This more than 20-billion-year timeline of our universe shows the best estimates of major events from the universe's beginning to anticipated future events. Zero on the scale is the present day. A large step on the scale is one billion years; a small step, one hundred million years. The past is denoted by a minus sign: e.g., the oldest rock on Earth was formed about four billion years ago and this is marked at -4e+09 years, where 4e+09 represents 4 times 10 to the power of 9. 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 ...

" event most likely happened 13.8 billion years ago; see

age of the universe In physical cosmology, the age of the universe is the time elapsed since the Big Bang. Astronomers have derived two different measurements of the age of the universe: a measurement based on direct observations of an early state of the universe, ...

Timeline

ImageSize = width:773 height:2000 PlotArea = left:60 right:60 bottom:45 top:45 AlignBars = early Colors = id:period1 value:rgb(1,1,0.7) # light yellow id:period2 value:rgb(0.7,0.7,1) # light blue id:events value:rgb(1,0.7,1) # light purple id:time1 Value:yellowgreen id:time2 value:lightorange id:elapse1 Value:coral id:elapse2 Value:lavender id:grayKindOf Value:gray(0.93) id:WhiteDwarf Value:rgb(0.92,0.92,1) id:phanerozoic value:rgb(0.435,0.854,0.929) id:cenozoic value:rgb(0.964,0.925,0.223) id:mesozoic value:rgb(0.027,0.792,0.917) id:paleozoic value:rgb(0.572,0.764,0.627) id:precambrian value:rgb(0.996,0.356,0.443) id:proterozoic value:rgb(0.996,0.298,0.407) id:neoproterozoic value:rgb(0.996,0.717,0.341) id:mesoproterozoic value:rgb(0.996,0.721,0.446) id:paleoproterozoic value:rgb(0.996,0.356,0.443) id:archean value:rgb(0.996,0,0.486) id:neoarchean value:rgb(0.996,0.65,0.729) id:mesoarchean value:rgb(0.996,0.486,0.639) id:paleoarchean value:rgb(0.996,0.356,0.592) id:eoarchean value:rgb(0.933,0,0.490) id:hadean value:rgb(0.796,0.011,0.505) id:prenectarian value:rgb(0.561,0.098,0.149) id:nectarian value:rgb(0.898,0.329,0.071) id:imbrian value:rgb(0,0.481,0.811) id:earlyimbrian value:rgb(0,0.404,0.741) id:lateimbrian value:rgb(0,0.557,0.882) id:eratosthenian value:rgb(0.655,0.839,0.027) id:copernican value:rgb(1,0.961,0) id:sidericol value:rgb(1,0.4,0.3) id:theiicol value:rgb(1,0.2,0.5) id:phyllocol value:rgb(0.7,0.4,1) Period = from:-13700000000 till:8000000000 TimeAxis = orientation:vertical ScaleMajor = unit:year increment:1000000000 start:-13000000000 ScaleMinor = unit:year increment:100000000 start:-13700000000 TextData = fontsize:M # tabs:(210-left) pos:(10,1990) text:"Years from now" LineData = layer:front at: 7500000000 frompos:60 tillpos:71 width:0.5 color:teal # Helium flash points:(71,1910)(104,1832) width:0.5 color:teal points:(104,1832)(115,1832) width:0.5 color:teal at: 0 width:10 color:tan1 layer:back # This present day at:-4670000000 frompos:60 tillpos:74 width:0.5 color:teal # Giant planets formed points:(74,839)(104,811) width:0.5 color:teal points:(104,811)(115,811) width:0.5 color:teal at:-4730000000 frompos:60 tillpos:71 width:0.5 color:teal # Ancient supernova points:(71,833)(104,795) width:0.5 color:teal points:(104,795)(115,795) width:0.5 color:teal BarData = bar:Bar1 bar:Dummy1 bar:Dummy2 bar:Dummy3 bar:GalaxyBar bar:SunBar bar:LifeBar bar:SuperEonBar bar:EonBar bar:EraBar bar:LunarBar bar:MarsBar PlotData= width:53 textcolor:black fontsize:M bar:Bar1 mark:(line,teal) color:events align:left shift:(40,-5) from:-13700000000 till:-13300000000 mark:(line,white) text:" 10-17 million years - Habitable epoch begins" shift:(290,2) at:-13700000000 text:" Origin of our universe, Big Bang theory" shift:(240,4) from:-13600000000 till:-13300000000 mark:(line,white) text:"

Reionization In the fields of Big Bang theory and cosmology, reionization is the process that caused matter in the universe to reionize after the lapse of the " dark ages". Reionization is the second of two major phase transitions of gas in the universe (t ...

