kelvins. At this temperature, the hadrons and antihadrons annihilate each other, leaving behind leptons and antileptons - possible disappearance of antiquarks.
  • ca. 13,790 Ma (ca. 1 second): Gravity governs the expansion of the universe: neutrinos decouple from matter creating a cosmic neutrino background.

The Formation of the Universe - Matter Era

Photon Epoch

  • ca. 13,790 Ma (ca. 10 seconds): Photon epoch begins: Most of the leptons and antileptons annihilate each other. As electrons and positrons annihilate, a small number of unmatched electrons are left over - disappearance of the positrons.
  • ca. 13,790 Ma (ca. 10 seconds): Universe dominated by photons of radiation - ordinary matter particles are coupled to light and radiation while dark matter particles start building non-linear structures. Because charged electrons and protons hinder the emission of light, the universe becomes a super-hot glowing fog.
  • ca. 13,790 Ma (ca. 3 minutes): Primordial Nucleosynthesis: nuclear fusion begins as lithium and heavy hydrogen (deuterium) and helium nuclei form from protons and neutrons.
  • ca. 13,790 Ma (ca. 20 minutes): Nuclear fusion ceases: normal matter consists of 75% hydrogen and 25% helium - free electrons begin scattering light.
  • ca. 13,790 Ma (ca. 70,000 yrs): Matter domination in Universe: onset of gravitational collapse as the Jeans Length at which the smallest structure can form begins to fall.

Cosmic Dark Age

  • ca. 13,790 Ma (ca. 377,000 yrs): Dark Ages (cosmology) begin - Recombination: electrons combine with nuclei to form atoms mostly hydrogen and helium. The glow from our infant Universe is unveiled. Distributions of hydrogen and helium at this time remains constant as the electron-baryon plasma thins. The temperature falls to 3000 degrees Kelvin.
  • ca. 13,790 Ma (ca. 377,000 yrs): Ordinary matter particles decouple from radiation. The photons fly free releasing a Cosmic Microwave Background. The universe becomes neutral and transparent. the Afterglow light pattern source taken by later satellites is the farthest back our instruments can see. The Cosmic Microwave Background is also the only light source: with no stars there is no other source of light. The Universe empty except for the neutral clouds of hydrogen and helium.
  • ca. 13,790 Ma (ca. 400,000 yrs): Density waves begin imprinting characteristic polarization (waves) signals.
  • ca. 13,790 Ma (ca. 10 million yrs): With a trace of heavy elements in the Universe, Abiogenesis (chemistry of life) begins operating.
  • ca. 13,700 Ma (ca. 100 million yrs): Gravitational collapse: ordinary matter particles fall into the structures created by dark matter.
  • ca. 13,700 Ma (ca. 100 million yrs): Reionization begins: smaller (stars) and larger non-linear structures (quasars) begin to take shape - their ultraviolet light ionizes remaining neutral gas
  • 13,600–13,500 Ma: 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.
  • 13,600-13,500 Ma: As reionization intensifies, photons of light scatter off free protons and electrons - Universe becomes opaque again
  • ca. 13,600 Ma: HD 140283, the "Methuselah" Star, formed, the unconfirmed oldest star observed in the Universe. Because it is a Population II star, some suggestions have been raised that second generation star formation may have begun very early on.[2]
  • 13,600 Ma: age of the oldest known star - SMSS J031300.36-670839.3.
  • ca. 13,500 Ma: First large-scale astronomical objects, protogalaxies and quasars may have begun forming.
  • ca. 13,500 Ma: 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.
  • 13,3700 Ma (380 million yrs): UDFj-39546284, current record holder for oldest known quasar.[3]
  • 13,3300 Ma (ca. 420 million yrs): The quasar MACS0647-JD, forms


  • 13,200 Ma: Renaissance of the Universe - end of the Dark Ages as visible light begins dominating throughout.
  • 13,200 Ma: Possible formation of the Milky Way Galaxy (although some estimates of HD 140283 place the origin as far back as 13.7 or at least 13.6 billion years).
  • 13,200 Ma: Oldest confirmed star in Milky Way Galaxy, HE 1523-0901.
  • 13,200 Ma: Extent of the Hubble Extreme Deep Field.
  • 13,150 Ma: GRB 090423, the oldest gamma ray burst recorded suggests that supernovas may have happened very early on in the evolution of the Universe[4]
  • 13,100 Ma: Galaxies form.
  • ca. 13.1 Ma: Evolution of galaxies may have begun: As more galaxies form, smaller galaxies begin merging to form larger ones. Galaxy classes may have also begun forming at this time including Blazars, Seyfert galaxies, radio galaxies, normal galaxies (elliptical, Spiral galaxies, barred spiral) and dwarf galaxies.
  • 13,100 Ma: UDFy-38135539, the first distant quasar to be observed from the reionization phase, forms.
  • 13,100 Ma: Dwarf galaxy z8 GND 5296 forms.
  • 13,060 Ma: 47 Tucanae, second brightest globular cluster in the Milky Way, forms
  • 13,040 Ma: EGS-zs8-1, the most distant starburst or Lyman-break galaxy 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.
  • 13,000 Ma: Farthest extent of Hubble Ultra Deep Field.
  • 13,000 Ma: HE0107-5240, one of the oldest Population II stars, forms as part of a binary star system.
  • 13,000 Ma: LAE J095950.99+021219.1, the Bogwiggit Galaxy, one of the most remote Lyman alpha emitter galaxies, forms. Lyman alpha emitters are considered to be the progenitors of spiral galaxies like the Milky Way.
  • 12,970 Ma: Galaxy or possible proto-galaxy A1689-zD1 forms.
  • 12,910 Ma: Galaxy SXDF-NB1006-2 forms
  • 12,900 Ma: 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.
  • 12.880 Ma: Galaxy IOK-1 a Lyman alpha emitter galaxy, forms.
  • 12.800 Ma: Galaxy HCM-6A, the most distant normal galaxy observed, forms
  • 12,800 MA: HE1327-2326, population II star, speculated to have formed from remnants of earlier Population III stars.
  • 12,800 Ma: Visual limit of the Hubble Deep Field.