, first stars began to shine" at:-13600000000 text: " Oldest stars in the Universe" at:-13100000000 text:" Formation of the first galaxies" shift:(40,0) at:-10000000000 text:" Earliest Population I stars" at: -4730000000 text:" Ancient supernova possibly~ triggers formation of the Sun" shift:(40,-44) mark:(line,white) at: -4670000000 text:" Giant planets formed" shift:(40,-32) mark:(line,white) at: -4630000000 text:" Sun ignites hydrogen fusion~ 4.63 billion years ago (or 4.57)" shift:(40,-4) at: -4570000000 text:" Formation of the Earth, 4.57 billion~ years ago (or 4.54)" mark:(line,white) shift:(357,-12) at: -4400000000 text:" Zircon, oldest mineral" shift:(40,-5) at: -4030000000 text:" Oldest rock~formation on Earth" from:-600000000 till:-500000000 mark:(line,white) text:" Evolution of multicellular life" at: -220000000 text:"

Evolution of mammals The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian sub-period of the late Carboniferous period. By the mid-Triassic, there were many synapsid species that looked l ...

" at: 0 text:" The present day" mark:(line,tan1) fontsize:L at: 1000000000 text:" Sun becomes too hot for life~ on Earth's surface" at: 1900000000 text:" Earth's oceans have evaporated" at: 3500000000 text:" Sun has increased~its emitted power by 40%" at: 3600000000 text:" Moon Triton crashes into~its planet Neptune" shift:(40,15) at: 5000000000 text:" Collision risk~Earth - Mars - Mercury" at: 7500000000 text:" Sun ignites helium fusion,~ starting with helium flash" mark:(line,white) shift:(40,-84) at: 7630000000 text:"Sun casts out its outer layers,~ making a planetary nebula,~leaving the hot core in the~ center, emitting 100 times~more power than Sun today" at: end text:"Sun has cooled down to the ~same power as today. It will ~continue cooling until it ~ becomes a Black dwarf." shift:(40,23) bar:GalaxyBar mark:(line,white) align:center shift:(0,0) color:skyblue from:-10100000000 till:-6500000000 text:" Formation of the Milky Way galactic disk" from: -4670000000 till:-4570000000 text:" Formation of~Terrestrial planets" shift:(-30,20) align:left from: -4180000000 till:-4080000000 text:" Late Heavy~Bombardment, while~ planet Neptune~ migrates outwards~away from Sun" shift:(-45,62) align:left from: 3000000000 till: 4000000000 text:" Milky Way and Andromeda~ galaxies may collide and merge~ to elliptical one" shift:(0,10) align:left bar:SunBar mark:(line,white) align:center shift:(0,0) from:-4680000000 till:-4630000000 text:" Sun as Protostar" shift:(3,-14) color:claret mark:(line,claret) from:-4630000000 till: 5400000000 text:" Sun as Main-sequence star" color:yellow shift:(0,20) from: 5400000000 till: 7500000000 text:" Sun as Red giant, emitting~ 2,700 times more power than now.~Earth probably swallowed by Sun." color:magenta align:left shift:(-70,0) from: 7500000000 till: 7600000000 text:"Sun as~ Horizontal~branch star" color:yelloworange shift:(0,-18) from: 7600000000 till: 7630000000 text:" Sun as Asymptotic~giant" color:red shift:(0,3) from: 7630000000 till: 8000000000 text:" Sun as White dwarf" color:whiteDwarf shift:(0,5) bar:LifeBar align:center shift:(0,0) at:-4570000000 mark:(line,teal) text:"

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 ...

~delivered~to Earth" shift:(0,16) from:-4400000000 till:-2700000000 text:" Emergence of~Life on Earth" color:time1 shift:(0,30) from:-2700000000 till: 1000000000 text:"Life on Earth" color:drabgreen from: 1000000000 till: 5400000000 text:" Measures are taken~to cope with the~heating sun.~Otherwise only:~ ~ Shielded~Life on Earth?" color:time1 shift:(0,-35) from: 5400000000 till: end text:" Life on Titan?" color:time2 shift:(0,5) bar:SuperEonBar color:yellow align:center shift:(0,0) from:-4570000000 till: -542000000 color:precambrian text:"

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 th ...

" from: 1000000000 till: 5400000000 color:time2 shift:(0,0) text:"

Life on Mars? "Life on Mars?" is a song by English singer-songwriter David Bowie, first released on his 1971 album ''Hunky Dory''. In 1968, Bowie was commissioned to write English lyrics for the Claude François French song " Comme d'habitude". After his l ...

" from: 7500000000 till: end color:time1 shift:(0,10) align:left text:"Very Shielded ~

Life on Mars The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ...

?~ if planet still exists" # The click point of the links become misplaced (one inch to the left) when using align:right bar:EonBar color:yellow align:center shift:(0,0) at: 350000000 shift:(30,0) mark:(line,white) fontsize:L text:" Earth's geological time scale of" at: 150000000 mark:(line,white) text:" Eons:" from: -542000000 till: 0 color:phanerozoic text:"

Phanerozoic The Phanerozoic Eon is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 538.8 million years to the present, and it began with the Cambrian Period, when anim ...

" from:-2500000000 till: -542000000 color:proterozoic text:"

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 i ...

" from:-4000000000 till:-2500000000 color:archean text:"

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 during the Arc ...

" from:-4570000000 till:-4000000000 color:hadean text:"

Hadean The Hadean ( ) is a geologic eon of Earth history preceding the Archean. On Earth, the Hadean began with the planet's formation about 4.54 billion years ago (although the start of the Hadean is defined as the age of the oldest solid materia ...

" shift:(0,5) bar:EraBar color:blue mark:(line,grayKindOf) align:left shift:(0,0) at:150000000 mark:(line,white) text:" Eras:" from: -65500000 till:0 color:cenozoic text:"

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

" from: -251000000 till: -65500000 color:mesozoic mark:(line,white) text:"

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

" from: -542000000 till: -251000000 color:paleozoic mark:(line,white) text:"

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ...

" from:-1000000000 till: -542000000 text:

Neoproterozoic The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is prec ...

color:neoproterozoic from:-1600000000 till: -1000000000 text:

Mesoproterozoic The Mesoproterozoic Era is a geologic era that occurred from . The Mesoproterozoic was the first era of Earth's history for which a fairly definitive geological record survives. Continents existed during the preceding era (the Paleoproterozoic), ...

color:mesoproterozoic from:-2500000000 till: -1600000000 text:

Paleoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions ( eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...

color:paleoproterozoic from:-2800000000 till: -2500000000 text:

Neoarchean The Neoarchean (; also spelled Neoarchaean) is the last geologic era in the Archean eon that spans from 2800 to 2500 million years ago—the period being defined chronometrically and not referencing a specific level in a rock section on Ear ...

color:neoarchean from:-3200000000 till: -2800000000 text:

Mesoarchean The Mesoarchean (, also spelled Mesoarchaean) is a geologic era in the Archean Eon, spanning , which contains the first evidence of modern-style plate subduction and expansion of microbial life. The era is defined chronometrically and is not r ...

color:mesoarchean from:-3600000000 till: -3200000000 text:

Paleoarchean The Paleoarchean (), also spelled Palaeoarchaean (formerly known as early Archean), is a geologic era within the Archaean Eon. The name derives from Greek "Palaios" ''ancient''. It spans the period of time . The era is defined chronometrically a ...

color:paleoarchean from:-4000000000 till: -3600000000 text: Eoarchean shift:(0,0) color:eoarchean from:-4570000000 till: -4000000000 text:

color:hadean bar:LunarBar color:yellow mark:(line,grayKindOf) align:left shift:(0,0) at:225000000 mark:(line,white) text:" Moon's:" from: -1100000000 till: 0 text: Copernican color:copernican from: -3200000000 till: -1100000000 shift:(0,-18) text: Eratosthenian color:eratosthenian # from:-3850000000 till: -3200000000 text:Imbrian color:imbrian from: -3800000000 till: -3200000000 shift:(0,-5) text:"

Upper Imbrian The Imbrian is a lunar geologic period divided into two epochs, the Early and Late. Early Imbrian In the lunar geologic timescale, the Early Imbrian epoch occurred from 3,850 million years ago to about 3,800 million years ago. It overlaps the end ...

" color:lateimbrian from: -3850000000 till: -3800000000 text:" Lower Imbrian" shift:(0,0) color:earlyimbrian from:-3920000000 till: -3850000000 shift:(0,-5) text:

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 fo ...

color:nectarian from: -4570000000 till: -3920000000 text:

Pre-Nectarian The pre-Nectarian period of the lunar geologic timescale runs from 4.533 billion years ago (the time of the initial formation of the Moon) to 3.920 billion years ago, when the Nectaris Basin was formed by a large impact. It is followed by the Necta ...

color:prenectarian bar:MarsBar color:yellow mark:(line,grayKindOf) align:left shift:(0,0) at: 6000000000 align:center text:"ZOOM OUT~ The Stelliferous Era" mark:(line,white) at:225000000 mark:(line,white) text:" Mars':" from: -3500000000 till: 0 text:Siderikan shift:(0,0) color:sidericol from: -4000000000 till: -3500000000 text:Theiikian color:theiicol shift:(0,5) from: -4570000000 till: -4000000000 text:Phyllocian color:phyllocol shift:(0,-9) at:-13700000000 align:center color:time1 mark:(line,white) shift:(0,2) text:" The Primordial Era~PREVIOUS"

Timeline

See also