Galaxy Epoch

  • 12.799 Ma (ca. 1 billion yrs): Reionization complete - the Universe becomes transparent again. Galaxy evolution continues as more modern looking galaxies form and develop. 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.
  • 12,799 Ma (ca. 1 billion yrs): Galaxies may have begun clustering creating the largest structures in the Universe so far - the first galaxy clusters and galaxy superclusters appear.
  • 12,700 Ma: Possible formation of globular clusters in Milky Way's Galactic halo.
  • 12,700 Ma: Age of the quasar CFHQS 1641+3755.
  • 12,700 Ma: 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, a gas giant known as the "Genesis Planet" or "Methusaleh", orbiting a pulsar and a white dwarf, the oldest observed extrasolar planet in Universe, forms
  • 12,670 Ma: Globular Cluster Messier 53 forms 60,000 light-years from the galactic centre of the Milky Way
  • 12,540 Ma: Messier 80 globular cluster forms in Milky Way - known for large number of "blue stragglers"
  • 12,500 Ma: Age of Cayrel's Star, BPS C531082-0001, a neutron capture star, among the oldest Population II stars in Milky Way.
  • 12,500 Ma: Quasar RD1, first object observed to exceed redshift 5, forms.
  • 12,200 Ma: Most energetic gamma ray burst lasting 23 minutes, GRB 080916C, recorded.
  • 12,000 Ma: SN 1000+0216, the oldest observed supernova occurs - possible pulsar formed.
  • 12,000 Ma: Globular Cluster Messier 15, known to have an intermediate black hole and the only globular cluster observed to include a planetary nebula, Pease I, forms
  • 11,780 Ma: Globular Cluster NGC 6752, third brightest, forms in Milky Way
  • 11,700 Ma: Quasar PKS 2000-330 forms.
  • 11,520 Ma: Omega Centauri, largest globular cluster in the Milky Way forms
  • 11 Ma: Formation of Gliese 581 planetary system: Gliese 581 c, the first observed ocean planet and Gliese 581 d, a super-earth planet, possibly the first observed habitable planets, form. Gliese 581 d 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.
  • 10,700 Ma: BX442, oldest grand design spiral galaxy observed, forms
  • 10,500 Ma: Supernova SN UDS10Wil recorded
  • 10,200 Ma: NGC 2808 globular cluster forms: 3 generations of stars form within the first 200 million years
  • 10,000 Ma: Quasar 3C 9 forms
  • 10,000 Ma: The Andromeda galaxy forms from a galactic merger - begins a collision course with the Milky Way.
  • 10,000 Ma: Barnard's Star, red dwarf star, may have formed.
  • 10,000 Ma: Beethoven Burst GRB 991216 recorded
  • 10,000 Ma: Gliese 677 Cc, a planet in the habitable zone of its parent star, Gliese 667, one of the most physically similar known exoplanets to Earth, forms
  • 9,900 Ma: 16 Cygni Bb, the first gas giant observed in a single star orbit in a trinary star system, forms - orbiting moons considered to have habitable properties or at the least capable of supporting water
  • 9,500 Ma: Fierce star formation in Andromeda making it into a luminous infra-red galaxy
  • 9,000 Ma: 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, moons, asteroids, and icy comets
  • 8.800 Ma: Galaxy collision: spiral arms of the Milky Way form leading to major period of star formation.
  • 8.700 Ma: 55 Cancri B, a "hot Jupiter", first planet to be observed orbiting as part of a star system, forms.
  • 8.100 Ma: HD 176051 planetary system, known as the first observed through astrometrics, forms


  • 8,000 Ma: Acceleration: dark energy begins dominating Universe - after being slowed for billions of years by gravity abundant dark matter takes hold and the cosmic expansion begins to speed up. As the cosmic expansion accelerates, the rate of galaxy interactions decreases - although near misses continue to distort some while collisions increase the size of others, distance makes the galaxy merger process less likely. Many galaxies like NGC 4565 become relatively stable - ellipticals result from collisions of spirals with some like IC 1101 being extremely massive.
  • 8,000 - present Ma: 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 may have happened much earlier, perhaps around the same time galaxies first started appearing. Either way the observable universe becomes more modern looking.
  • 8,000 - 2,000 Ma: Epsilon Eridani,third closest star to the Sun forms
  • 8,000 Ma: Rigel or Beta Orionis, an alpha cygni variable, forms
  • 7,100 Ma: Orange Giant, Arcturus, forms
  • 7,000 Ma: North Star, Polaris, one of the significant navigable stars, forms
  • 6,340 Ma: Mu Arae planetary system forms: of four planets orbiting a yellow star, Mu Arae c is among the first terrestrial planets to be observed from Earth
  • 6,000 Ma: Formation of Mira or Omicron ceti, binary star system
  • 6,000 Ma: Formation of Alpha Centauri Star System, closest star to the Sun
  • 6,000 Ma: GJ 1214 b, or Glease 1214 b, potential earth-like planet, forms
  • 5,900 -5,400 Ma: Capella star system forms
  • 5,800 Ma: Tau Ceti, nearby yellow star forms: five planets eventually evolve from its planetary nebula, orbiting the star - Tau Ceti e considered planet to have potential life since it orbits the hot inner edge of the star's habitable zone
  • 5,500 Ma: GRB 101225A, the "Christmas Burst", considered the longest at 28 minutes, recorded
  • 5,000 Ma: Lalande 21185, red dwarf in Ursa Major, forms
  • 4,850 Ma: Proxima Centauri forms completing the Alpha Centauri binary system

The earliest Solar System

In the earliest solar system history, the Sun, the planetesimals and the jovian planets were formed. The inner solar system aggregated more slowly than the outer, so the terrestrial planets were not yet formed, including Earth and Moon.

Hadean Eon

Main article: Hadean

Archean Eon

Main article: Archean

Eoarchean Era

Main article: Eoarchean

Paleoarchean Era

Mesoarchean Era

Neoarchean Era

Proterozoic Eon

Main article: Proterozoic

Paleoproterozoic Era

Main article: Paleoproterozoic

Siderian Period

Rhyacian Period

Orosirian Period

Statherian Period

Mesoproterozoic Era

Main article: Mesoproterozoic

Calymmian Period

Ectasian Period

Stenian Period

Neoproterozoic Era

Main article: Neoproterozoic

Tonian Period

Cryogenian Period

Ediacaran Period

Phanerozoic Eon

Main article: Phanerozoic

Paleozoic Era

Main article: Paleozoic

Cambrian Period

Ordovician Period

Silurian Period

  • 443.4 ± 1.5 Ma: Beginning of the Silurian and the end of the Ordovician Period.
  • 420 Ma: First creature took a breath of air. First ray-finned fish and land scorpions.
  • 410 Ma: First toothed fish and nautiloids.

Devonian Period

Carboniferous Period

Permian Period

Mesozoic Era

Main article: Mesozoic

Triassic Period

Jurassic Period

Cretaceous Period

Cenozoic Era

Main article: Cenozoic

Paleogene Period

Neogene Period

Quaternary Period

For later events, see Timeline of human prehistory.

Etymology of period names

Period Started Root word Meaning Reason for name
Siderian 2500 Ma Greek sidēros iron ref. the banded iron formations
Rhyacian 2300 Ma Gk. rhyax lava flow much lava flowed
Orosirian 2050 Ma Gk. oroseira mountain range much orogeny in this period's latter half
Statherian 1800 Ma Gk. statheros steady continents became stable cratons
Calymmian 1600 Ma Gk. calymma cover platform covers developed or expanded
Ectasian 1400 Ma Gk. ectasis stretch platform covers expanded
Stenian 1200 Ma Gk. stenos narrow much orogeny, which survives as narrow metamorphic belts
Tonian 1000 Ma Gk. tonos stretch The continental crust stretched as Rodinia broke up
Cryogenian 850 Ma Gk. cryogenicos cold-making In this period all the Earth froze over
Ediacaran 635Ma Ediacara Hills stony ground place in Australia where the Ediacaran biota fossils were found
Cambrian 541Ma Latin Cambria Wales ref. to the place in Great Britain where Cambrian rocks are best exposed
Ordovician 485.4 Ma Celtic Ordovices Tribe in north Wales, where the rocks were first identified
Silurian 443.4 Ma Ctc. Silures Tribe in south Wales, where the rocks were first identified
Devonian 419.2Ma Devon County in England in which rocks from this period were first identified
Carboniferous 358.9 Ma Lt. carbo coal Global coal beds were laid in this period
Permian 298.9Ma Perm Krai Region in Russia where rocks from this period were first identified
Triassic 252.17 Ma Lt. trias triad In Germany this period forms three distinct layers
Jurassic 201.3Ma Jura Mountains Mountain range in the Alps in which rocks from this period were first identified
Cretaceous 145Ma Lt. creta chalk More chalk formed in this period than any other
Paleogene 66Ma Gk. palaiogenos "ancient born"
Neogene 23.03Ma Gk. neogenos "new born"
Quaternary 2.58 Ma Lt. quaternarius "fourth" This was initially deemed the "fourth" period after the now-obsolete "primary", "secondary" and "tertiary" periods.


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See also